Battery (electricity)

Quantum mechanics

Engineering

State of charge

Materials science

Chromatography

Coherence (philosophical gambling strategy)

Nuclear physics

Power (physics)

Computer science

Coherence time

Flux qubit

Thermodynamics

Physics

Extraction (chemistry)

Charge qubit

Work (physics)

Phase qubit

Quantum

Charge (physics)

Qubit

Chemistry

Topology (electrical circuits)

Electrical engineering

Physical Review Letters

We analyze work extraction from a qubit into a waveguide (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 battery's charge) can be adjusted. We show that the extracted work is bounded by the qubit's ergotropy, and that the bound is saturated for a large enough battery's charge. If this charge is small, work can still be extracted. Its amount is controlled by the quantum coherence initially injected in the qubit's 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.

The Energetic Cost of Work Extraction