A geometric approach to quantum thermodynamics: from quantum fluctuations to optimal protocols

A geometric approach to quantum thermodynamics: from quantum fluctuations to optimal protocols

Seminar author:Martí Perarnau Llobet

Event date and time:12/17/2019 12:00:pm

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The average dissipation generated during a slow thermodynamic process can be characterised by introducing a metric on the space of Gibbs states, in such a way that minimally-dissipating protocols correspond to geodesic trajectories. Furthermore, the dissipation is proportional to the work fluctuations for classical systems (which follows from the fluctuation-dissipation relation (FDR)), so that minimising dissipation also minimises fluctuations. In this talk, I will explain how this geometric picture is modified in the quantum regime. First, I will show that slowly driven quantum systems violate the classical FDR whenever quantum coherence is generated along the protocol, implying that quantum non-commutativity prohibits finding slow protocols that minimise both dissipation and fluctuations simultaneously. Instead, we develop a quantum geometric framework to find processes with an optimal trade-off between the two quantities. Furthermore, I will show that such quantum fluctuations lead to a non-Gaussian work distribution, in contrast to the Gaussian shape typically found in classical slow processes.

This talk is based on: arXiv:1810.05583, arXiv:1905.07328, and arXiv:1911.04306.