Relationship between statistical sums of canonical and grand canonical ensembles of interacting particles

2000 ◽  
Vol 43 (6) ◽  
pp. 479-482
Author(s):  
A. N. Vall
Author(s):  
Michael P. Allen ◽  
Dominic J. Tildesley

This chapter contains the essential statistical mechanics required to understand the inner workings of, and interpretation of results from, computer simulations. The microcanonical, canonical, isothermal–isobaric, semigrand and grand canonical ensembles are defined. Thermodynamic, structural, and dynamical properties of simple and complex liquids are related to appropriate functions of molecular positions and velocities. A number of important thermodynamic properties are defined in terms of fluctuations in these ensembles. The effect of the inclusion of hard constraints in the underlying potential model on the calculated properties is considered, and the addition of long-range and quantum corrections to classical simulations is presented. The extension of statistical mechanics to describe inhomogeneous systems such as the planar gas–liquid interface, fluid membranes, and liquid crystals, and its application in the simulation of these systems, are discussed.


1997 ◽  
Vol 55 (21) ◽  
pp. 14222-14229 ◽  
Author(s):  
E. M. Vandeworp ◽  
Kathie E. Newman

Author(s):  
Abel Camacho ◽  
Alfredo Macías ◽  
Abel Camacho–Galván

2006 ◽  
Vol 16 (09) ◽  
pp. 2713-2719 ◽  
Author(s):  
KESTUTIS STALIUNAS

Momentum distributions and temporal power spectra of nonzero temperature Bose–Einstein condensates are calculated using a Gross–Pitaevskii model. The distributions are obtained for micro-canonical ensembles (conservative Gross–Pitaevskii equation) and for grand-canonical ensembles (Gross–Pitaevskii equation with fluctuations and dissipation terms). Use is made of equivalence between statistics of the solutions of conservative Gross–Pitaevskii and dissipative complex Ginzburg–Landau equations. In all cases the occupation numbers of modes follow a 〈Nk〉 ∝ k-2 dependence, which corresponds in the long wavelength limit (k → 0) to Bose–Einstein distributions. The temporal power spectra are of 1/fα form, where: α = 2 - D/2 with D the dimension of space.


2016 ◽  
Vol 30 (31) ◽  
pp. 1650378 ◽  
Author(s):  
L. S. Ferreira ◽  
L. N. Jorge ◽  
A. A. Caparica ◽  
D. A. Nascimento ◽  
Minos A. Neto ◽  
...  

In this work, we apply entropic sampling simulations to a three-state model which has exact solutions in the microcanonical and grand-canonical ensembles. We consider N chains placed on an unidimensional lattice, such that each site may assume one of the three states: empty (state 1), with a single molecule energetically null (state 2), and with a single molecule with energy [Formula: see text] (state 3). Each molecule, which we will treat here as dimers, consists of two monomers connected one to each other by a rod. The thermodynamic properties such as internal energy, densities of dimers and specific heat were obtained as functions of temperature, where the analytic results in the microcanonical and grand-canonical ensembles were successfully confirmed by the entropic sampling simulations.


The theory of quantum-mechanical grand canonical ensembles is used to derive for the case of a perfect Bose-Einstein gas the average number of particles in the different energy levels, the fluctuations in these numbers and the equation of state. The Einstein condensation phenomenon is then discussed, and it is shown that in a p-v diagram (v being the specific volume) the isotherm consists of two analytically different parts in the limit where the number of particles in the system, JV, goes to infinity. It is also shown that for finite N at the critical volume ∂ n p/∂v n is of the order N1/3 (n-2) in accordance with a result obtained by Wergeland & Hove-Storhoug.


2003 ◽  
Vol 81 (12) ◽  
pp. 1363-1375 ◽  
Author(s):  
M H Dehghani ◽  
H KhajehAzad

We compute the conserved quantities of the four-dimensional Kerr–Newman–de Sitter (KNdS) black hole through the use of the counterterm renormalization method, and obtain a generalized Smarr formula for the mass as a function of the entropy, the angular momentum, and the electric charge. The first law of thermodynamics associated to the cosmological horizon of KNdS is also investigated. Using the minimal number of intrinsic boundary counterterms, we consider the quasilocal thermodynamics of an asymptotic de Sitter–Reissner–Nordstrom black hole, and find that the temperature is equal to the product of the surface gravity (divided by 2π) and the Tolman red-shift factor. We also perform a quasilocal stability analysis by computing the determinant of Hessian matrix of the energy with respect to its thermodynamic variables in both the canonical and the grand-canonical ensembles and obtain a complete set of phase diagrams. We then turn to the quasilocal thermodynamics of four-dimensional Kerr–Newman–de Sitter black hole for virtually all possible values of the mass, the rotation, and the charge parameters that leave the quasilocal boundary inside the cosmological event horizon, and perform a quasilocal stability analysis of KNdS black hole.PACS Nos.:04.70.Dy, 04.62.+v, 04.60.–m


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