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1.
The transition rate and stochastic resonance (SR) of a Brownian particle moving in a confined system under the presence of entropic barriers are investigated when the system is driven by non-Gaussian noise. The explicit expressions of the transition rate and the spectral power amplification (SPA) are obtained, respectively. The effects of the parameter q indicating the departure from the Gaussian noise and the correlation timeτ of the non-Gaussian noise on the transition rate and the SPA are discussed. Research results show that: (i) The transition rate as a function of the noise strength exhibits a maximum. This maximum for transition rate identifies the phenomenon of entropic resonant activation (ERA), the parameter q and the noise correlation timeτ weaken the ERA of the system; (ii) The curves of SPA appear a transition from one peak to double-peak, and then to one peak again as the noise correlation timeτ of non-Gaussian noise increases. 相似文献
2.
3.
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 相似文献
4.
We study the effect of time delay in the FitzHugh-Nagumo neural model with correlations between multiplicative and additive noise terms. Based on the corresponding Fokker-Planck equation, the explicit expressions of the stationary probability distribution function (SPDF), the mean first passage time (MFPT) and the signal-to-noise ratio (SNR) are obtained, respectively. Research results show that: (i) the system undergoes a succession of two phase transitions (i.e., the reentrance phenomenon) as the noise correlation parameter is increased and a (single) phase transition as the time delay is increased. (ii) The MFPT as a function of the multiplicative noise intensity exhibits a maximum. This maximum for MFPT identifies the noise enhanced stability (NES) effect, the noise correlation parameter intensifies the NES effect while the time delay, and the additive noise intensity weakens it. (iii) The existence of a maximum in the SNR as a function of the multiplicative noise intensity is the identifying characteristic of the stochastic resonance (SR) phenomenon, the noise correlation parameter enhances the SR while the time delay, and the additive noise intensity weaken it. 相似文献
5.
In this paper, we investigate a mathematical model for describing the growth of tumor cell under immune response, which is
driven by cross-correlation between multiplicative and additive colored noises as well as the nonzero cross-correlation in
between. The expression of the mean first-passage time (MFPT) is obtained by virtue of the steepest-descent approximation.
It is found: (i) When the noises are negatively cross-correlated (λ<0), then the escape is faster than in the case with no correlation (λ=0); when the noises are positively cross-correlated (λ>0), then the escape is slower than in the case with no correlation. Moreover, in the case of positive cross-correlation,
the escape time has a maximum for a certain intensity of one of the noises, i.e., the maximum for MFPT identifies the noise
enhanced stability of the cancer state. (ii) The effect of the cross-correlation time τ
3 on the MFPT is completely opposite for λ>0 and λ<0. (iii) The self-correlation times τ
1 and τ
2 of colored noises can enhance stability of the cancer state, while the immune rate β can reduce it. 相似文献
6.
Lu-Chun Du 《Physics letters. A》2008,372(34):5529-5533
The normalized correlation function C(s) of an optical bistable system driven by cross-correlated noises is investigated. Based on the numerical computation and simulation results, it is found that: (1) The intensity of multiplicative noise D and the intensity of additive noise Q play opposite roles on C(s), i.e., D enhances the rate of fluctuation decay of transmitted light intensity and Q slows down the rate of fluctuation decay of the transmitted light intensity; (2) The strength of correlations between the multiplicative and additive noises λ slows down the rate of decay of intensity fluctuation; (3) For the case of positive correlated noises (λ>0), the increasing cooperativity parameter C slows down the rate of decay of intensity fluctuation firstly and then enhances it; (4) For the case of negative correlated noises (λ<0), the increasing C almost does not affect the rate of decay of intensity fluctuation firstly and then enhances it. 相似文献
7.
Controlling the noise enhanced stability effect via noise recycling in a metastable system 总被引:1,自引:0,他引:1
Z. L. Jia D. C. Mei 《The European Physical Journal B - Condensed Matter and Complex Systems》2012,85(4):139
We analyze the role of the delay time τ
d
and the fraction ε of recycled noise on the enhancement of the mean first-passage time (MFPT) in a metastable system with recycled noise, generated
by the superposition of a primary Gaussian noise source with a second component of constant delay. The results indicate that
MFPT as a function of the noise intensity D shows either a non-monotonic behavior with a maximum or a divergent behavior, which is the identifying characteristic of
the noise enhanced stability (NES) phenomenon. The increasing of τ
d
or ε strengthens the NES effect for ε > 0. However, for ε < 0, there is a critical value of τ
d
, below which we observe an increase of MFPT whose maximum goes to infinity, and above which the divergent behavior tends
to disappear and MFPT versus D shows a transition from one peak to two peaks and eventually one peak as τ
d
or |ε| increases. Moreover, we also discuss the effect of different initial conditions. These observations illustrate that the
noise recycling may be used as an effective scheme for controlling the NES effect. 相似文献
8.
The stochastic resonance (SR) phenomenon induced by a multiplicative periodic signal in a logistic growth model with correlated
noises is studied by using the theory of signal-to-noise ratio (SNR) in the adiabatic limit. The expressions of the SNR are obtained. The effects of multiplicative noise intensity α and additive noise intensity D, and correlated intensity λ on the SNR are discussed respectively. It is found that the existence of a maximum in the SNR is the identifying characteristic of the SR phenomena. In comparison with the SR induced by additive periodic signal, some
new features are found: (1) When SNR as a function of λ for fixed ratio of α and D, the varying of α can induce a stochastic multi-resonance, and can induce a re-entrant transition of the peaks in SNR vs λ; (2) There exhibits a doubly critical phenomenon for SNR vs D and λ, i.e., the increasing of D (or λ) can induce the critical phenomenon for SNR with respect to λ (or D); (3) The doubly stochastic resonance effect appears when α and D are simultaneously varying in SNR, i.e., the increment of one noise intensity can help the SR on another noise intensity come forth.
相似文献
9.
C.W. Xie D.C. Mei L. Cao D.J. Wu 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(1):83-86
The relative escape rate (RER) for Brownian particles in an asymmetric bistable sawtooth potential driven by cross correlations
between multiplicative white noise and additive white noise is studied. A new expression of the mean first-passage time is
derived under the condition of piecewise linear potentials and discontinuous diffusion function. Based on the results of RER
numerically calculated, it is found that (i) under positively correlated noises action (i.e. λ > 0, and λ is the correlation strength), the escape rate exhibits the suppression platform as the intensity of multiplicative
noise varies. The effect of suppression becomes more pronounced with the growth of height of the deterministic potential barrier
for transition, and with the increase of λ. However, for the case of uncorrelated noises (λ = 0) and of negatively correlated
noises (λ < 0), the suppression platform disappears. (ii) The positive correlation between noises amplifies the change of
the escape rate with the height of barrier for transition, while the negative correlation between noises suppresses this change.
Received 20 November 2002 / Received in final form 19 October 2003 Published online 23 May 2003
RID="a"
ID="a"e-mail: kmdcmei@public.km.yn.cn 相似文献
10.
LI Dong-Xi XU Wei GUO Yong-Feng WANG Liang 《理论物理通讯》2008,49(3):689-695
The mean first-passage time (MFPT) of an asymmetric bistable system between multiplicative non-Gaussian noise and additive Gaussian white noise with nonzero cross-correlation time is investigated. Firstly, the non-Markov process is reduced to the Markov process through a path-integral approach; Secondly, the approximate Fokker Planck equation is obtained by applying the unified colored noise approximation and the.Novikov Theorem. The steady-state probability distribution (SPD) is also obtained. The basal functional analysis and simplification are employed to obtain the approximate expressions of MFPT T^±. The effects of the asymmetry parameter β, the non-Gaussian parameter (measures deviation from Gaussian character) r, the noise correlation times τ and τ2, the coupling coefficient A, the intensities D and a of noise on the MFPT are discussed. It is found that the asymmetry parameter β, the non-Gaussian parameter r and the coupling coefficient A can induce phase transition. Moreover, the main findings are that the effect of self-existent parameters (D, α, and τ) of noise and cross-correlation parameters (A, 7-2) between noises on MFPT T^± is different. 相似文献
11.
研究了由关联乘性色噪声及加性白噪声驱动的非对称双稳系统中势阱的非对称性及噪声对系统两个方向平均首次穿越时间的影响. 首先利用一致有色噪声近似推导了系统的稳态概率密度的表达式,根据最速下降法推导了平均首次穿越时间的表达式. 数值结果表明:势阱的非对称性对两个方向的平均首次穿越时间的影响是不同的;由于噪声的关联性,即使对于关联乘性色噪声及加性白噪声驱动的对称双稳系统,两个方向的平均首次穿越时间也不再相等;在lnT+-r和lnT-关键词:
平均首次穿越时间
非对称双稳系统
乘性色噪声
加性白噪声 相似文献
12.
We study the mean first passage time (MFPT) over the fluctuatingpotential barrier for a stochastic model of motor proteins in the case of environmental perturbation proposed by J.H. LI et al. [Phys. Rev. E57 (1998) 39171. The MFPT is derived for a particle over the fluctuating potential barrier. It is shown that (i) there is resonant activation for the MFPT as a function of the flipping rate of the fluctuating potential barrier; (ii) the additive and multiplicative noises can weaken the resonant activation, but the correlations between them enhance the resonant activation; (iii) the susceptibility of the resonant activation to the multiplicative noise is far larger than that to the additive noise. 相似文献
13.
研究了受色高斯噪声驱动的肿瘤细胞增长系统的瞬态态性质(平均首通时间T). 据Novikov定理和Fox近似方法得到相应的Fokker-Planck方程,使用最快下降法得到了肿瘤细胞增长系统的平均首通时间的解析表达式.经过数值计算,结果表明:肿瘤增长系统的T在正关联(0<λ<1, λ为关联噪声强度)和负关联(-1<λ<0)呈现出不同的特性. 正关联时,噪声强度和对应的关联时间在态转化过程中起着相反的作用;然而,负关联时,肿瘤增长系统的关键词:
色噪声
肿瘤细胞增长系统
平均首通时间 相似文献
14.
15.
Considering the time-delayed feedback and environmental perturbations in spin-crossover system, we construct a stochastic delayed differential equation to study the state transitions from the low spin (LS) state to the high spin (HS) state in spin-crossover solids. It is shown that the delayed feedback and noise can induce optical bistability and state transitions. The mean first-passage time (MFPT) of the transition from the LS state to the HS state as the function of the noise intensity exhibits a maximum, and the noise-enhanced stability is observed. However the MFPT decreases with increase of the delayed feedback intensity, thus the delayed feedback accelerates the conversion from the LS state to the HS state. 相似文献
16.
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. 相似文献
17.
Bao-quan Ai Hua Zheng Xue-rong Zhang Ning-xing Wang Liang-gang Liu 《International Journal of Theoretical Physics》2006,45(11):2143-2149
The transient properties of a bistable system with the stochastic potentials are investigated. The explicit expressions of the mean first-passage time (MFPT) are obtained by using a steepest-descent approximation. The results show that the MFPT of the system increases with the amplitude Δ of the stochastic potential, decreases with the noise intensity D and the correlation length l. The stochastic potential makes against the particle moving towards the destination. 相似文献
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19.
研究了乘性色噪声和加性白噪声驱动的光学双稳系统中噪声对系统两个方向平均首通时间T+(xs1→xs2)和T-(xs2→xs1)的影响(平均首通时间是指从一稳态出发越过势垒到另一稳态所用时间的平均值).通过Novikov定理和Fox近似方法得到相应的Fokker-Planck方程,利用最速下降法得到T+(xs1→xs2)和T-(xs2→xs1)的表达式.研究发现:乘性噪声强度Q和加性噪声强度D对T+(xs1→xs2)的影响相同,对T-(xs2→xs1)的影响不同;T+(xs1→xs2)随乘性色噪声自关联时间τ的增大而增大,但随噪声间的交叉关联强度λ的增大而减小;T-(xs2→xs1)随τ的增大而减小,随λ的增大而增大.
关键词:
平均首通时间
光学双稳系统
乘性色噪声
加性白噪声 相似文献
20.
Effects of signal modulation and coloured cross-correlation of coloured noises on the diffusion of a harmonic oscillator
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The diffusion in a harmonic oscillator driven by coloured noises
$\xi(t)$ and $\eta(t)$ with coloured cross-correlation in which
one of the noises is modulated by a biased periodic signal is
investigated. The exact expression of diffusion coefficient d as a
function of noise parameter, signal parameter, and oscillator
frequency is derived. The findings in this paper are as follows. 1)
The curves of d versus noise intensity D and d versus noises
cross-correlation time $\tau_3$ exist as two different phases. The
transition between the two phases arises from the change of the
cross-correlation coefficient $\lambda$ of the two
Ornstein--Uhlenbeck (O-U) noises. 2) Changing the value of $\tau_3$, the curves of d versus Q, the intensity of colored noise
that is modulated by the signal, can transform from a phase having a
minimum to a monotonic phase. 3) Changing the value of signal
amplitude A, d versus Q curves can transform from a phase
having a minimum to a monotonic phase. The above-mentioned results
demonstrate that a like noise-induced transition appears in the
model. 相似文献