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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-4571
DTSTART:20170824T160000Z
DURATION:PT1H0M0S
DTSTAMP:20260419T003613Z
LAST-MODIFIED:20171120T163636Z
LOCATION:5280 Chamberlin Hall
SUMMARY:O(N) invariance of the multi-field bounce\, Theory Seminar (Hi
 gh Energy/Cosmology)\, Kfir Blum\, Weizmann Institute of Science
DESCRIPTION:In his 1977 paper on vacuum decay in field theory: The Fat
 e of the False Vacuum\, Coleman considered the problem of a single sca
 lar field and assumed that the minimum action tunnelling field configu
 ration\, the bounce\, is invariant under O(4) rotations in Euclidean s
 pace. A proof of the O(4) invariance of the bounce was provided later 
 by Coleman\, Glaser\, and Martin (CGM)\, who extended the proof to N>2
  Euclidean dimensions but\, again\, restricted non-trivially to a sing
 le scalar field. As far as we know a proof of O(N) invariance of the b
 ounce with more than one scalar fields has not been reported in the QF
 T literature\, even though it was assumed in many works since. We make
  progress towards closing this gap. Following CGM we define the reduce
 d problem of finding a field configuration minimizing the kinetic ener
 gy at fixed potential energy. Given a solution of the reduced problem\
 , the minimum action bounce can always be obtained from it by means of
  a scale transformation. We show that if a solution of the reduced pro
 blem exists\, then it and the minimum action bounce derived from it ar
 e indeed O(N) symmetric. We review complementary results in the mathem
 atical literature that established the existence of a minimizer under 
 specified criteria. 
URL:https://www.physics.wisc.edu/events/?id=4571
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