742 research outputs found
N=1 super Yang-Mills on a (3+1) dimensional transverse lattice with one exact supersymmetry
We formulate =1 super Yang-Mills theory in 3+1 dimensions on a two
dimensional transverse lattice using supersymmetric discrete light cone
quantization in the large- limit. This formulation is free of fermion
species doubling. We are able to preserve one supersymmetry. We find a rich,
non-trivial behavior of the mass spectrum as a function of the coupling
, and see some sort of "transition" in the structure of a bound
state as we go from the weak coupling to the strong coupling. Using a toy model
we give an interpretation of the rich behavior of the mass spectrum. We present
the mass spectrum as a function of the winding number for those states whose
color flux winds all the way around in one of the transverse directions. We use
two fits to the mass spectrum and the one that has a string theory
justification appears preferable. For those states whose color flux is
localized we present an extrapolated value for for some low energy bound
states in the limit where the numerical resolution goes to infinity.Comment: 23(+2 for v3) pages, 19 figures; v2: a footnote added; v3: an
appendix, comments, references added. The version to appear PR
D-brane Description of New Open String Solutions in AdS(5)
In this paper we find D-brane descriptions of some of new open string
solutions that were found in 0804.3438[hep-th]. These D5-brane and D3-brane
configurations give gravitational dual descriptions of Wilson loops in some
particular representations.Comment: 13 pages, references adde
Effects of a fundamental mass term in two-dimensional super Yang-Mills theory
We show that adding a vacuum expectation value to a gauge field left over
from a dimensional reduction of three-dimensional pure supersymmetric
Yang-Mills theory generates mass terms for the fundamental fields in the
two-dimensional theory while supersymmetry stays intact. This is similar to the
adjoint mass term that is generated by a Chern-Simons term in this theory. We
study the spectrum of the two-dimensional theory as a function of the vacuum
expectation value and of the Chern-Simons coupling. Apart from some symmetry
issues a straightforward picture arises. We show that at least one massless
state exists if the Chern-Simons coupling vanishes. The numerical spectrum
separates into (almost) massless and very heavy states as the Chern-Simons
coupling grows. We present evidence that the gap survives the continuum limit.
We display structure functions and other properties of some of the bound
states.Comment: 17 pp., 10 figs; substantially revised version to be published in
Phys. Rev.
Strings ending on branes from supergravity
We study geometries produced by brane intersections preserving eight
supercharges. Typical examples of such configurations are given by fundamental
strings ending on Dp branes and we construct gravity solutions describing such
intersections. The geometry is specified in terms of two functions obeying
coupled differential equations and the boundary conditions are determined by
distributions of D branes. We show that a consistency of type IIB supergravity
constrains the allowed positions of the branes. The shapes of branes derived
from gravity are found to be in a perfect agreement with profiles predicted by
the DBI analysis. We also discuss related 1/4-BPS systems in M theory.Comment: 81 pages, added ref
D1D5 microstate geometries from string amplitudes
We reproduce the asymptotic expansion of the D1D5 microstate geometries by
computing the emission amplitudes of closed string states from disks with mixed
D1D5 boundary conditions. Thus we provide a direct link between the
supergravity and D-brane descriptions of the D1D5 microstates at non-zero
string coupling. Microscopically, the profile functions characterizing the
microstate solutions are encoded in the choice of a condensate for the twisted
open string states connecting D1 and D5 branes.Comment: 21 pages; added reference
Radiation from the non-extremal fuzzball
The fuzzball proposal says that the information of the black hole state is
distributed throughout the interior of the horizon in a `quantum fuzz'. There
are special microstates where in the dual CFT we have `many excitations in the
same state'; these are described by regular classical geometries without
horizons. Jejjala et.al constructed non-extremal regular geometries of this
type. Cardoso et. al then found that these geometries had a classical
instability. In this paper we show that the energy radiated through the
unstable modes is exactly the Hawking radiation for these microstates. We do
this by (i) starting with the semiclassical Hawking radiation rate (ii) using
it to find the emission vertex in the CFT (iii) replacing the Boltzman
distributions of the generic CFT state with the ones describing the microstate
of interest (iv) observing that the emission now reproduces the classical
instability. Because the CFT has `many excitations in the same state' we get
the physics of a Bose-Einstein condensate rather than a thermal gas, and the
usually slow Hawking emission increases, by Bose enhancement, to a classically
radiated field. This system therefore provides a complete gravity description
of information-carrying radiation from a special microstate of the nonextremal
hole.Comment: corrected typo
Spectrum and thermodynamic properties of two-dimensional N=(1,1) super Yang-Mills theory with fundamental matter and a Chern-Simons term
We consider N=(1,1) super Yang-Mills theory in 1+1 dimensions with
fundamentals at large-N_c. A Chern-Simons term is included to give mass to the
adjoint partons. Using the spectrum of the theory, we calculate thermodynamic
properties of the system as a function of the temperature and the Yang-Mills
coupling. In the large-N_c limit there are two non-communicating sectors, the
glueball sector, which we presented previously, and the meson-like sector that
we present here. We find that the meson-like sector dominates the
thermodynamics. Like the glueball sector, the meson sector has a Hagedorn
temperature T_H, and we show that the Hagedorn temperature grows with the
coupling. We calculate the temperature and coupling dependence of the free
energy for temperatures below T_H. As expected, the free energy for weak
coupling and low temperature grows quadratically with the temperature. Also the
ratio of the free energies at strong coupling compared to weak coupling,
r_{s-w}, for low temperatures grows quadratically with T. In addition, our data
suggest that r_{s-w} tends to zero in the continuum limit at low temperatures.Comment: 34 p
Note on Generalized Janus Configurations
We study several aspects of generalized Janus configuration, which includes a
theta term. We investigate the vacuum structure of the theory and find that
unlike the Janus configuration without theta term there is no nontrivial
vacuum. We also discuss BPS soliton configuration both by supersymmetry
analysis and from energy functional. The half BPS configurations could be
realized by introducing transverse (p,q)-strings in original brane
configuration corresponding to generalized Janus configuration. It turns out
the BPS soliton could be taken as modified dyon. We discuss the solution of
half BPS equations for the sharp interface case. Moreover we construct less
supersymmetric Janus configuration with theta term.Comment: 27 pages; References adde
Pulsating Strings in Deformed Backgrounds
This is a brief summary on pulsating strings in beta deformed backgrounds
found recently.Comment: 8 pages. Talk presented at Quantum Theory and Symmetries 7, Prague,
August 7-13, 201
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