Parametrically Enhanced Ergotropy and Charging Power in a Three-Mode Bosonic Quantum Battery

Abstract

Quantum batteries are quantum systems that potentially serve as fuel for other quantum devices by receiving and supplying energy. In this work, we propose a theoretical scheme to enhance ergotropy and charging power of quantum Battery in the system under consideration through squeezed light. Moreover, The system comprises a coherently driven charger cavity, a strongly dissipative auxiliary cavity acting as a mediator, and an energy--storage battery cavity. Quantum nonreciprocity and directional energy flow are established via destructive quantum interference between the direct coupling path and the loss--engineered indirect path. A degenerate optical parametric amplifier integrated into the charger cavity acts as an active, phase--sensitive energy source that injects two--photon quantum excitations and anomalous correlations. Using a strictly open--quantum--system framework derived directly from the Lindblad master equation, we obtain the full expectation--value dynamics and stationary states. We show that active parametric driving drastically increases the stored energy and peak charging power while maintaining nonreciprocal energy trapping in the battery. We achieve a multi-order-of-magnitude boost in the battery's stored energy, charging power, and ergotropy. We also analyze the effects of pure dephasing on the charging power, ergotropy, and extractable work quality.. Although two--photon pumping introduces photon--number fluctuations that slightly lower the fractional ergotropy ratio ${\cal W}_{\rm B}/{\cal E}_{\rm B}$, the absolute extractable work remains substantially elevated compared to unassisted configurations.

The paper studies whether active parametric pumping can increase stored energy, charging power, and extractable work in a bosonic battery while retaining loss-engineered directional transfer. The model comprises a coherently driven charger cavity, a strongly damped auxiliary cavity, and a battery cavity. A phase-dependent direct charger–battery coupling interferes with the auxiliary-mediated pathway; a degenerate optical parametric amplifier in the charger supplies additional photon pairs. The analysis uses a local Lindblad master equation and numerical evolution of first moments, populations, and normal and anomalous correlations. Parameter scans examine parametric gain, coupling strength and phase, detuning, auxiliary loss, and pump phase. For reference parameters $g_1=g_2=g_3=\sqrt{2}\kappa$, $\kappa_2=10\kappa$, $\kappa_1=\kappa_3=\kappa$, and $\Omega=0.5\kappa$, increasing the parametric gain from zero to $\lambda=\kappa$ reportedly raises peak instantaneous charging power by more than fourfold and increases peak and stationary ergotropy. The stationary extractable fraction $\mathcal W_{\rm B}/\mathcal E_{\rm B}$ decreases to approximately $0.6$ at $\lambda=\kappa$. Charging also occurs without coherent driving, with the parametric pump as the sole energy source. Added charger dephasing reduces peak power and ergotropy. The paper distinguishes the battery-to-charger energy ratio from energy-transfer efficiency: a ratio above unity does not measure the fraction of external energy stored. It also states that stationary results apply only within the dynamically stable gain range, and that assessing efficiency requires accounting for energy supplied by the parametric pump. No resource-matched efficiency advantage is established.