Content of SPECIAL TOPIC — Quantum computing and quantum sensing in our journal

Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For selected: Download citations EndNote Ris BibTeX Toggle thumbnails Select M2CS: A microwave measurement and control system for large-scale superconducting quantum processors Jiawei Zhang(张家蔚), Xuandong Sun(孙炫东), Zechen Guo(郭泽臣), Yuefeng Yuan(袁跃峰), Yubin Zhang(张玉斌), Ji Chu(储继), Wenhui Huang(黄文辉), Yongqi Liang(梁咏棋), Jiawei Qiu(邱嘉威), Daxiong Sun(孙大雄), Ziyu Tao(陶子予), Jiajian Zhang(张家健), Weijie Guo(郭伟杰), Ji Jiang(蒋骥), Xiayu Linpeng(林彭夏雨), Yang Liu(刘阳), Wenhui Ren(任文慧), Jingjing Niu(牛晶晶), Youpeng Zhong(钟有鹏), and Dapeng Yu(俞大鹏) Chin. Phys. B, 2024, 33 (12): 120309.   DOI: 10.1088/1674-1056/ad8a49 Abstract （516）   HTML （0）    PDF （3748KB）（168）       Knowledge map    As superconducting quantum computing continues to advance at an unprecedented pace, there is a compelling demand for the innovation of specialized electronic instruments that act as crucial conduits between quantum processors and host computers. Here, we introduce a microwave measurement and control system (M$^{2}$CS) dedicated to large-scale superconducting quantum processors. M$^{2}$CS features a compact modular design that balances overall performance, scalability and flexibility. Electronic tests of M$^{2}$CS show key metrics comparable to commercial instruments. Benchmark tests on transmon superconducting qubits further show qubit coherence and gate fidelities comparable to state-of-the-art results, confirming M$^{2}$CS's capability to meet the stringent requirements of quantum experiments running on intermediate-scale quantum processors. The compact and scalable nature of our design holds the potential to support over 1000 qubits after upgrade in stability and integration. The M$^{2}$CS architecture may also be adopted to a wider range of scenarios, including other quantum computing platforms such as trapped ions and silicon quantum dots, as well as more traditional applications like microwave kinetic inductance detectors and phased array radar systems. Select A family of quantum von Neumann architecture Dong-Sheng Wang(王东升) Chin. Phys. B, 2024, 33 (8): 080302.   DOI: 10.1088/1674-1056/ad50be Abstract （393）   HTML （2）    PDF （567KB）（356）       Knowledge map    We develop universal quantum computing models that form a family of quantum von Neumann architectures, with modular units of memory, control, CPU, and internet, besides input and output. This family contains three generations characterized by dynamical quantum resource theory, and it also circumvents no-go theorems on quantum programming and control. Besides universality, such a family satisfies other desirable engineering requirements on system and algorithm design, such as modularity and programmability, hence serves as a unique approach to building universal quantum computers. Select Automatic architecture design for distributed quantum computing Ting-Yu Luo(骆挺宇), Yu-Zhen Zheng(郑宇真), Xiang Fu(付祥), and Yu-Xin Deng(邓玉欣) Chin. Phys. B, 2024, 33 (12): 120302.   DOI: 10.1088/1674-1056/ad7c2c Abstract （390）   HTML （0）    PDF （1523KB）（340）       Knowledge map    In distributed quantum computing (DQC), quantum hardware design mainly focuses on providing as many as possible high-quality inter-chip connections. Meanwhile, quantum software tries its best to reduce the required number of remote quantum gates between chips. However, this “hardware first, software follows” methodology may not fully exploit the potential of DQC. Inspired by classical software-hardware co-design, this paper explores the design space of application-specific DQC architectures. More specifically, we propose AutoArch, an automated quantum chip network (QCN) structure design tool. With qubits grouping followed by a customized QCN design, AutoArch can generate a near-optimal DQC architecture suitable for target quantum algorithms. Experimental results show that the DQC architecture generated by AutoArch can outperform other general QCN architectures when executing target quantum algorithms. Select A nanosecond level current pulse capture taper optical fiber probe based on micron level nitrogen-vacancy color center diamond Yuchen Bian(卞雨辰), Yangfan Mao(毛扬帆), Honghao Chen(陈鸿浩), Shiyu Ge(葛仕宇), Wentao Lu(卢文韬), Chengkun Wang(王成坤), Sihan An(安思瀚), and Guanxiang Du(杜关祥) Chin. Phys. B, 2024, 33 (12): 120301.   DOI: 10.1088/1674-1056/ad78da Abstract （389）   HTML （1）    PDF （1970KB）（273）       Knowledge map    This work demonstrates a micron-sized nanosecond current pulse probe using a quantum diamond magnetometer. A micron-sized diamond crystal affixed to a fiber tip is integrated on the end of a conical waveguide. We demonstrate realtime visualization of a single 100 nanosecond pulse and discrimination of two pulse trains of different frequencies with a coplanar waveguide and a home-made PCB circuit. This technique finds promising applications in the display of electronic stream and can be used as a pulse discriminator to simultaneously receive and demodulate multiple pulse frequencies. This method of detecting pulse current is expected to provide further detailed analysis of the internal working state of the chip. Select Enhanced sensing of anharmonicities in a gain-based anti-PT symmetric system Ya-Wei Zeng(曾亚伟), Tian-Le Yang(杨天乐), Qi-Yin Lin(林琪茵), and Wan-Jun Su(苏万钧) Chin. Phys. B, 2024, 33 (12): 124201.   DOI: 10.1088/1674-1056/ad8a4d Abstract （382）   HTML （0）    PDF （1169KB）（289）       Knowledge map    We study the enhanced sensing of weak anharmonicities in a gain-based cavity-magnon-waveguide coupled system. By dissipatively coupling the two subsystems through a mediating waveguide, the Hamiltonian of the system is tailored to be anti-parity-time symmetric. Unique to the gain condition, the eigenvalues exhibit two singularities with linewidth suppression, distinguishing them from those of gain-free systems. Under the gain condition, a counter-intuitive bistable signature emerges even at low drive powers. As the effective gain approaches a certain value, this bistability yields a significantly enhanced spin-current response of the magnon mode. Consequently, the sensitivity, quantified by an enhancement factor, is enhanced remarkably compared to the linewidth suppression scenario. Moreover, the high enhancement factor can be sustained over a broad gain-bandwidth and also stays large even when the coherent coupling becomes considerably strong. Based on the integrated cavity-magnon-waveguide systems, this scheme can be used for sensing different physical quantities related to the Kerr-type nonlinearity and has potential applications in high-precision measuring microwave-signal nonlinearities. Select Nonlinear time-reversal interferometry with arbitrary quadratic collective-spin interaction Zhiyao Hu(胡知遥), Qixian Li(李其贤), Xuanchen Zhang(张轩晨), He-Bin Zhang(张贺宾), Long-Gang Huang(黄龙刚), and Yong-Chun Liu(刘永椿) Chin. Phys. B, 2024, 33 (8): 080601.   DOI: 10.1088/1674-1056/ad4ff7 Abstract （370）   HTML （2）    PDF （10363KB）（219）       Knowledge map    Atomic nonlinear interferometry has wide applications in quantum metrology and quantum information science. Here we propose a nonlinear time-reversal interferometry scheme with high robustness and metrological gain based on the spin squeezing generated by arbitrary quadratic collective-spin interaction, which could be described by the Lipkin-Meshkov-Glick (LMG) model. We optimize the squeezing process, encoding process, and anti-squeezing process, finding that the two particular cases of the LMG model, one-axis twisting and two-axis twisting outperform in robustness and precision, respectively. Moreover, we propose a Floquet driving method to realize equivalent time reverse in the atomic system, which leads to high performance in precision, robustness, and operability. Our study sets a benchmark for achieving high precision and high robustness in atomic nonlinear interferometry. Select Nonlinear enhanced mass sensor based on optomechanical system Xin-Xin Man(满鑫鑫), Jing Sun(孙静), Wen-Zhao Zhang(张闻钊), Lijuan Luo(罗丽娟), and Guangri Jin(金光日) Chin. Phys. B, 2024, 33 (12): 120303.   DOI: 10.1088/1674-1056/ad84cf Abstract （363）   HTML （0）    PDF （1133KB）（284）       Knowledge map    A high-precision and tunable mass detection scheme based on a double-oscillator optomechanical system is proposed. By designating one of the oscillators as the detection port, tiny mass signals can be probed through the frequency shift of the output spectrum, utilizing the system's optomechanically induced transparency (OMIT) effect. By solving the output of the optical mode, we demonstrate that the system exhibits two OMIT windows due to the double-oscillator coupling, with one window being strongly dependent on the mass to be detected. Characterizing the spectrum around this window enables high magnification and precise detection of the input signal under nonlinear parameter conditions. Additionally, our scheme shows resilience to environmental temperature variations and drive strength perturbations. Select Vector magnetometry in zero bias magnetic field using nitrogen-vacancy ensembles Chunxing Li(李春兴), Fa-Zhan Shi(石发展), Jingwei Zhou(周经纬), and Peng-Fei Wang(王鹏飞) Chin. Phys. B, 2024, 33 (10): 100701.   DOI: 10.1088/1674-1056/ad73af Abstract （351）   HTML （1）    PDF （2756KB）（156）       Knowledge map    The application of the vector magnetometry based on nitrogen-vacancy (NV) ensembles has been widely investigated in multiple areas. It has the superiority of high sensitivity and high stability in ambient conditions with microscale spatial resolution. However, a bias magnetic field is necessary to fully separate the resonance lines of optically detected magnetic resonance (ODMR) spectrum of NV ensembles. This brings disturbances in samples being detected and limits the range of application. Here, we demonstrate a method of vector magnetometry in zero bias magnetic field using NV ensembles. By utilizing the anisotropy property of fluorescence excited from NV centers, we analyzed the ODMR spectrum of NV ensembles under various polarized angles of excitation laser in zero bias magnetic field with a quantitative numerical model and reconstructed the magnetic field vector. The minimum magnetic field modulus that can be resolved accurately is down to $\sim 0.64 $ G theoretically depending on the ODMR spectral line width (1.8 MHz), and $\sim 2 $ G experimentally due to noises in fluorescence signals and errors in calibration. By using $^{13}$C purified and low nitrogen concentration diamond combined with improving calibration of unknown parameters, the ODMR spectral line width can be further decreased below 0.5 MHz, corresponding to $\sim 0.18 $ G minimum resolvable magnetic field modulus. Select Exact quantum dynamics for two-level systems with time-dependent driving Zhi-Cheng He(贺郅程), Yi-Xuan Wu(吴奕璇), and Zheng-Yuan Xue(薛正远) Chin. Phys. B, 2024, 33 (12): 120310.   DOI: 10.1088/1674-1056/ad8a4c Abstract （341）   HTML （0）    PDF （1790KB）（649）       Knowledge map    It is well known that the time-dependent Schrrödinger equation can only be solved exactly in very rare cases, even for two-level quantum systems. Thus, finding the exact quantum dynamics under a time-dependent Hamiltonian is not only fundamentally important in quantum physics but also facilitates active quantum manipulations for quantum information processing. In this work, we present a method for generating nearly infinite analytically assisted solutions to the Schrödinger equation for a qubit under time-dependent driving. These analytically assisted solutions feature free parameters with only boundary restrictions, making them applicable in a variety of precise quantum manipulations. Due to the general form of the time-dependent Hamiltonian in our approach, it can be readily implemented in various experimental setups involving qubits. Consequently, our scheme offers new solutions to the Schrödinger equation, providing an alternative analytical framework for precise control over qubits. Select On-chip quantum NOON state sensing for temperature and humidity Weihong Luo(罗伟宏), Chao Wu(吴超), Yuxing Du(杜昱星), Chang Zhao(赵畅), Miaomiao Yu(余苗苗), Pingyu Zhu(朱枰谕), Kaikai Zhang(张凯凯), and Ping Xu(徐平) Chin. Phys. B, 2024, 33 (10): 100305.   DOI: 10.1088/1674-1056/ad72e2 Abstract （278）   HTML （1）    PDF （1792KB）（418）       Knowledge map    A maximal photon number entangled state, namely NOON state, can be adopted for sensing with a quantum enhanced precision. In this work, we designed silicon quantum photonic chips containing two types of Mach-Zehnder interferometers wherein the two-photon NOON state, sensing element for temperature or humidity, is generated. Compared with classical light or single photon case, two-photon NOON state sensing shows a solid enhancement in the sensing resolution and precision. As the first demonstration of on-chip quantum photonic sensing, it reveals the advantages of photonic chips for high integration density, small-size, stability for multiple-parameter sensing serviceability. A higher sensing precision is expected to beat the standard quantum limit with a higher photon number NOON state.