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1.
Stochastic resonance in a gain--noise model of a single-mode laser driven by pump noise and quantum noise with cross-correlation between real and imaginary parts under direct signal modulation 下载免费PDF全文
Stochastic resonance (SR) is studied in a gain--noise model of a
single-mode laser driven by a coloured pump noise and a quantum noise
with cross-correlation between real and imaginary parts under a
direct signal modulation. By using a linear approximation method, we
find that the SR appears during the variation of signal-to-noise
ratio (SNR) separately with the pump noise self-correlation time
\tau , the noise correlation coefficient between the real part and
the imaginary part of the quantum noise \lambdaq , the
attenuation coefficient \gamma and the deterministic steady-state
intensity I_0 . In addition, it is found that the SR can be
characterized not only by the dependence of SNR on the noise
variables of \tau and \lambdaq, but also by the
dependence of SNR on the laser system variables of \gamma and I0. Thus our investigation extends the characteristic quantity of SR
proposed before. 相似文献
2.
Influences of noise correlation and time delay on stochastic resonance induced by multiplicative signal in a cancer growth system 下载免费PDF全文
This paper investigates the stochastic resonance (SR)
phenomenon induced by the multiplicative periodic signal in a cancer
growth system with the cross-correlated noises and time delay. To
describe the periodic change of the birth rate due to the periodic
treatment, a multiplicative periodic signal is added to the system.
Under the condition of small delay time, the analytical expression
of the signal-to-noise ratio R_{\rm SNR} is derived in the
adiabatic limit. By numerical calculation, the effects of the
cross-correlation strength \lambda and the delay time \tau on
R_{\rm SNR} are respectively discussed. The existence of a peak in
the curves of R_{\rm SNR} as a function of the noise intensities
indicates the occurrence of the SR phenomenon. It is found that
\lambda and \tau play opposite role on the SR phenomenon, i.e.,
the SR is suppressed by increasing \lambda whereas it is enhanced
with the increase of \tau, which is different from the case where
the periodic signal is additive. 相似文献
3.
Tao Yang Qinglin Han Chunhua Zeng Hua Wang Yunchang Fu Chun Zhang 《Central European Journal of Physics》2014,12(6):383-391
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. 相似文献
4.
CHENGQing-Hua CAOLi WANGJun WUDa-Jin 《理论物理通讯》2004,42(4):553-556
We present an analytic investigation of the signal-to-noise ratio (SNR) by studying a signal modulated model of a single-mode laser system driven by pump noise and quantum noise with correlated real and imaginary parts,and find there is a maximum in the curve of the dependence of SNR upon the cross-correlation coefficient λq between the real part and the imaginary part, i.e., stochastic resonance appears in the SNR vs. λq curve. Moreover, when the SNR is at the maximum, the cross-correlation coefficient λq = O, which is coincidentally at the minimum of the mean normalized intensity fluctuation. The influences on stochastic resonance by the intensities of the pump and the quantum noise, the amplitude of the modulation signal, and the net gain of the laser are also studied. Furthermore, in order to ensure that the results obtained in this paper is reliable, the valid range for the linear approximation method is discussed. 相似文献
5.
The phenomenon of stochastic resonance (SR) is found in a single-mode laser system driven by the colored pump noise with signal modulation and the quantum noise with cross-correlation between the real and imaginary parts. When the net gain a0 changes, it is found that, 1) the shape of the curve of the signal-tonoise ratio (SNR) versus the pump noise self-correlation time T exhibits a changing process of multiform SR, from single-peak SR to simultaneous existence of resonances and suppressions; 2) the curve of SNR versus signal frequency Ω experiences a complicated changing process from the monotonous descending to the simultaneous appearances of a maximum and a minimum, and finally to monotonous descending; 3)the curve of SNR versus cross-correlation coefficient between the real and imaginary parts of the quantum noise λq appears an acute single-peak SR. Therefore, the net gain a0 greatly influences the characteristic of SR of laser system. 相似文献
6.
Stochastic resonance in a bistable system with coloured correlation between additive and multiplicative noise 下载免费PDF全文
The phenomenon of stochastic resonance (SR) in a bistable nonlinear system with coupling between additive and multiplicative noises is investigated when the correlation between two noise terms is coloured. It is found that the signal-to-noise ratio (SNR) of the system is affected not only by the coupling strength λ between two noise terms, but also by the noise correlation time τ. The SNR is changed from a single peak, to two peaks with a dip, and then to a monotonically decreasing function with noise strength. The dependence of the SR on the initial conditions is entirely caused by the coupling strength λ between two noise terms. 相似文献
7.
8.
Simulation study of the two-time intensity correlation function of a two-mode laser system with both pump and quantum noises 下载免费PDF全文
This paper investigates the two-time intensity correlation
function of a two-mode ring laser system subjected to both pump
and quantum noises by stochastic simulation. It finds that the
decay rate of the intensity correlation function of one mode gets
faster with decreasing values of relevant parameters, i.e., the
coupling constant ξ, the cross-correlation coefficient λ
, the difference of the pump parameters Δa and the pump
parameter a1; however, its variations get complex in the other
mode when relevant parameters are changed. The investigating results
also show that the effects of the mode competition on intensity
correlation function are obvious. 相似文献
9.
This paper investigates a genotype selection model subjected to both a multiplicative coloured noise and an additive coloured noise with different correlation time τ1 and τ2 by means of the numerical technique. By directly simulating the Langevin Equation, the following results are obtained. (1) The multiplicative coloured noise dominates, however, the effect of the additive coloured noise is not neglected in the practical gene selection process. The selection rate μ decides that the selection is propitious to gene A haploid or gene B haploid. (2) The additive coloured noise intensity and the correlation time τ2 play opposite roles. It is noted that α and τ2 can not separate the single peak, while can make the peak disappear and ~-2 can make the peak be sharp. (3) The multiplicative coloured noise intensity D and the correlation time τ1 can induce phase transition, at the same time they play opposite roles and the reentrance phenomenon appears. In this case, it is easy to select one type haploid from the group with increasing D and decreasing τ1. 相似文献
10.
Stochastic resonance in a time-delayed asymmetric bistable system with mixed periodic signal 下载免费PDF全文
This paper studies the phenomenon of stochastic resonance
in an asymmetric bistable system with time-delayed feedback and
mixed periodic signal by using the theory of signal-to-noise ratio
in the adiabatic limit. A general approximate Fokker--Planck
equation and the expression of the signal-to-noise ratio are derived
through the small time delay approximation at both fundamental
harmonics and mixed harmonics. The effects of the additive noise
intensity $Q$, multiplicative noise intensity $D$, static asymmetry
$r$ and delay time $\tau$ on the signal-to-noise ratio are
discussed. It is found that the higher mixed harmonics and the
static asymmetry $r$ can restrain stochastic resonance, and the
delay time $\tau $ can enhance stochastic resonance. Moreover, the
longer the delay time $\tau $ is, the larger the additive noise
intensity $Q$ and the multiplicative noise intensity $D$ are, when
the stochastic resonance appears. 相似文献
11.
Stochastic resonance in a single-mode laser driven by quadratic pump noise and amplitude-modulated signal 总被引:1,自引:0,他引:1 下载免费PDF全文
This paper investigates the phenomenon of stochastic resonance in a
single-mode laser driven by quadratic pump noise and
amplitude-modulated signal. A new linear approximation approach is
advanced to calculate the signal-to-noise ratio. In the linear
approximation only the drift term is linearized, the multiplicative
noise term is unchangeable. It is found that there appears not only
the standard form of stochastic resonance but also the broad sense
of stochastic resonance, especially stochastic multiresonance
appears in the curve of signal-to-noise ratio as a function of
coupling strength λ between the real and imaginary parts of
the pump noise. 相似文献
12.
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14.
15.
计算了受信号调制的色泵噪声和实虚部间关联的量子噪声驱动的单模激光损失模型的输出光强信噪比.发现信噪比R随泵噪声自关联时间τ、调制信号频率Ω和量子噪声实虚部间关联系数λq的变化均存在随机共振,这种现象扩展了“信噪比R对噪声强度的变化曲线具有极大值”的典型随机共振. 若以Ω为参数,当Ω增加时,R随τ的关系曲线经历了从同时出现共振和抑制到单峰共振,最后到单调上升的变化,呈现多种形式的随机共振.若以τ为参数,当τ增加时,R随Ω的关系曲线经历了从单调上升到同时出现共振和抑制,最后又到单调下降的变化过程.R随λq的关
关键词:
噪声
信噪比
随机共振 相似文献
16.
Properties of field quantum entropy evolution in the Jaynes--Cummings model with initial squeezed coherent states field 下载免费PDF全文
The properties of the field quantum entropy evolution in a system of
a single-mode squeezed coherent state field interacting with a
two-level atom is studied by utilizing the complete quantum theory,
and we focus our attention on the discussion of the influences of
field squeezing parameter $\gamma $, atomic distribution angle
$\theta $ and coupling strength $g$ between the field and the atom
on the properties of the evolution of field quantum entropy. The
results obtained from numerical calculation indicate that the
amplitude of oscillation of field quantum entropy evolution
decreases with the increasing of squeezing parameter $\gamma $, and
that both atomic distribution angle $\theta $ and coupling strength
$g$ between the field and the atom can influence the periodicity of
field quantum entropy evolution. 相似文献
17.
ZHANG Liang-Ying CAO Li WU Da-Jin 《理论物理通讯》2008,49(5):1310-1314
A single-mode laser noise model driven by quadratic colored pump noise and amplitude modulation signal is proposed. The real and imaginary
parts of the pump noise are assumed to be cross-correlation. The effect of
cross-correlation of noise and amplitude modulation of signal on laser
statistical properties is studied by using the linearized approximation. The
analytic expression of signal-to-noise ratio (SNR) is calculated. It is
found that the phenomena of stochastic resonance (SR) respectively exist in the
curves of the SNR versus the noise cross-correlation coefficient λ
and the SNR versus the pump parameter a, as well as the SNR versus the
signal frequency
ω in our model. It is shown that there are three different typies of SR in the model: the conventional form of SR, the SR in the broad sense, and the bona fide SR. 相似文献
18.
Stochastic resonance driven by time-modulated correlated coloured noise sources in a single-mode laser 总被引:1,自引:0,他引:1 下载免费PDF全文
This paper investigates the phenomenon of stochastic resonance in a
single-mode laser driven by time-modulated correlated coloured noise
sources. The power spectrum and signal-to-noise ratio R of the
laser intensity are calculated by the linear approximation. The
effects caused by noise self-correlation time τ1, τ2
and cross-correlated time τ3 for stochastic resonance
are analysed in two ways: τ1, τ2 and τ3 are
taken to be the independent variables and the parameters
respectively. The effects of the gain coefficient Γ and loss
coefficient K on the stochastic resonance are also discussed. It is found that besides the presence of the standard form and the broad sense of stochastic resonance, the number of extrema
in the curve of R versus K is reduced with the increase of the
gain coefficient Γ. 相似文献
19.
We study a realistic simulation model for the propagation of slow-combustion fronts in paper. In the simulations the deterministic part of the dynamics is that of the KPZ equation. The stochastic part, including in particular the short-range noise correlations, is taken from images of the structure of real paper samples. The parameters of the simulations are determined by using an inverse method applied to the experimental front data and by comparing the simulated and the experimental effective-noise distributions. Our model predicts well the shape of the spatial and temporal correlation functions, including the location of the crossovers from short-range (SR) to long-range (LR) behavior. The values of the exponents
,
,
and
agree with the experimental ones. The apparent SR exponents are found to be the same for different types of quenched noise. The correlated noise is shown to have a major contribution to the effective, measured nonlinearity. We discuss in detail how to implement the noise so as to obtain a realistic simulation model.Received: 25 September 2003, Published online: 30 January 2004PACS:
05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion - 64.60.Ht Dynamic critical phenomena 相似文献
20.
Optical bistability and multistability in a three-level Δ-type atomic system under the nonresonant condition 下载免费PDF全文
Under a nonresonant condition, we theoretically investigate hybrid
absorptive-dispersive optical bistability and multistability
behaviours in a three-level Δ-type system by using a microwave
field to drive a hyperfine transition between two upper excited
states inside a unidirectional ring cavity. We find that the optical
bistability and multistability behaviours can be controlled by
adjusting the intensity of the microwave field or the intensity of
the coherent coupling field. Furthermore, our studies show an
interesting phenomenon of the transition from the optical
bistability to the optical multistability only by changing the
negative detuning of the coupling field into the positive detuning
of the coupling field. 相似文献