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PRODID:UW-Madison-Physics-Events
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SEQUENCE:2
UID:UW-Physics-Event-9084
DTSTART:20250317T180000Z
DTEND:20250317T193000Z
DTSTAMP:20260413T151510Z
LAST-MODIFIED:20250317T192248Z
LOCATION:Chamberlin 5280
SUMMARY:Observable CMB B-modes from Cosmological Phase Transitions\, T
 heory Seminar (High Energy/Cosmology)\, Gordan Krnjaic\, Fermilab
DESCRIPTION:A B-mode polarization signal in the cosmic microwave backg
 round (CMB) is widely regarded as smoking gun evidence for gravitation
 al waves produced during inflation. Here we demonstrate that tensor pe
 rturbations from a cosmological phase transition can produce a B-mode 
 signal whose strength rivals that of testable inflationary predictions
  across a range of observable scales. Although phase transitions arise
  from causal sub-horizon physics\, they nevertheless exhibit a white-n
 oise power spectrum on super-horizon scales. Power is suppressed on th
 e large scales relevant for CMB B-mode polarization\, but it is not ne
 cessarily negligible. For appropriately chosen phase transition parame
 ters\, the maximal B-mode amplitude can compete with inflationary pred
 ictions that can be tested with current and future experiments. These 
 scenarios can be differentiated by performing measurements on multiple
  angular scales\, since the phase transition signal predicts peak powe
 r on smaller scales. Event recording: https://youtu.be/sRjbrmKf360
URL:https://www.physics.wisc.edu/events/?id=9084
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