1,115 research outputs found
Wilson Loops in the Large N Limit at Finite Temperature
Using a proposal of Maldacena we compute in the framework of the supergravity
description of N coincident D3 branes the energy of a quark anti-quark pair in
the large N limit of U(N) N=4 SYM in four dimensions at finite temperature.Comment: 7 pages, LaTeX2e, 5 eps figures; references added and corrected,
typos correcte
On the M-Theory Approach to (Compactified) 5D Field Theories
We construct M-theory curves associated with brane configurations of SU(N),
SO(N) and 5d supersymmetric gauge theories compactified on a circle.
From the curves we can account for all the existing different SU(N) field
theories with . This is the correct bound for . We
remark on the exceptional case SU(2). The bounds obtained for SO(N) and
are and , respectively.Comment: 18 pages, minor correction
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
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
How Sensitive is the CMB to a Single Lens?
We study the imprints of a single lens, that breaks statistical isotropy, on
the CMB and calculate the signal to noise ratio (S/N) for its detection. We
emphasize the role of non-Gaussianities induced by LCDM weak lensing in this
calculation and show that typically the S/N is much smaller than expected. In
particular we find that the hypothesis that a void (texture) is responsible for
the WMAP cold spot can barely (cannot) be tested via weak lensing of the CMB.Comment: Accepted for publication in JCAP, 24 pages, 5 figure
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
Non-Supersymmetric Deformations of Non-Critical Superstrings
We study certain supersymmetry breaking deformations of linear dilaton
backgrounds in different dimensions. In some cases, the deformed theory has
bulk closed strings tachyons. In other cases there are no bulk tachyons, but
there are localized tachyons. The real time condensation of these localized
tachyons is described by an exactly solvable worldsheet CFT. We also find some
stable, non-supersymmetric backgrounds.Comment: 33 pages, references adde
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