Construction of spin models displaying quantum criticality from quantum field theory

TL;DR

This paper introduces a method to construct one-dimensional spin chain models exhibiting quantum criticality at finite temperatures, using quantum field theory correlators, with analytical purification and Monte Carlo analysis.

Contribution

The authors develop a novel approach to generate finite temperature quantum critical spin models from quantum field theory correlators, enabling detailed phase diagram studies.

Findings

Models display a region of quantum criticality.

Monte Carlo simulations effectively analyze low-temperature phases.

Constructed states closely resemble thermal states of simple Hamiltonians.

Abstract

We provide a method for constructing finite temperature states of one-dimensional spin chains displaying quantum criticality. These models are constructed using correlators of products of quantum fields and have an analytical purification. Their properties can be investigated by Monte-Carlo simulations, which enable us to study the low-temperature phase diagram and to show that it displays a region of quantum criticality. The mixed states obtained are shown to be close to the thermal state of a simple nearest neighbour Hamiltonian.