共查询到20条相似文献,搜索用时 15 毫秒
1.
Philippe A. Jacquet 《Journal of statistical physics》2009,134(4):709-748
We introduce a model for charge and heat transport based on the Landauer-Büttiker scattering approach. The system consists
of a chain of N quantum dots, each of them being coupled to a particle reservoir. Additionally, the left and right ends of the chain are
coupled to two particle reservoirs. All these reservoirs are independent and can be described by any of the standard physical
distributions: Maxwell-Boltzmann, Fermi-Dirac and Bose-Einstein. In the linear response regime, and under some assumptions,
we first describe the general transport properties of the system. Then we impose the self-consistency condition, i.e. we fix
the boundary values (T
L,μ
L) and (T
R,μ
R), and adjust the parameters (T
i
,μ
i
), for i=1,…,N, so that the net average electric and heat currents into all the intermediate reservoirs vanish. This condition leads to
expressions for the temperature and chemical potential profiles along the system, which turn out to be independent of the
distribution describing the reservoirs. We also determine the average electric and heat currents flowing through the system
and present some numerical results, using random matrix theory, showing that these currents are typically governed by Ohm
and Fourier laws. 相似文献
2.
Dominik Janzing 《Journal of statistical physics》2010,138(4-5):767-779
There are non-Gaussian time series that admit a causal linear autoregressive moving average (ARMA) model when regressing the future on the past, but not when regressing the past on the future. The reason is that, in the latter case, the regression residuals are not statistically independent of the regressor. In previous work, we have experimentally verified that many empirical time series indeed show such a time inversion asymmetry. For various physical systems, it is known that time-inversion asymmetries are linked to the thermodynamic entropy production in non-equilibrium states. Here we argue that unidirectional linearity is also accompanied by entropy generation. To this end, we study the dynamical evolution of a physical toy system with linear coupling to an infinite environment and show that the linearity of the dynamics is inherited by the forward-time conditional probabilities, but not by the backward-time conditionals. The reason is that the environment permanently provides particles that are in a product state before they interact with the system, but show statistical dependence afterwards. From a coarse-grained perspective, the interaction thus generates entropy. We quantitatively relate the strength of the non-linearity of the backward process to the minimal amount of entropy generation. The paper thus shows that unidirectional linearity is an indirect implication of the thermodynamic arrow of time, given that the joint dynamics of the system and its environment is linear. 相似文献
3.
Anosov systems are mathematical models for chaotic systems in statistical mechanics and fluid dynamics. Most of these systems
enjoy the property of positive entropy production. We introduce the concept of specific information gain (or specific relative
entropy) h(μ+,μ−) in Anosov systems and prove that it is identical to the entropy production rate e
p
(μ+) defined by Ruelle and Gallavotti in Anosov systems. From this point of view, the entropy production rate e
p
(μ+ characterizes the degree of macroscopic irreversibility of the system.
Received: 2 August 1999 / Accepted: 14 April 2000 相似文献
4.
The process of heat conduction in one-dimensional dimerized systems is studied by means of numerical simulation. Taking into account the difference between the strong bond and the weak one of the systems, our calculation indicates that heat conduction in the lattice is anomalous. For the typical parameter related to a real physical system, the divergent exponent is shown to be in agreement with that predicted by the mode-coupling theory. Moreover, our study shows that the homogeneous chain is the best thermal conductor. 相似文献
5.
Based on fractal theory, two types of random Sierpinski carpets (RSCs) and their periodic structures are generated to model the structures of natural porous media, and the heat conduction in these structures is simulated by the finite volume method. The calculated results indicate that in a certain range of length scales, the size and spatial arrangement of pores have significant influence on the effective thermal conductivity, and the heat conduction presents the aeolotropic characteristic. Above the length scale, however, the influence of size and spatial arrangement of pores on the effective thermal conductivity reduces gradually with the increasing characteristic size of porous media, the aeolotropic characteristic is weakened gradually. It is concluded that the periodicity in structures of porous media is not equal to the periodicity in heat conduction. 相似文献
6.
In this paper we give an exact infinite-series expression for the bi-partite entanglement entropy of the quantum Ising model
in the ordered regime, both with a boundary magnetic field and in infinite volume. This generalizes and extends previous results
involving the present authors for the bi-partite entanglement entropy of integrable quantum field theories, which exploited
the generalization of the form factor program to branch-point twist fields. In the boundary case, we isolate in a universal
way the part of the entanglement entropy which is related to the boundary entropy introduced by Affleck and Ludwig, and explain
how this relation should hold in more general QFT models. We provide several consistency checks for the validity of our form
factor results, notably, the identification of the leading ultraviolet behaviour both of the entanglement entropy and of the
two-point function of twist fields in the bulk theory, to a great degree of precision by including up to 500 form factor contributions. 相似文献
7.
The evolution of the field entropy and the entanglement between the atom and the field for the system of a single-mode vacuum
field interacting with a Ξ-type three-level atom have been studied by using the reduced quantum entropy. The influences of the detuning of the light
field and the setting of the initial state of the atom on the field entropy and entanglement of the system under consideration
are discussed emphatically. It is showed that the detuning of the light field and the setting of the initial state of the
atom play an important role for the evolution of the field entropy and the entanglement between the atom and the field. The
general conclusions reached are illustrated by numerical results. 相似文献
8.
Phase Leading of Temperature Variations in Cavity Caused by Heat Conduction Between Air and Rock
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It is well known that the terrestrial temperature varies with the period of 24 hours mainly due to the rotation of the earth in the field of the solar radiation. However, we observed the phenomenon that the semldiurnal(12 hour) temperature oscillation is dominant in our underground laboratory. By the spectrum analysis, the close correlation between the variations of temperature and atmospheric pressure was discovered, and the result of phase analysis showed that the phase of semidiurnal pressure lags behind that of the semidiurnal temperature. A model of heat conduction between air and rock is presented to explain the semidiurnal temperature oscillation observed in the underground laboratory. 相似文献
9.
The effects of time delay on stochastic resonance (SR) in a bistable system with time delay, correlated noises and periodic
signal are studied by using the theory of signal-to-noise ratio (SNR). The expression of the SNR is derived under the adiabatic
limit and the small delay time approximation. It is found that: (i) For the case of no correlations between multiplicative
and additive noise, the delay time τ can enhance the SNR as a function of the multiplicative noise intensity α and it can restrain the SNR as a function of the additive noise intensity D; (ii) For the case of correlations between multiplicative and additive noise, τ can induce a minimum and maximum in curve of the SNR as a function of α, and can intensively restrain the SNR as a function of the D and there is a critical value of delay tim τ
c
=0.1 in the height of the SNR peak with change of τ, i.e., when τ takes value blow τ
c
, the τ boosts up the SNR as a function of the strength λ of correlations between multiplicative and additive noise, however, when τ takes value above τ
c
, the τ restrains that. 相似文献
10.
Paramita Chakraborty 《Journal of statistical physics》2009,136(3):527-551
The path of a tracer particle through a porous medium is typically modeled by a stochastic differential equation (SDE) driven
by Brownian noise. This model may not be adequate for highly heterogeneous media. This paper extends the model to a general
SDE driven by a Lévy noise. Particle paths follow a Markov process with long jumps. Their transition probability density solves
a forward equation derived here via pseudo-differential operator theory and Fourier analysis. In particular, the SDE with
stable driving noise has a space-fractional advection-dispersion equation (fADE) with variable coefficients as the forward
equation. This result provides a stochastic solution to anomalous diffusion models, and a solid mathematical foundation for
particle tracking codes already in use for fractional advection equations. 相似文献
11.
Tomographic approach to describing both the states in classical statistical mechanics and the states in quantum mechanics
using the fair probability distributions is reviewed. The entropy associated with the probability distribution (tomographic
entropy) for classical and quantum systems is studied. The experimental possibility to check the inequalities like the position–momentum
uncertainty relations and entropic uncertainty relations are considered. 相似文献
12.
A hyperbolic model of non-Fourier heat conduction with non-uniform heat source is used to simulate the transient heat transfer in a high-pulse-pumped solid-state laser medium. The temperature fields are numerically analysed using the finite difference method combined with the TDMA algorithm for different pump power densities, pulse durations, thermal relaxation time and cooling intensities, respectively. The calculated results are compared with those predicted by the parabolic heat conduction model based on the Fourier law. The results indicate that the non-Fourier heat conduction phenomenon in laser media should be considered when the pump power density exceeds 104 W/m^2 or under low pulse duration. In addition, the conditions of non-Fourier effects and their influencing factors are analysed. 相似文献
13.
The stationary properties of a saturation laser model with cross-correlation between the real and imaginary parts of the quantum
noise are investigated theoretically. Using the Novikov theorem and the Sargent technique, we obtain the analytic expressions
of the stationary probability density distribution, the mean, the variance and the skewness of the saturation laser model.
The cross-correlation coefficient λ and other parameters can make the stationary probability density distribution P
st
(I) generate interesting two-extrema structure, one-extremum structure, or no-extremum structure. It is clearly found that a
first- order-like-transition is induced by the coupling strength |λ| of the complex quantum noise terms in the saturation laser model. When the laser system is operated above the threshold,
the mean 〈I〉 becomes larger and the output of the laser intensity increases; however the coupling strength |λ| attenuates the output of the laser intensity. When the laser is operated near and below the threshold, the mean 〈I〉 becomes smaller, the output of the laser intensity decreases, and |λ| still attenuates the output of the laser intensity. When a periodic signal is added to a saturation laser model with cross-correlation
between quantum noise terms, the interesting stochastic resonance phenomena occur at λ=0. The noise intensity Q decreases the values of the resonance peak, however, the amplitude of the periodic signal B enhances the values of the resonance peak. 相似文献
14.
Li-Chun Zhang Huai-Fan Li Yue-Qin Wu Ren Zhao 《International Journal of Theoretical Physics》2010,49(7):1587-1594
Taking the reaction of the radiation to the spacetime into consideration, we discuss Hawking radiation spectrum and Bekenstein-Hawking
entropy correction in Friedmann-Robertson-Walker (FRW) universe by the analytical continuation method. We derive the radiation
spectrum that satisfies the unitary principle and the logarithmic correction term of entropy in FRW universe. 相似文献
15.
Melanie J. I. Müller Stefan Klumpp Reinhard Lipowsky 《Journal of statistical physics》2008,133(6):1059-1081
Intracellular transport is mediated by molecular motors that pull cargos along cytoskeletal filaments. Many cargos move bidirectionally
and are transported by two teams of motors which move into opposite directions along the filament. We have recently introduced
a stochastic tug-of-war model for this situation. This model describes the motion of the cargo as a Markov process on a two-dimensional
state space defined by the numbers of active plus and active minus motors. In spite of its simplicity, this tug-of-war model
leads to a complex dependence of the cargo motility on the motor parameters. We present new numerical results for the dependence
on the number of involved motors. In addition, we derive a simple and intuitive sharp maxima approximation, from which one
obtains the cargo motility state from only four simple inequalities. This approach provides a fast and reliable method to
determine the cargo motility. 相似文献
16.
Ren Zhao Li-Chun Zhang Huai-Fan Li Yue-Qin Wu 《International Journal of Theoretical Physics》2008,47(12):3083-3090
Using the quantum statistical method, the difficulty of solving the wave equation on the background of the black hole is avoided.
We directly solve the partition functions of Bose and Fermi field on the background of an axisymmetric Kerr-Newman black hole
using the new equation of state density motivated by the generalized uncertainty principle in the quantum gravity. Then near
the black hole horizon, we calculate entropies of Bose and Fermi field between the black hole horizon surface and the hypersurface
with the same inherent radiation temperature measured by an observer at an infinite distance. In our results there are not
cutoffs and little mass approximation introduced in the conventional brick-wall method. The series expansion of the black
hole entropy is obtained. And this series is convergent. It provides a way for studying the quantum statistical entropy of
a black hole in a non-spherical symmetric spacetime. 相似文献
17.
Michael Wilkinson 《Journal of statistical physics》2010,139(2):345-353
The Ornstein-Uhlenbeck process may be used to generate a noise signal with a finite correlation time. If a one-dimensional
stochastic process is driven by such a noise source, it may be analysed by solving a Fokker-Planck equation in two dimensions.
In the case of motion in the vicinity of an attractive fixed point, it is shown how the solution of this equation can be developed
as a power series. The coefficients are determined exactly by using algebraic properties of a system of annihilation and creation
operators. 相似文献
18.
Vjekoslav Sajfert Ljiljana Mašković Jovan P. Šetrajčić Bratislav Tošić 《International Journal of Theoretical Physics》2008,47(5):1137-1146
The stochastic approach to the problem of deformed bulk structures is a unique possibility for obtaining a so–so real picture
of physical processes in these structures. The chain of identical atoms with random distances between neighbours as well as
the chain with random masses at equal distances is analysed. These analyses were generalized to complex chains, which are
spatially and mass deformed. The approximations used were incommensurability; one and more rough, continual approximation.
The probabilities are of exponential type. It means that the error in estimation on the basis of stochastical method can go
to 100% maximally. 相似文献
19.
Stochastic resonance in a bias linear system with multiplicative and additive noise 总被引:7,自引:0,他引:7
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In this paper, the stochastic resonance in a bias linear system
subjected multiplicative
and additive dichotomous noise is investigated. Using the linear-response
theory and the properties of the dichotomous noise, this paper finds
the exact expressions
for the first two moments and the signal-to-noise ratio
(SNR). It is shown that the SNR is a non-monotonic function of the
correlation time of the multiplicative and additive noise, and it varies
non-monotonously with the intensity and asymmetry of the multiplicative
noise as well as the external field frequency. Moreover, the SNR depends on
the system bias, the intensity of the cross noise between the multiplicative
and additive noise, and the strength and asymmetry of the additive noise. 相似文献
20.
M. S. Ateto 《International Journal of Theoretical Physics》2010,49(2):276-292
The wave function of a system governed by the time-dependent nonlinear Jaynes-Cummings (JC) model is obtained. We compute
analytically the eigenvalues of the reduced field density operator by which the dynamics of the entropy of entanglement of
the cavity field are analyzed. The influences of the atomic motion, the field-mode structure and the Kerr-like medium on this
phenomenon are illustrated. The population dynamics of an excited atom is also discussed for the same set of parameters. The
cavity field is assumed to be initially excited in either a Fock or a coherent states. The cavity excitation in a Fock state
generates a class of an entanglement without death with fixed amplitude by adjusting the parameters of the atomic motion as
well as the Kerr and the field-mode structure. In case of a coherent cavity, the only phenomenon to be noted is the periodical
behavior of the dynamics under study when the atomic motion is considered. Although the Kerr medium affects the strength of
the entanglement negatively, the entropy of entanglement loses its zeros where the Kerr is taken into consideration. 相似文献