984 research outputs found
Information Loss and Anomalous Scattering
The approach of 't Hooft to the puzzles of black hole evaporation can be
applied to a simpler system with analogous features. The system is
dimensional electrodynamics in a linear dilaton background. Analogues of black
holes, Hawking radiation and evaporation exist in this system. In perturbation
theory there appears to be an information paradox but this gets resolved in the
full quantum theory and there exists an exact -matrix, which is fully
unitary and information conserving. 't Hooft's method gives the leading terms
in a systematic approximation to the exact result.Comment: 18 pages, 3 figures (postscript files available soon on request),
(earlier version got corrupted by mail system
Classical integrability of chiral and classical curves
In this letter, classical chiral is studied in the lightcone gauge
. The once integrated equation of motion for the current is shown to
be of the Lax form, which demonstrates an infinite number of conserved
quantities. Specializing to gauge group SU(2), we show that solutions to the
classical equations of motion can be identified with a very large class of
curves. We demonstrate this correspondence explicitly for two solutions. The
classical fermionic fields associated with these currents are then obtained.Comment: Final version to appear in Mod. Phys. Lett. A. A reference and two
footnotes added. 6 pages revte
Exact String Theory Instantons by Dimensional Reduction
We identify exact gauge-instanton-like solutions to (super)-string theory
using the method of dimensional reduction. We find in particular the Polyakov
instanton of 3d QED, and a class of generalized Yang-Mills merons. We discuss
their marginal deformations, and show that for the instanton they
correspond to a dissociation of vector- and axial-magnetic charges.Comment: LateX, 15pp., CERN-TH.7100/93, CPTh-A276.11.93 (Minor Errors
Corrected
Thermodynamics and area in Minkowski space: Heat capacity of entanglement
Tracing over the degrees of freedom inside (or outside) a sub-volume V of
Minkowski space in a given quantum state |psi>, results in a statistical
ensemble described by a density matrix rho. This enables one to relate quantum
fluctuations in V when in the state |psi>, to statistical fluctuations in the
ensemble described by rho. These fluctuations scale linearly with the surface
area of V. If V is half of space, then rho is the density matrix of a canonical
ensemble in Rindler space. This enables us to `derive' area scaling of
thermodynamic quantities in Rindler space from area scaling of quantum
fluctuations in half of Minkowski space. When considering shapes other than
half of Minkowski space, even though area scaling persists, rho does not have
an interpretation as a density matrix of a canonical ensemble in a curved, or
geometrically non-trivial, background.Comment: 17 page
Corrections to D-brane Action and Generalized Boundary State
In this paper, we generalize a boundary state to the one incorporating
non-constant gauge field strength as an external background coupled to the
boundary of a string worldsheet in bosonic string theory. This newly defined
boundary state satisfies generalized nonlinear boundary conditions with
non-constant gauge field strength, and is BRST invariant. The divergence
immanent in this boundary state coincide with the one calculated in a string
sigma model. We extract the relevant massless part of this generalized boundary
state, and give a part of the D-brane action with the non-constant gauge field
strength, that is, derivative corrections to the D-brane action.Comment: 21 pages, LaTeX, 2 eps figures, a reference added, typos correcte
Resonance NLS Solitons as Black Holes in Madelung Fluid
A new resonance version of NLS equation is found and embedded to the
reaction-diffusion system, equivalent to the anti-de Sitter valued Heisenberg
model, realizing a particular gauge fixing condition of the Jackiw-Teitelboim
gravity. The space-time points where dispersion change the sign correspond to
the event horizon, and the soliton solutions to the AdS black holes. The
soliton with velocity bounded above describes evolution on the hyperboloid with
nontrivial winding number and create under collisions the resonance states with
a specific life time.Comment: Plain Tex, 12 pages, 6 figure
QUANTUM CORRECTIONS AND EXTREMAL BLACK HOLES
We consider static solutions of two dimensional dilaton gravity models as toy
laboratories to address the question of the final fate of black holes. A non
perturbative correction to the CGHS potential term is shown to lead classically
to an extremal black hole geometry, thus providing a plausible solution to
Hawking evaporation paradox. However, the full quantum theory does not admit an
extremal solution.Comment: 12 pages, LaTex, no figures. We have improved the main argument
leading to the non-existence of an extremal black hole in the quantum theor
More on Membranes in Matrix Theory
We study noncompact and static membrane solutions in Matrix theory. Demanding
axial symmetry on a membrane embedded in three spatial dimensions, we obtain a
wormhole solution whose shape is the same with the catenoidal solution of
Born-Infeld theory. We also discuss another interesting class of solutions,
membranes embedded holomorphically in four spatial dimensions, which are 1/4
BPS.Comment: 7 pages, LaTeX; expanded to treat matrix membrane solutions with
electric flux, equivalently fundamental strings; to appear in Phys. Rev.
A finite cutoff on the string worldsheet?
D-brane backgrounds are specified in closed string theories by holes with
appropriate mixed Dirichlet and Neumann boundary conditions on the string
worldsheet. As presently stated, the prescription defining D-brane backgrounds
is such that the Einstein equation is not equivalent to the condition for scale
invariance on the string worldsheet. A modified D-brane prescription is found,
that leads to the desired equivalence, while preserving all known D-brane lore.
A possible interpretation is that the worldsheet cutoff is finite. Possible
connections to recent work of Maldacena and Strominger, and Gopakumar and Vafa
are suggested.Comment: 7 pages, RevTex; v2: typos corrected, superstring calculation
included, discussion expanded - to be published in Phys.Rev.
Real decoupling ghost quantization of the CGHS model for two dimensional black holes
A complete RST quantization of a CGHS model plus Strominger term is carried
out. In so doing a conformal invariant theory with is
found, that is, without ghosts contribution. The physical consequences of the
model are analysed and positive definite Hawking radiation is found.Comment: 14 pages, latex, no figures, marginal errors correcte
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