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Ground State Structure of Random Magnets

Sorin Bastea·Philip M. Duxbury
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Abstract

Using exact optimization methods, we find all of the ground states of +/- h random-field Ising magnets (RFIM) and of dilute antiferromagnets in a field (DAFF). The degenerate ground states are usually composed of isolated clusters (two-level systems) embedded in a frozen background. We calculate the paramagnetic response (sublattice response) and the ground state entropy for the RFIM (DAFF) due to these clusters. In both two and three dimensions there is a broad regime in which these quantities are strictly positive, even at irrational values of h/J (J is the exchange constant).

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Sorin Bastea, Philip M. Duxbury. 1998-10-08. Ground State Structure of Random Magnets. https://doi.org/10.1103/physreve.58.4261

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