
Feb 24 2012
UKZN Node Seminar:
Prof S G Ghosh
Astrophysics and Cosmology Research Unit in conjunction with NITheP
cordially invites you to a seminar by:
SPEAKER: Prof S G Ghosh, Centre for Theoretical Physics, Jamia Millia Islamia, New Delhi
TITLE: Gravitational collapse in 5D EinsteinGaussBonnet gravity
DATES: 24 February 2012
TIME: 13.15 pm – 14:15 pm
VENUE: Physics seminar room, H block, 3rd rd floor, Physics, University of KwaZuluNatal (Westville Campus)
Abstract:
We consider a Lemaitre  Tolman  Bondi type spacetime in Einstein gravity with the Gauss
Bonnet combination of quadratic curvature terms, and present exact solutions in closed form.
It turns out that the presence of the coupling constant of the GaussBonnet terms $alpha > 0$
completely changes the causal structure of the singularities from the analogous general
relativistic case. The gravitational collapse of inhomogeneous dust in the fivedimensional
GaussBonnet extended Einstein equations leads to formation of a massive, but weak, timelike
singularity which is forbidden in general relativity. Interestingly, this is a counterexample to
three conjectures: cosmic censorship conjecture, hoop conjecture and Seifert's conjecture.
Refreshments will served at 12:30pm
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