953 research outputs found
Black Hole Horizon Fluctuations
It is generally admitted that gravitational interactions become large at an
invariant distance of order from the black hole horizon. We show that due
to the ``atmosphere'' of high angular particles near the horizon strong
gravitational interactions already occur at an invariant distance of the order
of . The implications of these results for the origin of black
hole radiation, the meaning of black hole entropy and the information puzzle
are discussed.Comment: Latex, 22 pages (minor corrections and precisions added
Free Energies and Probe Actions for Near-horizon D-branes and D1 + D5 System
By working with the free energy for the type II supergravity near-horizon
solution of N coincident non-extremal Dp-branes we study the transitions among
the non-conformal Dp-brane system, the perturbative super Yang-Mills theory and
a certain system associated with M theory. We derive a relation between this
free energy and the action of a Dp-brane probe in the N Dp-brane background.
Constructing the free energy for the five dimensional black hole labeled by the
D1-brane and D5-brane charges we find the similar relation between it and the
action of a D1 or D5 brane probe in the D1 + D5 brane background. These
relations are explained by the massive open strings stretched between the
relevant D-branesComment: 14 pages, LaTeX2e, no figure
A Comment on Technical Naturalness and the Cosmological Constant
We propose a model of dynamical relaxation of the cosmological constant.
Technical naturalness of the model and the present value of the vacuum energy
density imply an upper bound on the supersymmetry breaking scale and the
reheating temperature at the TeV scale.Comment: 10 pages, ref. adde
Ribosomal RNA Synthesis in Chronic Lymphocytic Leukaemia
Lymphocytes from patients with chronic lymphocytic leukaemia make large amounts of stable, rapidly labelled high molecular weight RNA, but ribosomal RNA methylation is normal. However, fewer ribosomes are available for protein synthesis than in normal lymphocytes
Inflection Point Inflation and Time Dependent Potentials in String Theory
We consider models of inflection point inflation. The main drawback of such
models is that they suffer from the overshoot problem. Namely the initial
condition should be fine tuned to be near the inflection point for the universe
to inflate. We show that stringy realizations of inflection point inflation are
common and offer a natural resolution to the overshoot problem.Comment: 15 pages, 2 figures, refs. adde
Cosmological Imprints of Pre-Inflationary Particles
We study some of the cosmological imprints of pre-inflationary particles. We
show that each such particle provides a seed for a spherically symmetric cosmic
defect. The profile of this cosmic defect is fixed and its magnitude is linear
in a single parameter that is determined by the mass of the pre-inflationary
particle. We study the CMB and peculiar velocity imprints of this cosmic defect
and suggest that it could explain some of the large scale cosmological
anomalies.Comment: 31 pages, 7 figure
A UV completion of scalar electrodynamics
In previous works, we constructed UV-finite and unitary scalar field theories
with an infinite spectrum of propagating modes for arbitrary polynomial
interactions. In this paper, we introduce infinitely many massive vector fields
into a U(1) gauge theory to construct a theory with UV-finiteness and
unitarity.Comment: 25 page
Exotic polarizations of D2 branes and oblique vacua of (S)YM
We investigate the oblique vacua in the perturbed 2+1 dimensional gauge
theory living on D2 branes. The string theory dual of these vacua is expected
to correspond to polarizations of the D2 branes into NS5 branes with D4 brane
charge. We perturb the gauge theory by adding fermions masses. In the
nonsupersymmetric case, we also consider the effect of slight variations of the
masses of the scalars. For certain ranges of scalar masses we find oblique
vacua.
We show that D4 charge is an essential ingredient in understanding D2 -> NS5
polarizations. We find that some of the polarization states which appear as
metastable vacua when D4 charge is not considered are in fact unstable. They
decay by acquiring D4 charge, tilting and shrinking to zero size.Comment: 15 pages, 3 figures, LaTe
New Reducible Five-brane Solutions in M-theory
We construct new M-theory solutions of M5 branes that are a realization of
the fully localized ten dimensional NS5/D6 and NS5/D5 brane intersections.
These solutions are obtained by embedding self-dual geometries lifted to
M-theory. We reduce these solutions down to ten dimensions, obtaining new
D-brane systems in type IIA/IIB supergravity. The worldvolume theories of the
NS5-branes are new non-local, non-gravitational, six dimensional, T-dual little
string theories with eight supersymmetries.Comment: 19 pages, 4 figures, two paragraphs added in conclusions, typos
correcte
Black Hole Information vs. Locality
We discuss the limitations on space time measurement in the Schwarzchild
metric. We find that near the horizon the limitations on space time measurement
are of the order of the black hole radius. We suggest that it indicates that a
large mass black hole cannot be described by means of local field theory even
at macroscopic distances and that any attempt to describe black hole formation
and evaporation by means of an effective local field theory will necessarily
lead to information loss. We also present a new interpretation of the black
hole entropy which leads to , where is a constant of order which
does not depend on the number of fields.Comment: 19 pages, final version to appear in Phys. Rev.
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