  Universal fault-tolerant quantum computers, which promise to revolutionize
computing, are currently limited by excessive noise in their constituent
superconducting qubits. Determining the dominant sources of this excess noise
will lead to a clearer understanding of how to mitigate it in future
superconducting systems. Superconducting Nanowire Single-Photon Detectors
(SNSPDs) are devices that do not appear to suffer from such effects and have
extremely low dark-count backgrounds. We propose to use SNSPDs as
low-background laboratories to study noise accumulation processes in
superconducting systems with the purpose of explaining and mitigating noise in
related quantum information systems. Through these studies we also aim to
increase the sensitive wavelengths of SNSPDs above the current limits of 10
microns, which would open new regimes for dark matter detection, biology, space
sciences, and quantum sensing.
