A quantum battery with quadratic driving

Quantum batteries are energy storage devices built using quantum mechanical objects, which are developed with the aim of outperforming their classical counterparts. Proposing optimal designs of quantum batteries which are able to exploit quantum advantages requires balancing the competing demands for fast charging, durable storage and effective work extraction. Here we study theoretically a bipartite quantum battery model, composed of a driven charger connected to an energy holder, within two paradigmatic cases of a driven-dissipative open quantum system: linear driving and quadratic driving. The linear battery is governed by a single exceptional point which splits the response of the battery into two regimes, one of which induces a good amount of useful work. Quadratic driving leads to a squeezed quantum battery, which generates plentiful useful work near to critical points associated with dissipative phase transitions. Our theoretical results may be realized with parametric cavities or nonlinear circuits, potentially leading to the manifestation of a quantum battery exhibiting squeezing.