arXiv
(422.153 recursos)
This is one of the most extensive subject based repositories in the world in the field of physics, mathematics, astronomy, computer sciences and quantitative biology. This is the principal site with almost 20 mirror versions around the globe. The site is supported by an extensive collection of information and background documentation. An RSS feed is available for anyone interested in keeping up-to-date with newly added materials.
Mostrando recursos 1 - 20 de 58.392
1.
Charging Interacting Rotating Black Holes in Heterotic String Theory - Herrera-Aguilar, Alfredo
We present a formulation of the stationary bosonic string sector of the whole
toroidally compactified effective field theory of the heterotic string as a
double Ernst system which, in the framework of General Relativity describes, in
particular, a pair of interacting spinning black holes; however, in the
framework of low--energy string theory the double Ernst system can be
particularly interpreted as the rotating field configuration of two interacting
sources of black hole type coupled to dilaton and Kalb--Ramond fields. We
clarify the rotating character of the $B_{t\phi}$--component of the
antisymmetric tensor field of Kalb--Ramond and discuss on its possible torsion
nature. We also recall the fact that the double...
2.
Color Reflection Invariance and Monopole Condensation in QCD - Cho, Y. M.
We review the quantum instability of the Savvidy-Nielsen-Olesen (SNO) vacuum
of the one-loop effective action of SU(2) QCD, and point out a critical defect
in the calculation of the functional determinant of the gluon loop in the SNO
effective action. We prove that the gauge invariance, in particular the color
reflection invariance, exclude the unstable tachyonic modes from the gluon loop
integral. This guarantees the stability of the magnetic condensation in QCD.
3.
Localized Gauge Multiplet on a Wall - Maru, Nobuhito; Sakai, Norisuke
The localization of vector multiplets is examined using the {\cal N}=1
supersymmetric U(1) gauge theory with the Fayet-Iliopoulos term coupled to
charged chiral multiplets in four dimensions. The vector field becomes
localized on a BPS wall connecting two different vacua that break the gauge
symmetry. The vacuum expectation values of charged fields vanish
(approximately) around the center of the wall, causing the Higgs mechanism to
be ineffective. The mass of the localized vector multiplet is found to be the
inverse width of the wall. The model gives an explicit example of this general
phenomenon. A five-dimensional version of the model can also be constructed if
we abandon supersymmetry.
4.
Physical Degrees of Freedom of Non-local Theories - Gomis, Joaquim; Kamimura, Kiyoshi; Ramirez, Toni
We analyze the physical (reduced) space of non-local theories, around the
fixed points of these systems, by analyzing: i) the Hamiltonian constraints
appearing in the 1+1 formulation of those theories, ii) the symplectic two form
in the surface on constraints.
P-adic string theory for spatially homogeneous configurations has two fixed
points. The physical phase space around $q=0$ is trivial, instead around
$q=\frac 1g$ is infinite dimensional. For the special case of the rolling
tachyon solutions it is an infinite dimensional lagrangian submanifold. In the
case of string field theory, at lowest truncation level, the physical phase
space of spatially homogeneous configurations is two dimensional around $q=0$,
which is the...
5.
Supersymmetric Composite Models on Intersecting D-branes - Kitazawa, Noriaki
We construct supersymmetric composite models of quarks and leptons from type
IIA T^6/(Z_2 x Z_2) orientifolds with intersecting D6-branes. In case of T^6 =
T^2 x T^2 x T^2 with no tilted T^2, a composite model of the supersymmetric
SU(5) grand unified theory with three generations is constructed. In case of
that one T^2 is tilted, a composite model with SU(3)_c x SU(2)_L x U(1)_Y gauge
symmetry with three generations is constructed. These models are not realistic,
but contain fewer additional exotic particles and U(1) gauge symmetries due to
the introduction of the compositeness of quarks and leptons. The masses of some
exotic particles are naturally generated through...
6.
Supergravities with Minkowski x Sphere Vacua - Kerimo, J.; Liu, James. T.; Lu, H.; Pope, C. N.
Recently the authors have introduced a new gauged supergravity theory with a
positive definite potential in D=6, obtained through a generalised Kaluza-Klein
reduction from D=7. Of particular interest is the fact that this theory admits
certain Minkowski x Sphere vacua. In this paper we extend the previous results
by constructing gauged supergravities with positive definitive potentials in
diverse dimensions, together with their vacuum solutions. In addition, we prove
the supersymmetry of the generalised reduction ansatz. We obtain a
supersymmetric solution with no form-field fluxes in the new gauged theory in
D=9. This solution may be lifted to D=10, where it acquires an interpretation
as a time-dependent supersymmetric cosmological solution...
7.
Meanfield Approximation For Field Theories On The Worldsheet Revisited - Bardakci, Korkut
This work is the continuation of the earlier efforts to apply the mean field
approximation to the world sheet formulation of planar phi^3 theory. The
previous attempts were either simple but without solid foundation or well
founded but excessively complicated. In this article, we present an approach
both simple, and also systematic and well founded. We are able to carry through
the leading order mean field calculation analytically, and with a suitable
tuning of the coupling constant, we find string formation.
8.
D Branes and Phases on String Worldsheet - Okuda, Takuya; Ooguri, Hirosi
We generalize the worldsheet derivation of the topological open/closed string
duality given in hep-th/0205297 to cases when there are different types of D
branes on the open string side. We use the mirror Landau-Ginzburg description
to clarify the correspondence between D branes on the open string side and C
phases on the closed string side. We also discuss the duality from the point of
view of the B model.
9.
Noncommutative Moduli for Multi-Instantons - Ivanova, Tatiana A.; Lechtenfeld, Olaf; Mueller-Ebhardt, Helge
There exists a recursive algorithm for constructing BPST-type
multi-instantons on commutative R^4. When deformed noncommutatively, however,
it becomes difficult to write down non-singular instanton configurations with
topological charge greater than one in explicit form. We circumvent this
difficulty by allowing for the translational instanton moduli to become
noncommutative as well. This makes possible the ADHM construction of 't Hooft
multi-instanton solutions with everywhere self-dual field strengths on
noncommutative R^4.
10.
Braneworld inflation - Buchel, Alex; Ghodsi, Ahmad
We discuss various realizations of the four dimensional braneworld inflation
in warped geometries of string theory. In all models the inflaton field is
represented by a Dp probe brane scalar specifying its position in the warped
throat of the compactification manifold. We study existing inflationary throat
local geometries, and construct a new example. The inflationary brane is either
a D3- or a D5-brane of type IIB string theory. In the latter case the
inflationary brane is wrapping a two-cycle of the compactification manifold. We
discuss some phenomenological aspects of the model where slow-roll conditions
are under computational control.
11.
Revisiting D-branes in $AdS_3 \times S^3$ - Kumar, Jason; Rajaraman, Arvind
We find the most general supergravity solution in an $AdS^3 \times S^3$
background preserving an $AdS_2 \times S^2$ symmetry and half the
supersymmetries. Contrary to previous expectations from boundary state
arguments, it is shown that no solutions exist containing localized brane
sources.
12.
Zamolodchikov operator-valued relations for SL(2,R)_k WZNW model - Bertoldi, Gaetano; Giribet, Gaston
An infinite set of operator-valued relations that hold for reducible
representations of the sl(2)_k algebra is derived. These relations are
analogous to those recently obtained by Zamolodchikov which involve logarithmic
fields associated to the Virasoro degenerate representations in Liouville
theory. The fusion rules of the sl(2)_k algebra turn out to be a crucial step
in the analysis. The possible relevance of these relations for the boundary
theory in the AdS_3/CFT_2 correspondence is suggested.
13.
Brane Solutions with/without Rotation in PP-wave Spacetime - Nayak, Rashmi R.; Panigrahi, Kamal L.; Siwach, Sanjay
We present two classes of brane solutions in pp-wave spacetime. The first
class of branes with a rotation parameter are constructed in an exact string
background with NS-NS and R-R flux. The spacetime supersymmetry is analyzed by
solving the standard Killing spinor equations and is shown to preserve the same
amount of supersymmetry as the case without the rotation. This class of branes
do not admit regular horizon. The second class of brane solutions are
constructed by applying a null Melvin twist to the brane solutions of flat
spacetime supergravity. These solutions admit regular horizon. We also comment
on some thermodynamic properties of this class of solutions.
14.
Dimensional reduction of quantum fields on a brane - Haba, Z.
If we restrict a quantum field defined on a regular D dimensional curved
manifold to a d dimensional submanifold then the resulting field will still
have the singularity of the original D dimensional model. We show that a
singular background metric can force the restricted field to behave as a d
dimensional quantum field.
15.
RG Cascades in Hyperbolic Quiver Gauge Theories - Laamara, R. Ahl; Haddou, M. Ait Ben; Belhaj, A; Drissi, L. B; Saidi, E. H
In this paper, we provide a general classification of supersymmeric
QFT$_{4}$s into three basic sets: ordinary, affine and indefinite classes. The
last class, which has not been enough explored in literature, is shown to share
most of properties of ordinary and affine super QFT$_{4}$s. This includes,
amongst others, its embedding in type II string on local Calabi-Yau threefolds.
We give realizations of these supersymmetric QFT$_{4}$s as D-brane world volume
gauge theories. A special interest is devoted to hyperbolic subset for its
peculiar features and for the role it plays in type IIB background with non
zero axion. We also study RG flows and duality cascades in case of...
16.
ABC of N=8, d=1 supermultiplets - Bellucci, S.; Ivanov, E.; Krivonos, S.; Lechtenfeld, O.
We construct a variety of off-shell $N{=}8, d{=}1$ supermultiplets with
finite numbers of component fields as direct sums of properly constrained
$N{=}4, d{=}1$ superfields. We also show how these multiplets can be described
in $N{=}8, d{=}1$ superspace where the whole amount of supersymmetry is
manifest. Some of these multiplets can be obtained by dimensional reduction
{}from $N{=}2$ multiplets in $d{=}4$, whereas others cannot. We give examples
of invariant superfield actions for the multiplets constructed, including
$N{=}8$ superconformally invariant ones.
17.
De Sitter Bounces - Lu, H.; Vazquez-Poritz, J. F.; Wang, John E.
By analytically continuing recently-found instantons, we construct
time-dependent solutions of Einstein-Maxwell de Sitter gravity which smoothly
bounce between two de Sitter phases. These deformations of de Sitter space
undergo several stages in their time evolution. Four and five-dimensional de
Sitter bounces can be lifted to non-singular time-dependent solutions of
M-theory.
18.
Non-extremal D-instantons - Bergshoeff, E.; Collinucci, A.; Gran, U.; Roest, D.; Vandoren, S.
We construct the most general non-extremal deformation of the D-instanton
solution with maximal rotational symmetry. The general non-supersymmetric
solution carries electric charges of the SL(2,R) symmetry, which correspond to
each of the three conjugacy classes of SL(2,R). Our calculations naturally
generalise to arbitrary dimensions and arbitrary dilaton couplings.
We show that for specific values of the dilaton coupling parameter, the
non-extremal instanton solutions can be viewed as wormholes of non-extremal
Reissner-Nordstr\"om black holes in one higher dimension. We extend this result
by showing that for other values of the dilaton coupling parameter, the
non-extremal instanton solutions can be uplifted to non-extremal non-dilatonic
p-branes in p+1 dimensions higher.
Finally, we...
19.
Quantum Topology Change and Large N Gauge Theories - de Albuquerque, Luiz C.; Teotonio-Sobrinho, Paulo; Vaidya, Sachindeo
We study a model for dynamical localization of topology using ideas from
non-commutative geometry and topology in quantum mechanics. We consider a
collection $X$ of $N$ one-dimensional manifolds and the corresponding set of
boundary conditions (self-adjoint extensions) of the Dirac operator $D$. The
set of boundary conditions encodes the topology and is parameterized by unitary
matrices $g_N$. A particular geometry is described by a spectral triple
$x(g_N)=(A_X,{\cal H}_X, D(g_N))$. We define a partition function for the sum
over all $g_N$. In this model topology fluctuates but the dimension is kept
fixed. We use the spectral principle to obtain an action for the set of
boundary conditions. Together with invariance...
20.
D-Brane Dynamics in Dp-Brane Background - Panigrahi, Kamal L.
By using Dirac-Born-Infeld action we study the real time dynamics of D-branes
in the vicinity of a stack of Dp-branes where the role of the tachyon of the
open string models is played by the radial mode on the D-branes. We examine the
behaviour of the tachyon potential and study the hamiltonian formulation and
classical solutions of such systems. We also study the homogeneous solutions of
the classical equations of motion in these cases.
1.
