Bose Einstein Condensation and Thermodynamics Properties in Bose-Einstein Distribution (original) (raw)

Bose-Einstein Condensation of An Ideal Gas

An ideal gas consisting of non-interacting Bose particles is a fictitious system since every realistic Bose gas shows some level of particle-particle interaction. Nevertheless, such a mathematical model provides the simplest example for the realization of Bose-Einstein condensation. This simple model, first studied by A. Einstein [1], correctly describes important basic properties of actual non-ideal (interacting) Bose gas. In particular, such basic concepts as BEC critical temperature T c (or critical particle density n c ), condensate fraction N 0 /N and the dimensionality issue will be obtained.

Global thermodynamic variables description for a confined cold gas undergoing Bose-Einstein condensation

Nuclear Physics A, 2007

We have used the definition of global thermodynamic variables such as generalized pressure and generalized volume for atoms trapped in a non-uniform potential to evaluate their behavior during the crossing of the critical temperature during a Bose-Einstein condensation. Comparing the experimental results with a theory based on a Hartree-Fock method, we have shown the regime of validity for the approximation. * Financial support from DGAPA IN-117406-2 (Mexico). † Financial support from Fapesp, CNPq and CAPES (Brasil).

Quantum statistics of a charged bose gas in the ground state

Annals of Physics, 1969

A gas of interacting charged bosom is examined with the temperature-dependent methods of quantum statistical mechanics, and the ground-state properties are calculated. A somewhat new approach to the boson problem is introduced, which is compared to previous methods utilized in studying this and other problems. The energy of the ground state is found to be in substantial agreement with recent calculations employing different techniques, and a very recent discovery concerning the correct expansion for the depletion of the ground state is confirmed. Several other thermodynamic quantities are also discussed and calculated. * This work was based in part on a thesis (EAN) submitted to the faculty of the graduate school of the University of Wyoming in partial fulfillment of the requirements for the Ph.D. degree, 1969.

Statistical properties and condensate fluctuation of attractive Bose gas with finite number of particles

Physica A: Statistical Mechanics and its Applications, 2017

We study the condensate fluctuation and several statistics of weakly interacting attractive Bose gas of 7 Li atoms in harmonic trap. Using exact recursion relation we calculate canonical ensemble partition function and study the thermal evolution of the condensate. As 7 Li condensate is associated with collapse, the number of condensate atom is truly finite and it facilitates to study the condensate in mesoscopic region. Being highly correlated, we utilize the two-body correlated basis function to get the many-body effective potential which is further used to calculate the energy levels. Taking van der Waals interaction as interatomic interaction we calculate several quantities like condensate fraction N , root-mean-square fluctuation δn 0 and different orders of central moments. We observe the effect of finite size on the calculation of condensate fluctuations and the effect of attractive interaction over the noninteracting limit. We observe the depletion of the condensate with increase in temperature. The calculated moments nicely exhibit the mesoscopic effect. The sharp fall in the root-mean-square fluctuation near the critical point signifies the possibility of phase transition.

Calculation of thermodynamic properties of finite Bose-Einstein systems

Physical Review A, 1999

We derive an exact recursion formula for the calculation of thermodynamic functions of finite systems obeying Bose-Einstein statistics. The formula is applicable for canonical systems where the particles can be treated as noninteracting in some approximation, e.g. like Bose-Einstein condensates in magnetic traps. The numerical effort of our computation scheme grows only linear with the number of particles.

Bose-Einstein condensation and condensation of qqq-particles in equilibrium and non equilibrium thermodynamics: a new approach

In the setting of the principle of local equilibrium which asserts that the temperature is a function of the energy levels of the system, we exhibit plenty of steady states describing the condensation of free Bosons which are not in thermal equilibrium. The surprising facts are that the condensation can occur both in dimension less than 3 in configuration space, and even in excited energy levels. The investigation relative to non equilibrium suggests a new approach to the condensation, which allows an unified analysis involving also the condensation of q-particles, −1 ≤ q ≤ 1, where q = ±1 corresponds to the Bose/Fermi alternative. For such q-particles, the condensation can occur only if 0 < q ≤ 1, the case 1 corresponding to the standard Bose-Einstein condensation. In this more general approach, completely new and unexpected states exhibiting condensation phenomena naturally occur also in the usual situation of equilibrium thermodynamics. The new approach proposed in the present paper for the situation of 2 nd quantisation of free particles, is naturally based on the theory of the Distributions, which might hopefully be extended to more general cases.

Thermodynamics of the Bose-System with a Small Number of Particles

2001

A theoretical description of the interacting Bose-system is proposed. It is based on the extrapolation of the results obtained for the systems with a small number of particles N = 2, 3, 4, etc. to the bulk case of N = ∞. It is shown that already the system with N = 12, 13 behaves almost as a bulk in a wide temperature range. Special attention is paid to the phase transition in these systems. The hard sphere potential is used in calculations. The sequence of heat capacity maxima is approximated as C max N /N ≃ 13.6 − aN −ε with ε = 0.0608 giving the value of bulk heat capacity as 13.6 while experimental value is close to 16. The temperature of λ-transition is estimated as 2.1-2.3 K versus experimental 2.17 K. Quite good qualitative and satisfactory quantitative agreement with the experimental data has been achieved.

Bose-Einstein condensation in the three-sphere and in the infinite slab: analytical results

Bose-Einstein condensation in the three-sphere and in the infinite slab: Analytical results, 2013

We study the finite size effects on Bose-Einstein condensation (BEC) of an ideal non-relativistic Bose gas in the three-sphere (spatial section of the Einstein universe) and in a partially finite box which is infinite in two of the spatial directions (infinite slab). Using the framework of grand-canonical statistics, we consider the number of particles, the condensate fraction and the specific heat. After obtaining asymptotic expansions for large system size, which are valid throughout the BEC regime, we describe analytically how the thermodynamic limit behaviour is approached. In particular, in the critical region of the BEC transition, we express the chemical potential and the specific heat as simple explicit functions of the temperature, highlighting the effects of finite size. These effects are seen to be different for the two different geometries. We also consider the Bose gas in a one-dimensional box, a system which does not possess BEC in the sense of a phase transition even in the infinite volume limit.

Bose-Einstein condensation under external conditions

Physics Letters A, 1998

We discuss the phenomenon of Bose-Einstein condensation under general external conditions using connections between partition sums and the heat-equation. Thermodynamical quantities like the critical temperature are given in terms of the heat-kernel coefficients of the associated Schrödinger equation. The general approach is applied to situations where the gas is confined by arbitrary potentials or by boxes of arbitrary shape.