We show that a micromaser is an excellent model of quantum battery. A highly excited, pure, and effectively steady state of the cavity mode, charged by coherent qubits, can be achieved, also in the ultrastrong coupling regime of field-matter interaction. Stability of these appealing features against loss of coherence of the qubits and the effect of counter-rotating terms in the interaction Hamiltonian are also discussed.
@article{arxiv.2204.09995,
title = {Micromasers as Quantum Batteries},
author = {Vahid Shaghaghi and Varinder Singh and Giuliano Benenti and Dario Rosa},
journal= {arXiv preprint arXiv:2204.09995},
year = {2022}
}