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SUMMARY:Black Holes and the Structure of Spacetime - Maulik Parikh [IUCAA\
 , India]
DTSTART:20091014T131500Z
DTEND:20091014T141500Z
UID:TALK19896@talks.cam.ac.uk
CONTACT:Francis Bursa
DESCRIPTION:Black holes have taught us a variety of surprising lessons abo
 ut the structure of gravity and spacetime. In this two-part talk\, I will 
 first show that all diffeomorphism-invariant theories of gravity have a de
 ep connection to thermodynamics: the classical equations of gravitation al
 ways arise from thermodynamic equations applied locally. In the second par
 t\, I will show that a Gauss-Bonnet term in the gravitational action\, whi
 ch appears in the low-energy effective action of heterotic string theory\,
  can greatly enhance the nucleation of black holes in four-dimensional de 
 Sitter space. This leads to an upper bound on how curved empty de Sitter s
 pace can be.
LOCATION:MR3\, Centre for Mathematical Sciences
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