Speaker
Description
Both cosmogenic and terrestrial radiation are known to contribute to errors in superconducting qubits. There are multiple types and sources of ionizing radiation that can be relevant to these qubits, such as particle showers from cosmic rays, gamma radiation from surrounding earth and building materials, and radioactivity internal to the dilution fridge or qubit package itself. To investigate and disentangle these different contributions, we operate superconducting qubits in a shallow underground lab (30-meter water equivalent), which reduces the flux of cosmogenic muons by a factor of ~6 and cosmogenic hadrons by a factor of > 100. Qubit performance is measured with and without a lead gamma shield to isolate the effects of ambient gamma backgrounds.
