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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:2
UID:UW-Physics-Event-4908
DTSTART:20191018T203000Z
DURATION:PT1H0M0S
DTSTAMP:20260415T060858Z
LAST-MODIFIED:20191015T194543Z
LOCATION:2241 Chamberlin Hall
SUMMARY:Quantum Electrodynamics of Superconducting Circuits\, Physics 
 Department Colloquium\, Hakan Tureci\, Princeton/Rigetti Computing
DESCRIPTION:The demand for rapid and high-fidelity execution of initia
 lization\, gate and read-out operations casts tight constraints on the
  accuracy of quantum electrodynamic modeling of superconducting integr
 ated circuits. In particular\, radiative corrections to the properties
  of superconducting qubits\, such as their transition frequency (Lamb 
 shift) and the radiative decay rate (Purcell rate) have to be calculat
 ed to a high accuracy. In the pursuit of attaining the required accura
 cies we have found ourselves facing problems with divergent series aki
 n to those that have plagued the original quantum electrodynamics of a
  single electron in free space. Interestingly\, a semiclassical formul
 ation of the Purcell rate is found to provide finite and accurate resu
 lts. The reconciliation of the quantum and semiclassical results requi
 res the reconsideration of our basic approach to the quantization of t
 he electromagnetic field in a light-confining medium and the notion of
  normal modes. I will discuss a theoretical framework based on the Hei
 senberg-Langevin approach to address these fundamental questions. This
  framework allows the accurate computation of the quantum dynamics of 
 a superconducting qubit in an arbitrarily complex electromagnetic envi
 ronment and free of divergences that have plagued earlier approaches. 
 I will also discuss the effectiveness of this computational approach i
 n meeting the demands of present-day quantum computing research.
URL:https://www.physics.wisc.edu/events/?id=4908
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