The Non--Ergodicity Threshold: Time Scale for Magnetic Reversal
Abstract
We prove the existence of a non-ergodicity threshold for an anisotropic classical Heisenberg model with all-to-all couplings. Below the threshold, the energy surface is disconnected in two components with positive and negative magnetizations respectively. Above, in a fully chaotic regime, magnetization changes sign in a stochastic way and its behavior can be fully characterized by an average magnetization reversal time. We show that statistical mechanics predicts a phase--transition at an energy higher than the non-ergodicity threshold. We assess the dynamical relevance of the latter for finite systems through numerical simulations and analytical calculations. In particular, the time scale for magnetic reversal diverges as a power law at the ergodicity threshold with a size-dependent exponent, which could be a signature of the phenomenon.
Keywords
Cite
@article{arxiv.cond-mat/0410119,
title = {The Non--Ergodicity Threshold: Time Scale for Magnetic Reversal},
author = {G. L. Celardo and J. Barre and F. Borgonovi and S. Ruffo},
journal= {arXiv preprint arXiv:cond-mat/0410119},
year = {2014}
}
Comments
4 pages 4 figures