Inverse freezing in the Hopfield fermionic Ising spin glass with a transverse magnetic field

The Hopfield fermionic Ising spin glass (HFISG) model in the presence of a magnetic transverse field Gamma is used to study the inverse freezing transition. The mean field solution of this model allows introducing a parameter a that controls the frustration level. Particularly, in the present fermionic formalism, the chemical potential mu and the Gamma provide a magnetic dilution and quantum spin flip mechanism. respectively. Within the one step replica symmetry solution and the static approximation, the results show that the reentrant transition between the spin glass and the paramagnetic phases, which is related to the inverse freezing for a certain range of mu, is gradually suppressed when the level of frustration a is decreased. Nevertheless, the quantum fluctuations caused by Gamma can destroy this inverse freezing for any value of a. (C) 2010 Elsevier B.V. All rights reserved.