Superconducting Circuits: Controlling the Bath

Superconducting circuits are inherently open quantum systems, and advances in surface science and circuit design to reduce spurious coupling to an uncontrolled environment have resulted in state-of-the-art devices with coherence times in excess of 100 microseconds. Such long-lived coherence affords another modality where the environment can be modified by way of microwave control pulses to engineer a dressed Hamiltonian with new types of light-matter coupling. Alternatively, the bath can be monitored to tailor different measurement protocols. I will illustrate how bath engineering can use used to probe quantum uncertainty relations and realize real-time adaptive measurements, as well as present new methods for quantum state reconstruction based on machine learning techniques.