Thermal Pure Quantum States at Finite Temperature

TL;DR

This paper introduces a new thermal pure quantum (TPQ) state and a straightforward method to obtain it, enabling efficient calculation of finite-temperature properties of quantum systems from a single state realization.

Contribution

The authors propose a novel TPQ state and a simple method to generate it, simplifying finite-temperature quantum statistical calculations.

Findings

A new TPQ state is defined and constructed.

A single realization of the TPQ state suffices for all thermodynamic calculations.

The method streamlines finite-temperature quantum simulations.

Abstract

An equilibrium state can be represented by a pure quantum state, which we call a thermal pure quantum (TPQ) state. We propose a new TPQ state and a simple method of obtaining it. A single realization of the TPQ state suffices for calculating all statistical-mechanical properties, including correlation functions and genuine thermodynamic variables, of a quantum system at finite temperature.