Description:

Superconducting qubits are a leading quantum information technology, combining long-lived coherence with strong addressability and engineering flexibility. However, they are subject to decoherence due to environmental noise. A key source of this noise is fluctuations in the photon population of the cavity used to read out the qubit. I will present our recent result showing how this noise can be virtually eliminated by driving dissipation on demand. Using a parametrically-driven "dissipator," we induce strong loss by coupling to a cold bath mode. We use the dissipator to rapidly reset the cavity after measurement, speeding reset by more than an order of magnitude. We also show continuous cooling of the cavity, rapidly eliminating thermal photons and enhancing qubit coherence. This continuous cooling supports qubit coherence above 1 ms even with a bath temperature of 115 mK. I will discuss our results in the context of large-scale quantum processors, bosonic qubits, and studies of open quantum systems. 

Eli Levenson-Falk, Assistant Professor, University of Southern California