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Exactly solvable model of a quantum spin glass

Th. M. Nieuwenhuizen
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Abstract

A mean field spherical model with random couplings between pairs, quartets, and possibly higher multiplets of spins is considered. It has the same critical behavior as the Sherrington-Kirkpatrick model. It thus exhibits replica symmetry breaking. The order parameter function is solved exactly in the whole low temperature phase. The zero field cooled susceptibility remains finite at low $T$. Next a quantum version of the system is considered. Whereas the magnetic properties are not altered qualitatively, the thermodynamics is now regular at small temperatures.

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Th. M. Nieuwenhuizen. 1995-05-18. Exactly solvable model of a quantum spin glass. https://doi.org/10.1103/physrevlett.74.4289

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