BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Erik Nielsen (Sandia National Laboratories\, Albuquerque\, New Mex ico) DTSTART:20200612T003000Z DTEND:20200612T010000Z DTSTAMP:20260423T010133Z UID:UTSQSI/7 DESCRIPTION:Title: H old the onion: using fewer circuits to characterize your quoits\nby Er ik Nielsen (Sandia National Laboratories\, Albuquerque\, New Mexico) as pa rt of Centre for Quantum Software and Information Seminar Series\n\n\nAbst ract\nModel-based quantum tomography protocols like gate set tomography op timize a noise model with some number of parameters in order to fit experi mental data. As the number of qubits increases\, two issues emerge: 1) th e number of model parameters grows\, and 2) the cost of propagating quantu m states (density matrices) increases exponentially. The first issue can be addressed by considering reduced models that limit errors to being low -weight and geometrically local. \n\nIn this talk\, we focus on the second issue and present a method for performing approximate density matrix prop agation based on perturbative expansions of error generators. The method is tailored to the likelihood optimization problem faced by model-based to mography protocols. We will discuss the advantages and drawbacks of using this method when characterizing the errors in up to 8-qubit systems.\n\nH osted by A/Prof Chris Ferrie\, UTS Centre for Quantum Software and Informa tion. \n\nPlease note\, the starting time is only an estimate as Erik Nie lsen's seminar will follow directly after the ~30min seminar of Robin Blum e-Kohout.\n LOCATION:https://researchseminars.org/talk/UTSQSI/7/ END:VEVENT END:VCALENDAR