Behavior of Ising Spin Glasses in a Magnetic Field

Thomas Jorg, Helmut G. Katzgraber, Florent Krzakala

Published 2007-12-12, updated 2008-05-13Version 2

We study the existence of a spin-glass phase in a field using Monte Carlo simulations performed along a nontrivial path in the field--temperature plane that must cross any putative de Almeida-Thouless instability line. The method is first tested on the Ising spin glass on a Bethe lattice where the instability line separating the spin glass from the paramagnetic state is also computed analytically. While the instability line is reproduced by our simulations on the mean-field Bethe lattice, no such instability line can be found numerically for the short-range three-dimensional model.