English

Model glasses coupled to two different heat baths

Disordered Systems and Neural Networks 2009-10-31 v1 Statistical Mechanics

Abstract

In a pp-spin interaction spherical spin-glass model both the spins and the couplings are allowed to change in the course of time. The spins are coupled to a heat bath with temperature TT, while the coupling constants are coupled to a bath having temperature TJT_{J}. In an adiabatic limit (where relaxation time of the couplings is much larger that of the spins) we construct a generalized two-temperature thermodynamics. It involves entropies of the spins and the coupling constants. The application for spin-glass systems leads to a standard replica theory with a non-vanishing number of replicas, n=T/TJn=T/T_J. For p>2p>2 there occur at low temperatures two different glassy phases, depending on the value of nn. The obtained first-order transitions have positive latent heat, and positive discontinuity of the total entropy. This is the essentially non-equilibrium effect. The predictions of longtime dynamics and infinite-time statics differ only for n<1n<1 and p>2p>2. For p=2p=2 correlation of the disorder (leading to a non-zero nn) removes the known marginal stability of the spin glass phase. If the observation time is very large there occurs no finite-temperature spin glass phase. In this case there are analogies with the broken-ergodicity dynamics in the usual spin-glass models and non-equilibrium (aging) dynamics. A generalized fluctuation-dissipation relation is derived.

Keywords

Cite

@article{arxiv.cond-mat/9907090,
  title  = {Model glasses coupled to two different heat baths},
  author = {A. E. Allahverdyan and Th. M. Nieuwenhuizen and D. B. Saakian},
  journal= {arXiv preprint arXiv:cond-mat/9907090},
  year   = {2009}
}

Comments

revtex, 28 pages, 7 figures, 3 tables