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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Physics-TWaP
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SEQUENCE:1
UID:UW-Physics-Event-4571
DTSTART:20170824T160000Z
DURATION:PT1H0M0S
DTSTAMP:20190826T083346Z
LAST-MODIFIED:20171120T163636Z
LOCATION:5280 Chamberlin Hall
SUMMARY:O(N) invariance of the multi-field bounce\, Theory Seminar (High Energy/Cosmology)\, Kfir Blum\, Weizmann Institute of Science
DESCRIPTION:In his 1977 paper on vacuum decay in field theory: The Fate of the False Vacuum\, Coleman considered the problem of a single scalar field and assumed that the minimum action tunnelling field configuration\, the bounce\, is invariant under O(4) rotations in Euclidean space. 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 single scalar field. As far as we know a proof of O(N) invariance of the bounce with more than one scalar fields has not been reported in the QFT literature\, even though it was assumed in many works since. We make progress towards closing this gap. Following CGM we define the reduced problem of finding a field configuration minimizing the kinetic energy 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 problem exists\, then it and the minimum action bounce derived from it are indeed O(N) symmetric. We review complementary results in the mathematical literature that established the existence of a minimizer under specified criteria.
URL:http://www.physics.wisc.edu/twap/view.php?id=4571
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