当期目录

2024年, 第33卷, 第3期　刊出日期：2024-02-22 上一期    下一期

Select

Advances in neuromorphic computing: Expanding horizons for AI development through novel artificial neurons and in-sensor computing Yubo Yang(杨玉波), Jizhe Zhao(赵吉哲), Yinjie Liu(刘胤洁), Xiayang Hua(华夏扬), Tianrui Wang(王天睿), Jiyuan Zheng(郑纪元), Zhibiao Hao(郝智彪), Bing Xiong(熊兵), Changzheng Sun(孙长征), Yanjun Han(韩彦军), Jian Wang(王健), Hongtao Li(李洪涛), Lai Wang(汪莱), and Yi Luo(罗毅) 2024 (3):  30702-030702.  doi: 10.1088/1674-1056/ad1c58 摘要 ( 212 )   HTML ( 6 )   PDF(10310KB) ( 209 )   AI development has brought great success to upgrading the information age. At the same time, the large-scale artificial neural network for building AI systems is thirsty for computing power, which is barely satisfied by the conventional computing hardware. In the post-Moore era, the increase in computing power brought about by the size reduction of CMOS in very large-scale integrated circuits (VLSIC) is challenging to meet the growing demand for AI computing power. To address the issue, technical approaches like neuromorphic computing attract great attention because of their feature of breaking Von-Neumann architecture, and dealing with AI algorithms much more parallelly and energy efficiently. Inspired by the human neural network architecture, neuromorphic computing hardware is brought to life based on novel artificial neurons constructed by new materials or devices. Although it is relatively difficult to deploy a training process in the neuromorphic architecture like spiking neural network (SNN), the development in this field has incubated promising technologies like in-sensor computing, which brings new opportunities for multidisciplinary research, including the field of optoelectronic materials and devices, artificial neural networks, and microelectronics integration technology. The vision chips based on the architectures could reduce unnecessary data transfer and realize fast and energy-efficient visual cognitive processing. This paper reviews firstly the architectures and algorithms of SNN, and artificial neuron devices supporting neuromorphic computing, then the recent progress of in-sensor computing vision chips, which all will promote the development of AI. 参考文献 | 相关文章 | 计量指标

Select

Ultrafast photoemission electron microscopy: A multidimensional probe of nonequilibrium physics Yanan Dai(戴亚南) 2024 (3):  38703-038703.  doi: 10.1088/1674-1056/ad174a 摘要 ( 165 )   HTML ( 72 )   PDF(9360KB) ( 284 )   Exploring the realms of physics that extend beyond thermal equilibrium has emerged as a crucial branch of condensed matter physics research. It aims to unravel the intricate processes involving the excitations, interactions, and annihilations of quasi- and many-body particles, and ultimately to achieve the manipulation and engineering of exotic non-equilibrium quantum phases on the ultrasmall and ultrafast spatiotemporal scales. Given the inherent complexities arising from many-body dynamics, it therefore seeks a technique that has efficient and diverse detection degrees of freedom to study the underlying physics. By combining high-power femtosecond lasers with real- or momentum-space photoemission electron microscopy (PEEM), imaging excited state phenomena from multiple perspectives, including time, real space, energy, momentum, and spin, can be conveniently achieved, making it a unique technique in studying physics out of equilibrium. In this context, we overview the working principle and technical advances of the PEEM apparatus and the related laser systems, and survey key excited-state phenomena probed through this surface-sensitive methodology, including the ultrafast dynamics of electrons, excitons, plasmons, spins, etc., in materials ranging from bulk and nano-structured metals and semiconductors to low-dimensional quantum materials. Through this review, one can further envision that time-resolved PEEM will open new avenues for investigating a variety of classical and quantum phenomena in a multidimensional parameter space, offering unprecedented and comprehensive insights into important questions in the field of condensed matter physics. 参考文献 | 相关文章 | 计量指标

Select

Unveiling the early stage evolution of local atomic structures in the crystallization process of a metallic glass Lin Ma(马琳), Xiao-Dong Yang(杨晓东), Feng Yang(杨锋), Xin-Jia Zhou(周鑫嘉), and Zhen-Wei Wu(武振伟) 2024 (3):  36402-036402.  doi: 10.1088/1674-1056/ad24d6 摘要 ( 168 )   HTML ( 3 )   PDF(1057KB) ( 128 )   The early stage evolution of local atomic structures in a multicomponent metallic glass during its crystallization process has been investigated via molecular dynamics simulation. It is found that the initial thermal stability and earliest stage evolution of the local atomic clusters show no strong correlation with their initial short-range orders, and this leads to an observation of a novel symmetry convergence phenomenon, which can be understood as an atomic structure manifestation of the ergodicity. Furthermore, in our system we have quantitatively proved that the crucial factor for the thermal stability against crystallization exhibited by the metallic glass is not the total amount of icosahedral clusters, but the degree of global connectivity among them. 参考文献 | 相关文章 | 计量指标

Select

Ultrafast magneto-optical dynamics in nickel (111) single crystal studied by the integration of ultrafast reflectivity and polarimetry probes Hao Kuang(匡皓), Junxiao Yu(余军潇), Jie Chen(陈洁), H. E. Elsayed-Ali, Runze Li(李润泽), and Peter M. Rentzepis 2024 (3):  37802-037802.  doi: 10.1088/1674-1056/ad1983 摘要 ( 137 )   HTML ( 6 )   PDF(1430KB) ( 166 )   With the integration of ultrafast reflectivity and polarimetry probes, we observed carrier relaxation and spin dynamics induced by ultrafast laser excitation of Ni (111) single crystals. The carrier relaxation time within the linear excitation range reveals that electron-phonon coupling and dissipation of photon energy into the bulk of the crystal take tens of picoseconds. On the other hand, the observed spin dynamics indicate a longer time of about 120 ps. To further understand how the lattice degree of freedom is coupled with these dynamics may require the integration of an ultrafast diffraction probe. 参考文献 | 相关文章 | 计量指标

Select

A Yb optical clock with a lattice power enhancement cavity Chunyun Wang(王春云), Yuan Yao(姚远), Haosen Shi(师浩森), Hongfu Yu(于洪浮),Longsheng Ma(马龙生), and Yanyi Jiang(蒋燕义) 2024 (3):  30601-030601.  doi: 10.1088/1674-1056/ad1986 摘要 ( 162 )   HTML ( 3 )   PDF(1444KB) ( 195 )   We construct a power enhancement cavity to form an optical lattice in an ytterbium optical clock. It is demonstrated that the intra-cavity lattice power can be increased by about 45 times, and the trap depth can be as large as 1400Er when laser light with a power of only 0.6 W incident to the lattice cavity. Such high trap depths are the key to accurate evaluation of the lattice-induced light shift with an uncertainty down to ~ 1×10-18. By probing the ytterbium atoms trapped in the power-enhanced optical lattice, we obtain a 4.3 Hz-linewidth Rabi spectrum, which is then used to feedback to the clock laser for the close loop operation of the optical lattice clock. We evaluate the density shift of the Yb optical lattice clock based on interleaving measurements, which is -0.46(62) mHz. This result is smaller compared to the density shift of our first Yb optical clock without lattice power enhancement cavity mainly due to a larger lattice diameter of 344 μm. 参考文献 | 相关文章 | 计量指标

Select

Analysis of pseudo-random number generators in QMC-SSE method Dong-Xu Liu(刘东旭), Wei Xu(徐维), and Xue-Feng Zhang(张学锋) 2024 (3):  37509-037509.  doi: 10.1088/1674-1056/ad1e69 摘要 ( 136 )   HTML ( 7 )   PDF(514KB) ( 198 )   In the quantum Monte Carlo (QMC) method, the pseudo-random number generator (PRNG) plays a crucial role in determining the computation time. However, the hidden structure of the PRNG may lead to serious issues such as the breakdown of the Markov process. Here, we systematically analyze the performance of different PRNGs on the widely used QMC method known as the stochastic series expansion (SSE) algorithm. To quantitatively compare them, we introduce a quantity called QMC efficiency that can effectively reflect the efficiency of the algorithms. After testing several representative observables of the Heisenberg model in one and two dimensions, we recommend the linear congruential generator as the best choice of PRNG. Our work not only helps improve the performance of the SSE method but also sheds light on the other Markov-chain-based numerical algorithms. 参考文献 | 相关文章 | 计量指标

Select

Recent advances in protein conformation sampling by combining machine learning with molecular simulation Yiming Tang(唐一鸣), Zhongyuan Yang(杨中元), Yifei Yao(姚逸飞), Yun Zhou(周运), Yuan Tan(谈圆),Zichao Wang(王子超), Tong Pan(潘瞳), Rui Xiong(熊瑞), Junli Sun(孙俊力), and Guanghong Wei(韦广红) 2024 (3):  30701-030701.  doi: 10.1088/1674-1056/ad1a92 摘要 ( 138 )   HTML ( 8 )   PDF(3732KB) ( 205 )   The rapid advancement and broad application of machine learning (ML) have driven a groundbreaking revolution in computational biology. One of the most cutting-edge and important applications of ML is its integration with molecular simulations to improve the sampling efficiency of the vast conformational space of large biomolecules. This review focuses on recent studies that utilize ML-based techniques in the exploration of protein conformational landscape. We first highlight the recent development of ML-aided enhanced sampling methods, including heuristic algorithms and neural networks that are designed to refine the selection of reaction coordinates for the construction of bias potential, or facilitate the exploration of the unsampled region of the energy landscape. Further, we review the development of autoencoder based methods that combine molecular simulations and deep learning to expand the search for protein conformations. Lastly, we discuss the cutting-edge methodologies for the one-shot generation of protein conformations with precise Boltzmann weights. Collectively, this review demonstrates the promising potential of machine learning in revolutionizing our insight into the complex conformational ensembles of proteins. 参考文献 | 相关文章 | 计量指标

Select

Enhanced measurement precision with continuous interrogation during dynamical decoupling Jun Zhang(张军), Peng Du(杜鹏), Lei Jing(敬雷), Peng Xu(徐鹏), Li You(尤力), and Wenxian Zhang(张文献) 2024 (3):  30301-030301.  doi: 10.1088/1674-1056/ad1985 摘要 ( 166 )   HTML ( 4 )   PDF(1479KB) ( 169 )   Dynamical decoupling (DD) is normally ineffective when applied to DC measurement. In its straightforward implementation, DD nulls out DC signal as well while suppressing noise. This work proposes a phase relay method that is capable of continuously interrogating the DC signal over many DD cycles. We illustrate its efficacy when applied to the measurement of a weak DC magnetic field with an atomic spinor Bose-Einstein condensate. Sensitivities approaching standard quantum limit or Heisenberg limit are potentially realizable for a coherent spin state or a squeezed spin state of 10000 atoms, respectively, while ambient laboratory level noise is suppressed by DD. Our work offers a practical approach to mitigate the limitations of DD to DC measurement and would find other applications for resorting coherence in quantum sensing and quantum information processing research. 参考文献 | 相关文章 | 计量指标

Select

One-step quantum dialogue Peng-Hui Zhu(朱鹏辉), Wei Zhong(钟伟), Ming-Ming Du(杜明明), Xi-Yun Li(李喜云), Lan Zhou(周澜), and Yu-Bo Sheng(盛宇波) 2024 (3):  30302-030302.  doi: 10.1088/1674-1056/ad1c5c 摘要 ( 244 )   HTML ( 2 )   PDF(657KB) ( 210 )   Quantum dialogue (QD) enables two communication parties to directly exchange secret messages simultaneously. In conventional QD protocols, photons need to transmit in the quantum channel for two rounds. In this paper, we propose a one-step QD protocol based on the hyperentanglement. With the help of the non-local hyperentanglement-assisted Bell state measurement (BSM), the photons only need to transmit in the quantum channel once. We prove that our one-step QD protocol is secure in theory and numerically simulate its secret message capacity under practical experimental condition. Compared with previous QD protocols, the one-step QD protocol can effectively simplify the experiment operations and reduce the message loss caused by the photon transmission loss. Meanwhile, the non-local hyperentanglement-assisted BSM has a success probability of 100% and is feasible with linear optical elements. Moreover, combined with the hyperentanglement heralded amplification and purification, our protocol is possible to realize long-distance one-step QD. 参考文献 | 相关文章 | 计量指标

Select

Measuring small longitudinal phase shifts via weak measurement amplification Kai Xu(徐凯), Xiao-Min Hu(胡晓敏), Meng-Jun Hu(胡孟军), Ning-Ning Wang(王宁宁), Chao Zhang(张超), Yun-Feng Huang(黄运锋), Bi-Heng Liu(柳必恒), Chuan-Feng Li(李传锋), Guang-Can Guo(郭光灿), and Yong-Sheng Zhang(张永生) 2024 (3):  30602-030602.  doi: 10.1088/1674-1056/ad1c5a 摘要 ( 291 )   HTML ( 17 )   PDF(1036KB) ( 451 )   Weak measurement amplification, which is considered as a very promising scheme in precision measurement, has been applied to various small physical quantities estimations. Since many physical quantities can be converted into phase signals, it is interesting and important to consider measuring small longitudinal phase shifts by using weak measurement. Here, we propose and experimentally demonstrate a novel weak measurement amplification-based small longitudinal phase estimation, which is suitable for polarization interferometry. We realize one order of magnitude amplification measurement of a small phase signal directly introduced by a liquid crystal variable retarder and show that it is robust to the imperfection of interference. Besides, we analyze the effect of magnification error which is never considered in the previous works, and find the constraint on the magnification. Our results may find important applications in high-precision measurements, e.g., gravitational wave detection. 参考文献 | 相关文章 | 计量指标

Select

Image segmentation of exfoliated two-dimensional materials by generative adversarial network-based data augmentation Xiaoyu Cheng(程晓昱), Chenxue Xie(解晨雪), Yulun Liu(刘宇伦), Ruixue Bai(白瑞雪), Nanhai Xiao(肖南海), Yanbo Ren(任琰博), Xilin Zhang(张喜林), Hui Ma(马惠), and Chongyun Jiang(蒋崇云) 2024 (3):  30703-030703.  doi: 10.1088/1674-1056/ad23d8 摘要 ( 535 )   HTML ( 43 )   PDF(1065KB) ( 573 )   Mechanically cleaved two-dimensional materials are random in size and thickness. Recognizing atomically thin flakes by human experts is inefficient and unsuitable for scalable production. Deep learning algorithms have been adopted as an alternative, nevertheless a major challenge is a lack of sufficient actual training images. Here we report the generation of synthetic two-dimensional materials images using StyleGAN3 to complement the dataset. DeepLabv3Plus network is trained with the synthetic images which reduces overfitting and improves recognition accuracy to over 90%. A semi-supervisory technique for labeling images is introduced to reduce manual efforts. The sharper edges recognized by this method facilitate material stacking with precise edge alignment, which benefits exploring novel properties of layered-material devices that crucially depend on the interlayer twist-angle. This feasible and efficient method allows for the rapid and high-quality manufacturing of atomically thin materials and devices. 参考文献 | 补充材料 | 相关文章 | 计量指标

Select

Effect of overheating-induced minor addition on Zr-based metallic glasses Fu Yang(杨福), Zhenxing Bo(薄振兴), Yao Huang(黄瑶), Yutian Wang(王雨田), Boyang Sun(孙博阳), Zhen Lu(鲁振), Baoan Sun(孙保安), Yanhui Liu(柳延辉), Weihua Wang(汪卫华), and Mingxiang Pan(潘明祥) 2024 (3):  36401-036401.  doi: 10.1088/1674-1056/ad1823 摘要 ( 138 )   HTML ( 2 )   PDF(5128KB) ( 156 )   Melt treatment is well known to have an important influence on the properties of metallic glasses (MGs). However, for the MGs quenched from different melt temperatures with a quartz tube, the underlying physical origin responsible for the variation of properties remains poorly understood. In the present work, we systematically studied the influence of melt treatment on the thermal properties of a Zr50Cu36Al14 glass-forming alloy and unveiled the microscopic origins. Specifically, we quenched the melt at different temperatures ranging from 1.1Tl to 1.5Tl (Tl is the liquidus temperature) to obtain melt-spun MG ribbons and investigated the variation of thermal properties of the MGs upon heating. We found that glass transition temperature, Tg, increases by as much as 36 K, and the supercooled liquid region disappears in the curve of differential scanning calorimetry when the melt is quenched at a high temperature up to 1.5Tl. The careful chemical analyses indicate that the change in glass transition behavior originates from the incorporation of oxygen and silicon in the molten alloys. The incorporated oxygen and silicon can both enhance the interactions between atoms, which renders the cooperative rearrangements of atoms difficult, and thus enhances the kinetic stability of the MGs. 参考文献 | 补充材料 | 相关文章 | 计量指标

Select

Anomalous spin Josephson effect in spin superconductors Wen Zeng(曾文) and Rui Shen(沈瑞) 2024 (3):  37401-037401.  doi: 10.1088/1674-1056/ad1982 摘要 ( 179 )   HTML ( 6 )   PDF(634KB) ( 271 )   The spin superconductor state is the spin-polarized triplet exciton condensate, which can be viewed as a counterpart of the charge superconductor state. As an analogy of the charge Josephson effect, the spin Josephson effect can be generated in the spin superconductor/normal metal/spin superconductor junctions. Here we study the spin supercurrent in the Josephson junctions consisting of two spin superconductors with noncollinear spin polarizations. For the Josephson junctions with out-of-plane spin polarizations, the possible π-state spin supercurrent appears due to the Fermi momentum-splitting Andreev-like reflections at the normal metal/spin superconductor interfaces. For the Josephson junctions with in-plane spin polarizations, the anomalous spin supercurrent appears and is driven by the misorientation angle of the in-plane polarizations. The symmetry analysis shows that the appearance of the anomalous spin Josephson current is possible when the combined symmetry of the spin rotation and the time reversal is broken. 参考文献 | 相关文章 | 计量指标

Select

Creation and annihilation of artificial magnetic skyrmions with the electric field Jun Cheng(程军), Liang Sun(孙亮), Yike Zhang(张一可), Tongzhou Ji(吉同舟), Rongxing Cao(曹荣幸), Bingfeng Miao(缪冰锋), Yonggang Zhao(赵永刚), and Haifeng Ding(丁海峰) 2024 (3):  37501-037501.  doi: 10.1088/1674-1056/ad188f 摘要 ( 312 )   HTML ( 5 )   PDF(1824KB) ( 323 )   Recent theory and experiments show that artificial magnetic skyrmions can be stabilized at room temperature without the need for the external magnetic field, casting strong potentials for the device applications. In this work, we study the electric field manipulation of artificial magnetic skyrmions imprinted by Co disks on CoPt multilayers utilizing the micromagnetic simulations. We find that the reversible annihilation and creation of skyrmions can be realized with the electric field via the strain mediated magnetoelastic coupling. In addition, we also demonstrate controllable manipulation of individual skyrmion, which opens a new platform for constructing magnetic field-free and low-energy dissipation skyrmion based media. 参考文献 | 相关文章 | 计量指标

Select

Coercivity mechanism of La-Nd-Fe-B films with Y spacer layer Jun Ma(马俊), Xiao-Tian Zhao(赵晓天), Wei Liu(刘伟), Yang Li(李阳), Long Liu(刘龙), Xin-Guo Zhao(赵新国), and Zhi-Dong Zhang(张志东) 2024 (3):  37507-037507.  doi: 10.1088/1674-1056/ad1d4c 摘要 ( 127 )   HTML ( 3 )   PDF(2728KB) ( 137 )   The effect of the Y spacer layer on the phase composition, coercivity, and magnetization reversal processes of La-Nd-Fe-B films has been investigated. The addition of a 10 nm Y spacer layer increases the coercivity of the film to 1.36 T at 300 K and remains 0.938 T at 380 K. As the thickness of the Y spacer layer increases, Y participates in the formation of the main phase in the film, and further regulates the formation of La-B phases. The results of the first-order reversal curve (FORC) and micromagnetic fitting show that the coercivity of all the films is dominated by nucleation mechanism. The c-axis preferred orientation, good magnetic microstructure parameters and the largest dipole interaction enhance the coercivity. Therefore, the introduction of the Y spacer layer can be an effective way to improve the coercivity of La-Nd-Fe-B film over a wide temperature range of 150 K-380 K. 参考文献 | 相关文章 | 计量指标

Select

Nanoscale cathodoluminescence spectroscopy probing the nitride quantum wells in an electron microscope Zhetong Liu(刘哲彤), Bingyao Liu(刘秉尧), Dongdong Liang(梁冬冬), Xiaomei Li(李晓梅), Xiaomin Li(李晓敏), Li Chen(陈莉), Rui Zhu(朱瑞), Jun Xu(徐军), Tongbo Wei(魏同波), Xuedong Bai(白雪冬), and Peng Gao(高鹏) 2024 (3):  38502-038502.  doi: 10.1088/1674-1056/ad1c56 摘要 ( 189 )   HTML ( 1 )   PDF(1300KB) ( 186 )   To gain further understanding of the luminescence properties of multiquantum wells and the factors affecting them on a microscopic level, cathodoluminescence combined with scanning transmission electron microscopy and spectroscopy was used to measure the luminescence of In0.15Ga0.85N five-period multiquantum wells. The lattice-composition-energy relationship was established with the help of energy-dispersive x-ray spectroscopy, and the bandgaps of In0.15Ga0.85N and GaN in multiple quantum wells were extracted by electron energy loss spectroscopy to understand the features of cathodoluminescence spectra. The luminescence differences between different periods of multiquantum wells and the effects of defects such as composition fluctuation and dislocations on the luminescence of multiple quantum wells were revealed. Our study establishing the direct relationship between the atomic structure of InxGa1-xN multiquantum wells and photoelectric properties provides useful information for nitride applications. 参考文献 | 补充材料 | 相关文章 | 计量指标

Select

Decompositions of the Kadomtsev-Petviashvili equation and their symmetry reductions Zitong Chen(陈孜童), Man Jia(贾曼), Xiazhi Hao(郝夏芝), and Senyue Lou(楼森岳) 2024 (3):  30201-030201.  doi: 10.1088/1674-1056/ad1a96 摘要 ( 132 )   HTML ( 0 )   PDF(754KB) ( 104 )   Starting with a decomposition conjecture, we carefully explain the basic decompositions for the Kadomtsev-Petviashvili (KP) equation as well as the necessary calculation procedures, and it is shown that the KP equation allows the Burgers-STO (BSTO) decomposition, two types of reducible coupled BSTO decompositions and the BSTO-KdV decomposition. Furthermore, we concentrate ourselves on pointing out the main idea and result of Bäcklund transformation of the KP equation based on a special superposition principle in the particular context of the BSTO decompositions. Using the framework of standard Lie point symmetry theory, these decompositions are studied and the problem of computing the corresponding symmetry constraints is treated. 参考文献 | 相关文章 | 计量指标

Select

Adaptive interaction driven by the learning effect in the spatial prisoner's dilemma Jiaqi Li(李佳奇), Jianlei Zhang(张建磊), and Qun Liu(刘群) 2024 (3):  30202-030202.  doi: 10.1088/1674-1056/acf702 摘要 ( 99 )   HTML ( 1 )   PDF(1096KB) ( 99 )   We propose a computing model in which individuals can automatically adjust their interaction intensity with their mentor according to the learning effect. This model is designed to investigate the cooperative dynamics of the spatial prisoner's dilemma. More specifically, when the cumulative payoff of a learner is more than his reference earning, he will strengthen his interaction with his mentor; otherwise, he will reduce it. The experimental results indicate that this mechanism can improve the emergence of cooperation in a networked population and that the driving coefficient of interaction intensity plays an important role in promoting cooperation. Interestingly, under a certain social dilemma condition, there exists a minimal driving coefficient that leads to optimal cooperation. This occurs due to a positive feedback effect between the individual's satisfaction frequency and the number of effective neighbors. Moreover, we find that the experimental results are in accord with theoretical predictions obtained from an extension of the classical pair-approximation method. Our conclusions obtained by considering relationships with mentors can provide a new perspective for future investigations into the dynamics of evolutionary games within structured populations. 参考文献 | 相关文章 | 计量指标

Select

Discreet investors exert greater influence on cooperation in the public goods game Hong-Wei Kang(康洪炜), Zhan-Yao Jin(金展瑶), Ming-Yuan Li(李明远), Mie Wang(旺咩), Xing-Ping Sun(孙兴平), Yong Shen(沈勇), and Qing-Yi Chen(陈清毅) 2024 (3):  30203-030203.  doi: 10.1088/1674-1056/ad0113 摘要 ( 122 )   HTML ( 3 )   PDF(1523KB) ( 101 )   This paper studies the evolutionary process of cooperative behavior in a public goods game model with heterogeneous investment strategies in square lattices. In the proposed model, players are divided into defectors, cooperators and discreet investors. Among these, defectors do not participate in investing, discreet investors make heterogeneous investments based on the investment behavior and cooperation value of their neighbors, and cooperators invest equally in each neighbor. In real life, heterogeneous investment is often accompanied by time or economic costs. The discreet investors in this paper pay a certain price to obtain their neighbors' investment behavior and cooperation value, which quantifies the time and economic costs of the heterogeneous investment process. The results of Monte Carlo simulation experiments in this study show that discreet investors can effectively resist the invasion of the defectors, form a stable cooperative group and expand the cooperative advantage in evolution. However, when discreet investors pay too high a price, they lose their strategic advantage. The results in this paper help us understand the role of heterogeneous investment in promoting and maintaining human social cooperation. 参考文献 | 相关文章 | 计量指标

Select

Quintessence anisotropic stellar models in quadratic and Born-Infeld modified teleparallel Rastall gravity Allah Ditta, Tiecheng Xia(夏铁成), Irfan Mahmood, and Asif Mahmood 2024 (3):  30204-030204.  doi: 10.1088/1674-1056/acfaf9 摘要 ( 101 )   HTML ( 1 )   PDF(722KB) ( 91 )   This study aims to discuss anisotropic solutions that are spherically symmetric in the quintessence field, which describe compact stellar objects in the modified Rastall teleparallel theory of gravity. To achieve this goal, the Krori and Barua arrangement for spherically symmetric components of the line element is incorporated. We explore the field equations by selecting appropriate off-diagonal tetrad fields. Born-Infeld function of torsion f(T)=β√λT+1-1 and power law form h(T)=δTn are used. The Born-Infeld gravity was the first modified teleparallel gravity to discuss inflation. We use the linear equation of state pr=ξρ to separate the quintessence density. After obtaining the field equations, we investigate different physical parameters that demonstrate the stability and physical acceptability of the stellar models. We use observational data, such as the mass and radius of the compact star candidates PSRJ 1416-2230, Cen X-3, & 4U 1820-30, to ensure the physical plausibility of our findings. 参考文献 | 相关文章 | 计量指标

Select

Impact of different interaction behavior on epidemic spreading in time-dependent social networks Shuai Huang(黄帅), Jie Chen(陈杰), Meng-Yu Li(李梦玉),Yuan-Hao Xu(徐元昊), and Mao-Bin Hu(胡茂彬) 2024 (3):  30205-030205.  doi: 10.1088/1674-1056/ad147f 摘要 ( 120 )   HTML ( 1 )   PDF(588KB) ( 71 )   We investigate the impact of pairwise and group interactions on the spread of epidemics through an activity-driven model based on time-dependent networks. The effects of pairwise/group interaction proportion and pairwise/group interaction intensity are explored by extensive simulation and theoretical analysis. It is demonstrated that altering the group interaction proportion can either hinder or enhance the spread of epidemics, depending on the relative social intensity of group and pairwise interactions. As the group interaction proportion decreases, the impact of reducing group social intensity diminishes. The ratio of group and pairwise social intensity can affect the effect of group interaction proportion on the scale of infection. A weak heterogeneous activity distribution can raise the epidemic threshold, and reduce the scale of infection. These results benefit the design of epidemic control strategy. 参考文献 | 相关文章 | 计量指标

Select

Real eigenvalues determined by recursion of eigenstates Tong Liu(刘通) and Youguo Wang(王友国) 2024 (3):  30303-030303.  doi: 10.1088/1674-1056/ad1746 摘要 ( 107 )   HTML ( 1 )   PDF(1997KB) ( 97 )   Quantum physics is primarily concerned with real eigenvalues, stemming from the unitarity of time evolutions. With the introduction of PT symmetry, a widely accepted consensus is that, even if the Hamiltonian of the system is not Hermitian, the eigenvalues can still be purely real under specific symmetry. Hence, great enthusiasm has been devoted to exploring the eigenvalue problem of non-Hermitian systems. In this work, from a distinct perspective, we demonstrate that real eigenvalues can also emerge under the appropriate recursive condition of eigenstates. Consequently, our findings provide another path to extract the real energy spectrum of non-Hermitian systems, which guarantees the conservation of probability and stimulates future experimental observations. 参考文献 | 相关文章 | 计量指标

Select

Dilation, discrimination and Uhlmann's theorem of link products of quantum channels Qiang Lei(雷强), Liuheng Cao(操刘桁), Asutosh Kumar, and Junde Wu(武俊德) 2024 (3):  30304-030304.  doi: 10.1088/1674-1056/ad0ccb 摘要 ( 138 )   HTML ( 2 )   PDF(488KB) ( 92 )   We establish the Stinespring dilation theorem of the link product of quantum channels in two different ways, discuss the discrimination of quantum channels, and show that the distinguishability can be improved by self-linking each quantum channel n times as n grows. We also find that the maximum value of Uhlmann's theorem can be achieved for diagonal channels. 参考文献 | 相关文章 | 计量指标

Select

Complementary monogamy and polygamy properties among multipartite systems Tao Li(李陶), Jing-Yi Zhou(周静怡), Qi Sun(孙琪), Zhi-Xiang Jin(靳志祥), Deng-Feng Liang(梁登峰), and Ting Luo(罗婷) 2024 (3):  30305-030305.  doi: 10.1088/1674-1056/ad1748 摘要 ( 100 )   HTML ( 1 )   PDF(1397KB) ( 90 )   Monogamy and polygamy relations are essential properties of quantum entanglement, which characterize the distributions of entanglement in multipartite systems. In this paper, we establish the general monogamy relations for γ-th (0≤γ ≤α, α≥ 1) power of quantum entanglement based on unified-(q,s) entanglement and polygamy relations for δ-th (δ≥ β, 0≤β≤1) power of entanglement of assistance based on unified-(q,s) entanglement of assistance, which provides a complement to the previous research in terms of different parameter regions of γ and δ. These results are then applied to specific quantum correlations, e.g., entanglement of formation, Renyi-q entanglement of assistance and Tsallis-q entanglement of assistance to get the corresponding monogamy and polygamy inequalities. Moreover, typical examples are presented for illustration. 参考文献 | 相关文章 | 计量指标

Select

Does the Hartman effect exist in triangular barriers Qing-Ling Li(李青玲), Shuang Zheng(郑爽), and Zhi Xiao(肖智) 2024 (3):  30306-030306.  doi: 10.1088/1674-1056/acf2fe 摘要 ( 127 )   HTML ( 1 )   PDF(1871KB) ( 22 )   We study the phase, Larmor and dwell times of a particle scattered off triangular barriers (TBs). It is interesting that the dependences of dwell, reflective phase and Larmor times on the wave number, barrier width and height for a pair of mirror-symmetric (MS) exact triangular barriers (ETBs) are quite different, as the two ETBs have quite distinct scattering surfaces. In comparison, the dependence of the transmitted phase or Larmor times is exactly the same, since the transmitted amplitudes are the same for a pair of MS TBs. We further study the Hartman effect by defining the phase and Larmor velocities associated with the phase and Larmor times. We find no barrier width saturation effect for the transmitted and reflected times. This is indicated by the fact that all the velocities approach finite constants that are much smaller than the speed of light in vacuum for TBs with positive-slope impact faces. As for ETBs with vertical left edges, the naive velocities seem to also indicate the absence of the Hartman effect. These are quite distinct from rectangular barriers and may shed new light on the clarification of the tunneling time issues. 参考文献 | 相关文章 | 计量指标

Select

Parameter estimation in n-dimensional massless scalar field Ying Yang(杨颖) and Jiliang Jing(荆继良) 2024 (3):  30307-030307.  doi: 10.1088/1674-1056/ad1749 摘要 ( 117 )   HTML ( 1 )   PDF(671KB) ( 156 )   Quantum Fisher information (QFI) associated with local metrology has been used to parameter estimation in open quantum systems. In this work, we calculated the QFI for a moving Unruh-DeWitt detector coupled with massless scalar fields in n-dimensional spacetime, and analyzed the behavior of QFI with various parameters, such as the dimension of spacetime, evolution time, and Unruh temperature. We discovered that the QFI of state parameter decreases monotonically from 1 to 0 over time. Additionally, we noted that the QFI for small evolution times is several orders of magnitude higher than the QFI for long evolution times. We also found that the value of QFI decreases at first and then stabilizes as the Unruh temperature increases. It was observed that the QFI depends on initial state parameter θ, and Fθ is the maximum for θ=0 or θ=π, Fφ is the maximum for θ=π/2. We also obtain that the maximum value of QFI for state parameters varies for different spacetime dimensions with the same evolution time. 参考文献 | 相关文章 | 计量指标

Select

Effects of drive imbalance on the particle emission from a Bose-Einstein condensate in a one-dimensional lattice Long-Quan Lai(赖龙泉) and Zhao Li(李照) 2024 (3):  30308-030308.  doi: 10.1088/1674-1056/ad1172 摘要 ( 137 )   HTML ( 2 )   PDF(925KB) ( 171 )   Time-periodic driving has been an effective tool in the field of nonequilibrium quantum dynamics, which enables precise control of the particle interactions. We investigate the collective emission of particles from a Bose-Einstein condensate in a one-dimensional lattice with periodic drives that are separate in modulation amplitudes and relative phases. In addition to the enhancement of particle emission, we find that amplitude imbalances lead to energy shift and band broadening, while typical relative phases may give rise to similar gaps. These results offer insights into the specific manipulations of nonequilibrium quantum systems with tone-varying drives. 参考文献 | 相关文章 | 计量指标

Select

A new quantum key distribution resource allocation and routing optimization scheme Lin Bi(毕琳), Xiaotong Yuan(袁晓同), Weijie Wu(吴炜杰), and Shengxi Lin(林升熙) 2024 (3):  30309-030309.  doi: 10.1088/1674-1056/ad2503 摘要 ( 116 )   HTML ( 1 )   PDF(1012KB) ( 64 )   Quantum key distribution (QKD) is a technology that can resist the threat of quantum computers to existing conventional cryptographic protocols. However, due to the stringent requirements of the quantum key generation environment, the generated quantum keys are considered valuable, and the slow key generation rate conflicts with the high-speed data transmission in traditional optical networks. In this paper, for the QKD network with a trusted relay, which is mainly based on point-to-point quantum keys and has complex changes in network resources, we aim to allocate resources reasonably for data packet distribution. Firstly, we formulate a linear programming constraint model for the key resource allocation (KRA) problem based on the time-slot scheduling. Secondly, we propose a new scheduling scheme based on the graded key security requirements (GKSR) and a new micro-log key storage algorithm for effective storage and management of key resources. Finally, we propose a key resource consumption (KRC) routing optimization algorithm to properly allocate time slots, routes, and key resources. Simulation results show that the proposed scheme significantly improves the key distribution success rate and key resource utilization rate, among others. 参考文献 | 相关文章 | 计量指标

Select

Quantum geometric tensor and the topological characterization of the extended Su-Schrieffer-Heeger model Xiang-Long Zeng(曾相龙), Wen-Xi Lai(赖文喜), Yi-Wen Wei(魏祎雯), and Yu-Quan Ma(马余全) 2024 (3):  30310-030310.  doi: 10.1088/1674-1056/ad1170 摘要 ( 116 )   HTML ( 0 )   PDF(1336KB) ( 104 )   We investigate the quantum metric and topological Euler number in a cyclically modulated Su-Schrieffer-Heeger (SSH) model with long-range hopping terms. By computing the quantum geometry tensor, we derive exact expressions for the quantum metric and Berry curvature of the energy band electrons, and we obtain the phase diagram of the model marked by the first Chern number. Furthermore, we also obtain the topological Euler number of the energy band based on the Gauss-Bonnet theorem on the topological characterization of the closed Bloch states manifold in the first Brillouin zone. However, some regions where the Berry curvature is identically zero in the first Brillouin zone result in the degeneracy of the quantum metric, which leads to ill-defined non-integer topological Euler numbers. Nevertheless, the non-integer "Euler number" provides valuable insights and an upper bound for the absolute values of the Chern numbers. 参考文献 | 相关文章 | 计量指标

Select

A lightweight symmetric image encryption cryptosystem in wavelet domain based on an improved sine map Baichi Chen(陈柏池), Linqing Huang(黄林青), Shuting Cai(蔡述庭), Xiaoming Xiong(熊晓明), and Hui Zhang(张慧) 2024 (3):  30501-030501.  doi: 10.1088/1674-1056/ad1030 摘要 ( 98 )   HTML ( 2 )   PDF(15526KB) ( 64 )   In the era of big data, the number of images transmitted over the public channel increases exponentially. As a result, it is crucial to devise the efficient and highly secure encryption method to safeguard the sensitive image. In this paper, an improved sine map (ISM) possessing a larger chaotic region, more complex chaotic behavior and greater unpredictability is proposed and extensively tested. Drawing upon the strengths of ISM, we introduce a lightweight symmetric image encryption cryptosystem in wavelet domain (WDLIC). The WDLIC employs selective encryption to strike a satisfactory balance between security and speed. Initially, only the low-frequency-low-frequency component is chosen to encrypt utilizing classic permutation and diffusion. Then leveraging the statistical properties in wavelet domain, Gaussianization operation which opens the minds of encrypting image information in wavelet domain is first proposed and employed to all sub-bands. Simulations and theoretical analysis demonstrate the high speed and the remarkable effectiveness of WDLIC. 参考文献 | 相关文章 | 计量指标

Select

Dual-wavelength pumped latticed Fermi-Pasta-Ulam recurrences in nonlinear Schrödinger equation Qian Zhang(张倩), Xiankun Yao(姚献坤), and Heng Dong(董恒) 2024 (3):  30502-030502.  doi: 10.1088/1674-1056/ad181e 摘要 ( 139 )   HTML ( 1 )   PDF(2523KB) ( 139 )   We show that the nonlinear stage of the dual-wavelength pumped modulation instability (MI) in nonlinear Schrödinger equation (NLSE) can be effectively analyzed by mode truncation methods. The resulting complicated heteroclinic structure of instability unveils all possible dynamic trajectories of nonlinear waves. Significantly, the latticed-Fermi-Pasta-Ulam recurrences on the modulated-wave background in NLSE are also investigated and their dynamic trajectories run along the Hamiltonian contours of the heteroclinic structure. It is demonstrated that there has much richer dynamic behavior, in contrast to the nonlinear waves reported before. This novel nonlinear wave promises to inject new vitality into the study of MI. 参考文献 | 相关文章 | 计量指标

Select

A novel variable-order fractional chaotic map and its dynamics Zhouqing Tang(唐周青), Shaobo He(贺少波), Huihai Wang(王会海), Kehui Sun(孙克辉), Zhao Yao(姚昭), and Xianming Wu(吴先明) 2024 (3):  30503-030503.  doi: 10.1088/1674-1056/ad1a93 摘要 ( 137 )   HTML ( 2 )   PDF(37769KB) ( 168 )   In recent years, fractional-order chaotic maps have been paid more attention in publications because of the memory effect. This paper presents a novel variable-order fractional sine map (VFSM) based on the discrete fractional calculus. Specially, the order is defined as an iterative function that incorporates the current state of the system. By analyzing phase diagrams, time sequences, bifurcations, Lyapunov exponents and fuzzy entropy complexity, the dynamics of the proposed map are investigated comparing with the constant-order fractional sine map. The results reveal that the variable order has a good effect on improving the chaotic performance, and it enlarges the range of available parameter values as well as reduces non-chaotic windows. Multiple coexisting attractors also enrich the dynamics of VFSM and prove its sensitivity to initial values. Moreover, the sequence generated by the proposed map passes the statistical test for pseudorandom number and shows strong robustness to parameter estimation, which proves the potential applications in the field of information security. 参考文献 | 相关文章 | 计量指标

Select

Effects of connected automated vehicle on stability and energy consumption of heterogeneous traffic flow system Jin Shen(申瑾), Jian-Dong Zhao(赵建东), Hua-Qing Liu(刘华清), Rui Jiang(姜锐), and Zhi-Xin Yu(余智鑫) 2024 (3):  30504-030504.  doi: 10.1088/1674-1056/ad1383 摘要 ( 134 )   HTML ( 2 )   PDF(3473KB) ( 105 )   With the development of intelligent and interconnected traffic system, a convergence of traffic stream is anticipated in the foreseeable future, where both connected automated vehicle (CAV) and human driven vehicle (HDV) will coexist. In order to examine the effect of CAV on the overall stability and energy consumption of such a heterogeneous traffic system, we first take into account the interrelated perception of distance and speed by CAV to establish a macroscopic dynamic model through utilizing the full velocity difference (FVD) model. Subsequently, adopting the linear stability theory, we propose the linear stability condition for the model through using the small perturbation method, and the validity of the heterogeneous model is verified by comparing with the FVD model. Through nonlinear theoretical analysis, we further derive the KdV-Burgers equation, which captures the propagation characteristics of traffic density waves. Finally, by numerical simulation experiments through utilizing a macroscopic model of heterogeneous traffic flow, the effect of CAV permeability on the stability of density wave in heterogeneous traffic flow and the energy consumption of the traffic system is investigated. Subsequent analysis reveals emergent traffic phenomena. The experimental findings demonstrate that as CAV permeability increases, the ability to dampen the propagation of fluctuations in heterogeneous traffic flow gradually intensifies when giving system perturbation, leading to enhanced stability of the traffic system. Furthermore, higher initial traffic density renders the traffic system more susceptible to congestion, resulting in local clustering effect and stop-and-go traffic phenomenon. Remarkably, the total energy consumption of the heterogeneous traffic system exhibits a gradual decline with CAV permeability increasing. Further evidence has demonstrated the positive influence of CAV on heterogeneous traffic flow. This research contributes to providing theoretical guidance for future CAV applications, aiming to enhance urban road traffic efficiency and alleviate congestion. 参考文献 | 相关文章 | 计量指标

Select

Coexistence behavior of asymmetric attractors in hyperbolic-type memristive Hopfield neural network and its application in image encryption Xiaoxia Li(李晓霞), Qianqian He(何倩倩), Tianyi Yu(余天意),Zhuang Cai(才壮), and Guizhi Xu(徐桂芝) 2024 (3):  30505-030505.  doi: 10.1088/1674-1056/acf281 摘要 ( 140 )   HTML ( 1 )   PDF(30479KB) ( 140 )   The neuron model has been widely employed in neural-morphic computing systems and chaotic circuits. This study aims to develop a novel circuit simulation of a three-neuron Hopfield neural network (HNN) with coupled hyperbolic memristors through the modification of a single coupling connection weight. The bistable mode of the hyperbolic memristive HNN (mHNN), characterized by the coexistence of asymmetric chaos and periodic attractors, is effectively demonstrated through the utilization of conventional nonlinear analysis techniques. These techniques include bifurcation diagrams, two-parameter maximum Lyapunov exponent plots, local attractor basins, and phase trajectory diagrams. Moreover, an encryption technique for color images is devised by leveraging the mHNN model and asymmetric structural attractors. This method demonstrates significant benefits in correlation, information entropy, and resistance to differential attacks, providing strong evidence for its effectiveness in encryption. Additionally, an improved modular circuit design method is employed to create the analog equivalent circuit of the memristive HNN. The correctness of the circuit design is confirmed through Multisim simulations, which align with numerical simulations conducted in Matlab. 参考文献 | 相关文章 | 计量指标

Select

Parametric instability in the pure-quartic nonlinear Schrödinger equation Yun-Hong Zhang(张云红) and Chong Liu(刘冲) 2024 (3):  30506-030506.  doi: 10.1088/1674-1056/ad11e7 摘要 ( 157 )   HTML ( 0 )   PDF(3264KB) ( 175 )   We study the nonlinear stage of modulation instability (MI) in the non-intergrable pure-quartic nonlinear Schrödinger equation where the fourth-order dispersion is modulated periodically. Using the three-mode truncation, we reveal the complex recurrence of parametric resonance (PR) breathers, where each recurrence is associated with two oscillation periods (PR period and internal oscillation period). The nonlinear stage of parametric instability admits the maximum energy exchange between the spectrum sidebands and central mode occurring outside the MI gain band. 参考文献 | 相关文章 | 计量指标

Select

Microscopic mechanism of plasmon-mediated photocatalytic H2 splitting on Ag-Au alloy chain Yuhui Song(宋玉慧), Yirui Lu(芦一瑞), Axin Guo(郭阿鑫), Yifei Cao(曹逸飞), Jinping Li(李金萍), Zhengkun Fu(付正坤), Lei Yan(严蕾), and Zhenglong Zhang(张正龙) 2024 (3):  33101-033101.  doi: 10.1088/1674-1056/ad123d 摘要 ( 148 )   HTML ( 0 )   PDF(3141KB) ( 107 )   Alloy nanostructures supporting localized surface plasmon resonances has been widely used as efficient photocatalysts, but the microscopic mechanism of alloy compositions enhancing the catalytic efficiency is still unclear. By using time-dependent density functional theory (TDDFT), we analyze the real-time reaction processes of plasmon-mediated H2 splitting on linear Ag-Au alloy chains when exposed to femtosecond laser pulses. It is found that H2 splitting rate depends on the position and proportion of Au atoms in alloy chains, which indicates that specially designed Ag-Au alloy is more likely to induce the reaction than pure Ag chain. Especially, more electrons directly transfer from the alloy chain to the anti-bonding state of H2, thereby accelerating the H2 splitting reaction. These results establish a theoretical foundation for comprehending the microscopic mechanism of plasmon-induced chemical reaction on the alloy nanostructures. 参考文献 | 补充材料 | 相关文章 | 计量指标

Select

Core level excitation spectra of La and Mn ions in LaMnO3 Fujian Li(李福建), Xinlu Cheng(程新路), and Hong Zhang(张红) 2024 (3):  33201-033201.  doi: 10.1088/1674-1056/acfaf5 摘要 ( 107 )   HTML ( 0 )   PDF(1028KB) ( 97 )   Manganese-based perovskite is popular for research on ferromagnetic materials, and its spectroscopic studies are essential for understanding its electronic structure, dielectric, electrical, and magnetic properties. In this paper, the M-edge spectra of La ions and the M-edge, L-edge, and K-edge spectra of Mn ions in LaMnO3 are calculated by considering both the free-ion multiplet calculation and the crystal field effects. We analyze spectral shapes, identify peak origins, and estimate the oxidation states of La and Mn ions in LaMnO3 theoretically. It is concluded that La ions in LaMnO3 predominantly exist in the trivalent state, while Mn ions exist primarily in the trivalent state with a minor presence of tetravalent ions. Furthermore, the calculated spectra are in better conformity with the experimental spectra when the proportion of Mn3+ is 90% and Mn4+ is 10%. This article enhances our comprehension of the oxidation states of La and Mn within the crystal and also provides a valuable guidance for spectroscopic investigations of other manganates. 参考文献 | 相关文章 | 计量指标

Select

Theoretical investigations of population trapping phenomena in atomic four-color, three-step photoionization scheme Xiao-Yong Lu(卢肖勇) and Ya-Peng Sun(孙亚鹏) 2024 (3):  33202-033202.  doi: 10.1088/1674-1056/ad10fc 摘要 ( 121 )   HTML ( 1 )   PDF(2660KB) ( 82 )   The four-color three-step selective photoionization process of atom is very important in laser isotope separation technology. The population trapping phenomena and their influences are studied theoretically in monochromatic and non-monochromatic laser fields based on the density matrix theory in this work. Time evolutions of the photoionization properties of the four-color, three-step process are given. The population trapping effects occur intensely in monochromatic excitation, while it gradually turns weak as the laser bandwidth increases. The effects of bandwidth, Rabi frequency, time delay, and frequency detuning on the population trapping effect are investigated in monochromatic and non-monochromatic laser fields. The effects of laser process parameters and atomic parameters on the effective selective photoionization are also discussed. The ionization probability and selectivity factors, as evaluation indexes, are difficult to improve synchronously by adjusting systematic parameters. Besides, the existence of metastable state may play a negative role when its population is low enough. 参考文献 | 相关文章 | 计量指标

Select

Theoretical investigation of electron-impact ionization of W8+ ion Shiping Zhang(张世平), Fangjun Zhang(张芳军), Denghong Zhang(张登红), Xiaobin Ding(丁晓彬), Jun Jiang(蒋军), Luyou Xie(颉录有), Yulong Ma(马玉龙), Maijuan Li(李麦娟), Marek Sikorski, and Chenzhong Dong(董晨钟) 2024 (3):  33401-033401.  doi: 10.1088/1674-1056/ad1487 摘要 ( 145 )   HTML ( 1 )   PDF(822KB) ( 106 )   The electron-impact single ionization cross section for W8+ ion has been calculated using flexible atomic code, employing the level-to-level distorted-wave approximation. This calculations takes into account contributions form both direct ionization (DI) and excitation autoionization (EA). However, the theoretical predictions, based solely on the ground state, tends to underestimate the experimental values. This discrepancy can be mitigated by incorporation contributions from excited states. We extended the theoretical analysis, including the contributions from the long-lived metastable states with lifetimes exceeding 1.5×10-5 s. We employed two statistical models to predict the fraction of ground state ions in the parent ion beam. Assuming a 79% fraction of parent ions in ground configuration, the experiment measurements align with the predictions. Furthermore we derived the theoretical cross-section for the ground state as correlated plasma rate coefficients, and compared it with existing data. Despite the uncertainty in our calculations, our results are still acceptable. 参考文献 | 相关文章 | 计量指标

Select

On-chip ultrafast stackable dielectric laser positron accelerator Bin Sun(孙斌), Yangfan He(何阳帆), Chenhao Pan(潘晨浩), Sijie Fan(樊思劼), Du Wang(王度), Shaoyi Wang(王少义), and Zongqing Zhao(赵宗清) 2024 (3):  34101-034101.  doi: 10.1088/1674-1056/ad188e 摘要 ( 173 )   HTML ( 1 )   PDF(2095KB) ( 172 )   We present a first on-chip positron accelerator based on dielectric laser acceleration. This innovative approach significantly reduces the physical dimensions of the positron acceleration apparatus, enhancing its feasibility for diverse applications. By utilizing a stacked acceleration structure and far-infrared laser technology, we are able to achieve a seven-stage acceleration structure that surpasses the distance and energy gain of using the previous dielectric laser acceleration methods. Additionally, we are able to compress the positron beam to an ultrafast sub-femtosecond scale during the acceleration process, compared with the traditional methods, the positron beam is compressed to a greater extent. We also demonstrate the robustness of the stacked acceleration structure through the successful acceleration of the positron beam. 参考文献 | 相关文章 | 计量指标

Select

Singular optical propagation properties of two types of one-dimensional anti-PT-symmetric periodic ring optical waveguide networks Yanglong Fan(樊阳龙), Xiangbo Yang(杨湘波), Huada Lian(练华达), Runkai Chen(陈润楷),Pengbo Zhu(朱蓬勃), Dongmei Deng(邓冬梅), Hongzhan Liu(刘宏展), and Zhongchao Wei(韦中超) 2024 (3):  34201-034201.  doi: 10.1088/1674-1056/ad12ab 摘要 ( 117 )   HTML ( 0 )   PDF(3199KB) ( 57 )   Two types of one-dimensional (1D) anti-PT-symmetric periodic ring optical waveguide networks, consisting of gain and loss materials, are constructed. The singular optical propagation properties of these networks are investigated. The results show that the system composed of gain materials exhibits characteristics of ultra-strong transmission and bidirectional reflection. Conversely, the system composed of loss materials demonstrates equal transmittance and reflectance at some frequencies. In both the systems, a new type of total reflection phenomenon is observed. When the imaginary part of the refractive indices of waveguide segments is smaller than 10-5, the system shows bidirectional transparency with the transmittance tending to be 1 and reflectivity to be smaller than 10-8 at some bands. When the refractive indices of the waveguide segments are real, the system will be bidirectional transparent at the full band. These findings may deepen the understanding of anti-PT-symmetric optical systems and optical waveguide networks, and possess potential applications in efficient optical energy storage, ultra-sensitive optical filters, ultra-sensitive all-optical switches, integrated optical chips, stealth physics, and so on. 参考文献 | 相关文章 | 计量指标

Select

Simultaneous guidance of electromagnetic and elastic waves via glide symmetry phoxonic crystal waveguides Lin-Lin Lei(雷林霖), Ling-Juan He(何灵娟), Qing-Hua Liao(廖清华), Wen-Xing Liu(刘文兴), and Tian-Bao Yu(于天宝) 2024 (3):  34202-034202.  doi: 10.1088/1674-1056/ad0ec7 摘要 ( 102 )   HTML ( 0 )   PDF(6721KB) ( 104 )   A phoxonic crystal waveguide with the glide symmetry is designed, in which both electromagnetic and elastic waves can propagate along the glide plane at the same time. Due to the glide symmetry, the bands of the phoxonic crystal super-cell degenerate in pairs at the boundary of the Brillouin zone. This is the so-called band-sticking effect and it causes the appearance of gapless guided-modes. By adjusting the magnitude of the glide dislocation the edge bandgaps, the bandgap of the guided-modes at the boundary of the Brillouin zone, can be further adjusted. The photonic and phononic guided-modes can then possess only one mode for a certain frequency with relatively low group velocities, achieving single-mode guided-bands with relatively flat dispersion relationship. In addition, there exists acousto-optic interaction in the cavity constructed by the glide plane. The proposed waveguide has potential applications in the design of novel optomechanical devices. 参考文献 | 相关文章 | 计量指标

Select

A polarization sensitive interferometer: Delta interferometer Chao-Qi Wei(卫超奇), Jian-Bin Liu(刘建彬), Yi-Fei Dong(董翼飞), Yu-Nong Sun(孙雨农), Yu Zhou(周宇), Huai-Bin Zheng(郑淮斌), Yan-Yan Liu(刘严严), Xiu-Sheng Yan(闫秀生), Fu-Li Li(李福利), and Zhuo Xu(徐卓) 2024 (3):  34203-034203.  doi: 10.1088/1674-1056/acf996 摘要 ( 129 )   HTML ( 0 )   PDF(966KB) ( 123 )   A new type of polarization sensitive interferometer is proposed, named the Delta interferometer, inspired by its geometry resembling the Greek letter Delta. The main difference between the Delta interferometer and other existing interferometers, such as Michelson, Mach-Zehnder and Young's double-slit interferometers, is that the two interfering paths are asymmetrical in the Delta interferometer. The visibility of the first-order interference pattern observed in the Delta interferometer is dependent on the polarization of the incidental light. Optical coherence theory is employed to interpret this phenomenon and single-mode continuous-wave laser light is employed to verify the theoretical predictions. The theoretical and experimental results are consistent. The Delta interferometer is a perfect tool to study the reflection of electromagnetic fields in different polarizations and may find applications in polarization-sensitive scenarios. 参考文献 | 相关文章 | 计量指标

Select

Efficient single-pixel imaging encrypted transmission based on 3D Arnold transformation Zhen-Yu Liang(梁振宇), Chao-Jin Wang(王朝瑾), Yang-Yang Wang(王阳阳), Hao-Qi Gao(高皓琪), Dong-Tao Zhu(朱东涛), Hao-Li Xu(许颢砾), and Xing Yang(杨星) 2024 (3):  34204-034204.  doi: 10.1088/1674-1056/acf204 摘要 ( 130 )   HTML ( 0 )   PDF(2797KB) ( 131 )   Single-pixel imaging (SPI) can transform 2D or 3D image data into 1D light signals, which offers promising prospects for image compression and transmission. However, during data communication these light signals in public channels will easily draw the attention of eavesdroppers. Here, we introduce an efficient encryption method for SPI data transmission that uses the 3D Arnold transformation to directly disrupt 1D single-pixel light signals and utilizes the elliptic curve encryption algorithm for key transmission. This encryption scheme immediately employs Hadamard patterns to illuminate the scene and then utilizes the 3D Arnold transformation to permutate the 1D light signal of single-pixel detection. Then the transformation parameters serve as the secret key, while the security of key exchange is guaranteed by an elliptic curve-based key exchange mechanism. Compared with existing encryption schemes, both computer simulations and optical experiments have been conducted to demonstrate that the proposed technique not only enhances the security of encryption but also eliminates the need for complicated pattern scrambling rules. Additionally, this approach solves the problem of secure key transmission, thus ensuring the security of information and the quality of the decrypted images. 参考文献 | 相关文章 | 计量指标

Select

Diffraction deep neural network-based classification for vector vortex beams Yixiang Peng(彭怡翔), Bing Chen(陈兵), Le Wang(王乐), and Shengmei Zhao(赵生妹) 2024 (3):  34205-034205.  doi: 10.1088/1674-1056/ad0142 摘要 ( 136 )   HTML ( 0 )   PDF(1189KB) ( 145 )   The vector vortex beam (VVB) has attracted significant attention due to its intrinsic diversity of information and has found great applications in both classical and quantum communications. However, a VVB is unavoidably affected by atmospheric turbulence (AT) when it propagates through the free-space optical communication environment, which results in detection errors at the receiver. In this paper, we propose a VVB classification scheme to detect VVBs with continuously changing polarization states under AT, where a diffractive deep neural network (DDNN) is designed and trained to classify the intensity distribution of the input distorted VVBs, and the horizontal direction of polarization of the input distorted beam is adopted as the feature for the classification through the DDNN. The numerical simulations and experimental results demonstrate that the proposed scheme has high accuracy in classification tasks. The energy distribution percentage remains above 95% from weak to medium AT, and the classification accuracy can remain above 95% for various strengths of turbulence. It has a faster convergence and better accuracy than that based on a convolutional neural network. 参考文献 | 相关文章 | 计量指标

Select

Enhancing the Goos-Hänchen shift based on quasi-bound states in the continuum through material asymmetric dielectric compound gratings Xiaowei Jiang(江孝伟), Bin Fang(方彬), and Chunlian Zhan(占春连) 2024 (3):  34206-034206.  doi: 10.1088/1674-1056/acf661 摘要 ( 132 )   HTML ( 2 )   PDF(3042KB) ( 92 )   Quasi-bound state in the continuum (QBIC) resonance is gradually attracting attention and being applied in Goos-Hänchen (GH) shift enhancement due to its high quality (Q) factor and superior optical confinement. Currently, symmetry-protected QBIC resonance is often achieved by breaking the geometric symmetry, but few cases are achieved by breaking the material symmetry. This paper proposes a dielectric compound grating to achieve a high Q factor and high-reflection symmetry-protectede QBIC resonance based on material asymmetry. Theoretical calculations show that the symmetry-protected QBIC resonance achieved by material asymmetry can significantly increase the GH shift up to -980 times the resonance wavelength, and the maximum GH shift is located at the reflection peak with unity reflectance. This paper provides a theoretical basis for designing and fabricating high-performance GH shift tunable metasurfaces/dielectric gratings in the future. 参考文献 | 相关文章 | 计量指标

Select

Generation of orbital angular momentum hologram using a modified U-net Zhi-Gang Zheng(郑志刚), Fei-Fei Han(韩菲菲), Le Wang(王乐), and Sheng-Mei Zhao(赵生妹) 2024 (3):  34207-034207.  doi: 10.1088/1674-1056/ad12aa 摘要 ( 138 )   HTML ( 2 )   PDF(3925KB) ( 140 )   Orbital angular momentum (OAM) holography has become a promising technique in information encryption, data storage and opto-electronic computing, owing to the infinite topological charge of one single OAM mode and the orthogonality of different OAM modes. In this paper, we propose a novel OAM hologram generation method based on a densely connected U-net (DCU), where the densely connected convolution blocks (DCB) replace the convolution blocks of the U-net. Importantly, the reconstruction process of the OAM hologram is integrated into DCU as its output layer, so as to eliminate the requirement to prepare training data for the OAM hologram, which is required by conventional neural networks through an iterative algorithm. The experimental and simulation results show that the OAM hologram can rapidly be generated with the well-trained DCU, and the reconstructed image's quality from the generated OAM hologram is significantly improved in comparison with those from the Gerchberg-Saxton generation method, the Gerchberg-Saxton based generation method and the U-net method. In addition, a 10-bit OAM multiplexing hologram scheme is numerically demonstrated to have a high capacity with OAM hologram. 参考文献 | 相关文章 | 计量指标

Select

Engineering the spectra of photon triplets generated from micro/nanofiber Chuan Qu(瞿川), Dongqin Guo(郭东琴), Xiaoxiao Li(李笑笑), Zhenqi Liu(刘振旗), Yi Zhao(赵义), Shenghai Zhang(张胜海), and Zhengtong Wei(卫正统) 2024 (3):  34208-034208.  doi: 10.1088/1674-1056/ad1c5d 摘要 ( 122 )   HTML ( 0 )   PDF(1375KB) ( 114 )   Quantum light sources are the core resources for photonics-based quantum information processing. We investigate the spectral engineering of photon triplets generated by third-order spontaneous parametric down-conversion in micro/nanofiber. The phase mismatching at one-third pump frequency gives rise to non-degenerate photon triplets, the joint spectral intensity of which has an elliptical locus with a fixed eccentricity of √6/3. Therefore, we propose a frequency-division scheme to separate non-degenerate photon triplets into three channels with high heralding efficiency for the first time. Choosing an appropriate pump wavelength can compensate for the fabrication errors of micro/nanofiber and also generate narrowband, non-degenerate photon triplet sources with a high signal-to-noise ratio. Furthermore, the long-period micro/nanofiber grating introduces a new controllable degree of freedom to tailor phase matching, resulting from the periodic oscillation of dispersion. In this scheme, the wavelength of photon triplets can be flexibly tuned using quasi-phase matching. We study the generation of photon triplets from this novel perspective of spectrum engineering, and we believe that this work will accelerate the practical implementation of photon triplets in quantum information processing. 参考文献 | 相关文章 | 计量指标

Select

Versatile and controlled quantum teleportation network Yao-Yao Zhou(周瑶瑶), Peng-Xian Mei(梅鹏娴), Yan-Hong Liu(刘艳红), Liang Wu(吴量), Yan-Xiang Li(李雁翔), Zhi-Hui Yan(闫智辉), and Xiao-Jun Jia(贾晓军) 2024 (3):  34209-034209.  doi: 10.1088/1674-1056/ad1981 摘要 ( 184 )   HTML ( 0 )   PDF(2460KB) ( 177 )   A quantum teleportation network involving multiple users is essential for future quantum internet. So far, controlled quantum teleportation has been demonstrated in a three-user network. However, versatile and controlled quantum teleportation network involving more users is in demand, which satisfies different combinations of users for practical requirements. Here we propose a highly versatile and controlled teleportation network that can switch among various combinations of different users. We use a single continuous-variable six-partite Greenberger-Horne-Zeilinger (GHZ) state to realize such a task by choosing the different measurement and feedback operations. The controlled teleportation network, which includes one sub-network, two sub-networks and three sub-networks, can be realized for different application of user combinations. Furthermore, the coherent feedback control (CFC) can manipulate and improve the teleportation performance. Our approach is flexible and scalable, and would provide a versatile platform for demonstrations of complex quantum communication and quantum computing protocols. 参考文献 | 相关文章 | 计量指标

Select

On the generation of high-quality Nyquist pulses in mode-locked fiber lasers Yuxuan Ren(任俞宣), Jinman Ge(葛锦蔓), Xiaojun Li(李小军), Junsong Peng(彭俊松), and Heping Zeng(曾和平) 2024 (3):  34210-034210.  doi: 10.1088/1674-1056/acfa87 摘要 ( 169 )   HTML ( 1 )   PDF(966KB) ( 190 )   Nyquist pulses have wide applications in many areas, from electronics to optics. Mode-locked lasers are ideal platforms to generate such pulses. However, how to generate high-quality Nyquist pulses in mode-locked lasers remains elusive. We address this problem by managing different physical effects in mode-locked fiber lasers through extensive numerical simulations. We find that net dispersion, linear loss, gain and filter shaping can affect the quality of Nyquist pulses significantly. We also demonstrate that Nyquist pulses experience similariton shaping due to the nonlinear attractor effect in the gain medium. Our work may contribute to the design of Nyquist pulse sources and enrich the understanding of pulse shaping dynamics in mode-locked lasers. 参考文献 | 相关文章 | 计量指标

Select

Estimating the yield stress of soft materials via laser-induced breakdown spectroscopy Shuhang Gong(龚书航), Yaju Li(李亚举), Dongbin Qian(钱东斌), Jinrui Ye(叶晋瑞), Kou Zhao(赵扣), Qiang Zeng(曾强), Liangwen Chen(陈良文), Shaofeng Zhang(张少锋), Lei Yang(杨磊), and Xinwen Ma(马新文) 2024 (3):  34211-034211.  doi: 10.1088/1674-1056/ad12a9 摘要 ( 131 )   HTML ( 1 )   PDF(1284KB) ( 63 )   Taking three typical soft samples prepared respectively by loose packings of 77-, 95-, and 109-μm copper grains as examples, we perform an experiment to investigate the energy-dependent laser-induced breakdown spectroscopy (LIBS) of soft materials. We discovered a reversal phenomenon in the trend of energy dependence of plasma emission intensity: increasing initially and then decreasing separated by a well-defined critical energy. The trend reversal is attributed to the laser-induced recoil pressure at the critical energy just matching the sample's yield strength. As a result, a one-to-one correspondence can be well established between the samples' yield stress and the critical energy that is easily obtainable from LIBS measurements. This allows us to propose an innovative method for estimating the yield stress of soft materials via LIBS with attractive advantages including in-situ remote detection, real-time data collection, and minimal destructive to sample. 参考文献 | 相关文章 | 计量指标

Select

Tunable spectral continuous shift of high-order harmonic generation in atoms by a plasmon-assisted shaping pulse Yuan Wang(王源), Yulong Li(李玉龙), Yue Qiao(乔月), Na Gao(高娜),Fu-Ming Guo(郭福明), Zhou Chen(陈洲), Lan-Hai He(赫兰海),Yu-Jun Yang(杨玉军), Xi Zhao(赵曦), and Jun Wang(王俊) 2024 (3):  34212-034212.  doi: 10.1088/1674-1056/ad10fb 摘要 ( 123 )   HTML ( 1 )   PDF(5966KB) ( 96 )   We delve into the phenomenon of high-order harmonic generation within a helium atom under the influence of a plasmon-assisted shaping pulse. Our findings reveal an intriguing manipulation of the frequency peak position in the harmonic emission by adjusting the absolute phase parameter within the frequency domain of the shaping pulse. This phenomenon holds potential significance for experimental setups necessitating precisely tuned single harmonics. Notably, we observe a modulated shift in the created harmonic photon energy, spanning an impressive range of 1.2 eV. This frequency peak shift is rooted in the asymmetry exhibited by the rising and falling edges of the laser pulse, directly influencing the position of the peak frequency emission. Our study quantifies the dependence of this tuning range and the asymmetry of the laser pulse, offering valuable insights into the underlying mechanisms driving this phenomenon. Furthermore, our investigation uncovers the emergence of semi-integer order harmonics as the phase parameter is altered. We attribute this discovery to the intricate interference between harmonics generated by the primary and secondary return cores. This observation introduces an innovative approach for generating semi-integer order harmonics, thus expanding our understanding of high-order harmonic generation. Ultimately, our work contributes to the broader comprehension of complex phenomena in laser-matter interactions and provides a foundation for harnessing these effects in various applications, particularly those involving precise spectral control and the generation of unique harmonic patterns. 参考文献 | 相关文章 | 计量指标

Select

Controllable optical bistability in a Fabry-Pérot cavity with a nonlinear three-dimensional Dirac semimetal Hong-Xia Yuan(袁红霞), Jia-Xue Li(李佳雪), Qi-Jun Ma(马奇军), Hai-Shan Tian(田海山),Yun-Yang Ye(叶云洋), Wen-Xin Luo(罗文昕), Xing-Hua Wu(吴杏华), and Le-Yong Jiang(蒋乐勇) 2024 (3):  34213-034213.  doi: 10.1088/1674-1056/acfdfe 摘要 ( 116 )   HTML ( 1 )   PDF(1223KB) ( 88 )   Optical bistability (OB) is capable of rapidly and reversibly transforming a parameter of an optical signal from one state to another, and homologous nonlinear optical bistable devices are core components of high-speed all-optical communication and all-optical networks. In this paper, we theoretically investigated the controllable OB from a Fabry-Pérot (FP) cavity with a nonlinear three-dimensional Dirac semimetal (3D DSM) in the terahertz band. The OB stems from the third-order nonlinear bulk conductivity of the 3D DSM and the resonance mode has a positive effect on the generation of OB. This FP cavity structure is able to tune the OB because the transmittance and the reflectance can be modulated by the Fermi energy of the 3D DSM. We believe that this FP cavity configuration could provide a reference concept for realizing tunable bistable devices. 参考文献 | 相关文章 | 计量指标

Select

Decoupling of temporal/spatial broadening effects in Doppler wind LiDAR by 2D spectral analysis Zhen Liu(刘珍), Yun-Peng Zhang(张云鹏), Xiao-Peng Zhu(竹孝鹏), Ji-Qiao Liu(刘继桥), De-Cang Bi(毕德仓), and Wei-Biao Chen(陈卫标) 2024 (3):  34214-034214.  doi: 10.1088/1674-1056/ad10fd 摘要 ( 138 )   HTML ( 2 )   PDF(700KB) ( 260 )   Pulse echo accumulation is commonly employed in coherent Doppler wind LiDAR (light detection and ranging) under the assumption of steady wind. Here, the measured spectral data are analyzed in the time dimension and frequency dimension to cope with the temporal wind shear and achieve the optimal accumulation time. A hardware-efficient algorithm combining the interpolation and cross-correlation is used to enhance the wind retrieval accuracy by reducing the frequency sampling interval and then reduce the spectral width calculation error. Moreover, the temporal broadening effect and spatial broadening effect are decoupled according to the strategy we developed. 参考文献 | 相关文章 | 计量指标

Select

High-efficiency ultra-fast all-optical photonic crystal diode based on the lateral-coupled nonlinear elliptical defect Daxing Li(李大星), Kaizhu Liu(刘凯柱), Chunlong Yu(余春龙), Kuo Zhang(张括),Yueqin Liu(刘跃钦), and Shuai Feng(冯帅) 2024 (3):  34215-034215.  doi: 10.1088/1674-1056/ad0117 摘要 ( 144 )   HTML ( 1 )   PDF(2264KB) ( 37 )   An all-optical Fano-like diode featuring a nonlinear lateral elliptical micro-cavity and a reflecting column in the photonic crystal waveguide is proposed. The asymmetric micro-cavity is constructed by removing one rod and changing the shape of the lateral rod from a circle to an ellipse. A reflecting pillar is also introduced into the waveguide to construct an F-P cavity with the elliptical defect and enhance the asymmetric transmission for the incident light wave transmitting rightwards and leftwards, respectively. By designing the size of the ellipse and optimizing a reflecting rod at a suitable position, a maximum forward light transmittance of -1.14 dB and a minimum backward transmittance of -57.66 dB are achieved at the working wavelength of 1550.47 nm. The corresponding response time is about 10 ps when the intensity of the pump light beam resonant at 637 nm is 3.97 W/μm2. 参考文献 | 相关文章 | 计量指标

Select

High-order Bragg forward scattering and frequency shift of low-frequency underwater acoustic field by moving rough sea surface Ya-Xiao Mo(莫亚枭), Chao-Jin Zhang(张朝金), Li-Cheng Lu(鹿力成), Qi-Hang Sun(孙启航), and Li Ma(马力) 2024 (3):  34301-034301.  doi: 10.1088/1674-1056/ad108f 摘要 ( 124 )   HTML ( 2 )   PDF(7345KB) ( 95 )   Acoustic scattering modulation caused by an undulating sea surface on the space-time dimension seriously affects underwater detection and target recognition. Herein, underwater acoustic scattering modulation from a moving rough sea surface is studied based on integral equation and parabolic equation. And with the principles of grating and constructive interference, the mechanism of this acoustic scattering modulation is explained. The periodicity of the interference of moving rough sea surface will lead to the interference of the scattering field at a series of discrete angles, which will form comb-like and frequency-shift characteristics on the intensity and the frequency spectrum of the acoustic scattering field, respectively, which is a high-order Bragg scattering phenomenon. Unlike the conventional Doppler effect, the frequency shifts of the Bragg scattering phenomenon are multiples of the undulating sea surface frequency and are independent of the incident sound wave frequency. Therefore, even if a low-frequency underwater acoustic field is incident, it will produce obvious frequency shifts. Moreover, under the action of ideal sinusoidal waves, swells, fully grown wind waves, unsteady wind waves, or mixed waves, different moving rough sea surfaces create different acoustic scattering processes and possess different frequency shift characteristics. For the swell wave, which tends to be a single harmonic wave, the moving rough sea surface produces more obvious high-order scattering and frequency shifts. The same phenomena are observed on the sea surface under fully grown wind waves, however, the frequency shift slightly offsets the multiple peak frequencies of the wind wave spectrum. Comparing with the swell and fully-grown wind waves, the acoustic scattering and frequency shift are not obvious for the sea surface under unsteady wind waves. 参考文献 | 相关文章 | 计量指标

Select

Wave nature of Rosensweig instability Liu Li(李柳), Decai Li(李德才), Zhiqiang Qi(戚志强), Lu Wang(王璐), and Zhili Zhang(张志力) 2024 (3):  34701-034701.  doi: 10.1088/1674-1056/ad1485 摘要 ( 118 )   HTML ( 0 )   PDF(9156KB) ( 30 )   The explicit analytical solution of Rosensweig instability spikes' shapes obtained by Navier-Stokes (NS) equation in diverse magnetic field H vertical to the flat free surface of ferrofluids are systematically studied experimentally and theoretically. After carefully analyzing and solving the NS equation in elliptic form, the force balanced surface equations of spikes in Rosensweig instability are expressed as cosine wave in perturbated magnetic field and hyperbolic tangent in large magnetic field, whose results both reveal the wave-like nature of Rosensweig instability. The results of hyperbolic tangent form are perfectly fitted to the experimental results in this paper, which indicates that the analytical solution is basically correct. Using the forementioned theoretical results, the total energy of the spike distribution pattern is calculated. By analyzing the energy components under different magnetic field intensities H, the hexagon-square transition of Rosensweig instability is systematically discussed and explained in an explicit way. 参考文献 | 相关文章 | 计量指标

Select

Wave field structure and power coupling features of blue-core helicon plasma driven by various antenna geometries and frequencies Chao Wang(王超), Jia Liu(刘佳), Lei Chang(苌磊), Ling-Feng Lu(卢凌峰), Shi-Jie Zhang(张世杰), and Fan-Tao Zhou(周帆涛) 2024 (3):  35201-035201.  doi: 10.1088/1674-1056/ad1486 摘要 ( 96 )   HTML ( 1 )   PDF(6113KB) ( 98 )   This paper deals with wave propagation and power coupling in blue-core helicon plasma driven by various antennas and frequencies. It is found that compared to non-blue-core mode, for blue-core mode, the wave can propagate in the core region, and it decays sharply outside the core. The power absorption is lower and steeper in radius for blue-core mode. Regarding the effects of antenna geometry for blue-core mode, it shows that half helix antenna yields the strongest wave field and power absorption, while loop antenna yields the lowest. Moreover, near axis, for antennas with m = +1, the wave field increases with axial distance. In the core region, the wave number approaches to a saturation value at much lower frequency for non-blue-core mode compared to blue-core mode. The total loading resistance is much lower for blue-core mode. These findings are valuable to understanding the physics of blue-core helicon discharge and optimizing the experimental performance of blue-core helicon plasma sources for applications such as space propulsion and material treatment. 参考文献 | 相关文章 | 计量指标

Select

Three-dimensional magnetic reconnection in complex multiple X-point configurations in an ancient solar-lunar terrestrial system Xiang-Lei He(何向磊), Ao-Hua Mao(毛傲华), Meng-Meng Sun(孙萌萌), Ji-Tong Zou(邹继同), and Xiao-Gang Wang(王晓钢) 2024 (3):  35202-035202.  doi: 10.1088/1674-1056/ad0b02 摘要 ( 122 )   HTML ( 0 )   PDF(4888KB) ( 133 )   Magnetic reconnection processes in three-dimensional (3D) complex field configurations have been investigated in different magneto-plasma systems in space, laboratory, and astrophysical systems. Two-dimensional (2D) features of magnetic reconnection have been well developed and applied successfully to systems with symmetrical property, such as toroidal fusion plasmas and laboratory experiments with an axial symmetry. But in asymmetric systems, the 3D features are inevitably different from those in the 2D case. Magnetic reconnection structures in multiple celestial body systems, particularly star-planet-Moon systems, bring fresh insights to the understanding of the 3D geometry of reconnection. Thus, we take magnetic reconnection in an ancient solar-lunar terrestrial magneto-plasma system as an example by using its crucial parameters approximately estimated already and also some specific applications in pathways for energy and matter transports among Earth, ancient Moon, and the interplanetary magnetic field (IMF). Then, magnetic reconnection of the ancient lunar-terrestrial magnetospheres with the IMF is investigated numerically in this work. In a 3D simulation for the Earth-Moon-IMF system, topological features of complex magnetic reconnection configurations and dynamical characteristics of magnetic reconnection processes are studied. It is found that a coupled lunar-terrestrial magnetosphere is formed, and under various IMF orientations, multiple X-points emerge at distinct locations, showing three typical magnetic reconnection structures in such a geometry, i.e., the X-line, the triple current sheets, and the A-B null pairs. The results can conduce to further understanding of reconnection physics in 3D for plasmas in complex magnetic configurations, and also a possible mechanism for energy and matters transport in evolutions of similar astrophysical systems. 参考文献 | 相关文章 | 计量指标

Select

Hollow cathode effect in radio frequency hollow electrode discharge in argon Liu-Liang He(贺柳良), Feng He(何锋), and Ji-Ting Ouyang(欧阳吉庭) 2024 (3):  35203-035203.  doi: 10.1088/1674-1056/ad1a89 摘要 ( 111 )   HTML ( 0 )   PDF(1799KB) ( 136 )   Radio frequency capacitively coupled plasma source (RF-CCP) with a hollow electrode can increase the electron density through the hollow cathode effect (HCE), which offers a method to modify the spatial profiles of the plasma density. In this work, the variations of the HCE in one RF period are investigated by using a two-dimensional particle-in-cell/Monte-Carlo collision (PIC/MCC) model. The results show that the sheath electric field, the sheath potential drop, the sheath thickness, the radial plasma bulk width, the electron energy distribution function (EEDF), and the average electron energy in the cavity vary in one RF period. During the hollow electrode sheath's expansion phase, the secondary electron heating and sheath oscillation heating in the cavity are gradually enhanced, and the frequency of the electron pendular motion in the cavity gradually increases, hence the HCE is gradually enhanced. However, during the hollow electrode sheath's collapse phase, the secondary electron heating is gradually attenuated. In addition, when interacting with the gradually collapsed hollow electrode sheaths, high-energy plasma bulk electrons in the cavity will lose some energy. Furthermore, the frequency of the electron pendular motion in the cavity gradually decreases. Therefore, during the hollow electrode sheath's collapse phase, the HCE is gradually attenuated. 参考文献 | 相关文章 | 计量指标

Select

Numerical studies for plasmas of a linear plasma device HIT-PSI with geometry modified SOLPS-ITER Min Wang(王敏), Qiuyue Nie(聂秋月), Tao Huang(黄韬), Xiaogang Wang(王晓钢), and Yanjie Zhang(张彦杰) 2024 (3):  35204-035204.  doi: 10.1088/1674-1056/ad16d4 摘要 ( 145 )   HTML ( 2 )   PDF(1397KB) ( 236 )   The HIT-PSI is a linear plasma device built for physically simulating the high heat flux environment of future reactor divertors to test/develop advanced target plate materials. In this study, the geometry-modified SOLPS-ITER program is employed to examine the effects of the magnetic field strength and neutral pressure in the device on the heat flux experienced by the target plate of the HIT-PSI device. The findings of the numerical simulation indicate a positive correlation between the magnetic field strength and the heat flux density. Conversely, there is a negative correlation observed between the heat flux density and the neutral pressure. When the magnetic field strength at the axis exceeds 1 tesla and the neutral pressure falls below 10 Pa, the HIT-PSI has the capability to attain a heat flux of 10 MW·m-2 at the target plate. The simulation results offer a valuable point of reference for subsequent experiments at HIT-PSI. 参考文献 | 相关文章 | 计量指标

Select

Residual stress modeling of mitigated fused silica damage sites with CO2 laser annealing Chuanchao Zhang(张传超), Wei Liao(廖威), Lijuan Zhang(张丽娟), Xiaolong Jiang(蒋晓龙), Zhenhua Fang(方振华), and Xiaodong Jiang(蒋晓东) 2024 (3):  36101-036101.  doi: 10.1088/1674-1056/acf447 摘要 ( 104 )   HTML ( 0 )   PDF(1306KB) ( 83 )   A numerical model based on measured fictive temperature distributions is explored to evaluate the residual stress fields of CO2 laser-annealed mitigated fused silica damage sites. The proposed model extracts the residual strain from the differences in thermoelastic contraction of fused silica with different fictive temperatures from the initial frozen-in temperatures to ambient temperature. The residual stress fields of mitigated damage sites for the CO2 laser-annealed case are obtained by a finite element analysis of equilibrium equations and constitutive equations. The simulated results indicate that the proposed model can accurately evaluate the residual stress fields of laser-annealed mitigated damage sites with a complex thermal history. The calculated maximum hoop stress is in good agreement with the reported experimental result. The estimated optical retardance profiles from the calculated radial and hoop stress fields are consistent with the photoelastic measurements. These results provide sufficient evidence to demonstrate the suitability of the proposed model for describing the residual stresses of mitigated fused silica damage sites after CO2 laser annealing. 参考文献 | 相关文章 | 计量指标

Select

Photostability of colloidal single photon emitter in near-infrared regime at room temperature Si-Yue Jin(靳思玥) and Xing-Sheng Xu(许兴胜) 2024 (3):  36102-036102.  doi: 10.1088/1674-1056/ad1090 摘要 ( 96 )   HTML ( 0 )   PDF(1344KB) ( 132 )   The photostability of a colloidal single photon emitter in near-infrared regime at room temperature is investigated. The fluorescence lifetime, blinking phenomenon, and anti-bunching effect of a single CdTeSe/ZnS quantum dot with an emission wavelength of 800 nm at room temperature are studied. The second-order correlation function at zero delay time is much smaller than 0.1, which proves that the emission from single quantum dots at 800 nm is a highly pure single-photon source. The effects of the irradiation duration on the fluorescence from single quantum dots are analyzed. The experimental results can be explained by a recombination model including a multi-nonradiative recombination center model and a multi-charged model. 参考文献 | 相关文章 | 计量指标

Select

Electronic effects on radiation damage in α-iron: A molecular dynamics study Lin Jiang(江林), Min Li(李敏), Bao-Qin Fu(付宝勤), Jie-Chao Cui(崔节超), and Qing Hou(侯氢) 2024 (3):  36103-036103.  doi: 10.1088/1674-1056/ad0ec4 摘要 ( 113 )   HTML ( 0 )   PDF(2935KB) ( 134 )   Iron (Fe)-based alloys, which have been widely used as structural materials in nuclear reactors, can significantly change their microstructure properties and macroscopic properties under high flux neutron irradiation during operation, thus, the problems associated with the safe operation of nuclear reactors have been put forward naturally. In this work, a molecular dynamics simulation approach combined with electronic effects is developed for investigating the primary radiation damage process in α-Fe. Specifically, the influence of electronic effects on the collision cascade in Fe is systematically evaluated based on two commonly used interatomic potentials for Fe. The simulation results reveal that both electronic stopping (ES) and electron-phonon coupling (EPC) can contribute to the decrease of the number of defects in the thermal spike phase. The application of ES reduces the number of residual defects after the cascade evolution, whereas EPC has a reverse effect. The introduction of electronic effects promotes the formation of the dispersive subcascade: ES significantly changes the geometry of the damaged region in the thermal spike phase, whereas EPC mainly reduces the extent of the damaged region. Furthermore, the incorporation of electronic effects effectively mitigates discrepancies in simulation outcomes when using different interatomic potentials. 参考文献 | 相关文章 | 计量指标

Select

Molecular dynamics study of primary radiation damage in TiVTa concentrated solid-solution alloy Yong-Peng Zhao(赵永鹏), Yan-Kun Dou(豆艳坤), Xin-Fu He(贺新福), Han Cao(曹晗),Lin-Feng Wang(王林枫), Hui-Qiu Deng(邓辉球), and Wen Yang(杨文) 2024 (3):  36104-036104.  doi: 10.1088/1674-1056/ad0146 摘要 ( 129 )   HTML ( 0 )   PDF(807KB) ( 140 )   The primary radiation damage in pure V and TiVTa concentrated solid-solution alloy (CSA) was studied using a molecular dynamics method. We have performed displacement cascade simulations to explore the generation and evolution behavior of irradiation defects. The results demonstrate that the defect accumulation and agglomeration in TiVTa CSA are significantly suppressed compared to pure V. The peak value of Frenkel pairs during cascade collisions in TiVTa CSA is much higher than that in pure V due to the lower formation energy of point defects. Meanwhile, the longer lifetime of the thermal spike relaxation and slow energy dissipation capability of TiVTa CSA can facilitate the recombination of point defects. The defect agglomeration rate in TiVTa CSA is much lower due to the lower binding energy of interstitial clusters and reduced interstitial diffusivity. Furthermore, the occurrence probability of dislocation loops in TiVTa CSA is lower than that in pure V. The reduction in primary radiation damage may enhance the radiation resistance of TiVTa CSA, and the improved radiation tolerance is primarily attributed to the relaxation stage and long-term defect evolution rather than the ballistic stage. These results can provide fundamental insights into irradiation-induced defects evolution in refractory CSAs. 参考文献 | 相关文章 | 计量指标

Select

Comparative study on phase transition behaviors of fractional molecular field theory and random-site Ising model Ting-Yu Liu(刘婷玉), Wei Zhao(赵薇), Tao Wang(王涛), Xiao-Dong An(安小冬), Lai Wei(卫来), and Yi-Neng Huang(黄以能) 2024 (3):  36403-036403.  doi: 10.1088/1674-1056/ad0cc7 摘要 ( 131 )   HTML ( 1 )   PDF(725KB) ( 132 )   Fractional molecular field theory (FMFT) is a phenomenological theory that describes phase transitions in crystals with randomly distributed components, such as the relaxor-ferroelectrics and spin glasses. In order to verify the feasibility of this theory, this paper fits it to the Monte Carlo simulations of specific heat and susceptibility versus temperature of two-dimensional (2D) random-site Ising model (2D-RSIM). The results indicate that the FMFT deviates from the 2D-RSIM significantly. The main reason for the deviation is that the 2D-RSIM is a typical system of component random distribution, where the real order parameter is spatially heterogeneous and has no symmetry of space translation, but the basic assumption of FMFT means that the parameter is spatially uniform and has symmetry of space translation. 参考文献 | 相关文章 | 计量指标

Select

Effects of vacancy and external electric field on the electronic properties of the MoSi2N4/graphene heterostructure Qian Liang(梁前), Xiangyan Luo(罗祥燕), Guolin Qian(钱国林), Yuanfan Wang(王远帆), Yongchao Liang(梁永超), and Quan Xie(谢泉) 2024 (3):  37101-037101.  doi: 10.1088/1674-1056/acef04 摘要 ( 115 )   HTML ( 0 )   PDF(4108KB) ( 102 )   Recently, the newly synthesized septuple-atomic layer two-dimensional (2D) material MoSi2N4 (MSN) has attracted attention worldwide. Our work delves into the effect of vacancies and external electric fields on the electronic properties of the MSN/graphene (Gr) heterostructure using first-principles calculation. We find that four types of defective structures, N-in, N-out, Si and Mo vacancy defects of monolayer MSN and MSN/Gr heterostructure are stable in air. Moreover, vacancy defects can effectively modulate the charge transfer at the interface of the MSN/Gr heterostructure as well as the work function of the pristine monolayer MSN and MSN/Gr heterostructure. Finally, the application of an external electric field enables the dynamic switching between n-type and p-type Schottky contacts. Our work may offer the possibility of exceeding the capabilities of conventional Schottky diodes based on MSN/Gr heterostructures. 参考文献 | 相关文章 | 计量指标

Select

Exciton-polaritons in a 2D hybrid organic-inorganic perovskite microcavity with the presence of optical Stark effect Kenneth Coker, Chuyuan Zheng(郑楚媛), Joseph Roger Arhin, Kwame Opuni-Boachie Obour Agyekum, and Weili Zhang(张伟利) 2024 (3):  37102-037102.  doi: 10.1088/1674-1056/ad1484 摘要 ( 116 )   HTML ( 2 )   PDF(1127KB) ( 141 )   This study investigates the properties of exciton-polaritons in a two-dimensional (2D) hybrid organic-inorganic perovskite microcavity in the presence of optical Stark effect. Through both steady and dynamic state analyses, strong coupling between excitons of perovskite and cavity photons is revealed, indicating the formation of polaritons in the perovskite microcavity. Besides, it is found that an external optical Stark pulse can induce energy shifts of excitons proportional to the pulse intensity, which modifies the dispersion characteristics of the polaritons. 参考文献 | 相关文章 | 计量指标

Select

Effect of electron-electron interaction on polarization process of exciton and biexciton in conjugated polymer Xiao-Xue Li(李晓雪), Hua Peng(彭华), Dong Wang(王栋), and Dong Hou(侯栋) 2024 (3):  37201-037201.  doi: 10.1088/1674-1056/ad0bf1 摘要 ( 121 )   HTML ( 0 )   PDF(11294KB) ( 96 )   By using one-dimensional tight-binding model modified to include electron-electric field interaction and electron-electron interaction, we theoretically explore the polarization process of exciton and biexciton in cis-polyacetylene. The dynamical simulation is performed by adopting the non-adiabatic evolution approach. The results show that under the effect of moderate electric field, when the strength of electron-electron interaction is weak, the singlet exciton is stable but its polarization presents obvious oscillation. With the enhancement of interaction, it is dissociated into polaron pairs, the spin-flip of which can be observed through modulating the interaction strength. For the triplet exciton, the strong electron-electron interaction restrains its normal polarization, but it is still stable. In the case of biexciton, the strong electron-electron interaction not only dissociate it, but also flip its charge distribution. The yield of the possible states formed after the dissociation of exciton and biexciton is also calculated. 参考文献 | 相关文章 | 计量指标

Select

Negative magnetoresistance in the antiferromagnetic semimetal V1/3TaS2 Zi Wang(王子), Xin Peng(彭馨), Shengnan Zhang(张胜男), Yahui Su(苏亚慧), Shaodong Lai(赖少东), Xuan Zhou(周旋), Chunxiang Wu(吴春翔), Tingyu Zhou(周霆宇), Hangdong Wang(王杭栋), Jinhu Yang(杨金虎), Bin Chen(陈斌), Huifei Zhai(翟会飞), Quansheng Wu(吴泉生), Jianhua Du(杜建华), Zhiwei Jiao(焦志伟), and Minghu Fang(方明虎) 2024 (3):  37301-037301.  doi: 10.1088/1674-1056/ad18aa 摘要 ( 137 )   HTML ( 3 )   PDF(1599KB) ( 232 )   Intercalated transition metal dichalcogenides (TMDCs) attract much attention due to their rich properties and potential applications. In this article, we grew successfully high-quality V1/3TaS2 crystals by a vapor transport method. We measured the magnetization, longitudinal resistivity ρxx(T, H), Hall resistivity ρxy(T, H), as well as performed calculations of the electronic band structure. It was found that V1/3TaS2 is an A-type antiferromagnet with the Neel temperature TN = 6.20 K, and exhibits a negative magnetoresistance (MR) near TN. Both band structure calculations and Hall resistivity measurements demonstrated it is a magnetic semimetal. 参考文献 | 相关文章 | 计量指标

Select

Exploring reservoir computing: Implementation via double stochastic nanowire networks Jian-Feng Tang(唐健峰), Lei Xia(夏磊), Guang-Li Li(李广隶), Jun Fu(付军), Shukai Duan(段书凯), and Lidan Wang(王丽丹) 2024 (3):  37302-037302.  doi: 10.1088/1674-1056/aceeea 摘要 ( 125 )   HTML ( 0 )   PDF(3697KB) ( 49 )   Neuromorphic computing, inspired by the human brain, uses memristor devices for complex tasks. Recent studies show that self-organizing random nanowires can implement neuromorphic information processing, enabling data analysis. This paper presents a model based on these nanowire networks, with an improved conductance variation profile. We suggest using these networks for temporal information processing via a reservoir computing scheme and propose an efficient data encoding method using voltage pulses. The nanowire network layer generates dynamic behaviors for pulse voltages, allowing time series prediction analysis. Our experiment uses a double stochastic nanowire network architecture for processing multiple input signals, outperforming traditional reservoir computing in terms of fewer nodes, enriched dynamics and improved prediction accuracy. Experimental results confirm the high accuracy of this architecture on multiple real-time series datasets, making neuromorphic nanowire networks promising for physical implementation of reservoir computing. 参考文献 | 相关文章 | 计量指标

Select

Coexistence of antiferromagnetism and unconventional superconductivity in a quasi-one-dimensional flat-band system: Creutz lattice Feng Xu(徐峰) and Lei Zhang(张磊) 2024 (3):  37402-037402.  doi: 10.1088/1674-1056/acf5d2 摘要 ( 118 )   HTML ( 0 )   PDF(762KB) ( 89 )   We study the coexistence of antiferromagnetism and unconventional superconductivity on the Creutz lattice which shows strictly flat bands in the noninteracting regime. The famous renormalized mean-field theory is used to deal with strong electron-electron repulsive Hubbard interaction in the effective low-energy t-J model, the superfluid weight of the unconventional superconducting state has been calculated via the linear response theory. An unconventional superconducting state with both spin-singlet and staggered spin-triplet pairs emerges beyond a critical antiferromagnetic coupling interaction, while antiferromagnetism accompanies this state. The superconducting state with only spin-singlet pairs is dominant with paramagnetic phase. The A phase is analogous to the pseudogap phase, which shows that electrons go to form pairs but do not cause a supercurrent. We also show the superfluid behavior of the unconventional superconducting state and its critical temperature. It is proven directly that the flat band can effectively raise the critical temperature of superconductivity. It is implementable to simulate and control strongly-correlated electrons' behavior on the Creutz lattice in the ultracold atoms experiment or other artificial structures. Our results may help the understanding of the interplay between unconventional superconductivity and magnetism. 参考文献 | 相关文章 | 计量指标

Select

Mechanical and magnetocaloric adjustable properties of Fe3O4/PET deformed nanoparticle film Fengguo Fan(范凤国) and Lintong Duan(段林彤) 2024 (3):  37502-037502.  doi: 10.1088/1674-1056/acf280 摘要 ( 104 )   HTML ( 0 )   PDF(4760KB) ( 99 )   The flexibility of nanoparticle films is a topic of rapidly growing interest in both scientific and engineering researches due to their numerous potential applications in a broad range of wearable electronics and biomedical devices. This article presents the elucidation of the properties of nanoparticle films. Here, a flexible film is fabricated based on polyethylene terephthalate (PET) and magnetic iron oxide at the nanoscale using layer-by-layer technology. The 2D thin flexible film material can be bent at different angles from 0° to 360°. With an increase in elastic deformation angles, the magnetocaloric effect of the film gradually increases in the alternating magnetic field. The test results from a vibrating sample magnetometer and a low-frequency impedance analyzer demonstrate that the film has a good magnetic response and anisotropy. The magnetocaloric effect and magnetic induction effect are controlled by deformation, providing a new idea for the application of elastic films. It combines the flexibility of the nanoparticle PET substrate and, in the future, it may be used for skin adhesion for administration and magnetic stimulation control. 参考文献 | 相关文章 | 计量指标

Select

Interacting topological magnons in a checkerboard ferromagnet Heng Zhu(朱恒), Hongchao Shi(施洪潮), Zhengguo Tang(唐政国), and Bing Tang(唐炳) 2024 (3):  37503-037503.  doi: 10.1088/1674-1056/ad01a2 摘要 ( 113 )   HTML ( 0 )   PDF(1024KB) ( 83 )   This work is devoted to studying the magnon-magnon interaction effect in a two-dimensional checkerboard ferromagnet with the Dzyaloshinskii-Moriya interaction. Using a first-order Green function method, we analyze the influence of magnon-magnon interaction on the magnon band topology. We find that Chern numbers of two renormalized magnon bands are different above and below the critical temperature, which means that the magnon band gap-closing phenomenon is an indicator for one topological phase transition of the checkerboard ferromagnet. Our results show that the checkerboard ferromagnet possesses two topological phases, and its topological phase can be controlled either via the temperature or the applied magnetic field due to magnon-magnon interactions. Interestingly, it is found that the topological phase transition can occur twice with the increase in the temperature, which is different from the results of the honeycomb ferromagnet. 参考文献 | 相关文章 | 计量指标

Select

Unconventional room-temperature negative magnetoresistance effect in Au/n-Ge:Sb/Au devices Xiong He(何雄), Fan-Li Yang(杨凡黎), Hao-Yu Niu(牛浩峪), Li-Feng Wang(王立峰), Li-Zhi Yi(易立志),Yun-Li Xu(许云丽), Min Liu(刘敏), Li-Qing Pan(潘礼庆), and Zheng-Cai Xia(夏正才) 2024 (3):  37504-037504.  doi: 10.1088/1674-1056/ad15f8 摘要 ( 176 )   HTML ( 0 )   PDF(2858KB) ( 74 )   Non-magnetic semiconductor materials and their devices have attracted wide attention since they are usually prone to exhibit large positive magnetoresistance (MR) effect in a low static magnetic field environment at room temperature. However, how to obtain a large room-temperature negative MR effect in them remains to be studied. In this paper, by designing an Au/n-Ge:Sb/Au device with metal electrodes located on identical side, we observe an obvious room-temperature negative MR effect in a specific 50 T pulsed high magnetic field direction environment, but not in a static low magnetic field environment. Through the analysis of the experimental measurement of the Hall effect results and bipolar transport theory, we propose that this unconventional negative MR effect is mainly related to the charge accumulation on the surface of the device under the modulation of the stronger Lorentz force provided by the pulsed high magnetic field. This theoretical analytical model is further confirmed by regulating the geometry size of the device. Our work sheds light on the development of novel magnetic sensing, magnetic logic and other devices based on non-magnetic semiconductors operating in pulsed high magnetic field environment. 参考文献 | 相关文章 | 计量指标

Select

Spin gap in quasi-one-dimensional S=3/2 antiferromagnet CoTi2O5 Hao-Hang Xu(徐浩航), Qing-Yuan Liu(刘庆元), Chao Xin(辛潮), Qin-Xin Shen(申沁鑫), Jun Luo(罗军), Rui Zhou(周睿), Jin-Guang Cheng(程金光), Jian Liu(刘健), Ling-Ling Tao(陶玲玲), Zhi-Guo Liu(刘志国), Ming-Xue Huo(霍明学), Xian-Jie Wang(王先杰), and Yu Sui(隋郁) 2024 (3):  37505-037505.  doi: 10.1088/1674-1056/ad1381 摘要 ( 151 )   HTML ( 4 )   PDF(1697KB) ( 155 )   Quasi-one-dimensional (1D) antiferromagnets are known to display intriguing phenomena especially when there is a spin gap in their spin-excitation spectra. Here we demonstrate that a spin gap exists in the quasi-1D Heisenberg antiferromagnet CoTi2O5 with highly ordered Co2+/Ti4+ occupation, in which the Co2+ ions with S=3/2 form a 1D spin chain along the a-axis. CoTi2O5 undergoes an antiferromagnetic transition at TN ~ 24 K and exhibits obvious anisotropic magnetic susceptibility even in the paramagnetic region. Although a gapless magnetic ground state is usually expected in a quasi-1D Heisenberg antiferromagnet with half-integer spins, by analyzing the specific heat, the thermal conductivity, and the spin-lattice relaxation rate (1/T1) as a function of temperature, we found that a spin gap is opened in the spin-excitation spectrum of CoTi2O5 around TN, manifested by the rapid decrease of magnetic specific heat to zero, the double-peak characteristic in thermal conductivity, and the exponential decay of 1/T1 below TN. Both the magnetic measurements and the first-principles calculations results indicate that there is spin-orbit coupling in CoTi2O5, which induces the magnetic anisotropy in CoTi2O5, and then opens the spin gap at low temperature. 参考文献 | 补充材料 | 相关文章 | 计量指标

Select

Enhanced resonance frequency in Co2FeAl thin film with different thicknesses grown on flexible graphene substrate Cai Zhou(周偲), Shaokang Yuan(袁少康), Dengyu Zhu(朱登玉), Yuming Bai(白宇明), Tao Wang(王韬), Fufu Liu(刘福福), Lulu Pan(潘禄禄), Cunfang Feng(冯存芳), Bohan Zhang(张博涵), Daping He(何大平), and Shengxiang Wang(汪胜祥) 2024 (3):  37506-037506.  doi: 10.1088/1674-1056/acfafa 摘要 ( 141 )   HTML ( 0 )   PDF(2409KB) ( 154 )   The flexible materials exhibit more favorable properties than most rigid substrates in flexibility, weight saving, mechanical reliability, and excellent environmental toughness. Particularly, flexible graphene film with unique mechanical properties was extensively explored in high frequency devices. Herein, we report the characteristics of structure and magnetic properties at high frequency of Co2FeAl thin film with different thicknesses grown on flexible graphene substrate at room temperature. The exciting finding for the columnar structure of Co2FeAl thin film lays the foundation for excellent high frequency property of Co2FeAl/flexible graphene structure. In-plane magnetic anisotropy field varying with increasing thickness of Co2FeAl thin film can be obtained by measurement of ferromagnetic resonance, which can be ascribed to the enhancement of crystallinity and the increase of grain size. Meanwhile, the resonance frequency which can be achieved by the measurement of vector network analyzer with the microstrip method increases with increasing thickness of Co2FeAl thin film. Moreover, in our case with graphene film, the resonance magnetic field is quite stable though folded for twenty cycles, which demonstrates that good flexibility of graphene film and the stability of high frequency magnetic property of Co2FeAl thin film grown on flexible graphene substrate. These results are promising for the design of microwave devices and wireless communication equipment. 参考文献 | 相关文章 | 计量指标

Select

Effect of In doping on the evolution of microstructure, magnetic properties and corrosion resistance of NdFeB magnets Yuhao Li(李豫豪), Xiaodong Fan(范晓东), Zhi Jia(贾智), Lu Fan(范璐), Guangfei Ding(丁广飞), Xincai Liu(刘新才), Shuai Guo(郭帅), Bo Zheng(郑波), Shuai Cao(曹帅), Renjie Chen(陈仁杰), and Aru Yan(闫阿儒) 2024 (3):  37508-037508.  doi: 10.1088/1674-1056/ad0e5c 摘要 ( 132 )   HTML ( 0 )   PDF(11036KB) ( 126 )   The grain boundary phase affects the magnetic properties and corrosion resistance of sintered NdFeB magnets. In this work, a small amount of In was added to NdFeB magnets by induction melting to systematically investigate its effect on the evolution of the microstructure, magnetic properties and corrosion resistance of NdFeB magnets. Microstructural analysis illustrated that minor In addition generated more grain boundary phases and an abundant amorphous phase at the triple-junction grain boundary. While the addition of In failed to enhance the magnetic isolation effect between adjacent matrix grains, its incorporation fortuitously elevated the electrochemical potential of the In-containing magnets. Besides, during corrosion, an In-rich precipitate phase formed, hindering the ingress of the corrosive medium into the magnet. Consequently, this significantly bolstered the corrosion resistance of the sintered NdFeB magnets. The phase formation, magnetic properties and corrosion resistance of In-doped NdFeB magnets are detailed in this work, which provides new prospects for the preparation of high-performance sintered NdFeB magnets. 参考文献 | 相关文章 | 计量指标

Select

Investigation of reflection anisotropy induced by micropipe defects on the surface of a 4H-SiC single crystal using scanning anisotropy microscopy Wei Huang(黄威), Jinling Yu(俞金玲), Yu Liu(刘雨), Yan Peng(彭燕),Lijun Wang(王利军), Ping Liang(梁平), Tangsheng Chen(陈堂胜), Xiangang Xu(徐现刚), Fengqi Liu(刘峰奇), and Yonghai Chen(陈涌海) 2024 (3):  37801-037801.  doi: 10.1088/1674-1056/acf27f 摘要 ( 127 )   HTML ( 0 )   PDF(3370KB) ( 80 )   Optical reflection anisotropy microscopy mappings of micropipe defects on the surface of a 4H-SiC single crystal are studied by the scanning anisotropy microscopy (SAM) system. The reflection anisotropy (RA) image with a 'butterfly pattern' is obtained around the micropipes by SAM. The RA image of the edge dislocations is theoretically simulated based on dislocation theory and the photoelastic principle. By comparing with the Raman spectrum, it is verified that the micropipes consist of edge dislocations. The different patterns of the RA images are due to the different orientations of the Burgers vectors. Besides, the strain distribution of the micropipes is also deduced. One can identify the dislocation type, the direction of the Burgers vector and the optical anisotropy from the RA image by using SAM. Therefore, SAM is an ideal tool to measure the optical anisotropy induced by the strain field around a defect. 参考文献 | 相关文章 | 计量指标

Select

Exploration of the coupled lattice Boltzmann model based on a multiphase field model: A study of the solid-liquid-gas interaction mechanism in the solidification process Chang-Sheng Zhu(朱昶胜), Li-Jun Wang(王利军), Zi-Hao Gao(高梓豪), Shuo Liu(刘硕), and Guang-Zhao Li(李广召) 2024 (3):  38101-038101.  doi: 10.1088/1674-1056/ad1a91 摘要 ( 114 )   HTML ( 0 )   PDF(1112KB) ( 150 )   A multiphase field model coupled with a lattice Boltzmann (PF-LBM) model is proposed to simulate the distribution mechanism of bubbles and solutes at the solid-liquid interface, the interaction between dendrites and bubbles, and the effects of different temperatures, anisotropic strengths and tilting angles on the solidified organization of the SCN-0.24wt.% butanedinitrile alloy during the solidification process. The model adopts a multiphase field model to simulate the growth of dendrites, calculates the growth motions of dendrites based on the interfacial solute equilibrium; and adopts a lattice Boltzmann model (LBM) based on the Shan-Chen multiphase flow to simulate the growth and motions of bubbles in the liquid phase, which includes the interaction between solid-liquid-gas phases. The simulation results show that during the directional growth of columnar dendrites, bubbles first precipitate out slowly at the very bottom of the dendrites, and then rise up due to the different solid-liquid densities and pressure differences. The bubbles will interact with the dendrite in the process of flow migration, such as extrusion, overflow, fusion and disappearance. In the case of wide gaps in the dendrite channels, bubbles will fuse to form larger irregular bubbles, and in the case of dense channels, bubbles will deform due to the extrusion of dendrites. In the simulated region, as the dendrites converge and diverge, the bubbles precipitate out of the dendrites by compression and diffusion, which also causes physical phenomena such as fusion and spillage of the bubbles. These results reveal the physical mechanisms of bubble nucleation, growth and kinematic evolution during solidification and interaction with dendrite growth. 参考文献 | 相关文章 | 计量指标

Select

Experimental investigation of omnidirectional multiphysics bilayer invisibility cloak with anisotropic geometry Huolei Feng(丰火雷), Xingwei Zhang(张兴伟), Limin Zhou(周利敏), Yuekai Zhang(张悦凯), and Yushan Ni(倪玉山) 2024 (3):  38102-038102.  doi: 10.1088/1674-1056/acf490 摘要 ( 109 )   HTML ( 0 )   PDF(16125KB) ( 53 )   Thermal-electric bilayer invisibility cloak can prevent the heat flux and electric current from touching the object without distorting the external temperature and electric potential fields simultaneously. In this paper, we design an omnidirectional thermal-electric invisibility cloak with anisotropic geometry. Based on the theory of neutral inclusion, the anisotropic effective thermal and electric conductivities of confocal elliptical bilayer core-shell structure are derived, thus obtaining the anisotropic matrix material to eliminate the external disturbances omnidirectionally. The inner shell of the cloak is selected as an insulating material to shield the heat flux and electric current. Then, the omnidirectional thermal-electric cloaking effect is verified numerically and experimentally based on the theoretical anisotropic matrix and manufactured composite structure, respectively. Furthermore, we achieve the thermal-electric cloaking effect under a specific direction of heat flux and electric current using the isotropic natural materials to broaden the selection range of materials. The method proposed to eliminate anisotropy and achieve the omnidirectional effect could also be expanded to other different physical fields for the metadevices with different functions. 参考文献 | 补充材料 | 相关文章 | 计量指标

Select

Logical stochastic resonance in a cross-bifurcation non-smooth system Yuqing Zhang(张宇青) and Youming Lei(雷佑铭) 2024 (3):  38201-038201.  doi: 10.1088/1674-1056/acf11e 摘要 ( 110 )   HTML ( 0 )   PDF(1358KB) ( 85 )   This paper investigates logical stochastic resonance (LSR) in a cross-bifurcation non-smooth system driven by Gaussian colored noise. In this system, a bifurcation parameter triggers a transition between monostability, bistability and tristability. By using Novikov's theorem and the unified colored noise approximation method, the approximate Fokker-Planck equation is obtained. Then we derive the generalized potential function and the transition rates to analyze the LSR phenomenon using numerical simulations. We simulate the logic operation of the system in the bistable and tristable regions respectively. We assess the impact of Gaussian colored noise on the LSR and discover that the reliability of the logic response depends on the noise strength and the bifurcation parameter. Furthermore, it is found that the bistable region has a more extensive parameter range to produce reliable logic operation compared with the tristable region, since the tristable region is more sensitive to noise than the bistable one. 参考文献 | 相关文章 | 计量指标

Select

Modeling the performance of perovskite solar cells with inserting porous insulating alumina nanoplates Zhaoyao Pan(潘赵耀), Jinpeng Yang(杨金彭), and Xiaoshuang Shen(沈小双) 2024 (3):  38501-038501.  doi: 10.1088/1674-1056/ad1480 摘要 ( 150 )   HTML ( 0 )   PDF(1033KB) ( 92 )   Peng et al. [Science 379 683 (2023)] reported an effective method to improve the performance of perovskite solar cells by using thicker porous insulator contact (PIC)-alumina nanoplates. This method overcomes the trade-off between the open-circuit voltage and the fill factor through two mechanisms: reduced surface recombination velocity and increased bulk recombination lifetime due to better perovskite crystallinity. From arguments of drift-diffusion simulations, we find that an increase in mobility and carrier recombination lifetime in bulk are the key factors for minimizing the resistance-effect from thicker PICs and achieving a maximum power conversion efficiency (PCE) at approximately 25% reduced contact area. Furthermore, the partially replacement of perovskite films with thicker PICs would result in a reduction in short-current density, but the relative low refractive index of the PICs imbedded into the high refractive index perovskite creates light trapping structures that compensate for this loss. 参考文献 | 补充材料 | 相关文章 | 计量指标

Select

Terahertz toroidal dipole metamaterial sensors for detection of aflatoxin B1 Jianwei Xu(徐建伟), Shoujian Ouyang(欧阳收剑), Shouxin Duan(段守鑫), Liner Zou(邹林儿), Danni Ye(叶丹妮), Sijia Yang(杨思嘉), and Xiaohua Deng(邓晓华) 2024 (3):  38701-038701.  doi: 10.1088/1674-1056/acef02 摘要 ( 114 )   HTML ( 4 )   PDF(3153KB) ( 68 )   Terahertz metamaterial biosensors have attracted significant attention in the biological field due to their advantages of label-free, real-time and in situ detection. In this paper, a highly sensitive metamaterial sensor with semi-ring mirror symmetry based on toroidal dipole resonance is designed for a new metamaterial biosensor. It is shown that a refractive index sensitivity of 337.5 GHz per refractive index unit can be achieved under an analyte of saturated thickness near a 1.33 THz transmission dip. For biosensor samples where aflatoxin B1 is dropped on the metamaterial surface in our experiment, dip amplitudes of transmission varying from 0.1904 to 0.203 and 0.2093 are observed as aflatoxin B1 concentrations are altered from 0 to 0.001 μg·ml-1 and to 0.01 μg·ml-1, respectively. Furthermore, when aflatoxin B1 concentrations are 0.1 μg·ml-1, 1 μg·ml-1, 10 μg·ml-1 and 100 μg·ml-1, dip amplitudes of 0.2179, 0.226, 0.2384 and 0.2527 and dip redshifts of 10.1 GHz, 20.1 GHz, 27.7 GHz and 37.6 GHz are respectively observed. These results illustrate high-sensitivity, label-free detection of aflatoxin B1, enriching the applications of sensors in the terahertz domain. 参考文献 | 相关文章 | 计量指标

Select

Studying the co-evolution of information diffusion, vaccination behavior and disease transmission in multilayer networks with local and global effects Liang'an Huo(霍良安) and Bingjie Wu(武兵杰) 2024 (3):  38702-038702.  doi: 10.1088/1674-1056/ad0114 摘要 ( 102 )   HTML ( 0 )   PDF(1558KB) ( 24 )   Today, with the rapid development of the internet, a large amount of information often accompanies the rapid transmission of disease outbreaks, and increasing numbers of scholars are studying the relationship between information and the disease transmission process using complex networks. In fact, the disease transmission process is very complex. Besides this information, there will often be individual behavioral measures and other factors to consider. Most of the previous research has aimed to establish a two-layer network model to consider the impact of information on the transmission process of disease, rarely divided into information and behavior, respectively. To carry out a more in-depth analysis of the disease transmission process and the intrinsic influencing mechanism, this paper divides information and behavior into two layers and proposes the establishment of a complex network to study the dynamic co-evolution of information diffusion, vaccination behavior, and disease transmission. This is achieved by considering four influential relationships between adjacent layers in multilayer networks. In the information layer, the diffusion process of negative information is described, and the feedback effects of local and global vaccination are considered. In the behavioral layer, an individual's vaccination behavior is described, and the probability of an individual receiving a vaccination is influenced by two factors: the influence of negative information, and the influence of local and global disease severity. In the disease layer, individual susceptibility is considered to be influenced by vaccination behavior. The state transition equations are derived using the micro Markov chain approach (MMCA), and disease prevalence thresholds are obtained. It is demonstrated through simulation experiments that the negative information diffusion is less influenced by local vaccination behavior, and is mainly influenced by global vaccination behavior; vaccination behavior is mainly influenced by local disease conditions, and is less influenced by global disease conditions; the disease transmission threshold increases with the increasing vaccination rate; and the scale of disease transmission increases with the increasing negative information diffusion rate and decreases with the increasing vaccination rate. Finally, it is found that when individual vaccination behavior considers both the influence of negative information and disease, it can increase the disease transmission threshold and reduce the scale of disease transmission. Therefore, we should resist the diffusion of negative information, increase vaccination proportions, and take appropriate protective measures in time. 参考文献 | 相关文章 | 计量指标

Select

Dynamics of information diffusion and disease transmission in time-varying multiplex networks with asymmetric activity levels Xiao-Xiao Xie(谢笑笑), Liang-An Huo(霍良安), Ya-Fang Dong(董雅芳), and Ying-Ying Cheng(程英英) 2024 (3):  38704-038704.  doi: 10.1088/1674-1056/ad1176 摘要 ( 117 )   HTML ( 0 )   PDF(1732KB) ( 150 )   While the interaction between information and disease in static networks has been extensively investigated, many studies have ignored the characteristics of network evolution. In this study, we construct a new two-layer coupling model to explore the interactions between information and disease. The upper layer describes the diffusion of disease-related information, and the lower layer represents the disease transmission. We then use power-law distributions to examine the influence of asymmetric activity levels on dynamic propagation, revealing a mapping relationship characterizing the interconnected propagation of information and diseases among partial nodes within the network. Subsequently, we derive the disease outbreak threshold by using the microscopic Markov-chain approach (MMCA). Finally, we perform extensive Monte Carlo (MC) numerical simulations to verify the accuracy of our theoretical results. Our findings indicate that the activity levels of individuals in the disease transmission layer have a more significant influence on disease transmission compared with the individual activity levels in the information diffusion layer. Moreover, reducing the damping factor can delay disease outbreaks and suppress disease transmission, while improving individual quarantine measures can contribute positively to disease control. This study provides valuable insights into policymakers for developing outbreak prevention and control strategies. 参考文献 | 相关文章 | 计量指标

Select

A multilayer network diffusion-based model for reviewer recommendation Yiwei Huang(黄羿炜), Shuqi Xu(徐舒琪), Shimin Cai(蔡世民), and Linyuan Lü(吕琳媛) 2024 (3):  38901-038901.  doi: 10.1088/1674-1056/ad181d 摘要 ( 161 )   HTML ( 0 )   PDF(1079KB) ( 222 )   With the rapid growth of manuscript submissions, finding eligible reviewers for every submission has become a heavy task. Recommender systems are powerful tools developed in computer science and information science to deal with this problem. However, most existing approaches resort to text mining techniques to match manuscripts with potential reviewers, which require high-quality textual information to perform well. In this paper, we propose a reviewer recommendation algorithm based on a network diffusion process on a scholar-paper multilayer network, with no requirement for textual information. The network incorporates the relationship of scholar-paper pairs, the collaboration among scholars, and the bibliographic coupling among papers. Experimental results show that our proposed algorithm outperforms other state-of-the-art recommendation methods that use graph random walk and matrix factorization and methods that use machine learning and natural language processing, with improvements of over 7.62% in recall, 5.66% in hit rate, and 47.53% in ranking score. Our work sheds light on the effectiveness of multilayer network diffusion-based methods in the reviewer recommendation problem, which will help to facilitate the peer-review process and promote information retrieval research in other practical scenes. 参考文献 | 相关文章 | 计量指标

Select

Speed limit effect during lane change in a two-lane lattice model under V2X environment Can Jin(金灿), Guang-Han Peng(彭光含), and Fang-Yan Nie(聂方彦) 2024 (3):  38902-038902.  doi: 10.1088/1674-1056/ad0bf6 摘要 ( 118 )   HTML ( 2 )   PDF(647KB) ( 137 )   Speed limit measures are ubiquitous due to the complexity of the road environment, which can be supplied with the help of vehicle to everything (V2X) communication technology. Therefore, the influence of speed limit on traffic system will be investigated to construct a two-lane lattice model accounting for the speed limit effect during the lane change process under V2X environment. Accordingly, the stability condition and the mKdV equation are closely associated with the speed limit effect through theory analysis. Moreover, the evolution of density and hysteresis loop is simulated to demonstrate the positive role of the speed limit effect on traffic stability in the cases of strong reaction intensity and high limited speed. 参考文献 | 相关文章 | 计量指标