Fermionic Quantum Spin Glass Transitions

TL;DR

This paper reviews recent analytical advances in understanding fermionic quantum spin glass transitions, including exact results, renormalization group calculations, and phase diagrams for different regimes.

Contribution

It provides a comprehensive analysis of fermionic QSG transitions, connecting thermal and zero-temperature transitions, and introduces a phase diagram with tricritical points caused by various mechanisms.

Findings

Exact results for infinite-range models

Renormalization group calculations for finite-range models

Phase diagram with tricritical quantum spin glass transitions

Abstract

This article reviews recent progress of the analytical theory of quantum spin glasses (QSG). Exact results for infinite range and one loop renormalisation group calculations for finite range models of either insulating or metallic type are presented. We describe characteristics of fermionic spin glass transitions and of fermionic correlations which are affected by these transitions and by spin glass order. Connections between tricritical thermal-- and $T=0$ QSG transitions are described. A general phase diagram with tricritical QSG transitions caused either by random chemical potential or by elastic electron scattering, and implying discontinuous $T=0$--transitions in weak and in strong filling regimes, is also derived.