72 research outputs found
Exact black hole solutions in shift symmetric scalar-tensor theories
We derive a variety of exact black hole solutions in a subclass of
Horndeski's scalar-tensor theory possessing shift symmetry, ,
and reflection symmetry, . The theory admits two arbitrary
functions of , and our solutions are constructed
without specifying the concrete form of the two functions, implying that black
hole solutions in specific scalar-tensor theories found in the literature can
be extended to a more general class of theories with shift symmetry. Our
solutions include a black hole in the presence of an effective cosmological
constant, the Nariai spacetime, the Lifshitz black hole, and other nontrivial
solutions, all of which exhibit nonconstant scalar-field profile.Comment: 10 pages. v2: Corrected an erroneous statement in the first version.
Matches version accepted by PTE
Floating Black Hole in the Karch-Randall Model and its Holographic Dual
To investigate the holography in the Karch-Randall (KR) braneworld model, we
construct time-symmetric initial data of black holes floating in the bulk, and
compare it with its holographic dual, which is described by four-dimensional
self-gravitating quantum field theory in asymptotically AdS_4 spacetime. We
also give a definition and an explicit formula of mass in the KR model
extending the definition by Abbott and Deser for asymptotically AdS spacetime.
We obtain supporting evidence for the holography in the KR model such as good
agreements of phase structures and characteristic values between the two
theories, and find clues that the Hawking-Page transition of the
four-dimensional quantum theory in a microcanonical ensemble is holographically
dual to a transition in the bulk black hole configuration.Comment: 24 pages, 11 figure
Angular momentum at null infinity in five dimensions
In this paper, using the Bondi coordinates, we discuss the angular momentum
at null infinity in five dimensions and address the Poincare covariance of the
Bondi mass and angular momentum. We also show the angular momentum loss/gain
law due to gravitational waves. In four dimensions, the angular momentum at
null infinity has the supertranslational ambiguity and then it is known that we
cannot construct well-defined angular momentum there. On the other hand, we
would stress that we can define angular momentum at null infinity without any
ambiguity in higher dimensions. This is because of the non-existence of
supertranslations in higher dimensions.Comment: 15 pages, published version in JM
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