Experimental Realization of a Tunable Non-Hermitian, Nonlinear Microwave Dimer: Theory and Model

Lattices microwave cavities have recently been used to simulate effective tight-binding Hamiltonians where interactions can be introduced by coupling to superconducting qubits, and time-reversal symmetry can be broken by coupling to magnetic materials like Yttrium-Iron-Garnet. However, in these models, the hopping rate between cavities is constant and limited to nearest neighbors. Here, we relax this constraint by coupling microwave cavities with cables, amplifiers, and phase shifters--realizing reconfigurable and tunable hopping between our high-Q 3D microwave cavities. Due to the inherent non-reciprocity of the amplifiers, we can separate the photon hopping into two distinct paths that can be independently tuned to realize non-Hermitian effective tight-binding Hamiltonians. Furthermore, the amplifiers introduce new types of nonlinearities beyond the typical Kerr nonlinearities explored in qubit-cavity systems— making this a new experimental platform for quantum simulation, nonlinear dynamics, and exploration of the intersections between Hermitian and non-Hermitian physics. This second talk will describe our theoretical model and future directions.