First-order microcanonical transitions in finite mean-field models
Year: 2004
Authors: Antoni M., Ruffo S., Torcini A.
Autors Affiliation: UMR-CNRS 6171 – Université d’Aix Marseille III, Av. Esc. Normandie-Niemen 13397 Marseille Cedex 20, France;
Dipartimento d’Energetica “S. Stecco” and CSDC Università di Firenze and INFN and INFM, V. S. Marta 3, 50139 Firenze, Italy;
Istituto Nazionale di Ottica Applicata, Largo E. Fermi 6, 50125 Firenze, Italy
Abstract: A microcanonical first-order transition, connecting a clustered to a homogeneous phase, is studied from both the thermodynamic and the dynamical point of view for an N-body Hamiltonian system with infinite-range couplings. In the microcanonical ensemble, specific heat can be negative, but besides that, a microcanonical first-order transition displays a temperature discontinuity as the energy is varied continuously (a dual phenomenon to the latent heat in the canonical ensemble). In the transition region, the entropy per particle exhibits, as a function of the order parameter, two relative maxima separated by a minimum. The relaxation of the metastable state is shown to be ruled by an activation process induced by intrinsic finite N fluctuations. In particular, numerical evidences are given that the escape time diverges exponentially with N, with a growth rate given by the entropy barrier.
Journal/Review: EUROPHYSICS LETTERS
Volume: 66 (5) Pages from: 645 to: 651
KeyWords: Metastable States; Relaxation; SystemDOI: 10.1209/epl/i2004-10028-6ImpactFactor: 2.229Citations: 31data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-11-10References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here