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1.
Within mean field approximation, a procedure is elaborated to consider noise induced phase transitions with arbitrary relations
between the noises of different degrees of freedom. The proposed approach is applied to investigate effects of cross correlation
between noises in the generalized synergetic model of Lorenz type. This cross correlation is shown to induce phase transitions
of the dynamical system under consideration. Additionally, we find the correlation between noises transforms a synergetic
behavior to a thermodynamic one.
Received 13 November 2002 Published online 11 April 2003
RID="a"
ID="a"e-mail: dikh@sumdu.edu.ua 相似文献
2.
P. Colet D. Walgraef M. San Miguel 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,11(3):517-524
We study the nature of the instability of the homogeneous steady states of the subcritical real Ginzburg-Landau equation in
the presence of group velocity. The shift of the absolute instability threshold of the trivial steady state, induced by the
destabilizing cubic nonlinearities, is confirmed by the numerical analysis of the evolution of its perturbations. It is also
shown that the dynamics of these perturbations is such that finite size effects may suppress the transition from convective
to absolute instability. Finally, we analyze the instability of the subcritical middle branch of steady states, and show,
analytically and numerically, that this branch may be convectively unstable for sufficiently high values of the group velocity.
Received 17 December 1998 相似文献
3.
J.M. Sancho A. Sánchez 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(1):127-131
We study the dynamics of fronts when both inertial effects and external fluctuations are taken into account. Stochastic fluctuations
are introduced as multiplicative white noise arising from a control parameter of the system. Contrary to the non-inertial
(overdamped) case, we find that important features of the system, such as the velocity selection picture, are not modified
by the noise. We then compute the overdamped limit of the underdamped dynamics in a more careful way, finding that it does
not exhibit any effect of noise either. Our result poses the question as to whether or not external noise sources can be measured
in physical systems of this kind.
Received 2 July 1999 and Received in final form 25 November 1999 相似文献
4.
S. Z. Ke D. J. Wu L. Cao 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,12(1):119-122
The colored noise problem is studied from the point of view of consistent Markovian approximations through extending unified
colored-noise approximation to the case of two-colored-noise driving systems. A bistable system simultaneously driven by multiplicative
and additive colored noise is investigated by means of the extended unified colored-noise approximation. It is found that,
for weak strength and color of the additive noise, the form of the stationary probability distribution changes from a unimodal
to a bimodal structure via a three modal one as the correlation time of the multiplicative colored noise increases, showing
the system undergoes a first order phase transition from a monostable to a bistable state. Numerical simulations support our
results.
Received 10 August 1998 and Received in final form 23 April 1999 相似文献
5.
C. Clanet E. Villermaux 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,6(4):529-536
We first introduce a simple and new method for the quantitative analysis of some nonlinear oscillating systems. It is shown
that if the dynamics of the system reduces to piecewise exponential growth and exponential damping phases, then the amplitude
and period of the motion can be computed with accuracy in the nonlinear regime without invoking linear stability arguments
or perturbative expansions. This method is then successfully applied to the delayed logistic application and to the Lotka-Volterra
prey-predator model. For both of these systems, we provide an accurate analytical expression for the period of the oscillations
in the nonlinear regime.
Received: 27 April 1998 / Received in final form: 25 June 1998 / Accepted: 29 June 1998 相似文献
6.
A. Bershadskii 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,9(4):691-693
It is shown that multifractal properties of some random and disordered systems can be simulated using thermodynamics of a
generalized ideal monoatomic gas in a fractal phase space.
Received 25 November 1998 and Received in final form 16 December 1998 相似文献
7.
M. Dugic D. Rakovic 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(4):781-790
We investigate the quantum-mechanical tunneling between the “patterns" of the, so-called, associative neural networks. Being
the relatively stable minima of the “configuration-energy" space of the networks, the “patterns" represent the macroscopically
distinguishable states of the neural nets. Therefore, the tunneling represents a macroscopic quantum effect, but with some
special characteristics. Particularly, we investigate the tunneling between the minima of approximately equal depth, thus
requiring no energy exchange. If there are at least a few such minima, the tunneling represents a sort of the “random walk"
process, which implies the quantum fluctuations in the system, and therefore “malfunctioning" in the information processing
of the nets. Due to the finite number of the minima, the “random walk" reduces to a dynamics modeled by the, so-called, Pauli
master equation. With some plausible assumptions, the set(s) of the Pauli master equations can be analytically solved. This
way comes the main result of this paper: the quantum fluctuations due to the quantum-mechanical tunneling can be “minimized"
if the “pattern"-formation is such that there are mutually “distant" groups of the “patterns", thus providing the “zone" structure
of the “pattern" formation. This qualitative result can be considered as a basis of the efficient deterministic functioning
of the associative neural nets.
Received 15 July 1999 相似文献
8.
C. Ruyer-Quil P. Manneville 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(2):357-369
New models of film flows down inclined planes have been derived by combining a gradient expansion at first or second order
to weighted residual techniques with polynomials as test functions. The two-dimensional formulation has been extended to account
for three-dimensional flows as well. The full second-order two-dimensional model can be expressed as a set of four coupled
evolution equations for four slowly varying fields, the thickness h, the flow rate q and two other quantities measuring the departure from the flat-film semi-parabolic velocity profile. A simplified model has
been obtained in terms of h and q only. Including viscous dispersion effects properly, it closely sticks to the asymptotic expansion in the appropriate limit.
Our new models improve over previous ones in that they remain valid deep into the strongly nonlinear regime, as shown by the
comparison of our results relative to travelling-wave and solitary-wave solutions with those of both direct numerical simulations
and experiments.
Received 14 September 1999 and Received in final form 6 January 2000 相似文献
9.
Julian Juhi-Lian Ting 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(3):527-530
The possibility of stochastic resonance of a quantum channel and hence the noise enhanced quantum channel capacity is explored
by considering one-Pauli channels which are more classical like. The fidelity of the channel is also considered.
Received 4 June 1999 相似文献
10.
N. Vandewalle M. Ausloos Ph. Boveroux A. Minguet 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,9(2):355-359
We present a method for visualizing the pattern which we believe to be a precursor signature of financial crashes (or ruptures).
The log-periodicity of the pattern is investigated through the envelope function technique. Three periods of the Dow Jones
Industrial Average (DJIA) are investigated: 1982-1987, 1992-1997 and 1993-1998. The presence of a rupture in the end of 1998
is outlined from data taken before the end of August 1998.
Received 15 October 1998 and Received in final form 19 November 1998 相似文献
11.
M. A. Fuentes H. S. Wio 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,52(2):249-253
With the aim of studying stochastic resonance (SR) in a
double-well potential when the noise source has a spectral density
of the form f-κ (with varying κ), we have extended
a procedure introduced by Kaulakys et al. (Phys. Rev. E 70,
020101 (2004)). In order to achieve an analytical understanding of
the results, we have obtained an effective Markovian approximation
that allows us to make a systematic study of the effect of such
noise on the SR phenomenon. A comparison of the numerical and
analytical results shows an excellent qualitative agreement
indicating that the effective Markovian approximation is able to
correctly describe the general trends. 相似文献
12.
G. Abramson J.L. Vega 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,9(2):361-364
Multifractal critical phenomena with infinite-temperature critical point and with complex coexistence of the infinite and
finite temperature critical points are considered and it is shown that strange attractors generated by cascades of period-doubling
bifurcations (Feigenbaum scenario) as well as fields of velocity differences in fluid turbulence belong to the former subclass
of the multifractal critical phenomena, while the real traffic processes and real currency exchange processes belong to the
last (complex) subclass of the multifractal critical phenomena. Data obtained by different authors are used for this purpose.
Received 5 February 1999 相似文献
13.
S. E. Mangioni H. S. Wio 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(1):67-73
We analyze the effect of a colored non Gaussian noise on a model of
a random walker moving along a ratchet potential. Such a model was
motivated by the transport properties of motor proteins, like
kinesin and myosin. Previous studies have been realized assuming
white noises. However, for real situations, in general we could
expect that those noises be correlated and non Gaussian. Among other
aspects, in addition to a maximum in the current as the noise
intensity is varied, we have also found another optimal value of the
current when departing from Gaussian behavior. We show the relevant
effects that arise when departing from Gaussian behavior,
particularly related to current's enhancement, and discuss its
relevance for both biological and technological situations. 相似文献
14.
Ying Zhang Gang Hu Shi Gang Chen Yugui Yao 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(1):51-57
A system of coupled master equations simplified from a model of noise-driven globally coupled bistable oscillators under periodic
forcing is investigated. In the thermodynamic limit, the system is reduced to a set of two coupled differential equations.
Rich bifurcations to subharmonics and chaotic motions are found. This behavior can be found only for certain intermediate
noise intensities. Noise with intensities which are too small or too large will certainly spoil the bifurcations. In a system
with large though finite size, the bifurcations to chaos induced by noise can still be detected to a certain degree.
Received 6 April 1999 and Received in final form 1 November 1999 相似文献
15.
B. Schulz S. Trimper M. Schulz 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(3):499-505
Random walks in one-dimensional environments with an additional dynamical feedback-coupling is analyzed numerically. The feedback
introduced via a generalized master equation is controlled by a memory kernel of strength the explicit form of which is motivated by arguments used in mode-coupling theories. Introducing several realizations of
the feedback mechanism within the simulations we obtain for a negative memory term, , superdiffusion in the long time limit while a positive memory leads to localization of the particle. The numerical simulations
are in agreement with recent predictions based on renormalization group techniques. A slight modification of the model including
an exponentially decaying memory term and some possible applications for glasses and supercooled liquids are suggested. The
relation to the true self-avoiding is discussed.
Received 16 September 1999 and Received in final form 27 December 1999 相似文献
16.
L. F. Matin A. Aghamohammadi M. Khorrami 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(3):243-246
The most general reaction-diffusion model on a Cayley
tree with nearest-neighbor interactions is introduced, which can
be solved exactly through the empty-interval method. The
stationary solutions of such models, as well as their dynamics,
are discussed. Concerning the dynamics, the spectrum of the
evolution Hamiltonian is found and shown to be discrete, hence
there is a finite relaxation time in the evolution of the system
towards its stationary state. 相似文献
17.
D. Chowdhury R.C. Desai 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(2):375-384
A Bus Route Model (BRM) can be defined on a one-dimensional lattice, where buses are represented by “particles” that are driven
forward from one site to the next with each site representing a bus stop. We replace the random sequential updating rules
in an earlier BRM by parallel updating rules. In order to elucidate the connection between the BRM with parallel updating
(BRMPU) and the Nagel-Schreckenberg (NaSch) model, we propose two alternative extensions of the NaSch model with space-/time-dependent
hopping rates. Approximating the BRMPU as a generalization of the NaSch model, we calculate analytically the steady-state
distribution of the time headways (TH) which are defined as the time intervals between the departures (or arrivals) of two
successive particles (i.e., buses) recorded by a detector placed at a fixed site (i.e., bus stop) on the model route. We compare these TH distributions with the corresponding results of our computer simulations
of the BRMPU, as well as with the data from the simulation of the two extended NaSch models. We also investigate interesting
kinetic properties exhibited by the BRMPU during its time evolution from random initial states towards its steady-states.
Received 16 December 1999 相似文献
18.
S.A. Hassan A.R. Vasconcellos R. Luzzi 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(1):131-139
We analyze in detail the nonlinear kinetics of a carrier system in a photoinjected plasma in semiconductors under the action
of constant illumination with ultraviolet light. We show that the spatially homogeneous steady-state becomes unstable, and
a charge density wave emerges after a critical intensity of the incident radiation is achieved. It is shown that this instability
can only follow in doped p-type materials. In bulk systems the critical intensity was found to be too high making the phenomenon not observable under
realistic experimental conditions. However, a more efficient electron excitation can be obtained in low dimensional p-type systems, like some molecular and biological polymers, where the interaction may follow by chemical interaction with
the medium. We show that for intensities beyond the critical threshold an increasing number of modes provide further contributions
(subharmonics) to the space inhomogeneity. It is conjectured that this process could lead the system to display chaotic-like
behavior.
Received 8 July 1998 and Received in final form 6 May 1999 相似文献
19.
O.V. Gerashchenko S.L. Ginzburg M.A. Pustovoit 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(2):335-338
An experimental (electronic circuit) realization and analytic studies of overdamped Kramers oscillator with an exponential
nonlinearity under combined effect of a large multiplicative noise and a small periodic signal were performed. Under certain
conditions, when the system exhibits on-off intermittency, it becomes sensitive to very small periodic signals, amplifying
them greatly.
Received 21 May 1999 and Received in final form 28 December 1999 相似文献
20.
Stochastic multiresonance in a bistable sawtooth potential driven by correlated multiplicative and additive noise 总被引:1,自引:0,他引:1
J. Wang L. Cao D.J. Wu 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(1):123-128
We present an analytic investigation of the signal-to-noise ratio (SNR) by studying the bistable sawtooth system driven by correlated Gaussian white noises. The analytic expression of SNR is obtained. Based on it, we detect the phenomenon of stochastic multiresonance, which arises from the dependence of SNR upon the noises correlation coefficient. Furthermore, there exists not only resonance, but also suppression in the SNR∼D (the additive noise intensity) curve and the SNR∼Q (the multiplicative noise intensity) curve.
Received 26 February 2002 / Received in final form 12 July 2002 Published online 17 September 2002 相似文献