# @PRL The first experimental verification of fluctuation relations in "Quantum Thermodynamics&qu

Highlighted as Editors’ Suggestion. 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 thermodynamic relevance with explicit non-equilibrium features. Although the experimental verification of such fundamental relations in the classical domain has encountered considerable 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. 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 characterization 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.

**Read more:** Physical Review Letters 113, 140601 (2014) | arXiv |highlighted as **Editors' Suggestion**

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Brazilian Physical Society (SBF): *Experimento revela efeitos quânticos na Termodinâmica*.

Revista Pesquisa FAPESP: *Spin engines (eng)* | Máquinas de spins (port) | PDF (port).