Thermodynamics of weakly measured systems.

Last updated March 12, 2018 by Alessandro Ferraro

Wednesday, March 7th 2018, 04:00 PM, Bell Lecture Theatre

Speaker: A. Romito (Lancaster University)

Abstract:The laws of thermodynamics classify energy changes for macroscopic systems as work performed by external driving and heat exchanged with the environment. The extension of thermodynamics to include quantum fluctuations faces unique challenges, such as the proper identification of heat and work and clarification of the role of quantum coherence. Quantum systems continuously monitored by an external detector have recently provided a formidable platform to explore energy exchanges with the environment at a quantum level, both theoretically and experimentally.

After reviewing the general features of thermodynamics and its extension at the quantum level, I will introduce thermodynamic quantities, heat and work, along single quantum trajectories of continuously monitored systems and present their observation in experiments with superconducting qubits. Specifically, I will show the consistency of the introduced quantities by showing that they fulfil the second law of thermodynamics in the form of a generalized Jarzynski equality in the presence of tailored quantum feedback. I will further discuss the role of information exchange between system and detector and discuss experimental results showing  that quantum back-action can lead to a loss of information in imperfect measurements. This is a genuine quantum feature and the experimental confirmations of these results shows the potential of quantum trajectories to explore thermodynamics at a quantum level.


We are a Research Cluster of the School of Mathematics and Physics at Queen’s University Belfast in Northern Ireland. Our research interests are focused primarily on computational and theoretical physics.

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