Proximity driven photon-tunneling in chiral quantum hybrid systems

TL;DR

This paper explores how the proximity and chirality of coupled microwave resonators influence photon tunneling, revealing controllable hybridization effects with potential applications in reconfigurable photonics and quantum technologies.

Contribution

It introduces a circuit QED model that describes proximity- and chirality-dependent coupling, providing a classical analogue of chiral quantum hybrid systems.

Findings

Strong modulation of transmission spectra with resonator spacing

Observation of mode splitting and dark states

Dependence of coupling on geometry and chirality

Abstract

We investigate photon tunneling in a pair of coupled inverted circular split-ring microwave resonators with four discrete chiral orientations. By varying the spacing between the resonators, we observe strong modulation of the transmission spectra, including mode splitting, interference effects, and the formation of dark states. Measurements on fabricated devices show clear signatures of hybridization that depend on both chirality and proximity, and these results are consistent with full-wave electromagnetic simulations. To describe the observed behavior, we develop a circuit quantum electrodynamics model that captures the dependence of the coupling strength on geometry and the reversal of its sign. Although the experimental excitation is classical, the system reproduces features expected from two quantized harmonic oscillators, providing a classical analogue of a chiral quantum hybrid platform. The ability to control photon tunneling through structural design and excitation parameters suggests potential applications in reconfigurable photonic devices, quantum communication, chiral sensing, and polarization-selective signal processing.