Abstract A quantum battery (QB) model composed of two atoms is studied, where the charger and battery elements are coupled to a multimode vacuum field that serves as the mediator for energy transfer. Different figures of merit such as ergotropy, charging time, and charging efficiency are analyzed, putting emphasis on the role of various control parameters on the charging performance. It is found that there is a range of angle between the transition dipole moments and interatomic axis in which the QB can be charged, and the optimal performance is achieved when the dipole moments are parallel to the interatomic axis. The charging performance also improves with the decrease of the interatomic distance. Besides, the ergotropy charged on the QB can be enhanced by enhancing the initial charger ergotropy and it is beneficial to charge the QB starting from its ground state.
Hu et al. (Fri,) studied this question.