Solvable Quantum Grassmann Matrices

TL;DR

This paper investigates solvable quantum models with fermionic degrees of freedom and non-local interactions, revealing phase transitions and thermal behavior through exact calculations in both Hilbert and bosonic frameworks.

Contribution

It introduces exactly solvable quantum Grassmann matrix models with explicit thermal partition functions and analyzes their phase structure and correlations at large N.

Findings

Existence of a phase transition at large N

Explicit expression for the thermal partition function

Decay of two-point functions at high temperature

Abstract

We explore systems with a large number of fermionic degrees of freedom subject to non-local interactions. We study both vector and matrix-like models with quartic interactions. The exact thermal partition function is expressed in terms of an ordinary bosonic integral, which has an eigenvalue repulsion term in the matrix case. We calculate real time correlations at finite temperature and analyze the thermal phase structure. When possible, calculations are performed in both the original Hilbert space as well as the bosonic picture, and the exact map between the two is explained. At large $N$, there is a phase transition to a highly entropic high temperature phase from a low temperature low entropy phase. Thermal two-point functions decay in time in the high temperature phase.