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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:2
UID:UW-Physics-Event-8143
DTSTART:20230504T150000Z
DTEND:20230504T230000Z
DTSTAMP:20260414T033220Z
LAST-MODIFIED:20230501T201936Z
LOCATION:5310 Chamberlin
SUMMARY:SQUID-Based Broadband Microwave Isolator\, R. G. Herb Condense
 d Matter Seminar\, Matt Beck\, IBM Yorktown Heights
DESCRIPTION:As superconducting quantum processors grow in size and com
 plexity\, so must the peripheral
\nhardware required for the control a
 nd readout of such processors. One singular piece of
\nhardware common
  to superconducting quantum processors setups is the microwave isolato
 r.
\nCurrent microwave isolator technology can be generally understood
  in the context of timereversal
\nsymmetry breaking via the use of fer
 rite materials. While generally exhibiting wide (>
\nGHz) bandwidths a
 nd large (>20 dB) directionality\, these ferrite-based devices are phy
 sically
\nlarge with volumes exceeding 15 cm^3. These devices can also
  introduce uncontrolled magnetic
\nfields at or near the quantum proce
 ssor resulting in deleterious effects such as frequency shifts\,
\nexc
 ess flux noise\, or flux vortex formation. For quantum processors at s
 cale to achieve quantum
\nadvantage\, a replacement must be found.
\nI
 n this talk\, I will describe work towards the realization of a superc
 onducting broadband
\nmicrowave isolator utilizing DC-SQUIDs. I will d
 etail how\, with appropriate application of
\nmicrowave flux drives\, 
 the non-linear inductance of the SQUIDs allows for power at the signal
 
\nfrequency travelling in the forward direction to be three-wave mixe
 d and back resulting in
\nconstructive interference and near unity tra
 nsmission. I will also show how\, in the reverse
\ndirection\, the sam
 e mixing process results in destructive interference and thus suppress
 ion of
\nthe signal frequency. Data will be presented on a variety of 
 nanofabricated devices. The data
\nshow excellent model-hardware corre
 lation where directionality greater than 15 dB at
\nbandwidths approac
 hing 700 MHz with minimal added insertion loss is achieved. Finally\, 
 further
\nextensions of the work will be discussed on how to achieve c
 ommercial levels of isolation and
\nthe realization of a fully superco
 nducting replacement of commercial ferrite isolators.
URL:https://www.physics.wisc.edu/events/?id=8143
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