Quantum many-body Jarzynski equality and dissipative noise on a digital quantum computer

TL;DR

This paper demonstrates the experimental validation of the quantum Jarzynski equality and Crooks relation in many-body quantum systems using trapped ion and superconducting qubit quantum computers, despite noise and device limitations.

Contribution

First experimental test of quantum Jarzynski equality and Crooks relation in many-body systems on noisy quantum hardware, overcoming current technical challenges.

Findings

Validates Jarzynski equality in many-body regime with dissipation

Shows accuracy of fluctuation relations on noisy quantum devices

Provides insights into error analysis in quantum simulators

Abstract

The quantum Jarzynski equality and the Crooks relation are fundamental laws connecting equilibrium processes with nonequilibrium fluctuations. They are promising tools to benchmark quantum devices and measure free energy differences. While they are well established theoretically and also experimental realizations for few-body systems already exist, their experimental validity in the quantum many-body regime has not been observed so far. Here, we present results for nonequilibrium protocols in systems with up to sixteen interacting degrees of freedom obtained on trapped ion and superconducting qubit quantum computers, which test the quantum Jarzynski equality and the Crooks relation in the many-body regime. To achieve this, we overcome present-day limitations in the preparation of thermal ensembles and in the measurement of work distributions on noisy intermediate-scale quantum devices. We discuss the accuracy to which the Jarzynski equality holds on different quantum computing platforms subject to platform-specific errors. The analysis reveals the validity of Jarzynski's equality in a regime with energy dissipation, compensated for by a fast unitary drive. This provides new insights for analyzing errors in many-body quantum simulators.