paper

Laser-annealing Josephson junctions for yielding scaled-up superconducting quantum processors

arXiv:2009.00781 · doi:10.1038/s41534-021-00464-5

Abstract

As superconducting quantum circuits scale to larger sizes, the problem of frequency crowding proves a formidable task. Here we present a solution for this problem in fixed-frequency qubit architectures. By systematically adjusting qubit frequencies post-fabrication, we show a nearly ten-fold improvement in the precision of setting qubit frequencies. To assess scalability, we identify the types of 'frequency collisions' that will impair a transmon qubit and cross-resonance gate architecture. Using statistical modeling, we compute the probability of evading all such conditions, as a function of qubit frequency precision. We find that without post-fabrication tuning, the probability of finding a workable lattice quickly approaches 0. However with the demonstrated precisions it is possible to find collision-free lattices with favorable yield. These techniques and models are currently employed in available quantum systems and will be indispensable as systems continue to scale to larger sizes.

arXiv comment9 pages, 6 figures, Supplementary Information. Update to correct typo in author name and in text. Updated acknowledgements and corrected typo in acknowledgements

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