Flux for a System with Infinite Globally Coupled Oscillators Driven by Temporal-Spatial Noises

The transport of a spatially periodic system with infinite globally coupled oscillators driven by temporalspatial noises is investigated. The probability current shows that the correlation of the multiplicative noises with the space, the spatial asymmetry, and the coupling among the different oscillators are ingredients for the transport of particles. It is a new phenomenon that the correlation of the multiplicative noises with the space can induce the nonzero flux.     

Transport for Stochastic System with Infinite Locally Coupled Oscillators

We consider the transport of particles for spatially periodic system with infinite locally coupled oscillators dirven by additive and multiplicative noises.A formula of the probability current derived by us shows that the coupling among the infinite oscillators is an ingredinent for transport.This coupling of the oscillators can induce transport of particles in the absence of the correlation of the additive and multiplicative noises,even without the multiplicative noise.     

Transport for Stochastic System with Infinite Locally Coupled Oscillators

We consider the transport of particles for spatially periodic system with infinite locally coupled oscillatorsdriven by additive and multiplicative noises. A formula of the probability current derived by us shows that the couplingamong the infinite oscillators is an ingredient for transport. This coupling of the oscillators can induce transport ofparticles in the absence of the correlation of the additive and multiplicative noises, even without the multiplicative noise.     

Flux in the Case of Gaussian White Noises

The transport of a spatially periodic system driven by additive and multiplicative Gaussian white noises (between which there is a correlation function) is investigated. The probability current (flux) shows .that the correlation function between the additive and multiplicative noises, and the spatial asymmetry are ingredients for the flux of particles. It is a new phenomenon that the correlation function between the additive and multiplicative noises can cause transport.     

Correlated effects of noise on symmetry of an asymmetric bistable system

The effects of correlation between additive and multiplicative noises on the symmetry of an asymmetric bistable system are investigated. The steady-state probability distribution function of the system was calculated by using analytical and numerical methods. Results indicate that i) for the case of positive correlation between noises, as the correlation strength between additive and multiplicative noises, λ, increases, the symmetry of the system is restored; ii) for the case of negative correlation between noises, as the absolute value of λ increases, the symmetry of the system is destroyed; and iii) the analytic prediction agrees well with the stochastic simulation result.     

噪音关联对单模激光光强定态几率分布的影响

从理论上对加性白噪音和乘性色噪音之间存在关联作用的单模激光立方模型进行了分析.通过数值计算得到;噪音关联时间和噪音关联强度参量对光强定态几率分布曲线有很大影响;特别地,当两噪音之间存在完全负关联时,光强被锁定在某一固定值处.     

色交叉关联噪声作用下集合种群的稳定性和平均灭绝时间

在Levins模型的基础上研究了色交叉关联噪声对集合种群稳定性的影响, 应用Fokker-Plank方程得到了系统的稳态概率密度函数, 运用最快下降法得到了平均灭绝时间的解析式. 结果表明: 两噪声色关联时, 加性噪声强度和乘性噪声强度均弱化集合种群的稳定性; 噪声关联强度强化集合种群的稳定性. 两噪声之间负关联时, 平均灭绝时间是加性噪声强度和乘性噪声强度的减函数, 是噪声关联时间的增函数; 两噪声之间正关联时, 平均灭绝时间是加性噪声强度和噪声关联时间乘性噪声强度的减函数, 是乘性噪声强度的非单调函数. 关键词： 集合种群 色交叉关联噪声 稳定性 平均灭绝时间     

噪声相互关联时间对Logistic系统亚稳态稳定性的影响

研究了噪声交叉关联时间对Logistic 系统亚稳态稳定性的影响.利用最陡下降法导出了系统亚稳态到稳态的平均第一通过时间的表达式. 数值计算结果表明:内噪声、外噪声、 内外噪声的相互关联时间削弱了亚稳态的稳定性,而内外噪声的关联增加了亚稳态的稳定性.     

色关联的色噪声驱动的分段非线性模型的平均首次穿越时间

研究了色关联的乘性高斯色噪声和加性高斯色噪声驱动的分段非线性系统中, 噪声强度和相关时间对平均首次穿越时间的影响. 利用一致有色噪声近似方法和最速下降方法, 推导出系统平均首次穿越时间的表达式. 研究结果表明: 系统的平均首次穿越时间随着乘性噪声的增加会出现单峰结构, 即“共振”现象, 峰值会随着加性噪声强度和噪声之间关联强度的增加而减小. 而平均首次穿越时间作为加性噪声的函数呈单调曲线, 说明乘性噪声和加性噪声对平均首次穿越时间的影响不同. 此外, 乘性和加性噪声关联时间以及互关联时间在正关联时和负关联时 对系统平均首次穿越时间的影响是不同的. 关键词： 色噪声 分段非线性系统 平均首次穿越时间     

色关联的乘性和加性色噪声激励下分段非线性模型的随机共振

研究了色关联的乘性和加性高斯色噪声与外周期信号共同激励下,分段非线性系统的随机共振.利用一致有色噪声近似和两态模型理论,推导出系统稳态概率密度和信噪比的解析表达式,分析了色噪声和周期信号对随机共振的影响,发现系统中存在传统的随机共振和真实的随机共振现象.同时,系统的信噪比曲线的峰值随着噪声互关联系数和互关联时间的增加而减小.     

Delay-induced state transition and resonance in periodically driven tumor model with immune surveillance

The phenomenon of stochastic resonance (SR) in a tumor growth model under the presence of immune surveillance is investigated. Time delay and cross-correlation between multiplicative and additive noises are considered in the system. The signal-to-noise ratio (SNR) is calculated when periodic signal is introduced multiplicatively. Our results show that: (i) the time delay can accelerate the transition from the state of stable tumor to that of extinction, however the correlation between two noises can accelerate the transition from the state of extinction to that of stable tumor; (ii) the time delay and correlation between two noises can lead to a transition between SR and double SR in the curve of SNR as a function of additive noise intensity, however for the curve of SNR as a function of multiplicative noise intensity, the time delay can cause the SR phenomenon to disappear, and the cross-correlation between two noises can lead to a transition from SR to stochastic reverse-resonance. Finally, we compare the SR phenomenon for the multiplicative periodic signal with that for additive periodic signal in the tumor growth model with immune surveillance.     

乘性噪音和加性噪音效应对脉孢菌生物钟体系内信号随机共振的增强

利用有和无外信号作用的脉孢菌生物钟体系,研究了与加性噪音相关或不相关的乘性噪音对加性噪音诱导出的内信号随机共振的影响作用.结果表明：无外信号的情况下,不论加性和乘性噪音相关与否,当乘性噪音强度小于临界值时,乘性噪音的加入使加性噪音诱导产生的内随机共振强度得到增强;当大于其临界值时,加性噪音的随机共振强度却得不到进一步增强,这说明脉孢菌生物钟体系能抵抗外噪音的干扰而维持自身的生理节奏.当加入外信号时,对于乘性和加性噪音不相关的情况,发现存在最佳频率（0.003 Hz）的外信号能使加性噪音诱导出的内信号随机共 关键词： 噪音 脉孢菌生物钟体系 内信号随机共振     

Effect of correlation between additive and multiplicative noises on the activation from a double well

We study the thermal activation problem of a bistable system driven by correlated additive and multiplicative noises by means of numerical simulation. We find that in the colored noise case the suppression effect of the positive correlation decreases and finally is released as the autocorrelation time tau of the colored noise grows. When tau is large enough, negative correlation becomes more suppressive than the positive correlation. Such phenomena are ascribed to the collaboration between noises as well as the memory effect of the multiplicative colored noise.     

关联噪声驱动的非对称双稳系统的随机共振

运用统一色噪声近似理论和两态模型理论,研究了周期矩形信号和关联的乘性色噪声和加性白噪声驱动的非对称双稳系统的随机共振现象,得到了适合信号任意幅值的信噪比表达式.信噪比是乘性噪声强度、加性噪声强度、乘性噪声自关联时间、噪声耦合强度的非单调函数,所以该双稳系统中出现了随机共振.同时,调节加性噪声强度比调节乘性噪声强度更容易产生随机共振.势阱静态非对称性和噪声之间的耦合强度对信噪比的影响是不同的. 关键词： 非对称双稳系统 随机共振 信噪比 周期矩形信号     

Effects of cross-correlated noises on the relaxation time of the bistable system

The stationary correlation function and the associated relaxation time for a general system driven by cross-correlated white noises are derived, by virtue of a Stratonovich-like ansatz. The effects of correlated noises on the relaxation time of a bistable kinetic model coupled to an additive and a multiplicative white noises are studied. It is proved that for small fluctuations the relaxation time T_c as a function of λ (the correlated intensity between noises) exhibits very different behaviours for αD (α and D, respectively, stand for the ntensities of additive and multiplicative noises). When α>D, T_c increases with increasing λ. But when α相似文献   

Correlation function of an optical bistable system with cross-correlated additive white noise and multiplicative colored noise

Considering an optical bistable system with cross-correlated additive white noise and multiplicative colored noise, we study the effects of correlation between the noises on the correlation function C（s） using the unified colored noise approximation and the Stratonovich deeoupling ansatz formalism. The effects of the self-correlation time τ of the multiplicative colored noise and the correlation intensity λ between the two noises are studied with numerical calculation. It is found that C（s） increases with the increase of the self-correlation timeτ, but decreases with the increase of the correlation intensity λ. At large value of τ, there is almost no change for C（s） when τ changes.     

Correlated Noises of the Stochastic Processes

The combined effect of several noises has been proposed recently. It has displayed that the presence of the correlation between noises can change the properties of the stochastic processes. In this paper, a general effective Fokker-Planck equation (FPE) with correlated noises is derived. The stationary distributions and the moments of two kinetic models under two correlated noise sources are obtained. The effects of the interference of additive and multiplicative noises are analyzed.     

Noise-induced transport in a periodic system driven by Gaussian white noises with intensive cross-correlation

An analytical investigation of overdamped Brownian particle in a periodic system driven by intensive cross-correlated Gaussian white noises is presented. The center idea of this Letter is to construct an exact soluble model to exhibit the possible new effect of the cross-correlated Gaussian white noises on the noise-induced transport. The model clearly shows the following new aspects of this transport: (1) There is one and only extreme in the J–Q curve for the case of weakly cross-correlated noises here J and Q denote the current and multiplicative noise intensity, respectively. (2) When the two noises are intensive correlative, the J–Q curve behaves three extrema. (3) The J–Q curve exhibits a giant suppression plateau between the two maxima as the noise correlation coefficient is increased further. (4) The direction of the current is controlled by two parameters.     

Dynamic Properties for a Single-mode Laser with δ-Correlation form Noises

By means of linear approximation method, we derive and discuss the intensity correlation function, correlation time, and power spectrum for the gain-noise model of a single-mode laser driven by multiplicative colored and additive white noises with δ-correlation form. It is found that: (1) The negative correlation between noises makes the evolution of the intensity correlation function with the time showing two forms: the monotonic attenuation and presence of the positive maximum value; while corresponding to all points on the critical line of the parameter graph for illustrating two forms, the evolution curve of the intensity correlation function with the time exhibits the initial plateau. (2) Due to the existence of the negative correlation between noises, an obvious character for the change of the intensity correlation time with the pump noise strength is that it has a crest value, and the relaxation process of the laser is slower-down than that of two independent noises. (3) The power spectrum exhibits only one peak.     

Effect of Correlated Noises in a Genetic Model

The Stratonovich stochastic differential equation is used to analyze genotype selection in the presence ot correlatecl Gaussian white noises. We study the steady state properties of the genotype selection and discuss the effects of the correlated noises. It is found that the degree of correlation of the noises can be used to select one type of genes from another type of mixing genes. The strong selection of genes caused by a large value of multiplicative noise intensity can be weakened by the intensive negative correlation.