38 research outputs found
Classical and Quantum Composite p-branes
We discuss classical composite p-brane solutions and their quantization using
the conjecture that their fluctuations may be described via degrees of freedom
of Dirichlet strings ended on these p-branes. We work with Dirichlet
(super)strings in framework of string field theory for open (super)strings. To
elaborate in this scheme the eleventh dimension modes we take just a collection
of Dirichlet strings which in their middle points have jumps in eleventh
dimension. This theory can be seen as string field theory in infinite momentum
frame of an eleven dimensional object.Comment: 7 pages, LaTex. Lecture at the XXXIII Karpacz Winter School "Duality
-- String and Fields
Regge Regime in QCD and Asymmetric Lattice Gauge Theory
We study the Regge regime of QCD as a special regime of lattice gauge theory
on an asymmetric lattice. This lattice has a spacing in the longitudinal
direction and a spacing in the transversal direction. The limit
corresponds to correlation functions with small
longitudinal and large transversal coordinates, i.e. large and small .
On this lattice the longitudinal dynamics is described by the usual
two-dimensional chiral field in finite volume and the transversal dynamics is
emerged through an effective interaction of boundary terms of the longitudinal
dynamics. The effective interaction depends crucially on the spectrum of the
two-dimensional chiral field. Massless exitations produce an effective
2-dimensional action which is different from the action recently proposed by
H.Verlinde and E.Verlinde. Massive exitations give raise to an effective action
located on the contour in the longitudinal plane.Comment: LATEX, 13 pages, SMI-15-9
The Master Field for the Half-Planar Approximation for Large Matrix Models and Boltzmann Field Theory
In this talk results of study in various dimensions of the Boltzmann master
field for a subclass of planar diagrams, so called half-planar diagrams, found
in the recent work by Accardi, Volovich and one of us (I.A.) are presented.Comment: Contr. Proc. Buckow Symposium (1995); 6 pages, LATEX uses
twoside.sty, fleqn.sty, espcrc2.sty, emlines.sty, bezier.st
UV/IR Mixing for Noncommutative Complex Scalar Field Theory, II (Interaction with Gauge Fields)
We consider noncommutative analogs of scalar electrodynamics and N=2 D=4 SUSY
Yang-Mills theory. We show that one-loop renormalizability of noncommutative
scalar electrodynamics requires the scalar potential to be an anticommutator
squared. This form of the scalar potential differs from the one expected from
the point of view of noncommutative gauge theories with extended SUSY
containing a square of commutator. We show that fermion contributions restore
the commutator in the scalar potential. This provides one-loop
renormalizability of noncommutative N=2 SUSY gauge theory. We demonstrate a
presence of non-integrable IR singularities in noncommutative scalar
electrodynamics for general coupling constants. We find that for a special
ratio of coupling constants these IR singularities vanish. Also we show that IR
poles are absent in noncommutative N=2 SUSY gauge theory.Comment: 9 pages, 16 EPS figure
Non-Abelian Wilson Surfaces
A definition of non-abelian genus zero open Wilson surfaces is proposed. The
ambiguity in surface-ordering is compensated by the gauge transformations.Comment: JHEP Latex, 10 pages, 6 figures; v2, refs and comments added in sec.
Tachyon condensation in cubic superstring field theory
It has been conjectured that at the stationary point of the tachyon potential
for the non-BPS D-brane or brane-anti-D-brane pair, the negative energy density
cancels the brane tension. We study this conjecture using a cubic superstring
field theory with insertion of a double-step inverse picture changing operator.
We compute the tachyon potential at levels (1/2,1) and (2,6). In the first case
we obtain that the value of the potential at the minimum is 97.5% of the non
BPS D-brane tension. Using a special gauge in the second case we get 105.8% of
the tension.Comment: 19 pages, LaTeX, 3 figures. Eqs. (3.2), (3.3) and (4.6) are
corrected, and new gauge fixing condition is use
Large N QCD at High Energies as Two-Dimensional Field Theory
Different aspects of the Verlinde and Verlinde relation between high-energy
effective scattering in QCD and a two-dimensional sigma-model are discussed.
Starting from a lattice version of the truncated 4-dimensional Yang-Mills
action we derive an effective theory with non-trivial longitudinal dynamics
which has a form of the lattice two-dimensional chiral field model with
non-trivial boundary conditions. To get quantum corrections coming from
non-trivial longitudinal dynamics to transversal high-energy effective action
one has to solve the two-dimensional chiral field model with non-trivial
boundary conditions. We do this within an approximation scheme which takes into
account one-dimensional excitations. Contributions of the one-dimensional
excitations to quantum corrections for the high-energy effective action are
calculated in the large N limit using the character expansion method.Comment: Latex, 14pages, one reference added+ some minor correction
Large-N Quenching in the Kazakov-Migdal Model
To study the behavior of the Kazakov-Migdal at large N the quenched momentum
prescription with constraints for treating the large N limit of gauge theories
is used. It is noted that it leads to a quartic dependence of an action on
unitary matrix instead of a quadratic dependence discussed in previous
considerations. Therefore the model is not exactly solvable in the weak
coupling limit. An approximation procedure for investigation of the model is
outlined. In this approximation an indication to a phase transition for
with is obtained.Comment: LaTex, 9 page
Stringy Dark Energy Model with Cold Dark Matter
Cosmological consequences of adding the Cold Dark Matter (CDM) to the exactly
solvable stringy Dark Energy (DE) model are investigated. The model is
motivated by the consideration of our Universe as a slowly decaying D3-brane.
The decay of this D-brane is described in the String Field Theory framework.
Stability conditions of the exact solution with respect to small fluctuations
of the initial value of the CDM energy density are found. Solutions with large
initial value of the CDM energy density attracted by the exact solution without
CDM are constructed numerically. In contrast to the LambdaCDM model the Hubble
parameter in the model is not a monotonic function of time. For specific
initial data the DE state parameter w_{DE} is also not monotonic function of
time. For these cases there are two separate regions of time where w_{DE} being
less than -1 is close to -1.Comment: 15 pages, 6 figures; references adde
A Simple Model Inducing QCD
A simple lattice model inducing a gauge theory is considered. The model
describes an interaction of a gauge field to an complex matrix
scalar field transforming as a field in the fundamental representation. In
contrast to the Kazakov-Migdal model the model contains only the linear
interaction between scalar and gauge lattice fields. This model does not suffer
from extra local U(1) symmetries. In an approximation of a translation
invariant master field the large N limit of the model is investigated. At large
N the gauge fields can be integrated out yielding an effective theory
describing an interaction of eigenvalues of the master field. The reduced model
exhibits phase transitions at the points and and the region
separates the strong and weak regions of the model. To study the behaviour of
the model at large in more systematic way the quenched momentum
prescription with constraints for treating the large N limit of gauge theories
is used. With the help of the technique of orthogonal polynomials nonlinear
equations describing the large N limit of the reduced model {\it with
quenching} are presented.Comment: LaTex, 10 page