22,213 research outputs found
An Exact Prediction of N=4 SUSYM Theory for String Theory
We propose that the expectation value of a circular BPS-Wilson loop in N=4
SUSYM can be calculated exactly, to all orders in a 1/N expansion and to all
orders in g^2 N. Using the AdS/CFT duality, this result yields a prediction of
the value of the string amplitude with a circular boundary to all orders in
alpha' and to all orders in g_s. We then compare this result with string
theory. We find that the gauge theory calculation, for large g^2 N and to all
orders in the 1/N^2 expansion does agree with the leading string theory
calculation, to all orders in g_s and to lowest order in alpha'. We also find a
relation between the expectation value of any closed smooth Wilson loop and the
loop related to it by an inversion that takes a point along the loop to
infinity, and compare this result, again successfully, with string theory.Comment: LaTeX, 22 pages, 3 figures. Argument corrected and two new sections
adde
Reduced Density Matrix Functional for Many-Electron Systems
Reduced density matrix functional theory for the case of solids is presented
and a new exchange correlation functional based on a fractional power of the
density matrix is introduced. We show that compared to other functionals, this
produces more accurate results for both finite systems. Moreover, it captures
the correct band gap behavior for conventional semiconductors as well as
strongly correlated Mott insulators, where a gap is obtained in absence of any
magnetic ordering.Comment: 4 figs and 1 tabl
Feasibility study of the ultraviolet spectral analysis of the lunar surface
Ultraviolet spectral analysis of granite, gabbro, and serpentinite samples to determine feasibility of mapping surface composition of moo
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Confinement and the analytic structure of the one body propagator in Scalar QED
We investigate the behavior of the one body propagator in SQED. The self
energy is calculated using three different methods: i) the simple bubble
summation, ii) the Dyson-Schwinger equation, and iii) the Feynman-Schwinger
represantation. The Feynman-Schwinger representation allows an {\em exact}
analytical result. It is shown that, while the exact result produces a real
mass pole for all couplings, the bubble sum and the Dyson-Schwinger approach in
rainbow approximation leads to complex mass poles beyond a certain critical
coupling. The model exhibits confinement, yet the exact solution still has one
body propagators with {\it real} mass poles.Comment: 5 pages 2 figures, accepted for publication in Phys. Rev.
String Theoretical Interpretation for Finite N Yang-Mills Theory in Two-Dimensions
We discuss the equivalence between a string theory and the two-dimensional
Yang-Mills theory with SU(N) gauge group for finite N. We find a sector which
can be interpreted as a sum of covering maps from closed string world-sheets to
the target space, whose covering number is less than N. This gives an
asymptotic expansion of 1/N whose large N limit becomes the chiral sector
defined by D.Gross and W.Taylor. We also discuss that the residual part of the
partition function provides the non-perturbative corrections to the
perturbative expansion.Comment: 15 pages, no figures, LaTeX2e, typos corrected, final version to
appear in Modern Physics Letters
Aspects of Large N Gauge Theory Dynamics as Seen by String Theory
In this paper we explore some of the features of large N supersymmetric and
nonsupersymmetric gauge theories using Maldacena's duality conjectures. We
shall show that the resulting strong coupling behavior of the gauge theories is
consistent with our qualitative expectations of these theories. Some of these
consistency checks are highly nontrivial and give additional evidence for the
validity of the proposed dualities.Comment: 31 pages, LaTeX, 11 eps figures, typos correcte
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