1. A Parity-Protected Superconductor-Semiconductor Qubit
- Author
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Larsen, T. W., Gershenson, M. E., Casparis, L., Kringhøj, A., Pearson, N. J., McNeil, R. P. G., Kuemmeth, F., Krogstrup, P., Petersson, K. D., and Marcus, C. M.
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Superconductivity - Abstract
Coherence of superconducting qubits can be improved by implementing designs that protect the parity of Cooper pairs on superconducting islands. Here, we introduce a parity-protected qubit based on voltage-controlled semiconductor nanowire Josephson junctions, taking advantage of the higher harmonic content in the energy-phase relation of few-channel junctions. A symmetric interferometer formed by two such junctions, gate-tuned into balance and frustrated by a half-quantum of applied flux, yields a cos(2{\phi}) Josephson element, reflecting coherent transport of pairs of Cooper pairs. We demonstrate that relaxation of the qubit can be suppressed tenfold by tuning into the protected regime.
- Published
- 2020
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