Locally Passive, Globally Charged Quantum Batteries: Coherence‐Controlled Work and the Robustness of the Stored Charge

ABSTRACT

A solvable charger–battery model is introduced in which quantum coherence controls both where a quantum battery's charge is stored and how robustly it survives noise. Charging converts the charger's coherence into charger–battery entanglement and splits the deposited work between a locally extractable part and a correlation‐locked part accessible only through joint operations; for a qubit, the split obeys an exact complementarity, and at maximal coherence, the battery is locally passive with the entire charge locked in correlations. Robustness follows local accessibility: the stored energy and locally extractable work are population‐based, immune to pure dephasing, and limited only by relaxation, with an energy half‐life, whereas the correlation‐locked work is fragile to both dephasing and relaxation. Dephasing, global and local depolarization, and amplitude damping are treated through a single gain–loss competition algebra, and the resulting storage lifetimes are made concrete with superconducting‐transmon parameters.