615 research outputs found
Some results and problems for anisotropic random walks on the plane
This is an expository paper on the asymptotic results concerning path
behaviour of the anisotropic random walk on the two-dimensional square lattice
Z^2. In recent years Mikl\'os and the authors of the present paper investigated
the properties of this random walk concerning strong approximations, local
times and range. We give a survey of these results together with some further
problems.Comment: 20 page
Higgsless Electroweak Theory following from the Spherical Geometry
A new formulation of the Electroweak Model with 3-dimensional spherical
geometry in the target space is suggested. The free Lagrangian in the spherical
field space along with the standard gauge field Lagrangian form the full
Higgsless Lagrangian of the model, whose second order terms reproduce the same
fields with the same masses as the Standard Electroweak Model. The vector
bosons and electron masses are generated automatically, so there is no need in
special mechanism.Comment: 6 page
New Confining N=1 Supersymmetric Gauge Theories
We examine N=1 supersymmetric gauge theories which confine in the presence of
a tree-level superpotential. We show the confining spectra which satisfy the 't
Hooft anomaly matching conditions and give a simple method to find the
confining superpotential. Using this method we fix the confining
superpotentials in the simplest cases, and show how these superpotentials are
generated by multi-instanton effects in the dual theory. These new type of
confining theories may be useful for model building, since the size of the
matter content is not restricted by an index constraint. Therefore, one expects
that a large variety of new confining spectra can be obtained using such
models.Comment: 26 pages, LaTe
Various Modified Solutions of the Randall-Sundrum Model with the Gauss-Bonnet Interaction
The Gauss-Bonnet interaction is the only consistent quadratic interaction
below the Planck scale in the Randall-Sundrum compactification. We study
various static and inflationary solutions including this Gauss-Bonnet
interaction.Comment: 23 pages including 1 eps figur
Supergravity Models for 3+1 Dimensional QCD
The most general black M5-brane solution of eleven-dimensional supergravity
(with a flat R^4 spacetime in the brane and a regular horizon) is characterized
by charge, mass and two angular momenta. We use this metric to construct
general dual models of large-N QCD (at strong coupling) that depend on two free
parameters. The mass spectrum of scalar particles is determined analytically
(in the WKB approximation) and numerically in the whole two-dimensional
parameter space. We compare the mass spectrum with analogous results from
lattice calculations, and find that the supergravity predictions are close to
the lattice results everywhere on the two dimensional parameter space except
along a special line. We also examine the mass spectrum of the supergravity
Kaluza-Klein (KK) modes and find that the KK modes along the compact D-brane
coordinate decouple from the spectrum for large angular momenta. There are
however KK modes charged under a U(1)xU(1) global symmetry which do not
decouple anywhere on the parameter space. General formulas for the string
tension and action are also given.Comment: 27 pages, LaTeX, 11 figures include
Chiral Compactification on a Square
We study quantum field theory in six dimensions with two of them compactified
on a square. A simple boundary condition is the identification of two pairs of
adjacent sides of the square such that the values of a field at two identified
points differ by an arbitrary phase. This allows a chiral fermion content for
the four-dimensional theory obtained after integrating over the square. We find
that nontrivial solutions for the field equations exist only when the phase is
a multiple of \pi/2, so that this compactification turns out to be equivalent
to a T^2/Z_4 orbifold associated with toroidal boundary conditions that are
either periodic or anti-periodic. The equality of the Lagrangian densities at
the identified points in conjunction with six-dimensional Lorentz invariance
leads to an exact Z_8\times Z_2 symmetry, where the Z_2 parity ensures the
stability of the lightest Kaluza-Klein particle.Comment: 28 pages, latex. References added. Clarifying remarks included in
section 2. Minor corrections made in section
Composite Intermediary and Mediator Models of Gauge-Mediated Supersymmetry Breaking
We discuss gauge-mediated models which employ a tree-level mass term in the
superpotential. We give explicit composite realizations in which the mass terms
are not fundamental. Instead, they arise as effective terms in the
superpotential from confining gauge dynamics.Comment: 20 pages, LaTeX, 1 figur
Toward a Systematic Holographic QCD: A Braneless Approach
Recently a holographic model of hadrons motivated by AdS/CFT has been
proposed to fit the low energy data of mesons. We point out that the infrared
physics can be developed in a more systematic manner by exploiting backreaction
of the nonperturbative condensates. We show that these condensates can
naturally provide the IR cutoff corresponding to confinement, thus removing
some of the ambiguities from the original formulation of the model. We also
show how asymptotic freedom can be incorporated into the theory, and the
substantial effect it has on the glueball spectrum and gluon condensate of the
theory. A simple reinterpretation of the holographic scale results in a
non-perturbative running for alpha_s which remains finite for all energies. We
also find the leading effects of adding the higher condensate into the theory.
The difficulties for such models to reproduce the proper Regge physics lead us
to speculate about extensions of our model incorporating tachyon condensation.Comment: 27 pages, LaTe
Quantum Deconstruction of a 5D SYM and its Moduli Space
We deconstruct the fifth dimension of the 5D SYM theory with SU(M) gauge
symmetry and Chern-Simons level k=M and show how the 5D moduli space follows
from the non-perturbative analysis of the 4D quiver theory. The 5D coupling
h=1/(g_5)^2 of the un-broken SU(M) is allowed to take any non-negative values,
but it cannot be continued to h<0 and there are no transitions to other phases
of the theory. The alternative UV completions of the same 5D SYM -- via M
theory on the C^3/Z_2M orbifold or via the dual five-brane web in type IIB
string theory -- have identical moduli spaces: h >= 0 only, and no flop
transitions. We claim these are intrinsic properties of the SU(M) SYM theory
with k=M.Comment: 46 Page
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