Subwavelength quantum battery based on an atomic ring array coupled with an incoherently driven atom

Many-body quantum batteries composed of $N$ two-level systems benefit from collective effects, demonstrating excellent charging performance. In this paper, we consider a charging scheme where an atomic ring array serves as the quantum battery system, coupled to a central charger atom that is pumped by an incoherent thermal source. Assuming no interactions among the atoms on the ring, the system can be described using the Dicke model, where collective coupling results in a significant initial charging power. When dipole-dipole interactions among the atoms are taken into account, the charging power of the battery decreases due to the introduction of intricate collective dissipation. However, the symmetric coherent interactions facilitate the rapid relaxation of the system's dynamics to the eigenstates, thereby increasing the proportion of useful work within the battery. Moreover, we investigate the impact of the ring size and the detuning of the charger atom on the steady-state ergotropy of the quantum battery. Our findings indicate that, at zero detuning, the system exhibits a larger effective charging ring size. As the magnitude of the detuning increases, the effective charging ring size decreases. By analyzing the radiation properties of the system in its steady state, we also explain why the steady-state ergotropy is higher when the charger atom is positively detuned.