arXiv subjects

Jincan Chen

Publications and source records attributed to Jincan Chen.

47 records · Page 3Linked to original sources

arXiv2012

Casimir effect of an ideal Bose gas trapped in a generic power-law potential

The Casimir effect of an ideal Bose gas trapped in a generic power-law potential and confined between two slabs with Dirichlet, Neumann, and periodic boundary conditions is investigated systematically, based on the grand potential of the ideal Bose gas, the Casimir potential and force are calculated. The scaling function is obtained and discussed. The special cases of free and harmonic potentials are also discussed. It is found that when T Tc, the Casimir force is an exponential decay function; and when T>>Tc, the Casimir force vanishes.

cond-mat.stat-mech↗

arXiv2010

The uncertainty measure for q-exponential distribution function

Based on the q-exponential distribution which has been observed in more and more physical systems, the varentropy method is used to derive the uncertainty measure of such an abnormal distribution function. The uncertainty measure obtained here can be considered as a new entropic form for the abnormal physical systems with complex interaction. The entropy obtained here also presents non-additive property for two independent subsystems and it will tend to the Boltzmann-Gibbs entropy when the nonextensive parameter q->1. It is very important to find that for different systems with any q, this entropic form is always concave and the systemic entropy is maximizable.

math-ph↗

arXiv2010

Self-similar motion for modeling anomalous diffusion and nonextensive statistical distributions

We introduce a new universality class of one-dimensional iteration model giving rise to self-similar motion, in which the Feigenbaum constants are generalized as self-similar rates and can be predetermined. The curves of the mean-square displacement versus time generated here show that the motion is a kind of anomalous diffusion with the diffusion coefficient depending on the self-similar rates. In addition, it is found that the distribution of displacement agrees to a reliable precision with the q-Gaussian type distribution in some cases and bimodal distribution in some other cases. The results obtained show that the self-similar motion may be used to describe the anomalous diffusion and nonextensive statistical distributions.

cond-mat.stat-mech↗

arXiv2009

A counterexample against the Lesche stability of a generic entropy functional

We provide a counterexample to show that the generic form of entropy S(p)=sum_i g(p_i) is not always stable against small variation of probability distribution (Lesche stability) even if is concave function on [0,1] and analytic on ]0,1]. Our conclusion is that the stability of such a generic functional needs more hypotheses on the property of the function g, or in other words, the stability of entropy cannot be discussed at this formal stage.

cond-mat.stat-mech↗

arXiv2008

Possible canonical distributions for finite systems with nonadditive energy

It is shown that a small system in thermodynamic equilibrium with a finite thermostat can have a q-exponential probability distribution which closely depends on the energy nonextensivity and the particle number of the thermostat. The distribution function will reduce to the exponential one at the thermodynamic limit. However, the nonextensivity of the system should not be neglected.

cond-mat.stat-mech↗

arXiv2008

Generalized measurement of uncertainty and the maximizable entropy

For a random variable we can define a variational relationship with practical physical meaning as dI=dbar(x)-bar(dx), where I is called as uncertainty measurement. With the help of a generalized definition of expectation, bar(x)=sum_(i)g(p_i)x_i, and the expression of dI, we can find the concrete forms of the maximizable entropies for any given probability distribution function, where g(p_i) may have different forms for different statistics which includes the extensive and nonextensive statistics.

cond-mat.stat-mech↗

arXiv2008

Inherent correlations between thermodynamics and statistic physics in extensive and nonextensive systems

With the help of a general expression of the entropies in extensive and nonextensive systems, some important relations between thermodynamics and statistical mechanics are revealed through the views of thermodynamics and statistic physics. These relations are proved through the MaxEnt approach once again. It is found that for a reversible isothermal process, the information contained in the first and second laws of thermodynamics and the MaxEnt approach is equivalent. Moreover, these relations are used to derive the probability distribution functions in nonextensive and extensive statistics and calculate the generalized forces of some interesting systems. The results obtained are of universal significance.

cond-mat.stat-mech↗

arXiv2007

A new expression of the probability distribution in incomplete statistics and fundamental thermodynamic relations

In order to overcome the limitations of the original expression of the probability distribution appearing in literature of Incomplete Statistics, a new expression of the probability distribution is derived, where the Lagrange multiplier %B% introduced here is proved to be identical with that introduced in the second and third choices for the internal energy constraint in Tsallis' statistics and to be just equal to the physical inverse temperature. It is expounded that the probability distribution described by the new expression is invariant through uniform translation of the energy spectrum. Moreover, several fundamental thermodynamic relations are given and the relationship between the new and the original expressions of the probability distribution is discussed.

cond-mat.stat-mech↗

arXiv2007

A basic problem in the correlations between statistics and thermodynamics

By using a fonctionelle of probability distributions, several different statistical physics including extensive and nonextensive statistics are unified in a general method. The essential equivalence between the MaxEnt process of the most probable probility distribution in these statistics and the famous thermodynamical relation dU=TdS is strictly proved without any additional assumption. Moreover, it is expounded that all the conclusions of these different statistics can be directly derived from the equivalent relation.

physics.data-an↗

arXiv2007

Nonextensibility of internal energy in incomplete statistics and the zeroth law of thermodynamics

On the basis of the entropy of incomplete statistics (IS) and the joint probability factorization condition, two controversial problems existing in IS are investigated, where one is what the correct expression of the internal energy for a composite system is and the other is whether the zeroth law of thermodynamics is true or not. Some new equivalent expressions of the internal energy of a composite system are derived through a precise mathematical calculation. Moreover, a self-consistent calculation is used to expound that the zeroth law of thermodynamics is also suitable for IS, but it can't be proven from theory. Finally, it is pointed out that the generalized zeroth law of thermodynamics and the expressions of the internal energy of a composite system derived in literature are incorrect, because two irrational assumptions have been implicitly introduced.

cond-mat.stat-mech↗

arXiv2005

Nonextensibility of energy in Tsallis' statistics and the zeroth law of thermodynamics

Two important problems existing in Tsallis' statistics are investigated, where one is whether energy is extensive or not, and the other is whether it is necessary to introduce the so-called generalized zeroth law of thermodynamics or not. The results obtained show clearly that like entropy, energy is also nonextensive in Tsallis' statistics, and that the zeroth law of thermodynamics has been implicitly used in Tsallis' statistics since 1988. Moreover, it is expounded that the standard energy additivity rule adopted by a great number of researchers is not suitable in Tsallis' statistics, because it not only violates the law of energy conservation but also its corollary is in contradiction with the zeroth law of thermodynamics.

cond-mat.stat-mech↗