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SEQUENCE:0
UID:UW-Physics-Event-3744
DTSTART:20151022T150000Z
DURATION:PT1H0M0S
DTSTAMP:20260419T110649Z
LAST-MODIFIED:20151012T165455Z
LOCATION:5310 Chamberlin Hall
SUMMARY:Programmable nonreciprocity in multi-mode parametric devices\,
  R. G. Herb Condensed Matter Seminar\, Dr. Leonardo Ranzani\, BBN/Rayt
 heon
DESCRIPTION:<br>
\nJosephson Parametric Amplifiers (JPAs) can perform 
 quantum-limited<br>
\nreadout of superconducting qubits. However\, sin
 ce they are<br>
\nreflection-based amplifiers\, an external RF circula
 tor is always<br>
\nnecessary to suppress back-action. A new approach 
 is to use directional<br>
\nparametric amplification by driving multip
 le parametric processes<br>
\nsimultaneously with different pump phase
 s. SQUID and SLUG amplifiers in<br>
\nfact operate by a similar mechan
 ism: the interference between parametric<br>
\nprocesses driven by int
 ernal oscillations at the Josephson frequency<br>
\nsuppresses the rev
 erse gain and explains the high level of isolation in<br>
\nthis devic
 es. In this talk I am going to discuss a general approach to<br>
\nthe
  study of parametric devices driven by multiple pump signals. As<br>
\
 nopposed to traditional JPAs\, where only two modes\, signal and idler
 \,<br>
\ninteract\, in multi-pump devices three or more modes are pump
 ed<br>
\nsimultaneously. I will show how to use directed graphs to com
 pute the<br>
\nscattering properties of such multi-mode devices and de
 sign parametric<br>
\nnonreciprocal components\, including circulators
  and directional amplifiers.
URL:https://www.physics.wisc.edu/events/?id=3744
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