Microwave Spectroscopy in Hybrid Semiconductor-based Josephson Junctions

Planar semiconductor-based Josephson junctions (JJs) offer a unique platform for realizing tunable qubits and the potential for hosting topological qubits. When these junctions are inserted in a cavity quantum electrodynamic (QED) circuit, the energy spectrum of Andreev bound states (ABSs) in the junction, can be probed using microwave spectroscopy. We study the ABSs of Al-InAs JJs by inductively coupling the JJ in a superconducting loop to a coplanar waveguide superconducting resonator. By monitoring the resonator's response using dispersive readout techniques, we probe for transitions between ABSs and quasiparticle poisoning events.