Metastable states, anomalous distributions and correlations in the HMF model

Details Metastable states, anomalous distributions and correlations in the HMF model Metastable states, anomalous distributions and correlations in the HMF model

2003-03-05

arxiv.org/abs/cond-mat/0303081v3

Physica D193 (2004) 315-328

Physics

Condensed Matter

Statistical Mechanics

15 pages, 10 figs. Revised version: fig.2 improved, conclusions expanded refs. updated. Invited talk at the Los Alamos int. co

Scientific paper

10.1016/j.physd.2004.01.029

We study the microscopic dynamics of the metastable Quasi-Stationary States (QSS) in the Hamiltonian Mean Field (HMF) model, a Hamiltonian system of N classical inertial spins with infinite-range interactions which shows a second order phase transition. In order to understand the origin of metastability, which appears in an energy region below the critical point, we consider two different classes of out-of-equilibrium initial conditions, both leading to QSS, and having respectively initial magnetization equal to one (M1 IC) and equal to zero (M0 IC). We compare the corresponding $\mu$-space, the resulting velocity pdfs and correlations, and the eventual aging features of the microscopic dynamics. In both cases the model exhibits non-gaussian pdfs, though anomalous correlations are present only when the system is started with an initial magnetization equal to one. In the M0 IC case the relaxation to equilibrium is almost exponential, while,for M1 IC, when correlations and aging are found, the decay is a power-law and the overall behavior can be very well reproduced by a Tsallis q-exponential function. These results contribute to clarify the overall scenario, which is more complex than previously expected and stress the importance of the dynamics in the relaxation process. The nonextensive statistical mechanics formalism proposed by Tsallis seems to be valid, in the out-of-equilibrium phase, when correlations and strong long-term memory effects emerge. This regime becomes stable if the $N\to \infty $ limit is performed before the $t\to \infty $ limit.

Affiliated with

Also associated with

No associations

Rating

Metastable states, anomalous distributions and correlations in the HMF model 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 Metastable states, anomalous distributions and correlations in the HMF model, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Metastable states, anomalous distributions and correlations in the HMF model will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-490313