Coherent control of steady state and dynamic ergotropy in bipartite quantum batteries

Abstract The ergotropy of a bipartite quantum battery is examined within an open system setup,
where the coupling between the holder component and the external energy supply is mediated by a 2-
level system charger. Various model prototypes of the holder such as harmonic oscillator and N -level
systems are considered with an analytical rigour with special reference to a 3- level system, highlighting
the interplay between coherent energy pumping through charger and thermal dissipation of both the
charger and holder due to a zero temperature bosonic bath. Special attention has been focused on
ergotropy for a 2-level system holder under steady state and dynamical regime. Although typical battery
charging cycles and their long-term performance depends on various characteristics of the reservoir, we
have exemplied that the ergotropy of a quantum battery is not solely determined by its microscopic
details of the system but is governed by more fundamental thermodynamic principle that applies across
various quantum models within Markovian framework. We have also demonstrated the intricate interplay
of coherent charger-holder coupling, external driving and damping parameters which can be utilized to
get an optimized 2-level system quantum battery. An attempt has also been made to model a chargerless
quantum battery with a predesigned source reservoir in a transport setup which is a novel example of
reservoir assisted charging.