Enhancing the charging performance of an atomic quantum battery

We study a quantum battery (QB) model composed of two atoms, where the charger and battery elements are coupled to a multimode vacuum field that serves as a 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. The optimal charging performance is achieved if the atomic dipole moments are perpendicular or parallel to the interatomic axis. The charging performance also improves with the decrease of the interatomic distance. Besides, the charged ergotropy can be enhanced by increasing the initial ergotropy of the charger and it is beneficial to charge the QB starting from a passive state.