We analyze work extraction from a qubit into a wave guide (WG) acting as a battery, where work is the coherent component of the energy radiated by the qubit. The process is stimulated by a wave packet whose mean photon number (the batterys charge) can be adjusted. We show that the extracted work is bounded by the qubits ergotropy, and that the bound is saturated for a large enough batterys charge. If this charge is small, work can still be extracted. Its amount is controlled by the quantum coherence initially injected in the qubits state, that appears as a key parameter when energetic resources are limited. This new and autonomous scenario for the study of quantum batteries can be implemented with state-of-the-art artificial qubits coupled to WGs.
Download