Experimental reconstruction of work distribution and verification of fluctuation relations at the full quantum level

TL;DR

This paper reports the first experimental verification of quantum fluctuation relations, specifically the Jarzynski and Crooks relations, by reconstructing work distributions in a quantum system using NMR techniques.

Contribution

It introduces a novel method for characterizing quantum work distributions, enabling experimental testing of fundamental quantum thermodynamic relations.

Findings

Successful experimental verification of quantum Jarzynski identity

First full reconstruction of quantum work distribution in NMR system

Advancement in quantum thermodynamics research methods

Abstract

Research on the out-of-equilibrium dynamics of quantum systems has so far produced important statements on the thermodynamics of small systems undergoing quantum mechanical evolutions. Key examples are provided by the Crooks and Jarzynski relations: taking into account fluctuations in non-equilibrium dynamics, such relations connect equilibrium properties of thermodynamical relevance with explicit non-equilibrium features. Although the experimental verification of such fundamental relations in the classical domain has encountered some success, their quantum mechanical version requires the assessment of the statistics of work performed by or onto an evolving quantum system, a step that has so far encountered considerable difficulties in its implementation due to the practical difficulty to perform reliable projective measurements of instantaneous energy states. In this paper, by exploiting a radical change in the characterization of the work distribution at the quantum level, we report the first experimental verification of the quantum Jarzynski identity and the Tasaki-Crooks relation following a quantum process implemented in a Nuclear Magnetic Resonance (NMR) system. Our experimental approach has enabled the full characterisation of the out-of-equilibrium dynamics of a quantum spin in a statistically significant way, thus embodying a key step towards the grounding of quantum-systems thermodynamics.