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CATEGORIES:Theoretical Physics Colloquium
SUMMARY:Holography and the self-tuning of the cosmological
constant - Elias Kiritsis\, APC Paris and Univers
ity of Crete
DTSTART;TZID=Europe/London:20171025T141500
DTEND;TZID=Europe/London:20171025T151500
UID:TALK81151AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/81151
DESCRIPTION:We propose a brane-world setup based on gauge/grav
ity duality in which the four-dimensional cosmolog
ical constant is set to zero by a dynamical self-a
djustment mechanism. The bulk contains Einstein gr
avity and a scalar field. We study holographic RG
flow solutions\, with the standard model brane sep
arating an infinite volume UV region and an IR reg
ion of finite volume. For generic values of the br
ane vacuum energy\, regular solutions exist such t
hat the four-dimensional brane is flat. Its positi
on in the bulk is determined dynamically by the ju
nction conditions. Analysis of linear fluctuations
shows that a regime of 4-dimensional gravity is p
ossible at large distances\, due to the presence o
f an induced gravity term. The graviton acquires a
n effective mass\, and a five-dimensional regime m
ay exist at large and/or small scales. We show th
at\, for a broad choice of bulk potentials\, flat-
brane solutions are manifestly stable and free of
ghosts. We compute the scalar contribution to the
force between brane-localized sources and show tha
t\, in certain models\, the vDVZ discontinuity is
absent and the effective interaction at short dist
ances is mediated by two transverse graviton helic
ities.
LOCATION:MR2\, Centre for Mathematical Sciences
CONTACT:David Marsh
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