518 research outputs found
Classification of BPS equations in higher dimensions
We systematically classify all possible Bogomol'nyi-Prasad-Sommerfield (BPS)
equations in Euclidean dimension . We discuss symmetries of BPS
equations and their connection with the self-dual Yang-Mills equations. Also,
we present a general method allowing to obtain the BPS equations in any
dimension. In addition, we find all BPS equations in the Minkowski space of
dimension and apply the obtained results to the supersymmetric
Yang-Mills theories. In conclusion, we discuss the possibility of using the
classification to construct soliton solutions of the low-energy effective
theory of the heterotic string.Comment: 31 pages, LaTe
Anomaly Cancellation in 2+1 dimensions in the presence of a domainwall mass
A Fermion in 2+1 dimensions, with a mass function which depends on one
spatial coordinate and passes through a zero ( a domain wall mass), is
considered. In this model, originally proposed by Callan and Harvey, the gauge
variation of the effective gauge action mainly consists of two terms. One comes
from the induced Chern-Simons term and the other from the chiral fermions,
bound to the 1+1 dimensional wall, and they are expected to cancel each other.
Though there exist arguments in favour of this, based on the possible forms of
the effective action valid far from the wall and some facts about theories of
chiral fermions in 1+1 dimensions, a complete calculation is lacking. In this
paper we present an explicit calculation of this cancellation at one loop valid
even close to the wall. We show that, integrating out the ``massive'' modes of
the theory does produce the Chern-Simons term, as appreciated previously. In
addition we show that it generates a term that softens the high energy
behaviour of the 1+1 dimensional effective chiral theory thereby resolving an
ambiguity present in a general 1+1 dimensional theory.Comment: 17 pages, LaTex file, CU-TP-61
Pseudoscalar Glueball, eta'-meson and its Excitation in the Chiral Effective Lagrangian
A generalization of the chiral effective lagrangian of order is
proposed which involves the -meson, its excitation, and the pseudoscalar
(PS) glueball. Model-independent constraints are found for the contributions to
the lagrangian of the above singlet states. Those allow one to independently
identify the nature of these singlet states in the framework of the approach.
The mixing among the iso-singlet states (including -state) is analysed,
and the hierarchy of the mixing angles is described which is defined by the
chiral and large- expansions. The recent PCAC results are reproduced,
which are related to the problem of the renormalization-group invariant
description of the and the PS glueball, and a further analysis of this
problem is performed.Comment: 19 pages LaTeX, no figures. Revised version accepted in Phis.Rev.
Properties of Intersecting p-branes in Various Dimensions
General properties of intersecting extremal p-brane solutions of gravity
coupled with dilatons and several different d-form fields in arbitrary
space-time dimensions are considered. It is show that heuristically expected
properties of the intersecting p-branes follow from the explicit formulae for
solutions. In particular, harmonic superposition and S-duality hold for all
p-brane solutions. Generalized T-duality takes place under additional
restrictions on the initial theory parameters .Comment: 14 pages, RevTeX, misprints are corrected and more Comments are
added, information about one of the authors (M.G.I.) available at
http://www.geocities.com/CapeCanaveral/Lab/419
Effective spatial dimension of extremal non-dilatonic black p-branes and the description of entropy on the world volume
By investigating the critical behavior appearing at the extremal limit of the
non-dilatonic, black p-branes in (d+p) dimensions, we find that some critical
exponents related to the critical point obey the scaling laws. From the scaling
laws we obtain that the effective spatial dimension of the non-dilatonic black
holes and black strings is one, and is p for the non-dilatonic black p-branes.
For the dilatonic black holes and black p-branes, the effective dimension will
depend on the parameters in theories. Thus, we give an interpretation why the
Bekenstein-Hawking entropy may be given a simple world volume interpretation
only for the non-dilatonic black p-branes.Comment: 4 pages, RevTex, no figures, to appear in Phys. Rev. Let
Intersecting Noncommutative D-branes and Baryons in Magnetic Fields
We study supersymmetric intersecting configurations of D-branes with B-field
backgrounds. Noncommutative D-brane or M-brane pairs can intersect
supersymmetrically over (p-1)-brane, as well as over (p-2)-brane like ordinary
branes. d=10 and d=11 supergravity solutions are obtained and the supersymmetry
projection rule is examined. As an application we study a noncommutative
D7-brane probe in noncommutative D3-brane background, intersecting at
noncommutative plane, which describes BPS baryons of noncommutative gauge
theory in the context of AdS/CFT correspondence.Comment: 15 pages;several important references are added and typos correcte
Quantum Cosmology of Kantowski-Sachs like Models
The Wheeler-DeWitt equation for a class of Kantowski-Sachs like models is
completely solved. The generalized models include the Kantowski-Sachs model
with cosmological constant and pressureless dust. Likewise contained is a
joined model which consists of a Kantowski-Sachs cylinder inserted between two
FRW half--spheres. The (second order) WKB approximation is exact for the wave
functions of the complete set and this facilitates the product structure of the
wave function for the joined model. In spite of the product structure the wave
function can not be interpreted as admitting no correlations between the
different regions. This problem is due to the joining procedure and may
therefore be present for all joined models. Finally, the {s}ymmetric {i}nitial
{c}ondition (SIC) for the wave function is analyzed and compared with the ``no
bouindary'' condition. The consequences of the different boundary conditions
for the arrow of time are briefly mentioned.Comment: 21 pages, uses LaTeX2e, epsf.sty and float.sty, three figures (50
kb); changes: one figure added, new interpretation of quantizing procedure
for the joined model and many minor change
Absorption cross section and Hawking radiation in two-dimensional AdS black hole
We calculate the absorption coefficient of scalar field on the background of
the two-dimensional AdS black hole, which is of relevance to Hawking radiation.
For the massless scalar field, we find that there does not exist any massless
radiation.Comment: 6 pages, revtex, no figure
Pole Term and Gauge Invariance in Deep Inelastic Scattering
In this paper we reconcile two contradictory statements about deep inelastic
scattering (DIS) in manifestly covariant theories: (i) the scattering must be
gauge invariant, even in the deep inelastic limit, and (ii) the pole term
(which is not gauge invariant in a covariant theory) dominates the scattering
amplitude in the deep inelastic limit. An ``intermediate'' answer is found to
be true. We show that, at all energies, the gauge dependent part of the pole
term cancels the gauge dependent part of the rescattering term, so that both
the pole and rescattering terms can be separately redefined in a gauge
invariant fashion. The resulting, redefined pole term is then shown to dominate
the scattering in the deep inelastic limit. Details are worked out for a simple
example in 1+1 dimensions.Comment: 10 figure
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