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VERSION:2.0
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BEGIN:VEVENT
DTSTAMP:20260917T183213Z
LAST-MODIFIED:20140916T130911Z
DTSTART:20140925T163000Z
DTEND:20140925T173000Z
UID:event1328@bu.edu
URL:http://physics.bu.edu/internal/events/show/1328
SUMMARY:Causality Constraints on Corrections to the Graviton Three-Point Co
	upling
DESCRIPTION:Featuring Alexander Zhiboedov\, Harvard University\n\nPart of t
	he HET Seminar Series.\n\nAbstract:\nWe consider higher derivative correcti
	ons to the graviton three-point coupling within a weakly coupled theory of 
	gravity. Lorentz invariance allows further structures beyond the one presen
	t in the Einstein theory. We argue that these are constrained by causality.
	 We devise a thought experiment involving a high energy scattering process 
	which leads to causality violation if the graviton three-point vertex conta
	ins the additional structures. This violation cannot be fixed by adding con
	ventional particles with spins J≤2. But\, it can be fixed by adding an in
	finite tower of extra massive particles with higher spins\, J>2. In AdS the
	ories this implies a constraint on the conformal anomaly coefficients ∣âˆ
	£a−cc∣∣≲1Δ2gap in terms of Δgap\, the dimension of the lightest s
	ingle particle operator with spin J>2. For inflation\, or de Sitter-like so
	lutions\, it indicates the existence of massive higher spin particles if th
	e gravity wave non-gaussianity deviates significantly from the one computed
	 in the Einstein theory
LOCATION:PRB 595\, 3 Cummington Mall\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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