What happens when a quantum battery powers a precision qubit interferometer

Geometric Landau-Zener interferometry, a technique for probing qubit dynamics via interference of adiabatic sweeps, normally assumes a classical, phase-stable microwave source. Swapping that source for a quantized bosonic mode governed by Jaynes-Cummings coupling splits the dynamics into photon-number-resolved sectors, each with its own avoided-crossing gap proportional to √n. A refocusing echo pulse that cleanly cancels dynamical phases in the classical case instead mixes excitation sectors in the quantum case, producing contrast loss and interferogram distortions. The result positions this interferometry scheme as a practical test for certifying true phase-coherent energy delivery from a quantum battery.