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SUMMARY:Constraints on holographic CFTs living on static but generally cur
 ved spacetimes - Toby Wiseman - Imperial
DTSTART:20151029T130000Z
DTEND:20151029T140000Z
UID:TALK60516@talks.cam.ac.uk
CONTACT:Dr. Piotr Tourkine
DESCRIPTION:The theme of this talk is to see what AdS-CFT brings to the ta
 ble in terms of understanding curved spacetime QFT. The idea is to explore
  how general properties of holographic CFTs with a gravity dual can be und
 erstood in terms of a purely geometric problem\, and studied using geometr
 ic tools. We consider holographic CFTs on static spacetimes\, where the sp
 atial part is compact but otherwise general. We assume the dual gravitatio
 nal description is given by pure gravity with a negative cosmological cons
 tant (ie. the universal sector). Firstly I will discuss how one can show f
 or a 2+1 dimensional CFT that the vacuum (or Casimir) energy is always neg
 ative\, unless the space the CFT lives on has constant curvature\, when th
 e energy may also vanish. This argument does not assume a smooth bulk geom
 etry (although any singularities have to be ‘good’). Secondly I will s
 how that in any dimension the spectrum of CFT fluctuations associated to s
 calar operators is bounded from below by the minimum scalar curvature of t
 he space the CFT lives on. Normalised by this quantity the `gap’ in the 
 spectrum of a scalar operator is minimized when the CFT is living on a sph
 ere. In fact this also holds for a conformally coupled free scalar. Optimi
 stically one might even conjecture such a bound holds more generally for C
 FTs.
LOCATION:Potter Room (first floor\, Pav. B)
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