Superconducting resonator pair coupled to common two-level systems through an electrical bridge

Atomic two level system defects (TLSs) are ubiquitous in superconducting quantum information processing devices and astronomy photon detectors, and therefore an understanding of them in new devices is of technological importance. We have developed a pair of resonators using the four nodes of an electrical bridge capacitance. This capacitor configuration allows the two resonators to share common TLSs in separately addressable resonator modes. The TLSs are within a deposited film of dielectric within the capacitors. One resonator from the pair is designed with a tunable inductor made from titanium nitride. It allows a relatively large frequency tuning range, up to 120 MHz, through application of a DC current. This design allows us to study virtually TLSs with nearly degenerate resonators. We will report on the degree to which resonator quality factor is limited by the TLSs.