Low-Loss Ferrite Circulator as a Tunable Chiral Quantum System

Abstract

Microwave circulators are usually treated as auxiliary, classical components in superconducting quantum computing. This study integrates the cavity-magnon polariton modes of a custom-built circulator with superconducting microwave cavities to implement a tunable nonreciprocal interaction. The apparatus is well described by a non-Hermitian Hamiltonian, yielding a theoretical framework to model other nonreciprocally coupled circuit elements on the same platform in the future. The experiment also showcases an experimental probe of the left and right eigenvectors associated with the non-Hermitian Hamiltonian.