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1997-01-20
Geometric Entropy and Curvature Coupling in Conical Spaces: zeta Function Approach
The local $\zeta-$function approach is implemented to regularize the natural path integral definition of the geometric entropy in the large mass black hole Euclidean manifold. The case of a massless field coupled with the (off-shell) singular curvature is considered. It is proved that the geometric entropy is independe...
9701099v2
1997-01-23
Quantum Affine Symmetry and Scattering Amplitudes of the Imaginary Coupled d_4(3) Affine Toda Field Theory
An exact S-matrix is conjectured for the imaginary coupled d_4(3) affine Toda field theory, using the U_q(g_2(1)) symmetry. It is shown that this S-matrix is consistent with the results for the case of real coupling using the breather-particle correspondence. For q a root of unity it is argued that the theory can be re...
9701118v3
1997-02-04
Vortex solutions of a Maxwell-Chern-Simons field coupled to four-fermion theory
We find the static vortex solutions of the model of Maxwell-Chern-Simons gauge field coupled to a (2+1)-dimensional four-fermion theory. Especially, we introduce two matter currents coupled to the gauge field minimally: the electromagnetic current and a topological current associated with the electromagnetic current. U...
9702029v1
1997-02-06
Gravitational Dressing of N=2 Sigma-Models Beyond Leading Order
We study the beta-function of the N=2 sigma-model coupled to N=2 induced supergravity. We compute corrections to first order in the semiclassical limit, $c \to -\infty$, beyond one-loop in the matter fields. As compared to the corresponding bosonic, metric sigma-model calculation, we find new types of contributions ari...
9702051v1
1997-02-17
Critical Couplings in the Nambu--Jona-Lasinio Model with the Constant Electromagnetic Fields
A detailed analysis is performed for the Nambu--Jona-Lasinio model coupled with constant (external) magnetic and/or electric fields in two, three, and four dimensions. The infrared cut-off is essential for a well-defined functional determinant by means of the proper time method. Contrary to the previous observation, th...
9702128v1
1997-03-11
New Couplings of Six-Dimensional Supergravity
We describe the couplings of six-dimensional supergravity, which contain a self-dual tensor multiplet, to $n_T$ anti-self-dual tensor matter multiplets, $n_V$ vector multiplets and $n_H$ hypermultiplets. The scalar fields of the tensor multiplets form a coset $SO(n_T,1)/SO(n_T)$, while the scalars in the hypermultiplet...
9703075v1
1997-03-19
Remarks on the Classical Size of D-Branes
We discuss different criteria for `classical size' of extremal Dirichlet p-branes in type-II supergravity. Using strong-weak coupling duality, we find that the size of the strong-coupling region at the core of the (p<3)-branes, is always given by the asymptotic string scale, if measured in the weakly coupled dual strin...
9703138v1
1997-03-26
Vortex solutions in axial or chiral coupled non-relativistic spinor- Chern-Simons theory
The interaction of a spin 1/2 particle (described by the non-relativistic "Dirac" equation of L\'evy-Leblond) with Chern-Simons gauge fields is studied. It is shown, that similarly to the four dimensional spinor models, there is a consistent possibility of coupling them also by axial or chiral type currents. Static sel...
9703184v1
1997-05-05
A Matrix String Interpretation of the Large N Loop Equation
The existence two S-dual descriptions of (N,1) string bound states suggests that the strong coupling behaviour of electric flux lines in large N 2D SYM theory has a dual description in terms of weakly coupled IIB string theory. In support of this identification, we propose a dual interpretation of the SYM loop equation...
9705029v4
1997-05-16
Unitary Matrix Models and Phase Transition
We study the unitary matrix model with a topological term. We call the topological term the theta term. In the symmetric model there is the phase transition between the strong and weak coupling regime at $\lambda_{c}=2$. If the Wilson term is bigger than the theta term, there is the strong-weak coupling phase transitio...
9705121v2
1997-05-20
Wilson renormalization group and improved perturbation theory
We discuss a resummed perturbation theory based on the Wilson renormalization group. In this formulation the Wilsonian flowing couplings, which generalize the running coupling, enter directly into the loop expansion. In the case of an asymptotically free theory the flowing coupling is well defined since the infrared La...
9705146v1
1997-06-13
Superstring dominated early universe and epoch dependent gauge coupling
We have explored the possibility that the universe at very early stage was dominated by (macroscopic) heterotic strings. We have found that the dimensionless parameter $G\mu$ for the heterotic strings varies from $10^{-2}$ to $10^{-4}$ as the universe evolve from the matter dominance to radiation dominance. This led to...
9706104v1
1997-07-03
Hawking Radiation for Non-minimally Coupled Matter from Generalized 2D Black Hole Models
It is well known that spherically symmetric reduction of General Relativity (SSG) leads to non-minimally coupled scalar matter. We generalize (and correct) recent results to Hawking radiation for a class of dilaton models which share with the Schwarzschild black hole non-minimal coupling of scalar fields and the basic ...
9707041v1
1997-11-25
On the equivalence of the self-dual and Maxwell-Chern-Simons models coupled to Fermions
We study the exact equivalence between the self-dual model minimally coupled with a Dirac field and the Maxwell-Chern-Simons model with non-minimal magnetic coupling to fermions. We show that the fermion sectors of the models are equivalent only if a Thirring like interaction is included. Using functional methods we ve...
9711184v1
1998-01-09
Conformal anomaly for dilaton coupled electromagnetic field
The derivation of the conformal anomaly for dilaton coupled electromagnetic field in curved space is presented. The models of this sort naturally appear in stringy gravity or after spherical reduction of multidimensional Einstein-Maxwell theory. It is shown that unlike the case of minimal vector in curved space or dila...
9801052v1
1998-01-29
The superspace geometry of gravitational Chern-Simons forms and their couplings to linear multiplets : a review
The superspace geometry of Chern-Simons forms is shown to be closely related to that of the 3-form multiplet. This observation allows to simplify considerably the geometric structure of supersymmetric Chern-Simons forms and their coupling to linear multiplets. The analysis is carried through in U_K(1) superspace, relev...
9801201v1
1998-02-05
Matrix string interactions
String configurations have been identified in compactified Matrix theory at vanishing string coupling. We show how the interactions of these strings are determined by the Yang-Mills gauge field on the worldsheet. At finite string coupling, this suggests the underlying dynamics is not well-approximated as a theory of st...
9802034v2
1998-03-06
A New Class of Integrable Models of 1+1 Dimensional Dilaton Gravity Coupled to Scalar Matter
Integrable models of 1+1 dimensional gravity coupled to scalar and vector fields are briefly reviewed. A new class of integrable models with nonminimal coupling to scalar fields is constructed and discussed.
9803059v1
1998-03-18
Type IIB $R^4 H^{4g-4}$ Conjectures
We propose $SL(2,Z)$ (and $SL(3,Z)$) invariant conjectures for all $R^4 H^{4g-4}$ couplings of Type IIB strings on $R^{10}$ (and $R^{8}\times T^2$), generalizing conjectures of Green and Gutperle (and Kiritsis and Pioline) for the $R^4$ coupling. A strong check for our conjectures is that on $T^2$ at weak coupling, the...
9803145v2
1998-03-23
Charged Particles in a 2+1 Curved Background
The coupling to a 2+1 background geometry of a quantized charged test particle in a strong magnetic field is analyzed. Canonical operators adapting to the fast and slow freedoms produce a natural expansion in the inverse square root of the magnetic field strength. The fast freedom is solved to the second order. At an...
9803187v1
1998-03-24
Stable Non-BPS States in String Theory
Many string theories contain states which are not BPS, but are stable due to charge conservation. In many cases the description of these states in the strong coupling limit remains unknown despite the existence of a weakly coupled dual theory. However, we show that in some cases duality symmetries in string theory do e...
9803194v2
1998-04-04
S-duality and Strong Coupling Behavior of Large N Gauge Theories with N=4 Supersymmetry
We analyze the strong coupling behavior of the large N gauge theories in 4-dimensions with N=4 supersymmetry by making use of S-duality. We show that at large values of the coupling constant $\lambda=g_{YM}^2N$ the j-th non-planar amplitude $f_j(\lambda) (j=0,1,2 ...)$ behaves as $f_j(\lambda)\approx \lambda^j$. Implic...
9804037v1
1998-04-29
Renormalisation Group Improved Thermal Coupling Constant In An External Field
Starting from renormalised Effective Lagrangian, in the presence of an external Chromo-Electric field at finite temperature, the expression for thermal coupling constant ($\alpha = (g^2)/(4 \pi)$) as a function of temperature and external field is derived, using finite temperature two parameter renormalisation group eq...
9804195v1
1998-06-29
The Nonperturbative Gauge Coupling of N=2 Supersymmetric Theories
We argue that the topology of the quantum coupling space and the low energy effective action on the Coulomb branch of scale invariant N=2 SU(n) gauge theories pick out a preferred nonperturbative definition of the gauge coupling up to non-singular holomorphic reparametrizations.
9806234v2
1998-07-10
Pseudo-anomalous U(1) symmetry in the strong coupling limit of the heterotic string
We discuss, in the context of the strongly coupled E_8 \times E_8 heterotic string proposed by Horava and Witten, the appearance of anomalous U(1)_X symmetries of a nonperturbative origin, related to the presence, after compactification, of five-branes in the five-dimensional bulk of the theory. We compute the gauge an...
9807079v1
1998-08-12
Anomalous D-brane and orientifold couplings from the boundary state
We compute scattering amplitudes involving both R-R and NS-NS fields in the presence of a D-brane or orientifold plane. These provide direct evidence for the anomalous couplings in the D-brane and orientifold actions. The D9-brane and O9-plane are found to couple to the first Pontrjagin class with the expected relative...
9808074v3
1998-09-19
The Auxiliary Field Method as a Powerful Tool for Nonperturbative Study
The auxiliary field method, defined through introducing an auxiliary (also called as the Hubbard-Stratonovich or the Mean-) field and utilizing a loop-expansion, gives an excellent result for a wide range of a coupling constant. The analysis is made for Anharmonic-Oscillator and Double-Well examples in 0-(a simple inte...
9809141v1
1998-10-01
Conformal Anomaly for Dilaton Coupled Theories from AdS/CFT Correspondence
Trace anomaly for dilaton coupled conformal theories on curved background with non-zero dilaton is found from supergravity side as an IR effect using AdS/CFT correspondence. For $d=2$ it coincides with the conformal anomaly for dilaton coupled scalar (up to total derivative term which is known to be ambiguous). In four...
9810008v1
1998-10-14
The Perturbative Gross Neveu Model Coupled to a Chern-Simons Field: A Renormalization Group Study
In 2+1 dimensions, for low momenta, using dimensional renormalization we study the effect of a Chern-Simons field on the perturbative expansion of fermions self interacting through a Gross Neveu coupling. For the case of just one fermion field, we verify that the dimension of operators of canonical dimension lower than...
9810106v1
1999-01-27
General massive gauge theory
The concept of perturbative gauge invariance formulated exclusively by means of asymptotic fields is used to construct massive gauge theories. We consider the interactions of $r$ massive and $s$ massless gauge fields together with $(r+s)$ fermionic ghost and anti-ghost fields. First order gauge invariance requires the ...
9901140v1
1999-02-04
Strongly Coupled Lattice Gauge Theories and Antiferromagnetic Spin Systems
In this thesis, I use the strong coupling expansion to investigate the multiflavor lattice Schwinger models in the hamiltonian formalism using staggered fermions. In particular, I am interested in analysing the mapping of these gauge theories onto quantum spin-1/2 antiferromagnetic Heisenberg chains. Exploting this map...
9902036v1
1999-04-02
A new perspective on matter coupling in 2d quantum gravity
We provide compelling evidence that a previously introduced model of non-perturbative 2d Lorentzian quantum gravity exhibits (two-dimensional) flat-space behaviour when coupled to Ising spins. The evidence comes from both a high-temperature expansion and from Monte Carlo simulations of the combined gravity-matter syste...
9904012v1
1999-04-06
Running gauge coupling and quark-antiquark potential from dilatonic gravity
The running gauge coupling and quark-antiquark potential in d-dimensions are calculated from the explicit solution of d+1-dimensional dilatonic gravity. This background interpolates between usual AdS in UV and flat space with singular dilaton in IR and it realizes two-boundaries AdS/CFT correspondence. The behaviour of...
9904036v3
1999-05-14
Propagating Torsion in 3D-Gravity and Dynamical Mass Generation
In this paper, fermions are minimally coupled to 3D-gravity where a dynamical torsion is introduced. A Kalb-Ramond field is non-minimally coupled to these fermions in a gauge-invariant way. We show that a 1-loop mass generation mechanism takes place for both the 2-form gauge field and the torsion. As for the fermions, ...
9905110v3
1999-07-29
Gravitational Couplings, Orientifolds and M-Planes
We examine string-theory orientifold planes of various types including the Sp and SO-odd planes, and deduce the gravitational Chern-Simons couplings on their world-volumes. Consistency checks are carried out in different spacetime dimensions using various dualities, including those relating string theory with F-theory ...
9907215v2
1999-08-04
Large N corrections to the strong coupling behaviour of SU(N)/Z_N lattice gauge theories
We derive a formula for the large N behaviour of the expectation values of an arbitrary product of Wilson loops in the adjoint representation. We show the consequences of our formula for the study of the large N strong coupling behaviour of SU(N)/Z_N pure gauge theories, and theories with matter fields in the adjoint r...
9908026v1
1999-08-12
Values of the Couplings and Internal Geometry
In this note we display an observation about the geometrical properties of the gauge group manifold of the standard electroweak theory, and the values of the gauge coupling constants. Heuristically obtained stucture relates the value 137.036... to the low energy U(1) coupling. The constuction resembles techniques recen...
9908086v1
1999-09-15
Oscillating Inflation with a non-minimally coupled scalar field
The oscillating inflation model recently proposed by Damour and Mukhanov is investigated with a non-minimal coupling. Numerical study confirms an inflationary behavior and the density perturbation is obtained. A successful inflation requires the gravity-dilaton coupling to be small.
9909106v1
1999-09-20
Hawking Radiation in the Dilaton Gravity with a Non-Minimally Coupled Scalar Field
We discuss the two-dimensional dilaton gravity with a scalar field as the source matter where the coupling with the gravity is given, besides the minimal one, through an external field. This coupling generalizes the conformal anomaly in the same way as those found in recent literature, but with a diferent motivation. T...
9909138v1
1999-09-23
Parametric holomorphy? Triviality versus Duality in Sinh-Gordon
Suppose a regularised functional integral depends holomorphically on a parameter that receives only a finite renormalization. Can one expect the correlation functions to retain the analyticity in the parameter after removal of the cutoff(s)? We examine the issue in the Sinh-Gordon theory by computing the intrinsic 4-po...
9909170v2
1999-10-15
Renormalization of QCD Coupling Constant in Terms of Physical Quantities
A renormalization scheme is suggested where QCD input parameters - quark mass and coupling constant - are expressed in terms of gauge invariant and infrared stable quantities. For the renormalization of coupling constant the quark anomalous electromagnetic moment is used; the latter is calculated in a two loop approxim...
9910120v1
1999-10-15
New S-dualities in N=2 supersymmetric SU(2) x SU(2) gauge theory
New S-dualities in a scale invariant N=2 gauge theory with SU(2) x SU(2) gauge group are derived from embeddings of the theory in two different larger asymptotically free theories. The true coupling space of the scale invariant theory is a 20-fold identification of the coupling space found in the M- and string-theory d...
9910125v1
1999-10-31
Non-renormalizability of a SSB gauge theory induced by a non-linear fermion-Higgs coupling of canonical dimension 4
We consider an abelian gauge theory with spontaneously broken symmetry containing a scalar-fermion coupling which is non-linear in the Higgs field. Although in the unitary gauge it reduces to a pure Yukawa term, suggesting that the theory is renormalizable, the one loop divergence structure in this gauge in the fermion...
9910257v2
1999-11-12
Static Potential in N=4 Supersymmetric Yang-Mills Theory
We compute the leading order perturbative correction to the static potential in ${\cal N}=4$ supersymmetric Yang-Mills theory. We show that the perturbative expansion contains infrared logarithms which, when resummed, become logarithms of the coupling constant. The resulting correction goes in the right direction to ma...
9911088v1
1999-12-04
On the Coupling of Gravitons to Matter
Using relationships between open and closed strings, we present a construction of tree-level scattering amplitudes for gravitons minimally coupled to matter in terms of gauge theory partial amplitudes. In particular, we present examples of amplitudes with gravitons coupled to vectors or to a single fermion pair. We als...
9912033v1
2000-02-28
Aspects of holography and rotating AdS black holes
A comparison is made between the thermodynamics of weakly and strongly coupled Yang-Mills with fixed angular momentum. The free energy of the strongly coupled Yang-Mills is calculated by using a dual supergravity description corresponding to a rotating black hole in an Anti de Sitter (AdS) background. All thermodynamic...
0002235v1
2000-03-09
Regular and black-hole solutions of the Einstein-Yang-Mills-Higgs equations; the case of nonminimal coupling
Regular and black-hole solutions of the spontaneously broken Einstein-Yang-Mills-Higgs theory with nonminimal coupling to gravity are shown to exist. The main characteristics of the solutions are presented and differences with respect to the minimally coupled case are studied. Since negative energy densities are found ...
0003073v2
2000-04-18
Chamseddine, Fröhlich, Grandjean Metric and Localized Higgs Coupling on Noncommutative Geometry
We propose a geometrized Higgs mechanism based on the gravitational sector in the Connes-Lott formulation of the standard model, which has been constructed by Chamseddine, Fr$\ddot{o}$hlic and Grandjean. The point of our idea is that Higgs-like couplings depend on the local coordinates of the four-dimensional continuum...
0004127v3
2000-05-11
New vortex solution in SU(3) gauge-Higgs theory
Following a brief review of known vortex solutions in SU(N) gauge-adjoint Higgs theories we show the existence of a new ``minimal'' vortex solution in SU(3) gauge theory with two adjoint Higgs bosons. At a critical coupling the vortex decouples into two abelian vortices, satisfying Bogomol'nyi type, first order, field ...
0005109v1
2000-05-19
Dynamics of N=2 Supersymmetric Chern-Simons Theories
We discuss several aspects of three dimensional N=2 supersymmetric gauge theories coupled to chiral multiplets. The generation of Chern-Simons couplings at low-energies results in novel behaviour including compact Coulomb branches, non-abelian gauge symmetry enhancement and interesting patterns of dynamically generated...
0005186v2
2000-12-08
Consistent gravitino couplings in non-supersymmetric strings
The massless spectrum of the ten dimensional USp(32) type I string has an N=1 supergravity multiplet coupled to non-supersymmetric matter. This raises the question of the consistency of the gravitino interactions. We resolve this apparent puzzle by arguing for the existence of a local supersymmetry which is non-linearl...
0012071v2
2001-01-01
Supergravity Couplings of Noncommutative D-branes
We discuss the supergravity couplings of noncommutative D-branes by considering the disk amplitudes with one closed string insertion. The result confirms a recent proposal for the general form of the noncommutative Yang-Mills operators coupling to the massless closed string modes. The construction involves smearing Yan...
0101016v2
2001-03-01
Critical Coupling in (1+1)-Dimensional Light-Front $φ^{4}$ Theory. II -effects of non-diagonal interactionof non-diagonal interactions-
Spontaneous symmetry breaking in (1+1)-dimensional $\phi^{4}$ theory is studied with discretized light-front quantization. Taking effects of non-diagonal interactions into account, the first few terms of the commutation relations $[a_{0},a_{n}]$ are recalculated in the $\hbar$ expansion. Our result of the critical coup...
0103002v2
2001-03-13
Strong-weak coupling duality in anisotropic current interactions
The recently proposed all orders beta function is further investigated. By using a strong-weak coupling duality of the beta function, and some added topology of the space of couplings we are able to extend the flows to arbitrarily large or small scales. Using a non-trivial RG invariant we are able to identify sine-Gord...
0103096v2
2001-04-16
M-theory and automorphic scattering
The strongly coupled limit of string scattering and the automorphic construction of the graviton S-matrix is compared with the eleven dimensional formulation of M-theory. In a particular scaling limit at strong string coupling, M-theory is described by eleven-dimensional supergravity which does not possess a dilaton, b...
0104132v4
2001-05-22
On Unification of RR Couplings
We consider the couplings of RR fields with open string sector for $Dp$-${\overline{Dp}}$ backgrounds of various $p$. Proposed approach, based on the approximation of the open string algebra by the algebra of differential operators, provides the unified description of these couplings and their interrelations.
0105228v3
2001-06-03
Four dimensional N=1 supersymmetrization of R^4 in superspace
We write an action, in four dimensional N=1 curved superspace, which contains a pure R^4 term with a coupling constant. Starting from the off-shell solution of the Bianchi identities, we compute the on-shell torsions and curvatures with this term. We show that their complete solution includes, for some of them, an infi...
0106023v2
2001-06-07
Einstein-Hilbert action on the brane for the bulk graviton
We find new closed string couplings on Dp-branes for the bosonic string. These couplings are quadratic in derivatives and therefore take the form of induced kinetic terms on the brane. For the graviton in particular we find the induced Einstein-Hilbert term as well as terms quadratic in the second fundamental tensor. W...
0106067v2
2001-06-22
(A)dS Backgrounds from Asymmetric Orientifolds
I present asymmetric orientifold models which, with the addition of RR fluxes, fix all the NS NS moduli including the dilaton. In critical string theory, this gives new AdS backgrounds with (discretely tunably) weak string coupling. Extrapolating to super-critical string theory, this construction leads to a promising c...
0106209v1
2001-06-29
Coupling integrable field theories to mechanical systems at the boundary
We present an integrable Hamiltonian which describes the sinh-Gordon model on the half line coupled to a non-linear oscillator at the boundary. We explain how we apply Sklyanin's formalism to a dynamical reflection matrix to obtain this model. This method can be applied to couple other integrable field theories to dyna...
0106275v1
2001-08-17
Searching for string theories of the standard model
We briefly review attempts to construct string theories that yield the standard model, concentrating on models with a geometric interpretation. Calabi-Yau compactifications are discussed in the context of both the weakly coupled heterotic string and the strongly coupled version, heterotic M-theory. Similarly, we consid...
0108127v1
2001-12-03
Gluon coupling strength in H_QCD with small cutoffs
This contribution presents the running triple-gluon-vertex coupling constant, g_lambda, in Hamiltonians for the gluons that are characterized by the size 1/lambda. The coupling constant is obtained from renormalization group equations for effective particles in canonical light-front QCD in third order perturbation theo...
0112018v1
2001-12-04
Bound States in n Dimensions (Especially n = 1 and n = 2)
We stress that in contradiction with what happens in space dimensions $n \geq 3$, there is no strict bound on the number of bound states with the same structure as the semi-classical estimate for large coupling constant and give, in two dimensions, examples of weak potentials with one or infinitely many bound states. W...
0112021v1
2002-01-14
Integer- and Non-Integer-Shift of the Chern-Simons Coupling under a Local Higher Covariant Derivative Regulator
The Chern-Simons coupling shift is calculated within the framework of the hybrid regularization based on a local higher covariant derivative regulator. When the Yang-Mills term is present in the theory the well-know integer-shift is obtained, but is absent, the shift value is non-integer. These results show a possibili...
0201086v1
2002-01-24
On three dimensional coupled bosons
This is a new version of the paper, which uses the same methods as in the previous version, but the model is now different. We study two complex scalar fields coupled through a quadratic interaction in 2+1 dimensions. We use the method of bilinears as suggested by Rajeev. The resulting classical theory is studied withi...
0201199v3
2002-02-19
Soliton Decay in Coupled System of Scalar Fields
A system of coupled scalar fields is introduced which possesses a spectrum of massive single-soliton solutions. Some of these solutions are unstable and decay into lower mass stable solitons. Some properties of the solutions are obtained using general principles including conservations of energy and topological charges...
0202122v2
2002-02-28
Running coupling in Yang-Mills theory - a flow equation study -
The effective average action of Yang-Mills theory is analyzed in the framework of exact renormalization group flow equations. Employing the background-field method and using a cutoff that is adjusted to the spectral flow, the running of the gauge coupling is obtained on all scales. In four dimensions and for the gauge ...
0202207v2
2002-04-22
An Elementary (Pseudo)Scalar at all scales
We consider an extended linear $\sigma $ model in which the fermions are quarks and are coupled to gluons. Equivalently, this is QCD extended by coupling the quarks to a colour singlet chiral multiplet of ($ \sigma, \vec \pi $) fields. This theory has a phase governed by a UV fixed point where all couplings are AF (asy...
0204177v1
2002-05-31
de Sitter black hole with a conformally coupled scalar field in four dimensions
A four-dimensional black hole solution of the Einstein equations with a positive cosmological constant, coupled to a conformal scalar field, is given. There is a curvature singularity at the origin, and scalar field diverges inside the event horizon. The electrically charged solution, which has a fixed charge-to-mass r...
0205319v2
2002-06-03
Nonequilibrium Dynamics of Coupled Quantum Systems
The nonequilibrium dynamics of coupled quantum oscillators subject to different time dependent quenches are analyzed in the context of the Liouville-von Neumann approach. We consider models of quantum oscillators in interaction that are exactly soluble in the cases of both sudden and smooth quenches. The time evolution...
0206022v3
2002-06-21
A Mean Field Approximation to the Worldsheet Model of Planar phi^3 Field Theory
We develop an approximation scheme for our worldsheet model of the sum of planar diagrams based on mean field theory. At finite coupling the mean field equations show a weak coupling solution that resembles the perturbative diagrams and a strong coupling solution that seems to represent a tensionless soup of field quan...
0206205v2
2002-09-23
Confinement of fermions by mixed vector-scalar linear potentials in two-dimensional space-time
The problem of confinement of fermions in 1+1 dimensions is approached with a linear potential in the Dirac equation by considering a mixing of Lorentz vector and scalar couplings. Analytical bound-states solutions are obtained when the scalar coupling is of sufficient intensity compared to the vector coupling.
0209196v2
2002-10-24
Interaction of global and local monopoles
We study the direct interaction between global and local monopoles. While in two previous papers, the coupling between the two sectors was only indirect through the coupling to gravity, we here introduce a new term in the potential that couples the Goldstone field and the Higgs field directly. We investigate the influe...
0210236v1
2003-03-13
Strong coupling in brane-induced gravity in five dimensions
Brane-induced gravity in five dimensions (Dvali--Gabadadze--Porrati model) exhibits modification of gravity at ultra-large distances, $r\gg r_c = M_{Pl}^2/M^3$ where $M$ is the five-dimensional gravity scale. This makes the model potentially interesting for explaining the observed acceleration of the Universe. We argue...
0303125v1
2003-04-01
More on the gauge-fixed D3-brane action with dilaton-axion coupling from N=1 superspace
The gauge-fixed action of a `spacetime-filling' D3-brane with dilaton-axion coupling is formulated in N=1 superspace. We investigate its symmetries by paying special attention to a possible non-linearly realized extra (hidden) supersymmetry, and emphasize the need of a linear superfield coupled to an abelian Chern-Simo...
0304002v2
2003-08-08
Level truncation and the quartic tachyon coupling
We discuss the convergence of level truncation in bosonic open string field theory. As a test case we consider the calculation of the quartic tachyon coupling $\gamma_4$. We determine the exact contribution from states up to level L=28 and discuss the $L\to\infty$ extrapolation by means of the BST algorithm. We determi...
0308059v1
2003-11-27
Solitons in systems of coupled scalar fields
We present a method to obtain soliton solutions to relativistic system of coupled scalar fields. This is done by examining the energy associated to static field configurations. In this case we derive a set of first-order differential equations that solve the equations of motion when the energy saturates its lower bound...
0311265v1
2004-01-27
Strong Coupling vs. 4-D Locality in Induced Gravity
We re-examine the problem of strong coupling in a regularized version of DGP (or ``brane-induced'') gravity. We find that the regularization of ref. hep-th/0304148 differs from DGP in that it does not exhibit strong coupling or ghosts up to cubic order in the interactions. We suggest that the nonlocal nature of the the...
0401211v2
2004-01-30
Coupling of Higher Spin Gauge Fields to a Scalar Field in $AdS_{d+1}$ and their Holographic Images in the $d$-Dimensional Sigma Model
The three-point functions of two scalar fields $\sigma$ and the higher spin field $h^{(\ell)}$ of HS(4) on the one side and of their proposed holographic images $\alpha$ and $\mathcal{J^{(\ell)}}$ of the minimal conformal O(N) sigma model of dimension three on the other side are evaluated at leading perturbative order ...
0401240v1
2004-04-29
Through the Looking Glass: AdS-FT with time dependent boundary conditions and black hole formation
I solve for the behavior of scalars in Lorentzian AdS with time dependent boundary conditions, focusing in particular on the dilaton. This corresponds, via the AdS-CFT correspondence, to considering a gauge theory with a time dependent coupling. Changes which keep the gauge coupling nonzero result in finite but physica...
0404244v1
2004-05-31
Holographic dark energy model with non-minimal coupling
We find that holographic dark energy model with non-minimally coupled scalar field gives rise to an accelerating universe by choosing Hubble scale as IR cutoff. We show viable range of a non-minimal coupling parameter in the framework of this model.
0405281v5
2004-05-31
Wavy Wilson Line and AdS/CFT
Wilson loops which are small deviations from straight, infinite lines, called wavy lines, are considered in the context of the AdS/CFT correspondence. A single wavy line and the connected correlation function of a straight and wavy line are considered. It is argued that, to leading order in ``waviness'', the functional...
0405288v1
2004-07-30
Gravity in Randall-Sundrum two D-brane model
We analyse Randall-Sundrum two D-brane model by linear perturbation and then consider the linearised gravity on the D-brane. The qualitative contribution from the Kaluza-Klein modes of gauge fields to the coupling to the gravity on the brane will be addressed. As a consequence, the gauge fields localised on the brane a...
0407268v1
2004-08-03
Two dimensional non-linear sigma models as a limit of the linear sigma models
We show how to obtain the O(N) non-linear sigma model in two dimensions as a strong coupling limit of the corresponding linear sigma model. In taking the strong coupling limit, the squared mass parameter must be given a specific coupling dependence that assures the finiteness of the physical mass scale. The relation di...
0408025v2
2004-09-03
Spin Chain for Quantum Strings
We review and compare the integrable structures in N=4 gauge theory and string theory on AdS5xS5. Recently, Bethe ansaetze for gauge theory/weak coupling and string theory/strong coupling were proposed to describe scaling dimensions in the su(2) subsector. Here we investigate the Bethe equations for quantum string theo...
0409054v2
2004-09-24
Marginal Deformations and Closed String Couplings in Open String Field Theory
We investigate analytic classical solutions in open string field theory which are constructed in terms of marginal operators. In the classical background, we evaluate a coupling between an on-shell closed string state and the open string field. The resulting coupling exhibits periodic behavior as expected from the marg...
0409249v1
2004-10-28
Renormalization group in the internal space
Renormalization group in the internal space consists of the gradual change of the coupling constants. Functional evolution equations corresponding to the change of the mass or the coupling constant are presented in the framework of a scalar model. The evolution in the mass which yields the functional generalization of ...
0410271v1
2005-03-07
Solution of the Dirac equation with non-minimal coupling to noncentral three-vector potential
We introduce non-minimal coupling to three-vector potential in the 3+1 dimensional Dirac equation. The potential is noncentral (angular-dependent) such that the Dirac equation separates completely in spherical coordinates. The relativistic energy spectrum and spinor wavefunctions are obtained for the case where the rad...
0503054v1
2005-06-02
The strong coupling effect and auxiliary fields in the DGP-model
The DGP-model with additional terms in the action is considered. These terms have a special form and include auxiliary scalar fields without kinetic terms, which are non-minimally coupled to gravity. The use of these fields allows one to exclude the mode, which corresponds to the strong coupling effect, from the theory...
0506020v1
2005-07-01
Dualisation of the Symmetric Space Sigma Model with Couplings
The first-order formulation of the G/K symmetric space sigma model of the scalar cosets of the supergravity theories is discussed when there is coupling of (m-1)-form matter fields. The Lie superalgebra which enables the dualized coset formulation is constructed for a general scalar coset G/K with matter coupling where...
0507007v1
2005-09-09
Numerical evidence for the Maldacena conjecture in two-dimensional N=(8,8) super Yang-Mills theory
The N=(8,8) super Yang-Mills theory in 1+1 dimensions is solved at strong coupling to directly confirm the predictions of supergravity at weak coupling. The calculations are done in the large-N_c approximation using Supersymmetric Discrete Light-Cone Quantization. The stress-energy correlator is obtained as a function ...
0509070v1
2005-10-17
Integral representation of the Ising model
The partition function of the 2D Ising model coupled to an external magnetic field is studied. We show that the sum over the spin variables can be reduced to an integration over a finite number of variables. This integration must be performed numerically. But in order to reduce the partition function we must introduce ...
0510143v1
2005-10-27
Dynamics of supertubes
We find the evolution of arbitrary excitations on 2-charge supertubes, by mapping the supertube to a string carrying traveling waves. We argue that when the coupling is increased from zero the energy of excitation leaks off to infinity, and when the coupling is increased still further a new set of long lived excitation...
0510235v1
2006-01-09
Renormalization group dependence of the QCD coupling
The general relation between the standard expansion coefficients and the beta function for the QCD coupling is exactly derived in a mathematically strict way. It is accordingly found that an infinite number of logarithmic terms are lost in the standard expansion with a finite order, and these lost terms can be given in...
0601051v1
2006-02-07
Thermal flow in the gravitational O(n) model
We study the massless flow from the critical point (dilute loops) to the low-temperature phase (dense loops) of the O(n) loop gas model when the model is coupled to 2D gravity. The flow is generated by the gravitationally dressed thermal operator \Phi_{1,3} coupled to the renormalized loop tension \lambda ~ T-T_c. We f...
0602075v2
2006-07-25
A supersymmetric matrix model: II. Exploring higher-fermion-number sectors
Continuing our previous analysis of a supersymmetric quantum-mechanical matrix model, we study in detail the properties of its sectors with fermion number F=2 and 3. We confirm all previous expectations, modulo the appearance, at strong coupling, of {\it two} new bosonic ground states causing a further jump in Witten's...
0607198v1
2006-09-13
Brane world scenario in the presence of a non-minimally coupled bulk scalar field
We present our recent work on brane world models with a non-minimally coupled scalar field. In [9] we examined the stability of these models against scalar field perturbations and we discussed possible physical implications, while in [10] we developed a numerical approach for the solution of the Einstein equations with...
0609089v2
2006-10-09
Generalized Gross-Neveu Models and Chiral Symmetry Breaking from String Theory
We consider intersecting D-brane models which have two dimensional chiral fermions localized at the intersections. At weak coupling, the interactions of these fermions are described by generalized Gross-Neveu models. At strong coupling, these configurations are described by the dynamics of probe D-branes in a curved ba...
0610087v1
2006-10-25
Confinement in (2+1)-Dimensional Gauge Theories at Weak Coupling
In axial gauge, the (2+1)-dimensional SU($N$) Yang-Mills theory is equivalent to a set of (1+1)-dimensional integrable models with a non-local coupling between charge densities. This fact makes it possible to determine the static potential between charges at weak coupling in an anisotropic version of the theory, and un...
0610262v1
2007-02-05
On the Strong Coupling Scaling Dimension of High Spin Operators
We give an exact analytic solution of the strong coupling limit of the integral equation which was recently proposed to describe the universal scaling function of high spin operators in N = 4 gauge theory. The solution agrees with the prediction from string theory, confirms the earlier numerical analysis and provides a...
0702028v1