We study the connection between the charging power of quantum batteries and the fluctuations of the extractable work. We prove that in order to have a nonzero rate of change of the extractable work, the state ρ W of the battery cannot be an eigenstate of a “free energy operator,” defined by F ≡ H W + β − 1 log ( ρ W ) , where H W is the Hamiltonian of the battery and β is the inverse temperature of a reference thermal bath with respect to which the extractable work is calculated. We do so by proving that fluctuations in the free energy operator upper bound the charging power of a quantum battery. Our findings also suggest that quantum coherence in the battery enhances the charging process, which we illustrate on a toy model of a heat engine.

Fluctuations in Extractable Work Bound the Charging Power of Quantum Batteries

Alioscia Hamma;
2020

Abstract

We study the connection between the charging power of quantum batteries and the fluctuations of the extractable work. We prove that in order to have a nonzero rate of change of the extractable work, the state ρ W of the battery cannot be an eigenstate of a “free energy operator,” defined by F ≡ H W + β − 1 log ( ρ W ) , where H W is the Hamiltonian of the battery and β is the inverse temperature of a reference thermal bath with respect to which the extractable work is calculated. We do so by proving that fluctuations in the free energy operator upper bound the charging power of a quantum battery. Our findings also suggest that quantum coherence in the battery enhances the charging process, which we illustrate on a toy model of a heat engine.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11588/893086
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