Quantum Spin Glasses

TL;DR

This paper discusses quantum phase transitions in Ising spin glasses under a transverse field, highlighting the unique quantum critical behavior and the emergence of a quantum Griffiths phase affecting physical properties.

Contribution

It provides an analysis of the quantum Griffiths phase in finite-dimensional spin glasses and its impact on observable physical quantities near the transition.

Findings

Diverging magnetic susceptibilities over a range of transverse fields

Presence of a quantum Griffiths phase in disordered spin glasses

Distinct universality class from classical phase transitions

Abstract

Ising spin glasses in a transverse field exhibit a zero temperature quantum phase transition, which is driven by quantum rather than thermal fluctuations. They constitute a universality class that is significantly different from the classical, thermal phase transitions. Most interestingly close to the transition in finite dimensions a quantum Griffiths phase leads to drastic consequences for various physical quantities: for instance diverging magnetic susceptibilities are observable over a whole range of transverse field values in the disordered phase.