Strong coupling and non-Hermitian control in inductively coupled wireless power transfer

Recent advances in non-Hermitian physics have shed light on the profound role of environmental interactions in open systems. Non-Hermitian electrical circuits have emerged as a versatile platform for studying and realizing exotic phenomena rooted in non-Hermitian quantum mechanics. Owing to the profound analogy between Kirchhoff's laws and the Schrödinger equation, resonant circuits provide an ideal testbed for non-Hermitian effects. In particular, two LCR circuits can be coupled coherently through inductive or capacitive elements, or dissipatively via resistors, allowing flexible control over system dynamics. Coherent coupling enables precise frequency tuning at the transmitter. In this work, we demonstrate strongly coupled wireless power transfer using two mutually inductively coupled series LCR resonators in a fully passive configuration. By adjusting resistances in the circuits, we achieve active control over the quality factor of the resonances, facilitating efficient power transmission under non-Hermitian conditions.