Enhancing the Charging Power of Quantum Batteries

Abstract

Can collective quantum effects make a difference in a meaningful thermodynamic operation? Focusing on energy storage and batteries, we demonstrate that quantum mechanics can lead to an enhancement in the amount of work deposited per unit time, i.e., the charging power, when N batteries are charged collectively. We first derive analytic upper bounds for the collective quantum advantage in charging power for two choices of constraints on the charging Hamiltonian. We then demonstrate that even in the absence of quantum entanglement this advantage can be extensive. For our main result, we provide an upper bound to the achievable quantum advantage when the interaction order is restricted; i.e., at most k batteries are interacting. This constitutes a fundamental limit on the advantage offered by quantum technologies over their classical counterparts.

Cooperative many-body enhancement of quantum thermal machine power

“…In that context, starting with the seminal work by Scully et al [7], extensive investigations have focused on the question whether quantum coherence in either the machine's working medium [8][9][10][11][12][13] or the energising (hot) bath (the 'fuel') [14-24] could either boost the power output or the efficiency of quantum engines. Whilst these investigations have been mainly theoretical, impressive experimental progress has also been made such as the first realisation of a heat engine based on a single atom [25], the demonstration of quantum-thermodynamic effects in the operation of a heat engine implemented by an ensemble of nitrogen-vacancy (NV) centres in diamond [26] and the simulation of a quantum engine fuelled by a squeezed-thermal bath in a classical setting [27].Here we explore the possibility of exploiting collective (cooperative) many-body effects in quantum heat engines and refrigerators [28][29][30][31][32][33][34][35][36]. These generic quantum effects have a common origin with Dicke superradiance [37], whereby light emission is collectively enhanced by the interaction of N atoms with a common environment (bath) such that its intensity scales with N 2 [37-62].…”

Tightening Quantum Speed Limits for Almost All States

“…In Refs. [32][33][34] QSLs are used to bound the charging power of non-degenerate multi-partite systems, which are treated as batteries. The latter results imply a significant speed advantage for entangling over local unitary driving of quantum systems, given the same external constraints.…”

Quantum magnetometry using two-stroke thermal machines

“…The engine transition then corresponds to the lasing threshold and instead of measuring energy currents one could base the magnetometry scheme on the measurement of the photon bunching parameter [76,77]. The change in work capacity or ergotropy [78-80] of a quantum system (quantum battery) [81,82], for example a quantum harmonic oscillator, coupled to the thermal machine, is then an indication for work output of the machine [77,83,84]. One could then consider estimating the weak magnetic field through measurement of the zero of the work output, by measuring the change in ergotropy of the quantum battery.…”