中国物理B ›› 2005, Vol. 14 ›› Issue (10): 2110-2116.doi: 10.1088/1009-1963/14/10/031

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Stochastic resonance and nonequilibrium dynamic phase transition of Ising spin system driven by a joint external field

邵元智, 钟伟荣, 林光明, 李坚灿   

  1. Institute of Condensed Matter, Department of Physics, Sun Yat-sen University, Guangzhou 510275, China
  • 收稿日期:2005-03-04 修回日期:2005-06-15 出版日期:2005-10-20 发布日期:2005-10-20
  • 基金资助:
    Project supported by the Natural Science Foundation of Guangdong Province, China (Grant No 031554).

Stochastic resonance and nonequilibrium dynamic phase transition of Ising spin system driven by a joint external field

Shao Yuan-Zhi (邵元智), Zhong Wei-Rong (钟伟荣), Lin Guang-Ming (林光明), Li Jian-Can (李坚灿)   

  1. Institute of Condensed Matter, Department of Physics, Sun Yat-sen University, Guangzhou 510275, China
  • Received:2005-03-04 Revised:2005-06-15 Online:2005-10-20 Published:2005-10-20
  • Supported by:
    Project supported by the Natural Science Foundation of Guangdong Province, China (Grant No 031554).

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摘要： The dynamic response and stochastic resonance of a kinetic Ising spin system (ISS) subject to the joint action of an external field of weak sinusoidal modulation and stochastic white-noise are studied by solving the mean-field equation of motion based on Glauber dynamics. The periodically driven stochastic ISS shows that the characteristic stochastic resonance as well as nonequilibrium dynamic phase transition (NDPT) occurs when the frequency \textit{$\omega $} and amplitude $h_{0}$ of driving field, the temperature $t$ of the system and noise intensity $D$ are all specifically in accordance with each other in quantity. There exist in the system two typical dynamic phases, referred to as dynamic disordered paramagnetic and ordered ferromagnetic phases respectively, corresponding to a zero- and a unit-dynamic order parameter. The NDPT boundary surface of the system which separates the dynamic paramagnetic phase from the dynamic ferromagnetic phase in the 3D parameter space of $h_{0}$-$t$-$D$ is also investigated. An interesting dynamical ferromagnetic phase with an intermediate order parameter of 0.66 is revealed for the first time in the ISS subject to the perturbation of a joint determinant and tochastic field. The intermediate order dynamical ferromagnetic phase is dynamically metastable in nature and owns a peculiar characteristic in its stability as well as the response to external driving field as compared with a fully order dynamic ferromagnetic phase.

Abstract: The dynamic response and stochastic resonance of a kinetic Ising spin system (ISS) subject to the joint action of an external field of weak sinusoidal modulation and stochastic white-noise are studied by solving the mean-field equation of motion based on Glauber dynamics. The periodically driven stochastic ISS shows that the characteristic stochastic resonance as well as nonequilibrium dynamic phase transition (NDPT) occurs when the frequency \textit{$\omega $} and amplitude $h_{0}$ of driving field, the temperature $t$ of the system and noise intensity $D$ are all specifically in accordance with each other in quantity. There exist in the system two typical dynamic phases, referred to as dynamic disordered paramagnetic and ordered ferromagnetic phases respectively, corresponding to a zero- and a unit-dynamic order parameter. The NDPT boundary surface of the system which separates the dynamic paramagnetic phase from the dynamic ferromagnetic phase in the 3D parameter space of $h_{0}$-$t$-$D$ is also investigated. An interesting dynamical ferromagnetic phase with an intermediate order parameter of 0.66 is revealed for the first time in the ISS subject to the perturbation of a joint determinant and tochastic field. The intermediate order dynamical ferromagnetic phase is dynamically metastable in nature and owns a peculiar characteristic in its stability as well as the response to external driving field as compared with a fully order dynamic ferromagnetic phase.

Key words: Ising spin system, stochastic resonance, dynamic phase transition, dynamical symmetry

中图分类号:  (Classical spin models)

  • 75.10.Hk
05.50.+q (Lattice theory and statistics) 05.40.Ca (Noise) 75.30.Kz (Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.))