Dealing with Flux Noise, Vortices, and Quasiparticles in Superconducting Qubits and Resonators
The performance of superconducting qubits has improved significantly over the past decade to the point where initial implementations of quantum error correction are already being pursued. Further advances in qubit performance require approaches to deal with the various mechanisms that lead to dephasing or relaxation in qubit circuits or microwave resonators. We are investigating an alternate qubit design, the asymmetric transmon, that allows for a reasonable range of flux-tunability with a greatly reduced sensitivity to magnetic flux noise. I will also describe our work to probe the loss in superconducting microwave circuits due to magnetic flux vortices, including experiments where we can measure a single vortex trapped in a microwave resonator. Finally, we are studying the loss in superconducting resonators due to quasiparticles, which can be generated either by background pair-breaking radiation or on-chip control circuitry. I will discuss some of our strategies to mitigate this quasiparticle loss.
Hosted by Kevin Osborn.