



01255nas a2200169   4500008004100000245007000041210006900111260001400180300000800194490000600202520075000208100002500958700001300983700003200996700002001028856003701048       2021                        eng d00aEnergy storage and coherence in closed and open quantum batteries0 aEnergy storage and coherence in closed and open quantum batterie  c7/15/2021  a5050 v53 a<p>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&#39;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.&nbsp;</p>1 aCaravelli, Francesco1 aYan, Bin1 aGarcía-Pintos, Luis, Pedro1 aHamma, Alioscia  uhttps://arxiv.org/abs/2012.1502601387nas a2200157   4500008004100000245002900041210002900070260001300099490000600112520096500118100002501083700003201108700003201140700002001172856003701192       2020                        eng d00aRandom Quantum Batteries0 aRandom Quantum Batteries  c5/5/20200 v23 a<p>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.</p>1 aCaravelli, Francesco1 aDe Wit, Ghislaine, Coulter-1 aGarcía-Pintos, Luis, Pedro1 aHamma, Alioscia  uhttps://arxiv.org/abs/1908.08064