Experimental Validation of Fully Quantum Fluctuation Theorems Using Dynamic Bayesian Networks

TL;DR

This paper experimentally verifies fully quantum fluctuation theorems for heat exchange in a quantum system, accounting for quantum correlations and coherence, advancing understanding of quantum thermodynamics.

Contribution

It provides the first experimental validation of detailed and integral quantum fluctuation theorems that include quantum correlations and coherence.

Findings

Confirmed quantum fluctuation relations for heat exchange.

Validated quantum correlations and coherence contributions.

Demonstrated refined second law formulations in quantum thermodynamics.

Abstract

Fluctuation theorems are fundamental extensions of the second law of thermodynamics for small systems. Their general validity arbitrarily far from equilibrium makes them invaluable in nonequilibrium physics. So far, experimental studies of quantum fluctuation relations do not account for quantum correlations and quantum coherence, two essential quantum properties. We here experimentally verify detailed and integral fully quantum fluctuation theorems for heat exchange using two quantum-correlated thermal spins-1/2 in a nuclear magnetic resonance setup. We confirm, in particular, individual integral fluctuation relations for quantum correlations and quantum coherence, as well as for the sum of all quantum contributions. These refined formulations of the second law are important for the investigation of fully quantum features in nonequilibrium thermodynamics.