Algebraic power scaling in a slowly-quenched bosonic quantum battery

Bosonic modes provide a promising platform for quantum batteries as a result of their unbounded energy spectrum. However, the energy that can be stored during a coherent charging process is limited due to coherent oscillations between the charger and battery. In this Letter, we show that by introducing a slow quench in the interaction between a coherently driven quadratic oscillator battery and a charger system, the maximum battery power ($P_{B,m}$) scales algebraically with the quench duration ($\tau_Q$), i.e., $P_{B,m} \propto \tau_Q^\alpha$, where $0<\alpha\leq2$ is a function of the quench ramp exponent. This finding implies that, counterintuitively, slower quenches lead to faster charging. Such a quench suppresses coherent energy oscillations between the battery and the charger, allowing an unbounded increase in power. Furthermore, we discuss the effect of charger dissipation, which imposes a finite limit on the maximum power. We also show that the temporal extensive scaling occurs in a broader context by mapping the system to a coherently driven Tavis-Cummings battery.