624 research outputs found
A Note on Gauge Invariant Operators in Noncommutative Gauge Theories and the Matrix Model
In this note we discuss local gauge-invariant operators in noncommutative gauge theories. Inspired by the connection of these theories with the Matrix model, we give a simple construction of a complete set of gauge-invariant operators. We make connection with the recent discussions of candidate operators which are dual to closed strings modes. We also discuss large Wilson loops which in the limit of vanishing noncommutativity, reduce to the closed Wilson loops of the ordinary gauge theory
Noncritical Strings, RG Flows and Holography
We derive an RG flow equation that is satisfied by the regularized partition function for noncritical strings in background fields. The flow refers to change in the position of a ``boundary'' in the liouville direction. The boundary is required to regularize the ultraviolet divergences in the partition function coming from integration over world-sheets of arbitrarily small area. From the point of view of the target space effective gravitational action that the partition function evaluates on-shell, the boundary regularizes {\it infrared} divergences coming from the infinite volume of the liouville direction. The RG flow equation that we obtain looks very much like the Hamilton-Jacobi constraint equation that an on-shell gauge-fixed gravitational action must satisfy
Supersymmetric Chern-Simons Theories with Vector Matter
In this paper we discuss SU(N) Chern-Simons theories at level k with both
fermionic and bosonic vector matter. In particular we present an exact
calculation of the free energy of the N=2 supersymmetric model (with one chiral
field) for all values of the 't Hooft coupling in the large N limit. This is
done by using a generalization of the standard Hubbard-Stratanovich method
because the SUSY model contains higher order polynomial interactions.Comment: 46 pages, 24 figures, v2: comments and references added, v3: a
footnote in Section 3.5 adde
Nielsen-Olesen Vortices in Noncommutative Abelian Higgs Model
We construct Nielsen-Olesen vortex solution in the noncommutative abelian
Higgs model. We derive the quantized topological flux of the vortex solution.
We find that the flux is integral by explicit computation in the large
limit as well as in the small limit. In the context of a tachyon
vortex on the brane-antibrane system we demonstrate that it is this topological
charge that gives rise to the RR charge of the resulting BPS D-brane. We also
consider the left-right-symmetric gauge theory which does not have a
commutative limit and construct an exact vortex solution in it.Comment: 24 pages, (v2) clarifying comments added regarding topological index
using coherent states; n-vortex solution added; version to appear in JHE
Rolling tachyon solution of two-dimensional string theory
We consider a classical (string) field theory of matrix model which was
developed earlier in hep-th/9207011 and subsequent papers. This is a
noncommutative field theory where the noncommutativity parameter is the string
coupling . We construct a classical solution of this field theory and show
that it describes the complete time history of the recently found rolling
tachyon on an unstable D0 brane.Comment: 19 pages, 2 figures, minor changes in text and additional references,
correction of decay time (version to appear in JHEP.
Exact Solution of the One-Dimensional Non-Abelian Coulomb Gas at Large N
The problem of computing the thermodynamic properties of a one-dimensional
gas of particles which transform in the adjoint representation of the gauge
group and interact through non-Abelian electric fields is formulated and solved
in the large limit. The explicit solution exhibits a first order
confinement-deconfinement phase transition with computable properties and
describes two dimensional adjoint QCD in the limit where matter field masses
are large.Comment: 8 pages, late
Search for Decay in LSND
We observe a net beam-excess of (stat) (syst) events,
above 160 MeV, resulting from the charged-current reaction of
and/or on C and H in the LSND detector. No beam related muon
background is expected in this energy regime. Within an analysis framework of
, we set a direct upper limit for this
branching ratio of at 90% confidence level.Comment: 4 pages, 4 figure
Influence of Water Stress on Groundnut Aphids
The groundnut aphid Aphis craccivora Koch is cosmopolitan
in distribution and infests many host plants belonging
to the leguminous grou
Noncommutative probability, matrix models, and quantum orbifold geometry
Inspired by the intimate relationship between Voiculescu's noncommutative
probability theory (of type A) and large-N matrix models in physics, we look
for physical models related to noncommutative probability theory of type B.
These turn out to be fermionic matrix-vector models at the double large-N
limit. In the context of string theory, they describe different orbifolded
string worldsheets with boundaries. Their critical exponents coincide with that
of ordinary string worldsheets, but their renormalised tree-level one-boundary
amplitudes differ.Comment: 22 pages, 8 eps figures, LaTeX2.09; title changed, mistakes correcte
Non-perturbative equivalences among large N gauge theories with adjoint and bifundamental matter fields
We prove an equivalence, in the large N limit, between certain U(N) gauge
theories containing adjoint representation matter fields and their orbifold
projections. Lattice regularization is used to provide a non-perturbative
definition of these theories; our proof applies in the strong coupling, large
mass phase of the theories. Equivalence is demonstrated by constructing and
comparing the loop equations for a parent theory and its orbifold projections.
Loop equations for both expectation values of single-trace observables, and for
connected correlators of such observables, are considered; hence the
demonstrated non-perturbative equivalence applies to the large N limits of both
string tensions and particle spectra.Comment: 40 pages, JHEP styl
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