A Hybrid 3D Qubit Architecture for Probing Quantum Materials

Superconducting quantum circuits are gaining traction as a platform for probing and characterizing new quantum materials due to their high coherence, strong coupling, and efficient control/readout. Using the tools of circuit QED, it is possible to explore material properties using coherent microwave photons at the single quantum level. We have designed and fabricated a transmon-like qubit with superconductor-TI-superconductor (S-TI-S) junctions in the 3D cavity architecture. The system is characterized by spectroscopic measurements, and time-domain measurements reveal coherence properties. The unconventional current-phase relationship in TI junctions could lead to noise resilience for certain decoherence channels. We discuss methods to realize frequency tunable 3D TI-Transmons by either using an on-chip voltage gate, or by forming an asymmetrical SQUID with one S-TI-S junction and one conventional S-I-S Josephson junction. Here, I will discuss our experimental progress, results, and future directions for using circuit QED devices for understanding new quantum materials.