3,035 research outputs found

### Semiclassical Corrections to the Cardy-Verlinde Formula of Kerr Black Holes

In this letter, we compute the corrections to the Cardy-Verlinde formula of
$4-$dimensional Kerr black hole. These corrections are considered within the
context of KKW analysis and arise as a result of the self-gravitational effect.
Then we show, one can taking into account the semiclassical corrections of the
Cardy-Verlinde entropy formula by just redefining the Virasoro operator $L_0$
and the central charge $c$.Comment: 8 page

### A Possible Resolution of the Black Hole Information Puzzle

The problem of information loss is considered under the assumption that the
process of black hole evaporation terminates in the decay of the black hole
interior into a baby universe. We show that such theories can be decomposed
into superselection sectors labeled by eigenvalues of the third-quantized baby
universe field operator, and that scattering is unitary within each
superselection sector. This result relies crucially on the quantum-mechanical
variability of the decay time. It is further argued that the decay rate in the
black hole rest frame is necessarily proportional to $e^{-S_{tot}}$, where
$S_{tot}$ is the total entropy produced during the evaporation process,
entailing a very long-lived remnant.Comment: 15 pages, 3 uuencoded figures. Revised version contains some
notational simplification

### Space Noncommutativity Corrections to the Cardy-Verlinde Formula

In this letter we compute the corrections to the Cardy-Verlinde formula of
Schwarzschild black holes. These corrections stem from the space
noncommutativity. Because the Schwarzschild black holes are non rotating, to
the first order of perturbative calculations, there is no any effect on the
properties of black hole due to the noncommutativity of space.Comment: 7 pages, no figures, accepted for publication in Int. J. Mod. Phys.

### Dimensional Mutation and Spacelike Singularities

I argue that string theory compactified on a Riemann surface crosses over at
small volume to a higher dimensional background of supercritical string theory.
Several concrete measures of the count of degrees of freedom of the theory
yield the consistent result that at finite volume, the effective dimensionality
is increased by an amount of order $2h/V$ for a surface of genus $h$ and volume
$V$ in string units. This arises in part from an exponentially growing density
of states of winding modes supported by the fundamental group, and passes an
interesting test of modular invariance. Further evidence for a plethora of
examples with the spacelike singularity replaced by a higher dimensional phase
arises from the fact that the sigma model on a Riemann surface can be naturally
completed by many gauged linear sigma models, whose RG flows approximate time
evolution in the full string backgrounds arising from this in the limit of
large dimensionality. In recent examples of spacelike singularity resolution by
tachyon condensation, the singularity is ultimately replaced by a phase with
all modes becoming heavy and decoupling. In the present case, the opposite
behavior ensues: more light degrees of freedom arise in the small radius
regime. I comment on the emerging zoology of cosmological singularities that
results.Comment: 15 pages, harvmac big. v2: 18 pages, harvmac big; added computation
of density of states and modular invariance check, enhanced discussion of
multiplicity of solutions all sharing the feature of increased density of
states, added reference

### How many black holes fit on the head of a pin?

The Bekenstein-Hawking entropy of certain black holes can be computed
microscopically in string theory by mapping the elusive problem of counting
microstates of a strongly gravitating black hole to the tractable problem of
counting microstates of a weakly coupled D-brane system, which has no event
horizon, and indeed comfortably fits on the head of a pin. We show here that,
contrary to widely held beliefs, the entropy of spherically symmetric black
holes can easily be dwarfed by that of stationary multi-black-hole
``molecules'' of the same total charge and energy. Thus, the corresponding
pin-sized D-brane systems do not even approximately count the microstates of a
single black hole, but rather those of a zoo of entropically dominant
multicentered configurations.Comment: 4 pages, fourth prize in the Gravity Research Foundation Essay
competition 200

### On the timelike Liouville three-point function

In a recent paper, D. Harlow, J. Maltz, and E. Witten showed that a
particular proposal for the timelike Liouville three-point function, originally
due to Al. Zamolodchikov and to I. Kostov and V. Petkova, can actually be
computed by the original Liouville path integral evaluated on a new integration
cycle. Here, we discuss a Coulomb gas computation of the timelike three-point
function and show that an analytic extension of the Selberg type integral
formulas involved reproduces the same expression, including the adequate
normalization. A notable difference with the spacelike calculation is pointed
out.Comment: 11 pages. v2 comments and references added. Appropriate credit is
given to Ref. arXiv:hep-th/0512346, where the Coulomb gas computation of the
c<1 theory has already been discusse

- â€¦