276 research outputs found
Supersymmetric Topological Quantum Field Theories Of Differential Forms I. Gauge p-forms
We consider the topological theory of Witten type for gauge differential
p-forms. It is shown that some topological invariants such as linking numbers
appear under quantization of this theory. The non-abelian generalization of the
model is discussed.Comment: 12 pages, Late
The Geometry of Small Causal Diamonds
The geometry of causal diamonds or Alexandrov open sets whose initial and
final events and respectively have a proper-time separation
small compared with the curvature scale is a universal. The corrections from
flat space are given as a power series in whose coefficients involve the
curvature at the centre of the diamond. We give formulae for the total 4-volume
of the diamond, the area of the intersection the future light cone of
with the past light cone of and the 3-volume of the hyper-surface of
largest 3-volume bounded by this intersection valid to .
The formula for the 4-volume agrees with a previous result of Myrheim.
Remarkably, the iso-perimetric ratio depends only on the energy density at the centre and is bigger
than unity if the energy density is positive. These results are also shown to
hold in all spacetime dimensions. Formulae are also given, valid to next
non-trivial order, for causal domains in two spacetime dimensions. We suggest a
number of applications, for instance, the directional dependence of the volume
allows one to regard the volumes of causal diamonds as an observable providing
a measurement of the Ricci tensor.Comment: 17 pages, no figures; Misprints in eqs.(62), (65), (66) and (81)
corrected; a new note on page 13 (with 2 new equations) adde
Horizon State, Hawking Radiation and Boundary Liouville Model
We demonstrate that the near-horizon physics, the Hawking radiation and the
reflection off the radial potential barrier, can be understood entirely within
a conformal field theory picture in terms of one- and two-point functions in
the boundary Liouville theory. An important element in this demonstration is
the notion of {\it horizon state}, the Hawking radiation being interpreted as a
result of the transition of horizon state to the ordinary states propagating
outside black hole horizon.Comment: Revtex, 5pages; final version to appear in Phys.Rev.Let
Black hole entropy: statistical mechanics agrees thermodynamics
We discuss the connection between different entropies introduced for black
hole. It is demonstrated on the two-dimensional example that the (quantum)
thermodynamical entropy of a hole coincides (including UV-finite terms) with
its statistical-mechanical entropy calculated according to 't Hooft and
regularized by Pauli-Villars.Comment: 10 pages, latex. Some new discussion added. Version to appear in Phys
Rev.
Quantum entropy of the Kerr black hole arising from gravitational perturbation
The quantum entropy of the Kerr black hole arising from gravitational
perturbation is investigated by using Null tetrad and \'t Hooft\'s brick-wall
model. It is shown that effect of the graviton\'s spins on the subleading
correction is dependent of the square of the spins and the angular momentum per
unit mass of the black hole, and contribution of the logarithmic term to the
entropy will be positive, zero, and negative for different value of .Comment: 8 pages, 1 figure, Latex. to appear in Phys. Rev.
Holography with Gravitational Chern-Simons Term
The holographic description in the presence of gravitational Chern-Simons
term is studied. The modified gravitational equations are integrated by using
the Fefferman-Graham expansion and the holographic stress-energy tensor is
identified. The stress-energy tensor has both conformal anomaly and
gravitational or, if re-formulated in terms of the zweibein, Lorentz anomaly.
We comment on the structure of anomalies in two dimensions and show that the
two-dimensional stress-energy tensor can be reproduced by integrating the
conformal and gravitational anomalies. We study the black hole entropy in
theories with a gravitational Chern-Simons term and find that the usual
Bekenstein-Hawking entropy is modified. For the BTZ black hole the modification
is determined by area of the inner horizon. We show that the total entropy of
the BTZ black hole is precisely reproduced in a boundary CFT calculation using
the Cardy formula.Comment: 19 pages, Latex; v3: minor corrections, some clarification
Non-minimal coupling and quantum entropy of black hole
Formulating the statistical mechanics for a scalar field with non-minimal
coupling in a black hole background we propose modification of
the original 't Hooft ``brick wall'' prescription. Instead of the Dirichlet
condition we suggest some scattering ansatz for the field functions at the
horizon. This modifies the energy spectrum of the system and allows one to
obtain the statistical entropy dependent on the non-minimal coupling. For
the entropy renormalizes the classical Bekenstein-Hawking entropy in
the correct way and agrees with the result previously obtained within the
conical singularity approach. For a positive , however, the results
differ.Comment: 16 pages, latex, no figures; an error in calculation of the entropy
corrected, the entropy now is positive for any non-minimal couplin
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