Experimental Validation of Fully Quantum Fluctuation Theorems Using Dynamic Bayesian Networks

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 apply a novel dynamic Bayesian network approach to experimentally test detailed and integral fully quantum fluctuation theorems for heat exchange between two quantum-correlated thermal spins-1/2 in a nuclear magnetic resonance setup. We concretely verify individual integral fluctuation relations for quantum correlations and quantum coherence, as well as for the sum of all quantum contributions. We further investigate the thermodynamic cost of creating correlations and coherence.

Automated summary

Experimental studies of quantum fluctuation relations often neglect important quantum properties like quantum correlations and coherence, which can have significant implications for understanding thermodynamic processes. Through experimental testing, the validity of fully quantum fluctuation theorems for heat exchange between quantum-correlated thermal spins-1/2 has been verified, demonstrating the integral fluctuation relations for quantum correlations and coherence in this process.