BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:4
UID:UW-Physics-Event-5154
DTSTART:20191031T160000Z
DURATION:PT1H0M0S
DTSTAMP:20260415T070556Z
LAST-MODIFIED:20191028T173705Z
LOCATION:5310 Chamberlin Hall
SUMMARY:Wrestling with ultrastrongly coupled parasitic modes in circui
 t quantum electrodynamics\, R. G. Herb Condensed Matter Seminar\, Dr. 
 Ivan Pechenezhskiy \, University of Maryland
DESCRIPTION:Several promising superconducting qubit designs\, includin
 g the protected ones\, require superconductors operating as perfect in
 ductors at microwave frequencies. As the value of the inductance incre
 ases with the inductor length\, so does the parasitic capacitance due 
 to the spatial extension of the inductor. Parasitic self-resonances fo
 rmed this way impede the potential applications of extremely large ind
 uctances. Even in the simplest superconducting qubit circuit\, in whic
 h a Josephson junction is shunted by a hyperinductor\, the distributed
  nature of parasitic capacitance leads to an ultrastrong coupling of t
 he parasitic modes to the qubit. This ultrastrong coupling of the para
 sitic modes prevents a perturbation theory treatment of the qubit exci
 tation spectra. While a complete quantum description of the underlying
  qubit circuit is computationally prohibitive\, diagonalization of an 
 effective multi-mode Hamiltonian reproduces the experimental data both
  below and above the lowest parasitic modes. On the experimental side\
 , the effects of the parasitic modes can be partially mitigated by rel
 easing the qubit circuit off the substrate. This trick enables the rea
 lization of a new qubit design — blochnium.
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URL:https://www.physics.wisc.edu/events/?id=5154
END:VEVENT
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