Better performance of quantum batteries in different environments compared to closed batteries

Abstract

We construct a central-spin battery model affected by noise or thermal bath and consider the impact of environment on battery performance. In a noisy environment, we show that the steady-state energy and ergotropy are related to the number of spins exposed to the noisy channel. In addition, we reveal the relationship between the steady-state energy and ergotropy with the quantum information lost in the battery. In a thermal bath, we find that the higher the mean occupation number of the thermal bath, the greater the steady-state energy. In particular, we find that, in two different environments, the steady-state energy and ergotropy are related to the effective magnetic-field strength of battery $B$, but not charger $h$. It is worth noting that, in the central-spin model, when $B$ is a constant and $|h/B\ensuremath{-}1|$ reaches a certain value, the steady-state energy and ergotropy with noise or thermal bath are always greater than or equal to the maximum energy and ergotropy of the corresponding closed battery. At the same time, we generalize the conclusions to the two-qubit, two-harmonic-oscillator, and harmonic-oscillator-qubit models.