Fermionic Ising glasses in magnetic transverse field with BCS pairing interaction

TL;DR

This paper investigates how a transverse magnetic field influences the phase transitions and boundaries in a fermionic Ising spin glass model with BCS pairing, revealing significant effects on phase stability and tricritical points.

Contribution

It introduces a novel analysis of the combined effects of transverse field and BCS pairing in a fermionic spin glass using integral formalism and replica symmetry.

Findings

Transverse field significantly alters the spin glass phase boundary.

The PAIR phase exhibits long-range order due to pair formation.

The tricritical point location shifts with the applied transverse field.

Abstract

We study a fermionic infinited-ranged Ising spin glass with a real space BCS interaction in the presence of an applied transverse field. The problem is formulated in the integral functional formalism where the SU(2) spins are given in terms of bilinear combinations of Grassmann fields. The problem is solved within static approximation and the replica symmetry ansatz combined with previous approaches used to study the critical behavior of the quantum Ising spin glass in a transverse field and the spin glass Heisenberg model with BCS pairing. Our results show that the transverse field has strong effect in the phase boundary of the spin glass phase and the PAIR phase in which there is a long range order corresponding to formations of pairs. The location of the tricritical point in the PAIR phase transition line is also affected.