BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Warped AdS3 black holes: classical stability and quantum field the
 ory - Hugo Ferreira (University of Nottingham)
DTSTART:20131122T130000Z
DTEND:20131122T140000Z
UID:TALK47882@talks.cam.ac.uk
CONTACT:Helvi Witek
DESCRIPTION:(2+1)-dimensional gravity allows us to study aspects of classi
 cal and quantum gravity in a simpler technical setting which retains much 
 of the conceptual complexity of the standard (3+1)-dimensional gravity. Ho
 wever\, pure Einstein gravity lacks propagating degrees of freedom in 2+1 
 dimensions. Topologically Massive Gravity is a deformation of GR which inc
 ludes propagating degrees of freedom. Besides the famous BTZ black hole so
 lution\, this theory has a whole new class of rotating black hole solution
 s -- the warped AdS3 black holes -- which can be viewed as deformed BTZ so
 lutions but which\, counterintuitively\, are not asymptotically AdS -- the
 y are actually (almost) asymptotically flat! This gives us a (2+1)-dimensi
 onal black hole which closely resembles the Kerr black hole in 3+1 dimensi
 ons.\n\nIn this talk\, I will describe the issues of mode stability and qu
 antum field theory of this interesting set of solutions. First\, I will sh
 ow that\, in contrast with the BTZ solution\, classical superradiance of a
  massive scalar field on the background of a warped AdS3 black hole is alw
 ays present. Despite this fact\, I then show that the black hole is classi
 cally stable to scalar perturbations\, namely there are no superradiant in
 stabilities\, even if it is enclosed by a stationary mirror with Dirichlet
  boundary conditions. This is a surprising result in view of the similarit
 y between the causal structure of the warped AdS3 black hole and the Kerr 
 spacetime in 3+1 dimensions\, which is classically unstable due to superra
 diant instabilities. Finally\, I will report on current progress on the co
 mputation of the renormalised stress-energy tensor of a scalar field in th
 e Hartle-Hawking vacuum using the Hadamard renormalisation technique. When
  finished\, this work will provide the first calculation of this kind for 
 a rotating black hole with asymptotics which resemble asymptotically flat 
 spacetimes.\n \nPart of this work has been published in Phys. Rev. D 87\, 
 124013 (2013).
LOCATION:Pavilion B Potter Room (B1.19)
END:VEVENT
END:VCALENDAR