TY - JOUR T1 - Energy storage and coherence in closed and open quantum batteries JF - Quantum Y1 - 2021 A1 - Francesco Caravelli A1 - Bin Yan A1 - Luis Pedro García-Pintos A1 - Alioscia Hamma AB -

We study the role of coherence in closed and open quantum batteries. We obtain upper bounds to the work performed or energy exchanged by both closed and open quantum batteries in terms of coherence. Specifically, we show that the energy storage can be bounded by the Hilbert-Schmidt coherence of the density matrix in the spectral basis of the unitary operator that encodes the evolution of the battery. We also show that an analogous bound can be obtained in terms of the battery's Hamiltonian coherence in the basis of the unitary operator by evaluating their commutator. We apply these bounds to a 4-state quantum system and the anisotropic XY Ising model in the closed system case, and the Spin-Boson model in the open case. 

VL - 5 U4 - 505 UR - https://arxiv.org/abs/2012.15026 U5 - https://doi.org/10.22331/q-2021-07-15-505 ER - TY - JOUR T1 - Random Quantum Batteries JF - Phys. Rev. Research Y1 - 2020 A1 - Francesco Caravelli A1 - Ghislaine Coulter-De Wit A1 - Luis Pedro García-Pintos A1 - Alioscia Hamma AB -

Quantum nano-devices are fundamental systems in quantum thermodynamics that have been the subject of profound interest in recent years. Among these, quantum batteries play a very important role. In this paper we lay down a theory of random quantum batteries and provide a systematic way of computing the average work and work fluctuations in such devices by investigating their typical behavior. We show that the performance of random quantum batteries exhibits typicality and depends only on the spectral properties of the time evolving operator, the initial state and the measuring Hamiltonian. At given revival times a random quantum battery features a quantum advantage over classical random batteries. Our method is particularly apt to be used both for exactly solvable models like the Jaynes-Cummings model or in perturbation theory, e.g., systems subject to harmonic perturbations. We also study the setting of quantum adiabatic random batteries.

VL - 2 UR - https://arxiv.org/abs/1908.08064 CP - 023095 U5 - https://doi.org/10.1103/PhysRevResearch.2.023095 ER -