BEGIN:VCALENDAR VERSION:2.0 CALSCALE:GREGORIAN PRODID:UW-Madison-Physics-Events BEGIN:VEVENT SEQUENCE:0 UID:UW-Physics-Event-2962 DTSTART:20130305T160000Z DURATION:PT1H0M0S DTSTAMP:20260420T020616Z LAST-MODIFIED:20130219T223910Z LOCATION:5280 Chamberlin Hall SUMMARY:Analysis of high-fidelity gate design and error thresholds for fault-tolerant superconducting quantum computing architectures\, R. G . Herb Condensed Matter Seminar\, Joydip Ghosh\, University of Georgia DESCRIPTION:Quantum computing with superconducting elements promises s calability and is widely regarded as a viable approach to develop a fa ult-tolerant architecture of a candidate quantum computer. In this tal k\, I first discuss our recent proposal to design high-fidelity contro lled-σz (CZ) operations using only DC bias control and th en explore the performance of various existing superconducting surface code based architectures under a realistic multi-parameter error mode l. Assuming phase or transmon qubits and using only low frequency qubi t-bias control\, our CZ operation exhibits threshold fidelity (intrins ic) with a realistic two-parameter pulse profile. In addition we have an analytic model that estimates the fidelities of CZ gates as a funct ion of various pulse parameters as well as quantifies the error due to any perturbation over an optimal pulse shape. Next we consider a real istic\, multi-parameter error model and investigate the performance of the surface code for three possible fault-tolerant superconducting ar chitectures. We map amplitude and phase damping to an asymmetric depol arization channel via the Pauli twirl approximation\, and obtain the l ogical error rate as a function of the qubit coherence time\, intrinsi c state preparation and gate and readout errors. A numerical Monte Car lo simulation is performed to obtain the logical error rates and a lea ding order analytic model is constructed to estimate their scaling beh avior below threshold. Our results suggest that large-scale fault-tole rant quantum computation should be possible with existing superconduct ing devices. URL:https://www.physics.wisc.edu/events/?id=2962 END:VEVENT END:VCALENDAR