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Slow Dynamics of Ising Models with Energy Barriers
Lipowski, Adam; Johnston, Des; Espriu, D. (Domènec)
Universitat de Barcelona
Using Monte Carlo simulations we study the dynamics of three-dimensional Ising models with nearest-, next-nearest-, and four-spin (plaquette) interactions. During coarsening, such models develop growing energy barriers, which leads to very slow dynamics at low temperature. As already reported, the model with only the plaquette interaction exhibits some of the features characteristic of ordinary glasses: strong metastability of the supercooled liquid, a weak increase of the characteristic length under cooling, stretched-exponential relaxation, and aging. The addition of two-spin interactions, in general, destroys such behavior: the liquid phase loses metastability and the slow-dynamics regime terminates well below the melting transition, which is presumably related with a certain corner-rounding transition. However, for a particular choice of interaction constants, when the ground state is strongly degenerate, our simulations suggest that the slow-dynamics regime extends up to the melting transition. The analysis of these models leads us to the conjecture that in the four-spin Ising model domain walls lose their tension at the glassy transition and that they are basically tensionless in the glassy phase.
2011-07-26
Física estadística
Termodinàmica
Sistemes dinàmics diferenciables
Statistical physics
Thermodynamics
Differentiable dynamical systems
(c) The American Physical Society, 1999
Article
The American Physical Society
         

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