记忆核对关联噪声驱动的双稳系统驰豫时间的影响  

Effects of memory kernel on relaxation time of a bistable system driven by cross-correlated noises

作　　者：贾正林[1] 

机构地区：[1]玉溪师范学院物理与教育技术系 云南玉溪653100

出　　处：《玉溪师范学院学报》2008年第4期32-39,共8页Journal of Yuxi Normal University

摘　　要：以关联噪声驱动的双稳系统为例,推导了系统驰豫时间的二阶近似表达式,研究了记忆核对系统驰豫时间的影响.结果表明,记忆核能使系统的驰豫时间变大,即减缓系统稳态涨落的衰减;当乘性和加性噪声间无关联时,记忆核对驰豫时间的影响随R(乘性噪声强度D和加性噪声强度α之比)的增大而增强,R一定时,它随D的增大而减弱;当乘性和加性噪声间存在相互关联时,关联强度λ较大和关联时间τ较小时,记忆核对驰豫时间的影响较小,但较小的λ和较大的τ使记忆核的影响变得十分显著.噪声间有关联和无关联两种情况下,均存在一个临界比值R=1,当R<1时记忆核对驰时间的影响不明显,而当R 1时其影响较为显著.The effects of the memory kernel on the relaxation time of a bistable system driven by the cross-correlated noises are investigated by means of the projection-operator method.The second-order approximate expression of the relaxation time of the system is derived.By numerical computations,it is found that:(1)The memory kernel does not influence the qualitative behavior of the relaxation time,which changes with the noise parameters varying.However,the value of relaxation time increases due to the memory kernel effect,i.e.,the memory kernel slows down the fluctuation decay of the dynamical variable;(2) When there is no cross-correlation between the multiplicative noise(D) and additive noise(α),the difference in the relaxation time(Δ) between the first-order approximation and the second-order approximation increases with R(R=D/α) increasing and decreases as D increases;(3) For the case of λ≠0(λ denotes the cross-correlation strength between the noise terms),when R is small,Δ increases with R increasing.The λ and τ play an opposite role on the Δ. However,the large λ and small τ can suppress the memory kernel effect for the case of large R;(4) There is a critical ratio R=1,the effect of the memory kernel on the relaxation time for the case of R·1 is more pronounced than that of R<1.

关 键 词：记忆核 驰豫时间 双稳系统 交叉关联噪声 

分 类 号：R73-33[医药卫生—肿瘤]