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CATEGORIES:DAMTP Friday GR Seminar
SUMMARY:Warped AdS3 black holes: classical stability and q
uantum field theory - Hugo Ferreira (University of
Nottingham)
DTSTART;TZID=Europe/London:20131122T130000
DTEND;TZID=Europe/London:20131122T140000
UID:TALK47882AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/47882
DESCRIPTION:(2+1)-dimensional gravity allows us to study aspec
ts of classical and quantum gravity in a simpler t
echnical setting which retains much of the concept
ual complexity of the standard (3+1)-dimensional g
ravity. However\, pure Einstein gravity lacks prop
agating degrees of freedom in 2+1 dimensions. Topo
logically Massive Gravity is a deformation of GR w
hich includes propagating degrees of freedom. Besi
des the famous BTZ black hole solution\, this theo
ry has a whole new class of rotating black hole so
lutions -- the warped AdS3 black holes -- which ca
n be viewed as deformed BTZ solutions but which\,
counterintuitively\, are not asymptotically AdS --
they are actually (almost) asymptotically flat! T
his gives us a (2+1)-dimensional black hole which
closely resembles the Kerr black hole in 3+1 dimen
sions.\n\nIn this talk\, I will describe the issue
s of mode stability and quantum field theory of th
is interesting set of solutions. First\, I will sh
ow that\, in contrast with the BTZ solution\, clas
sical superradiance of a massive scalar field on t
he background of a warped AdS3 black hole is alway
s present. Despite this fact\, I then show that th
e black hole is classically stable to scalar pertu
rbations\, namely there are no superradiant instab
ilities\, even if it is enclosed by a stationary m
irror with Dirichlet boundary conditions. This is
a surprising result in view of the similarity betw
een the causal structure of the warped AdS3 black
hole and the Kerr spacetime in 3+1 dimensions\, wh
ich is classically unstable due to superradiant in
stabilities. Finally\, I will report on current pr
ogress on the computation of the renormalised stre
ss-energy tensor of a scalar field in the Hartle-H
awking vacuum using the Hadamard renormalisation t
echnique. When finished\, this work will provide t
he first calculation of this kind for a rotating b
lack hole with asymptotics which resemble asymptot
ically flat spacetimes.\n \nPart of this work has
been published in Phys. Rev. D 87\, 124013 (2013).
LOCATION:Pavilion B Potter Room (B1.19)
CONTACT:Helvi Witek
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