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Molecular Foundry

HIGHLIGHTSLocalizing Sources of Quantum Decoherence
April 22, 2022

Scientific Achievement

TEM overview of Nb and Si interfaces (left) and XPS analysis of oxide evolution with etching (upper right). The schematic (lower right) shows the type and amount of loss from each oxide for superconducting niobium resonators operating in the single-quantum regime.

Attained Quality factors (Q’s) beyond the state-of-the-art in niobium co-planar resonators by removing surface oxides in devices with pristine substrate interfaces

Significance and Impact

Several leading qubit systems use superconducting Nb circuits, and enhanced circuit coherence is required to achieve fault-tolerant quantum computation

Research Details

  • Investigated quantum decoherence by modifying niobium-on-silicon resonators after fabrication with selective chemical etching
  • Showed that 93% of all quantum loss comes from the Si and Nb surface oxides
    M.V.P. Altoé, A. Banerjee, C. Berk, A. Hajr, A. Schwartzberg, C. Song, M. Alghadeer, S. Aloni, M.J. Elowson, J.M. Kreikebaum, E.K. Wong, S.M. Griffin, S. Rao , A. Weber-Bargioni, A.M. Minor, D.I. Santiago, S. Cabrini, I. Siddiqi, D.F. Ogletree, PRX Quantum 3, 020312 (2022) https://doi.org/10.1103/PRXQuantum.3.020312

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