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Speaker: Charles Stafford, Physics Dept, Univ of Arizona
Title: Consistent Quantum Thermodynamics from Local Observables
Abstract: There is no doubt that the Laws of Thermodynamics are consistent with Quantum Mechanics. However, the nonlocal character of quantum states has made it challenging to formulate a thermodynamic description of a quantum subsystem, such as a quantum machine strongly coupled to its environment. We show how to construct a consistent thermodynamic description of a quantum subsystem in terms of local quantum observables (e.g., internal energy, entropy, particle number) based on Hilbert-space partitioning of quantum operators. Thermodynamic quantities that do not correspond to quantum observables, such as work and heat, are shown to be inherently nonlocal, but can be included in the thermodynamics by treating the quantum subsystem as akin to a quantum impurity problem. This framework leads to a novel microscopic formula for the flow of entropy, which is used to analyze the unitary to dissipative crossover that underlies the continual increase in entropy of the universe.