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CATEGORIES:Quantum Fields and Strings Seminars
SUMMARY:Constraints on holographic CFTs living on static b
ut generally curved spacetimes - Toby Wiseman - Im
perial
DTSTART;TZID=Europe/London:20151029T130000
DTEND;TZID=Europe/London:20151029T140000
UID:TALK60516AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/60516
DESCRIPTION:The theme of this talk is to see what AdS-CFT brin
gs to the table in terms of understanding curved s
pacetime QFT. The idea is to explore how general p
roperties of holographic CFTs with a gravity dual
can be understood in terms of a purely geometric p
roblem\, and studied using geometric tools. We con
sider holographic CFTs on static spacetimes\, wher
e the spatial part is compact but otherwise genera
l. We assume the dual gravitational description is
given by pure gravity with a negative cosmologica
l constant (ie. the universal sector). Firstly I w
ill discuss how one can show for a 2+1 dimensional
CFT that the vacuum (or Casimir) energy is always
negative\, unless the space the CFT lives on has
constant curvature\, when the energy may also vani
sh. This argument does not assume a smooth bulk ge
ometry (although any singularities have to be ‘goo
d’). Secondly I will show that in any dimension th
e spectrum of CFT fluctuations associated to scala
r operators is bounded from below by the minimum s
calar curvature of the space the CFT lives on. Nor
malised by this quantity the `gap’ in the spectrum
of a scalar operator is minimized when the CFT is
living on a sphere. In fact this also holds for a
conformally coupled free scalar. Optimistically o
ne might even conjecture such a bound holds more g
enerally for CFTs.
LOCATION:Potter Room (first floor\, Pav. B)
CONTACT:Dr. Piotr Tourkine
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