Universality of Replica-Symmetry Breaking in the Transverse Field Sherrington–Kirkpatrick Model.

The existence theorem for replica-symmetry breaking (RSB) in the transverse field Sherrington–Kirkpatrick (SK) model is extended to the model with a general random exchange interactions. The relation between the expectation value of the exchange interaction energy and the Duhamel correlation function of spin operators can be obtained by an approximate integration by parts for general random interactions. In addition to the Falk–Bruch inequality, these explicit evaluations enable us to prove that the variance of overlap between two replica spin operators does not vanish under sufficiently weak transverse field in sufficiently low temperature. The absence of the ferromagnetic long range order is also shown to distinguish RSB from the Z 2 -symmetry breaking. [ABSTRACT FROM AUTHOR]