Physics – Condensed Matter – Statistical Mechanics
Scientific paper
2001-02-04
Physics
Condensed Matter
Statistical Mechanics
17 pages, 11 figures, submitted to Phys. Rev. E
Scientific paper
10.1103/PhysRevE.65.046143
The microcanonical properties of a two dimensional system of N classical particles interacting via a smoothed Newtonian potential as a function of the total energy E and the total angular momentum L are discussed. In order to estimate suitable observables a numerical method based on an importance sampling algorithm is presented. The entropy surface shows a negative specific heat region at fixed L for all L. Observables probing the average mass distribution are used to understand the link between thermostatistical properties and the spatial distribution of particles. In order to define a phase in non-extensive system we introduce a more general observable than the one proposed by Gross and Votyakov [Eur. Phys. J. B:15, 115 (2000)]: the sign of the largest eigenvalue of the entropy surface curvature. At large E the gravitational system is in a homogeneous gas phase. At low E there are several collapse phases; at L=0 there is a single cluster phase and for L>0 there are several phases with 2 clusters. All these pure phases are separated by first order phase transition regions. The signal of critical behaviour emerges at different points of the parameter space (E,L). We also discuss the ensemble introduced in a recent pre-print by Klinko & Miller; this ensemble is the canonical analogue of the one at constant energy and constant angular momentum. We show that a huge loss of informations appears if we treat the system as a function of intensive parameters: besides the known non-equivalence at first order phase transitions, there exit in the microcanonical ensemble some values of the temperature and the angular velocity for which the corresponding canonical ensemble does not exist, i.e. the partition sum diverges.
Fliegans Olivier
Gross D. H. E.
No associations
LandOfFree
Effect of angular momentum on equilibrium properties of a self-gravitating system does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Effect of angular momentum on equilibrium properties of a self-gravitating system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Effect of angular momentum on equilibrium properties of a self-gravitating system will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-517459