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We discuss the approach to asymptotic dynamics due to Kulish and Faddeev. We show that there are problems in applying this method to theories with four point interactions. The source of the difficulties is identified and a more general method is constructed. This is then applied to various theories including some where the coupling does switch off at large times and some where it does not.
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arxiv:hep-th/0002206
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Deformation quantization of bosonic strings is considered. We show that the light-cone gauge is the most convenient classical description to perform the quantization of bosonic strings in the deformation quantization formalism. Similar to the field theory case, the oscillator variables greatly facilitates the analysis. The mass spectrum, propagators and the Virasoro algebra are finally described within this deformation quantization scheme.
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arxiv:hep-th/0002212
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We overview some attempts to find S-duality analogues of non-supersymmetric Yang-Mills theory, in the context of gravity theories. The case of MacDowell-Mansouri gauge theory of gravity is discussed. Three-dimensional dimensional reductions from the topological gravitational sector in four dimensions, enable to recuperate the 2+1 Chern-Simons gravity and the corresponding S-dual theory, from the notion of self-duality in the four-dimensional theory.
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arxiv:hep-th/0003083
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We present a new class of solutions of D=10, N=2 chiral supergravity. A nonvanishing background for the field strength G_{MNR} of the complex two-form triggers AdS_3 x M_7 compactifications, where M_7 is a 7-dimensional compact manifold. When M_7 is a nonsymmetric coset space G/H, we can always find a set of constants G_{MNR} covariantly conserved and thus satisfying the field equations. For example the structure constants of G with indices in the G/H directions are a covariantly conserved tensor. In some symmetric G/H, where these structure constants vanish, there may still exist conserved 3-forms, yielding AdS_3 x G/H solutions. The conditions for supersymmetry of the AdS_3 x M_7 compactifications are derived, and tested for the supersymmetric solutions AdS_3 x S^3 x T^4 and AdS_3 x S^3 x S^3 x S^1. Finally, we show that the AdS_3 x S^3 x T^4 supersymmetric background can be seen as the sigma = 0 limit in a one-parameter class of solutions of the form AdS_3 x S^3 x CP^2, the parameter sigma being the inverse "radius" of CP^2. For sigma different from 0 all supersymmetries are broken.
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arxiv:hep-th/0003102
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Supersymmetric Ward identity for the low energy effective action in the standard background gauge is derived for {\it arbitrary} trajectories of supergravitons in Matrix Theory. In our formalism, the quantum-corrected supersymmetry transformation laws of the supergravitons are directly identified in closed form, which exhibit an intricate interplay between supersymmetry and gauge (BRST) symmetry. As an application, we explicitly compute the transformation laws for the source-probe configuration at 1-loop and confirm that supersymmetry fixes the form of the action completely, including the normalization, to the lowest order in the derivative expansion.
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arxiv:hep-th/0003161
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We consider the derivatives which appear in the context of noncommutative string theory. First, we identify the correct derivations to use when the underlying structure of the theory is a quasitriangular Hopf algebra. Then we show that this is a specific case of a more general structure utilising the Drinfel'd twist. We go on to present reasons as to why we feel that the low-energy effective action, when written in terms of the original commuting coordinates, should explicitly exhibit this twisting.
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arxiv:hep-th/0003234
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Shape Invariant potentials in the sense of [Gendenshte\"{\i}n L.\'E., JETP Lett. 38, (1983) 356] which depend on more than two parameters are not know to date. In [Cooper F., Ginocchio J.N. and Khare A., Phys. Rev. {\bf 36 D}, (1987) 2458] was posed the problem of finding a class of Shape Invariant potentials which depend on n parameters transformed by translation, but it was not solved. We analyze the problem using some properties of the Riccati equation and we find the general solution.
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arxiv:hep-th/0003266
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We consider systems of D6 branes in the presence of a nonzero $B$ field of different ranks. We study the scattering of gravitons in the corresponding supergravity backgrounds. We show that the nonzero $B$ field does not modify the form of the scattering potential. The graviton scattering equation has two solutions one normalizable and one non-normalizable. The normalizable solution does not lead to an absorption, however the non-normalizable one does. We analyse the absorption of gravitons by the branes and show that it is nonzero in the decoupling limit. This result suggests that even in the presence of a $B$ field the D6 branes worldvolume theory does not decouple from the bulk gravity. For comparison we analyse the form of the scattering potential and absorption for Dp branes with $p <5$ and for NS5 branes.
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arxiv:hep-th/0004011
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The topological nature of Chern-Simons term describing the interaction of a charge with magnetic monopole is manifested in two ways: it changes the plane dynamical geometry of a free particle for the cone dynamical geometry without distorting the free (geodesic) character of the motion, and in the limit of zero charge's mass it describes a spin system. This observation allows us to interpret the charge-monopole system alternatively as a free particle of fixed spin with translational and spin degrees of freedom interacting via the helicity constraint, or as a symmetric spinning top with dynamical moment of inertia and "isospin" U(1) gauge symmetry, or as a system with higher derivatives. The last interpretation is used to get the twistor formulation of the system. We show that the reparametrization and scale invariant monopole Chern-Simons term supplied with the kinetic term of the same invariance gives rise to the alternative description for the spin, which is related to the charge-monopole system in a spherical geometry. The relationship between the charge-monopole system and (2+1)-dimensional anyon is discussed in the light of the obtained results.
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arxiv:hep-th/0004032
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We study the quark-antiquark interaction in the large N limit of the superconformal field theory on D-3branes at a Calabi-Yau conical singularity. We compute the Wilson loop in the AdS_5xT^{11} supergravity background for the SU(2N)x SU(2N) theory. We also calculate the Wilson loop for the Higgs phase where the gauge group is broken to SU(N)x SU(N)x SU_D(N). This corresponds to a two center configuration with some of the branes at the singularity and the rest of them at a smooth point. The calculation exhibits the expected Coulomb dependence for the interaction. The angular distribution of the BPS states is different than the one for a spherical horizon.
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arxiv:hep-th/0004040
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We study the `enhancon', a spherical hypersurface apparently made of D-branes, which arises in string theory studies of large N SU(N) pure gauge theories with eight supercharges. When the gauge theory is 2+1 dimensional, the enhancon is an S^2. A relation to charge N BPS multi-monopoles is exploited to uncover many of its detailed properties. It is simply a spherical slice through an Atiyah-Hitchin-like submanifold of the charge $N$ BPS monopole moduli space. In the form of Nahm data, it is built from the N dimensional irreducible representation of SU(2). In this sense the enhancon is a non-commutative sphere, reminiscent of the spherical `dielectric' branes of Myers.
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arxiv:hep-th/0004068
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A set of on shell duality equations is proposed that leads to a map between strings moving on symmetric spaces with opposite curvatures. The transformation maps "waves" on a riemannian symmetric space to "waves" on its dual riemannian symmetric space. This transformation preserves the energy momentum tensor though it is not a canonical transformation. The preservation of the energy momentum tensor has a natural geometrical interpretation. The transformation maps "particle-like solutions" into static "soliton-like solutions". The results presented here generalize earlier results of E. Ivanov.
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arxiv:hep-th/0004120
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The Caswell-Wilczek analysis on the gauge dependence of the effective action and the renormalization group functions in Yang-Mills theories is generalized to generic, possibly power counting non renormalizable gauge theories. It is shown that the physical coupling constants of the classical theory can be redefined by gauge parameter dependent contributions of higher orders in $\hbar$ in such a way that the effective action depends trivially on the gauge parameters, while suitably defined physical beta functions do not depend on those parameters.
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arxiv:hep-th/0004138
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We generalize the results of Polchinski and Strassler regarding the N=1-preserving mass deformation of N=4 SU(N) SYM theories and its string theory dual to SO(N) and USp(2N) gauge groups. The string theory duals involve 5-branes wrapped on RP^2. In order to match with the field theory classification of vacua, the 3-brane charge carried by such 5-branes must be shifted by a half, and this follows from a conjectured generalization of results of Freed and Witten. Our results provide an elegant physical picture for the classification of classically massive vacua in the mass-deformed N=4 theories.
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arxiv:hep-th/0004151
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We obtain logarithmic behaviours of a four-point correlation function in the c=-2 conformal field theory by using the Feigin-Fuchs construction. It becomes an indeterminate form by a naive evaluation, but is obtained by introducing an appropriate regularization procedure.
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arxiv:hep-th/0004189
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We investigate, in a certain decoupling limit, the effect of having a constant C-field on the M-theory five-brane using an open membrane probe. We define an open membrane metric for the five-brane that remains non-degenerate in the limit. The canonical quantisation of the open membrane boundary leads to a noncommutative loop space which is a functional analogue of the noncommutative geometry that occurs for D-branes.
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arxiv:hep-th/0005026
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Higher dimensional Majorana-Weyl spacetimes present space-time dualities which are induced by the Spin(8) triality automorphisms. Different signature versions of theories such as 10-dimensional SYM's, superstrings, five-branes, F-theory, are shown to be interconnected via the S_3 permutation group. Bilinear and trilinear invariants under space-time triality are introduced and their possible relevance in building models possessing a space-versus-time exchange symmetry is discussed. Moreover the Cartan's ``vector/chiral spinor/antichiral spinor" triality of SO(8) and SO(4,4) is analyzed in detail and explicit formulas are produced in a Majorana-Weyl basis. This paper is the extended version of hep-th/9907148.
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arxiv:hep-th/0005035
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Classical relativistic system of point particles coupled with an electromagnetic field is considered in the three-dimensional representation. The gauge freedom connected with the chronometrical invariance of the four-dimensional description is reduced by use of the geometrical concept of the forms of relativistic dynamics. The remainder gauge degrees of freedom of the electromagnetic potential are analysed within the framework of Dirac's constrained Hamiltonian mechanics in the front form of dynamics. The results are implemented to the problems of relativistic statistical mechanics. Based on the corresponding Liouville equation the classical partition function of the system is written down in a gauge-invariant manner and an integration over field variables is performed.
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arxiv:hep-th/0005050
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Invariants for framed links in $S^3$ obtained from Chern-Simons gauge field theory based on an arbitrary gauge group (semi-simple) have been used to construct a three-manifold invariant. This is a generalization of a similar construction developed earlier for SU(2) Chern-Simons theory. The procedure exploits a theorem of Lickorish and Wallace and also those of Kirby, Fenn and Rourke which relate three-manifolds to surgeries on framed unoriented links. The invariant is an appropriate linear combination of framed link invariants which does not change under Kirby calculus. This combination does not see the relative orientation of the component knots. The invariant is related to the partition function of Chern-Simons theory. This thus provides an efficient method of evaluating the partition function for these field theories. As some examples, explicit computations of these manifold invariants for a few three-manifolds have been done.
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arxiv:hep-th/0005096
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In this note $D9$- and anti-$D9$-brane annihilation in type I string theory is probed by a $D1$-brane. We consider the covariant Green-Schwarz or twistor formulation of the probe theory. We expect the theory to be $\kappa$-invariant after the annihilation is completed. Conditions of the $\kappa$-invariance of the theory impose constraints on the background tachyon field. Solutions to the constraints define tachyon values which correspond to type I $D5$-branes as remnants of the annihilation. As a byproduct we get a theory which lies in the same universality class as the non-linear $\sigma$-model for the Atiyah-Drinfeld-Hitchin-Manin construction.
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arxiv:hep-th/0005105
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We investigate the dynamics of open membrane boundaries in a constant C-field background. We follow the analysis for open strings in a B-field background, and take some approximations. We find that open membrane boundaries do show noncommutativity in this case by explicit calculations. Membrane boundaries are one dimensional strings, so we face a new type of noncommutativity, that is, noncommutative strings.
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arxiv:hep-th/0005123
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We study the bulk effective theory of a class of orbifolds of the type IIB string with D5-branes, compactified to four dimensions. These constructions are connected, in a region of their moduli space, to some orbifolds of the type I and heterotic string. We compare the effective actions through the coupling of the R^2 term, and we argue that these orbifolds provide non-perturbative deformations of the latter, in which the gauge group is entirely non-perturbative.
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arxiv:hep-th/0005124
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We provide the exact time-dependent cosmological solutions in the Randall-Sundrum (RS) setup with bulk matter, which may be smoothly connected to the static RS metric. In the static limit of the extra dimension, the solutions are reduced to the standard Friedmann equations. In view of our solutions, we also propose an explanation for how the extra dimension is stabilized in spite of a flat modulus potential at the classical level.
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arxiv:hep-th/0005139
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We discuss examples of D-branes probing toric singularities, and the computation of their world-volume gauge theories from the geometric data of the singularities. We consider several such examples of D-branes on partial resolutions of the orbifolds ${\bf C^3/Z_2\times Z_2}$,${\bf C^3/Z_2\times Z_3}$ and ${\bf C^4/Z_2\times Z_2 \times Z_2}$.
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arxiv:hep-th/0005166
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We argue that a certain distribution of matter in higher dimensions can provide the correct behaviour of gravity in four dimensions. Some explicit examples illustrating the idea are considered.
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arxiv:hep-th/0005167
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In this work we compare the quantization of a massless scalar field in an inertial frame with the quantization in a rotating frame. We used the Trocheries-Takeno mapping to relate measurements in the inertial and the rotating frames. An exact solution of the Klein-Gordon equation in the rotating coordinate system is found and the Bogolubov transformation between the inertial and rotating modes is calculated, showing that the rotating observer defines a vacuum state different from the Minkowski one. We also obtain the response function of an Unruh-De Witt detector coupled with the scalar field travelling in a uniformly rotating world-line. The response function is obtained for two different situations: when the quantum field is prepared in the usual Minkowski vacuum state and when it is prepared in the Trocheries-Takeno vacuum state. We also consider the case of an inertial detector interacting with the field in the rotating vacuum.
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arxiv:hep-th/0005171
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A maximally supersymmetric configuration of super Yang-Mills living on a noncommutative torus corresponds to a constant curvature connection. On a noncommutative toroidal orbifold there is an additional constraint that the connection be equivariant. We study moduli spaces of (equivariant) constant curvature connections on noncommutative even-dimensional tori and on toroidal orbifolds. As an illustration we work out the cases of Z_{2} and Z_{4} orbifolds in detail. The results we obtain agree with a commutative picture describing systems of branes wrapped on cycles of the torus and branes stuck at exceptional orbifold points.
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arxiv:hep-th/0005174
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We examine the dual correspondence between holographic IIB superstring theory and N=4 super Yang-Mills theory at finite values of the coupling constants. In particular we analyze a field theory strong-coupling expansion which is the S-dual of the planar expansion. This expansion arises naturally as the AdS/CFT dual of the IIB superstring scattering amplitudes given a genus truncation property due to modular invariance. The space-time structure of the contributions to the field theory four-point correlation functions obtained from the IIB scattering elements is investigated in the example of the product of four conserved stress tensors, and is expressed as an infinite sum of field theory triangle integrals. The OPE structure of these contributions to the stress tensor four-point function is analyzed and shown not to give rise to any poles. Quantization of the string in the background of a five-form field strength is performed through a covariantized background field approach, and relations to the N=4 topological string are found.
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arxiv:hep-th/0005192
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We analyze the relation between the Lagrangian and Hamiltonian BRST symmetry generators for a recently proposed two-dimensional symmetry. In particular it is shown that this symmetry may be obtained from a canonical transformation in the ghost sector in a gauge independent way.
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arxiv:hep-th/0005203
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In this article we outline a rather general construction of diffeomorphism covariant coherent states for quantum gauge theories. By this we mean states $\psi_{(A,E)}$, labelled by a point (A,E) in the classical phase space, consisting of canonically conjugate pairs of connections A and electric fields E respectively, such that (a) they are eigenstates of a corresponding annihilation operator which is a generalization of A-iE smeared in a suitable way, (b) normal ordered polynomials of generalized annihilation and creation operators have the correct expectation value, (c) they saturate the Heisenberg uncertainty bound for the fluctuations of $\hat{A},\hat{E}$ and (d) they do not use any background structure for their definition, that is, they are diffeomorphism covariant. This is the first paper in a series of articles entitled ``Gauge Field Theory Coherent States (GCS)'' which aim at connecting non-perturbative quantum general relativity with the low energy physics of the standard model. In particular, coherent states enable us for the first time to take into account quantum metrics which are excited {\it everywhere} in an asymptotically flat spacetime manifold. The formalism introduced in this paper is immediately applicable also to lattice gauge theory in the presence of a (Minkowski) background structure on a possibly {\it infinite lattice}.
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arxiv:hep-th/0005233
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We study the $C_{n}$ and $BC_{n}$ Ruijsenaars-Schneider(RS) models with interaction potential of trigonometric and rational types. The Lax pairs for these models are constructed and the involutive Hamiltonians are also given. Taking nonrelativistic limit, we also obtain the Lax pairs for the corresponding Calogero-Moser systems.
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arxiv:hep-th/0006004
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We generalize, to any space-time dimension, the unitarity bounds of highest weight UIR's of the conformal groups with Lie algebras $so(2,d)$. We classify gauge theories invariant under $so(2,d)$, both integral and half-integral spins. A similar analysis is carried out for the algebras $so^*(2n)$. We study new unitary modules of the conformal algebra in $d>4$, that have no analogue for $d\leq 4$ as they cannot be obtained by "squaring" singletons. This may suggest the interpretation of higher dimensional non-trivial conformal field theories as theories of "tensionless" $p$-branes of which tensionless strings in $d=6$ are just particular examples.
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arxiv:hep-th/0006009
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We study the non-critical space-time non-commutative open string (NCOS) theory using a dual supergravity description in terms of a certain near-horizon limit of the F1-Dp bound state. We find the thermodynamics of NCOS theory from supergravity. The thermodynamics is equivalent to Yang-Mills theory on a commutative space-time. We argue that this fact does not have to be in contradiction with the expected Hagedorn behaviour of NCOS theory. To support this we consider string corrections to the thermodynamics. We also discuss the relation to Little String Theory in 6 dimensions.
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arxiv:hep-th/0006023
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We present two examples of non-trivial field theories which are scale invariant, but not conformally invariant. This is done by placing certain field theories, which are conformally invariant in flat space, onto curved backgrounds of a specific type. We define this using the AdS/CFT correspondence, which relates the physics of gravity in asymptotically Anti-de Sitter (AdS) spacetimes to that of a conformal field theory (CFT) in one dimension fewer. The AdS rotating (Kerr) black holes in five and seven dimensions provide us with the examples, since by the correspondence we are able to define and compute the action and stress tensor of four and six dimensional field theories residing on rotating Einstein universes, using the ``boundary counterterm'' method. The rotation breaks conformal but not scale invariance. The AdS/CFT framework is therefore a natural arena for generating such examples of non-trivial scale invariant theories which are not conformally invariant.
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arxiv:hep-th/0006037
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We present a model for a spacetime dependent cosmological {\it constant}. We make a realization of this model based on a possible quantum aspects of the initial stage of the universe and relate the cosmological constant with the chiral anomaly.
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arxiv:hep-th/0006061
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Following a previous work on Abelian (2,0)-gauge theories, one reassesses here the task of coupling (2,0) relaxed Yang-Mills super-potentials to a (2,0)-nonlinear Sigma-model, by gauging the isotropy or the isometry group of the latter. One pays special attention to the extra "chiral-like" component-field gauge potential that comes out from the relaxation of constraints.
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arxiv:hep-th/0006065
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We consider N=1 supersymmetric renormalization group flows of N=4 Yang-Mills theory from the perspective of ten-dimensional IIB supergravity. We explicitly construct the complete ten-dimensional lift of the flow in which exactly one chiral superfield becomes massive (the LS flow). We also examine the ten-dimensional metric and dilaton configurations for the ``super-QCD'' flow (the GPPZ flow) in which all chiral superfields become massive. We show that the latter flow generically gives rise to a dielectric 7-brane in the infra-red, but the solution contains a singularity that may be interpreted as a ``duality averaged'' ring distribution of 5-branes wrapped on S^2. At special values of the parameters the singularity simplifies to a pair of S-dual branes with (p,q) charge (1,\pm 1).
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arxiv:hep-th/0006066
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The near boundary limit of string theory in AdS_3 is analysed using the Wakimoto free field representation of SL(2,R). The theory is considered as a direct product of the SL(2,R)/U(1) coset and a free boson. Correlation functions are constructed generalizing to the non-compact case the integral representation of conformal blocks introduced by Dotsenko in the compact SU(2) CFT. Sectors of the theory obtained by spectral flow manifestly appear. The formalism naturally leads to consider scattering processes violating winding number conservation. The consistency of the procedure is verified in the factorization limit.
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arxiv:hep-th/0006070
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Based on the exact relationship to Random Matrix Theory, we derive the probability distribution of the k-th smallest Dirac operator eigenvalue in the microscopic finite-volume scaling regime of QCD and related gauge theories.
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arxiv:hep-th/0006111
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It is known that self-duality equations for multi-instantons on a line in four dimensions are equivalent to minimal surface equations in three dimensional Minkowski space. We extend this equivalence beyond the equations of motion and show that topological number, instanton moduli space and anti-self-dual solutions have representations in terms of minimal surfaces. The issue of topological charge is quite subtle because the surfaces that appear are non-compact. This minimal surface/instanton correspondence allows us to define a metric on the configuration space of the gauge fields. We obtain the minimal surface representation of an instanton with arbitrary charge. The trivial vacuum and the BPST instanton as minimal surfaces are worked out in detail. BPS monopoles and the geodesics are also discussed.
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arxiv:hep-th/0006135
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The divergence found by Nesterenko, Lambiase and Scarpetta in the Casimir energy on a semi-circular cylinder is attributed to the existence of edges.
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arxiv:hep-th/0006138
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The BRST-antiBRST invariant path integral formulation of classical mechanics of Gozzi et al is generalized to pseudomechanics. It is shown that projections to physical propagators may be obtained by BRST-antiBRST invariant boundary conditions. The formulation is also viewed from recent group theoretical results within BRST-antiBRST invariant theories. A natural bracket expressed in terms of BRST and antiBRST charges in the extended formulation is shown to be equal to the Poisson bracket. Several remarks on the operator formulation are made.
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arxiv:hep-th/0006177
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Using the average action defined with a continuum analog of the block spin transformation, we show the presence of gauge symmetry along the Wilsonian renormalization group flow. As a reflection of the gauge symmetry, the average action satisfies the quantum master equation(QME). We show that the quantum part of the master equation is naturally understood once the measure contribution under the BRS transformation is taken into account. Furthermore an effective BRS transformation acting on macroscopic fields may be defined from the QME. The average action is explicitly evaluated in terms of the saddle point approximation up to one-loop order. It is confirmed that the action satisfies the QME and the flow equation.
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arxiv:hep-th/0006180
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This note is intended to emphasize the existence of estimated Feynman integrals in three dimensions for the free energy of the O(1) scalar theory up to five loops which may be useful for other work. We also correct some misprints of the published paper.
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arxiv:hep-th/0006187
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In our previous paper (hep-th/9911087), we proposed a resolution for the fermion doubling problem in discrete field theories based on the fuzzy sphere and its cartesian products. In this paper after a review of that work, we bring out its relationship to the Ginsparg-Wilson approach.
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arxiv:hep-th/0006216
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In this note we present a operator formulation of gauge theories in a quantum phase space which is specified by a operator algebra. For simplicity we work with the Heisenberg algebra. We introduce the notion of the derivative (transport) and Wilson line (parallel transport) which enables us to construct a gauge theory in a simple way. We illustrate the formulation by a discussion of the Higgs mechanism and comment on the large N masterfield.
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arxiv:hep-th/0006219
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We study the compactification of OM-theory on tori and show a simple heuristic derivation of the $S$-duals of noncommutative open string theory in diverse dimensions from the OM-theoretical point of view. In particular, we identify the $S$-duality between noncommutative open string theory and noncommutative Yang-Mills theory in $(3+1)$ dimensions as the exchange of two circles of a torus on which OM-theory is compactified. Also, we briefly discuss $T$-duality between noncommutative open string theories.
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arxiv:hep-th/0006225
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We explore a mechanism to obtain the observational small value for the 4-dimensional vacuum energy through an exponential warp-factor suppression. Intriguingly the required suppression scale relates directly to the GUT scale. We demonstrate the mechanism explicitly in a 5-dimensional brane-world setup with warped geometry. Upon lifting the setup to 10-dimensional IIB string-theory, the relevance of the GUT scale becomes clear as the IIB string-theory description, which is based on D3-brane stacks, gives rise to a spontaneously broken SU(5) supersymmetric GUT theory with low-energy MSSM spectrum and Higgs doublet-triplet splitting.
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arxiv:hep-th/0006226
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We derive a closed expression for the SU(2) Born-Infeld action with the symmetrized trace for static spherically symmetric purely magnetic configurations. The lagrangian is obtained in terms of elementary functions. Using it, we investigate glueball solutions to the flat space NBI theory and their self-gravitating counterparts. Such solutions, found previously in the NBI model with the 'square root - ordinary trace' lagrangian, are shown to persist in the theory with the symmetrized trace lagrangian as well. Although the symmetrized trace NBI equations differ substantially from those of the theory with the ordinary trace, a qualitative picture of glueballs remains essentially the same. Gravity further reduces the difference between solutions in these two models, and, for sufficiently large values of the effective gravitational coupling, solutions tends to the same limiting form. The black holes in the NBI theory with the symmetrized trace are also discussed.
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arxiv:hep-th/0006242
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We show that the class of functions of topologically nontrivial gauge transformations in QCD includes a zero-mode of the Gauss law constraint. The equivalent unconstrained system compatible with Feynman's integral is derived in terms of topological invariant variables, where the zero-mode is identified with the winding number collective variable and leads to the dominance of the Wu-Yang monopole. Physical consequences of Feynman's path integral in terms of the topological invariant variables are studied.
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arxiv:hep-th/0006249
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We apply a (Moyal) deformation quantization to a bicomplex associated with the classical nonlinear Schrodinger equation. This induces a deformation of the latter equation to noncommutative space-time while preserving the existence of an infinite set of conserved quantities.
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arxiv:hep-th/0007015
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We determine the AdS exchange diagrams needed for the computation of 4--point functions of chiral primary operators in the SCFT_2 dual to the D=6 N=4b supergravity on the AdS_3\times S^3 background and compute the corresponding cubic couplings. We also address the issue of consistent truncation.
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arxiv:hep-th/0007061
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We investigate the role of quantum fluctuations in the system composed of two branes bounding a region of AdS. It is shown that the modulus effective potential generated by quantum fluctuations of both brane and bulk fields is incapable of stabilizing the space naturally at the separation needed to generate the hierarchy. Consequently, a classical stabilization mechanism is required. We describe the proper method of regulating the loop integrals and show that, for large brane separation, the quantum effects are power suppressed and therefore have negligible affects on the bulk dynamics once a classical stabilization mechanism is in place.
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arxiv:hep-th/0007065
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It is shown that the supergravity moduli spaces of D1-D5 and D2-D6 brane systems coincide with those of the Coulomb branches of the associated non-abelian gauge theories. We further discuss situations in which worldvolume brane actions include a potential term generated by probing certain supergravity backgrounds. We find that in many cases, the appearance of the potential is due to the application of the Scherk-Schwarz mechanism. We give some examples and discuss the existence of novel supersymmetric brane configurations.
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arxiv:hep-th/0007083
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We investigate superfluidity of the relativistic fermi-gas with gravitational interaction. The excitation spectrum is obtained within the linearized theory. While superfluidity may take place at a definite ratio of the Fermi momentum, rest mass and coupling constant, the metric coefficients play predominant role forming the gap of excitation spectrum.
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arxiv:hep-th/0007111
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We develop a perturbative expansion which allows the construction of non-abelian self-dual SU(2) Yang-Mills field configurations on the four-dimensional torus with topological charge 1/2. The expansion is performed around the constant field strength abelian solutions found by 't Hooft. Next to leading order calculations are compared with numerical results obtained with lattice gauge theory techniques.
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arxiv:hep-th/0007113
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We investigate the Laplacian Abelian gauge on the sphere S^4 in the background of a single `t Hooft instanton. To this end we solve the eigenvalue problem of the covariant Laplace operator in the adjoint representation. The ground state wave function serves as an auxiliary Higgs field. We find that the ground state is always degenerate and has nodes. Upon diagonalisation, these zeros induce toplogical defects in the gauge potentials. The nature of the defects crucially depends on the order of the zeros. For first-order zeros one obtains magnetic monopoles. The generic defects, however, arise from zeros of second order and are pointlike. Their topological invariant is the Hopf index S^3 -> S^2. These findings are corroborated by an analysis of the Laplacian gauge in the fundamental representation where similar defects occur. Possible implications for the confinement scenario are discussed.
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arxiv:hep-th/0007119
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Simple considerations about the fractal characteristic of the quantum-mechanical path give us the opportunity to derive the quantum black hole entropy in connection with the concept of fractal statistics. We show the geometrical origin of the numerical factor of four of the quantum black hole entropy expression and the statistics weight appears as a counting of the quanta of geometry.
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arxiv:hep-th/0007123
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Motivated by a recent conjecture [1] that quantum corrections and the UV/IR connection modify the classical relation between SUSY breaking and the cosmological constant to the phenomenologically acceptable : $M_{SUSY} \sim M_P (\Lambda /M_P^4)^{1/8}$, we study SUSY breaking by boundary conditions in noncommutative field theories. In commutative field theory the violations of SUSY are finite and vanish as the inverse fourth power of the radius of the SUSY violating circle. We show that in the noncommutative theory, as a consequence of its UV/IR connection, the perturbative corrections to SUSY breaking are infinite. We have not yet performed the nonperturbative resummations to extract the true behavior of the system.
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arxiv:hep-th/0007186
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We numerically construct time-symmetric initial data sets of a black hole in the Randall-Sundrum brane world model, assuming that the black hole is spherical on the brane. We find that the apparent horizon is cigar-shaped in the 5D spacetime.
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arxiv:hep-th/0007203
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Exploring the role of conformal theories of gravity in string theory, we show that the minimal (N=2) gauged supergravities in five dimensions induce the multiplets and transformations of N=1 four dimensional conformal supergravity on the spacetime boundary. N=1 Poincare supergravity can be induced by explicitly breaking the conformal invariance via a radial cutoff in the 5d space. The AdS/CFT correspondence relates the maximal gauged supergravity in five dimensions to N=4 super Yang-Mills on the 4d spacetime boundary. In this context we show that the conformal anomaly of the gauge theory induces conformal gravity on the boundary of the space and that this theory, via the renormalization group, encapsulates the gravitational dynamics of the skin of asymptotically AdS spacetimes. Our results have several applications to the AdS/CFT correspondence and the Randall-Sundrum scenario.
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arxiv:hep-th/0007211
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Bekenstein's conjectured entropy bound for a system of linear size R and energy E, S < 2 pi E R, has counterexamples for many of the ways in which the "system," R, E, and S may be defined. Here new ways are proposed to define these quantities for arbitrary nongravitational quantum field theories in flat spacetime, such as defining R as the smallest radius outside of which only vacuum expectation values occur. Difficulties of extending these definitions to gravitational quantum theories are noted.
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arxiv:hep-th/0007238
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We consider the supergravity dual of the N=1* theory at finite temperature by applying the Polchinski-Strassler construction to the black D3 brane solution of Type IIB supergravity. At finite temperature the 5-brane probe action is minimized when the probe falls to the horizon, although metastable minima with r>>r_H persist for a range of temperatures. Thermal effects on the 3-form source for the hypermultiplet mass m and its order m^2 back reaction on the other fields of the IIB theory are computed. We find unique solutions which are regular at the horizon and have the correct behavior on the boundary. For fixed temperature T, the horizon shrinks for increasing m^2 suggesting that there is a critical temperature separating the system into high and low temperature phases. In the high temperature phase 5-branes are unnecessary since there are no naked singularities. Using the order m^2 correction to the horizon area we calculate the correction to the entropy to be \Delta S =-0.1714N^2m^2T, which is less than the free field result.
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arxiv:hep-th/0007250
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Using a special ansatz for the metric, by straightforward computation we prove that gravi-dilaton effective action in higher dimensions is reduced to the p-brane action. The dual symmetry of the generic type $%a\longleftrightarrow \frac 1a$ is an important symmetry of the reduced action.
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arxiv:hep-th/0008014
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T-duality of gauge theories on a noncommutative $T^d$ can be extended to include fields with twisted boundary conditions. The resulting T-dual theories contain novel nonlocal fields. These fields represent dipoles of constant magnitude. Several unique properties of field theories on noncommutative spaces have simpler counterparts in the dipole-theories.
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arxiv:hep-th/0008030
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As a technical exercise with possible relevance to the holographic principle and string theory, the effective actions (functional determinants) for scalars and spinors on the squashed three-sphere identified under the action of a cyclic group, Z_m, are determined. Especially in the extreme oblate squashing limit, which has a thermodynamic interpretation, the high temperature behaviour is found as a function of m. Although the intermediate details for odd and even m are different, the final answers are the same. A thermodynamic interpretation for spinors is possible only for twisted periodicity conditions and m even.
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arxiv:hep-th/0008059
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In this note we examine the supermembrane action on Calabi-Yau 3-folds. We write down the Dirac-Born-Infeld part of the action, and show that it is invariant under the rigid spacetime supersymmetry.
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arxiv:hep-th/0008109
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We discuss both the UV and IR origin of the one-loop triangle gauge anomalies for noncommutative nonabelian chiral gauge theories with fundamental, adjoint and bi-fundamental fermions for U(N) groups. We find that gauge anomalies only come from planar triangle diagrams, the non-planar triangle contributions giving rise to no breaking of the Ward identies. Generally speaking, theories with fundamental and bi-fundamental chiral matter are anomalous. Theories with only adjoint chiral fermions are anomaly free.
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arxiv:hep-th/0008126
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We show how the spin 3/2 gravitino field can be localized on a brane in a general framework of supergravity theory. Provided that a scalar field coupled to the Rarita-Schwinger field develops an vacuum expectation value (VEV) whose phase depends on the 'radial' coordinate in extra internal space, the gravitino is localized on a brane with the exponentially decreasing warp factor by selecting an appropriate value of the VEV.
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arxiv:hep-th/0008134
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The procedure of the dimensional reduction related to the partition function of a quantum field living in curved space-time which is the warp product of a symmetric space is investigated.
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arxiv:hep-th/0008137
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We consider 2+1-dimensional classical noncommutative scalar field theory. The general ansatz for a radially symmetric solution is obtained. Some exact solutions are presented. Their possible physical meaning is discussed. The case of the finite $\theta$ is discussed qualitatively and illustrated by some numerical results.
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arxiv:hep-th/0008199
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The lump solution of \phi^3 field theory provides a toy model for unstable D-branes of bosonic string theory. The field theory living on this lump is itself a cubic field theory involving a tachyon, two additional scalar fields, and a scalar field continuum. Its action can be written explicitly because the fluctuation spectrum of the lump turns out to be governed by a solvable Schroedinger equation; the \ell=3 case of a series of reflectionless potentials. We study the multiscalar tachyon potential both exactly and in the level expansion, obtaining insight into issues of convergence, branches of the solution space, and the mechanism for removal of states after condensation. In particular we find an interpretation for the puzzling finite domain of definition of string field marginal parameters.
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arxiv:hep-th/0008227
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Using analytical methods, a nonpertubative vacuum is constructed recursively in the field theory for the open bosonic string. Evidence suggests it corresponds to the Lorentz-invariant endpoint of tachyon condensation on a D25-brane. The corresponding string field is a twisted squeezed state.
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arxiv:hep-th/0008252
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This survey intends to cover recent approaches to black hole entropy which attempt to go beyond the standard semiclassical perspective. Quantum corrections to the semiclassical Bekenstein-Hawking area law for black hole entropy, obtained within the quantum geometry framework, are treated in some detail. Their ramification for the holographic entropy bound for bounded stationary spacetimes is discussed. Four dimensional supersymmetric extremal black holes in string-based N=2 supergravity are also discussed, albeit more briefly.
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arxiv:hep-th/0009008
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An heuristic proof of the Riemman conjecture is proposed. It is based on the old idea of Polya-Hilbert. A discrete/fractal derivative self adjoint operator whose spectrum may contain the nontrivial zeroes of the zeta function is presented. To substantiate this heuristic proposal we show using generalized index-theory arguments, corresponding to the (fractal) spectral dimensions of fractal branes living in Cantorian-fractal space-time, how the required $negative$ traces associated with those derivative operators naturally agree with the zeta function evaluated at the spectral dimensions. The $\zeta (0) = - 1/2$ plays a fundamental role. Final remarks on the recent developments in the proof of the Riemann conjecture are made.
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arxiv:hep-th/0009014
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Nonminimal coupling of the inflaton field to the Ricci curvature of spacetime is generally unavoidable, and the paradigm of inflation should be generalized by including the corresponding term in the Lagrangian of the inflationary theory. This paper reports on the status of the programme of generalizing inflation. First, the problem of finding the correct value (or set of values) of the coupling constant is analyzed; the result has important consequences for the success or failure of inflationary scenarios. Then, the slow-roll approximation to generalized inflation is studied. Both the unperturbed inflating universe models and scalar/tensor perturbations are discussed, and open problems are pointed out.
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arxiv:hep-th/0009053
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We propose a correspondence between brane-antibrane systems and stable triples (E_1,E_2,T), where E_1,E_2 are holomorphic vector bundles and the tachyon T is a map between them. We demonstrate that, under the assumption of holomorphicity, the brane-antibrane field equations reduce to a set of vortex equations, which are equivalent to the mathematical notion of stability of the triple. We discuss some examples and show that the theory of stable triples suggests a new notion of BPS bound states and stability, and curious relations between brane-antibrane configurations and wrapped branes in higher dimensions.
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arxiv:hep-th/0009112
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The extraction of Wilson loops of confining gauge systems from their SUGRA (string) duals is reviewed. I start with describing the basic classical setup. A theorem that determines the classical values of the loops associated with a generalized background is derived. In particular sufficient conditions for confining behavior are stated . I then introduce quadratic quantum fluctuations around the classical configurations. I discuss in details the following models of confining behavior: (i) Strings in flat space-time, (ii) $AdS_5$ black hole and its correspondence with pure YM theory in three dimensions. In particular an attractive Luscher term is shown to be the outcome of the quantum fluctuations. (iii) Type 0 string model (iv) The Polchinski Strassler $N=1*$ model. In the latter case we show that SUGRA alone is not enough to get the correct nature of the loops, and only by incorporating the worldvolume phenomena of the five branes a coherent qualitative picture can be derived.
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arxiv:hep-th/0009146
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In this talk we will discuss the low energy dynamics of non-BPS branes constructed as stable brane/anti-brane pairs at an orbifold. In particular we will determine the effective field theory and compare its predictions with those of the full open string theory. While the position and vector degrees of freedom have the familiar form found in supersymmetric gauge theories, the massless modes orginating in the tachyonic sector display novel non-commuting flat directions. We will show that these flat directions persist to al orders in alpha'. Finally we will briefly report on the open string loop corrections.
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arxiv:hep-th/0009155
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The inflationary scenario for the brane world driven by the bulk inflaton is proposed. The quantum fluctuations of the inflaton is calculated and compared to those of the conventional 4-dimensional inflationary scenario. It is shown that the deviation of the primordial spectrum of this model from that of the conventional one is too small to be observed even if $AdS$ radius is very large. Hence, it turns out that the inflation caused by the bulk inflaton is viable in the context of brane world cosmology.
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arxiv:hep-th/0009160
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Following the formalism of enveloping algebras and star product calculus we formulate and analyze a model of gauge gravity on noncommutative spaces and examine the conditions of its equivalence to general relativity. The corresponding Seiberg-Witten maps are established which allow the definition of respective dynamics for a finite number of gravitational gauge field components on noncommutative spaces.
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arxiv:hep-th/0009163
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We use the method of Banerjee, Banerjee and Mitra and minimal homotopy paths to compute the consistent gauge anomaly for several superspace models of SSYM coupled to matter. We review the derivation of the anomaly for N=1 in four dimensions and then discuss the anomaly for two-dimensional models with (2,0) supersymmetry.
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arxiv:hep-th/0009192
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Representations of four-dimensional superconformal groups on harmonic superfields are discussed. It is argued that any representation can be given as a superfield on many superflag manifolds. Representations on analytic superspaces do not require constraints. We discuss short representations and how to obtain them as explicit products of fundamental fields. We also discuss superfields that transform under supergroups.
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arxiv:hep-th/0009217
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There is an interesting dichotomy between a space-time metric considered as external field in a flat background and the same considered as an intrinsic part of the geometry of space-time. We shall describe and compare two other external fields which can be absorbed into an appropriate redefinition of the geometry, this time a noncommutative one. We shall also recall some previous incidences of the same phenomena involving bosonic field theories. It is known that some such theories on the commutative geometry of space-time can be re-expressed as abelian-gauge theory in an appropriate noncommutative geometry. The noncommutative structure can be considered as containing extra modes all of whose dynamics are given by the one abelian action.
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arxiv:hep-th/0009230
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We derive the precise relation between level matching condition and fractional instanton numbers in six dimensional, abelian and supersymmetric orbifolds of E8 x E8 heterotic string theory. The fractional part of the two E8 instanton numbers is explicitly calculated in terms of the gauge twist. This relation is then used to show that the classification of these orbifolds can be given in terms of flat bundles away from the orbifold singularities under the only constraint that the sum of the fractional parts of the gauge instanton numbers match the fractional part of the gravitational instanton number locally at every fixed point. This directly carries over to M-theory on S^1/Z_2
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arxiv:hep-th/0009251
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The covariant descripion is constructed for the Wick-type symbols on symplectic manifolds by means of the Fedosov procedure. The geometry of the manifolds admitting this symbol is explored. The superextended version of the Wick-type star-product is introduced and a possible application of the construction to the noncommutative field theory is discussed.
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arxiv:hep-th/0010029
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The correlation functions of two-dimensional anyon fields in a KMS-state are studied. For T=0 the $n$-particle wave functions of noncanonical fermions of level $\alpha$, $\alpha$ odd, are shown to be of Laughlin type of order $\alpha$. For $T>0$ they are given by a simple finite-temperature generalization of Laughlin's wave function. This relates the first and second quantized pictures of the fractional quantum Hall effect.
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arxiv:hep-th/0010030
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The solution representing a brane-anti-brane system in matrix models breaks the usual matrix spacetime symmetry. We show that the spacetime symmetry on the branes is not breaking, rather appears as a combination of the matrix spacetime transformation and a gauge transformation. As a result, the tachyon field, itself an off-diagonal entry in longitudinal matrices, transforms nontrivially under rotations, decomposing into tensors of different ranks. We also show that the tachyon field can never be gauged away, and conjecture that this field is related to the usual complex scalar tachyon by a field redefinition. We also briefly discuss tachyon condensation.
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arxiv:hep-th/0010058
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We consider Standard Model fields living inside a thick four dimensional flat brane embedded in a (possibly warped) five dimensional space-time and estimate the electromagnetic corrections to the anomalous magnetic moment (g-2) of the electron and muon by including virtual massive fermion and gauge boson states. Constraints on the mass of the ``excited'' states (or thickness of the brane-world) are obtained.
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arxiv:hep-th/0010065
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We present a new estimate of the fine structure constant and the $\beta$-function of QED at an arbitrary scale. Using the non-perturbative but convergent series expression of the one loop effective action of QED that has been available recently we make a non-perturbative estimate of the running coupling and the $\beta$-function, and prove the renormalization group invariance of the effective action. The contrast between our result and the perturbative result is remarkable.
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arxiv:hep-th/0010073
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This is a very brief review of relations between Seiberg-Witten theories and integrable systems with emphasis on the perturbative prepotentials presented at the E.S.Fradkin Memorial Conference.
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arxiv:hep-th/0010078
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We investigated the bubble collisions during the first order phase transitions. Numerical results indicate that within the certain range of parameters the collision of two bubbles leads to formation of separate relatively long-lived quasilumps - configurations filled with scalar field oscillating around the true vacuum state. Energy is perfectly localized, and density is slightly pulsating around its maximum. This process is accompanied by radiation of scalar waves.
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arxiv:hep-th/0010120
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We consider asymtotically anti-de Sitter spacetimes in general dimensions. We review the origin of infrared divergences in the on-shell gravitational action, and the construction of the renormalized on-shell action by the addition of boundary counterterms. In odd dimensions, the renormalized on-shell action is not invariant under bulk diffeomorphisms that yield conformal transformations in the boundary (holographic Weyl anomaly). We obtain formulae for the gravitational stress energy tensor, defined as the metric variation of the renormalized on-shell action, in terms of coefficients in the asymptotic expansion of the metric near infinity. The stress energy tensor transforms anomalously under bulk diffeomorphisms broken by infrared divergences.
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arxiv:hep-th/0010138
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In this note we reexamine the possibility of constructing stable non-supersymmetric theories that exhibit an exponential density of states. For weakly coupled closed strings there is a general theorem, according to which stable theories with an exponential density of states must exhibit an almost exact cancellation of spacetime bosons and fermions (not necessarily level by level). We extend this result to open strings by showing that if the above cancellation between bosons and fermions does not occur, the open strings do not decouple from a closed string tachyon even in the NCOS scaling limit. We conclude with a brief comment on the proposed generalization of the AdS/CFT correspondence to non-supersymmetric theories.
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arxiv:hep-th/0010154
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We explore the applicability of the exact renormalization group to the study of tunnelling phenomena. We investigate quantum-mechanical systems whose energy eigenstates are affected significantly by tunnelling through a barrier in the potential. Within the approximation of the derivative expansion, we find that the exact renormalization group predicts the correct qualitative behaviour for the lowest energy eigenvalues. However, quantitative accuracy is achieved only for potentials with small barriers. For large barriers, the use of alternative methods, such as saddle-point expansions, can provide quantitative accuracy.
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arxiv:hep-th/0010180
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The effective action for quantum fields on a $d$-dimensional spacetime can be computed using a non local expansion in powers of the curvature. We show explicitly that, for conformal fields and up to quadratic order in the curvature, the non local effective action is equivalent to the $d+1$ action for classical gravity in $AdS_{d+1}$ restricted to a $d-1$-brane. This generalizes previous results about quantum corrections to the Newtonian potential and provides an alternative method for making local a non-local effective action. The equivalence can be easily understood by comparing the Kallen-Lehmann decomposition of the classical propagator with the spectral representation of the non local form factors in the quantum effective action.
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arxiv:hep-th/0010203
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We consider the quantum effects of bulk matter (scalars, spinors) in the Randall-Sundrum AdS$_5$ brane-world at nonzero temperature. The thermodynamic energy (modulus potential) is evaluated at low and high temperatures. This potential has an extremum which could be a minimum in some cases (for example, for a single fermion). That suggests a new dynamical mechanism to stabilize the thermal AdS$_5$ brane-world. It is shown that the brane separation required to solve the hierarchy scale problem may occur at a quite low temperature. A natural generalization in terms of the AdS/CFT correspondence (through the supergravity thermal contribution) is also possible.
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arxiv:hep-th/0010205
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We discuss what information can be safely extracted from background independent off-shell string theory. The major obstacle in doing so is that renormalization conditions of the underlying world-sheet theories are not exactly known. To get some insight, we first consider the tachyon and gauge field backgrounds and carry out computations in different renormalization schemes for both, bosonic string and superstring. Next, we use a principle of universality (renormalization scheme independence) to somehow compensate the missing of the renormalization conditions and get information we are looking for. It turns out that some asymptotics which are responsible for the potentials only obey the principle of universality.
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arxiv:hep-th/0010218
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The relation among spacetime supersymmetry algebras and superbrane actions is further explored. It is proved that $SL(2,\bR)$ belongs to the automorphism group of the ${\cal N}=2$ D=10 type IIB SuperPoincar\'e algebra. Its SO(2) subgroup is identified with a non-local SO(2) transformation found in hep-th/9806161. Performing T-duality, new non-local transformations are found in type IIA relating, among others, BIon configurations with two D2-branes intersecting at a point. Its M-theory origin is explained. These results show that part of the SuperPoincar\'e algebra automorphism group might be realized on the field theory as non-local transformations.
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arxiv:hep-th/0010242
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In this short note we show that (I) in a QCD-like theory with four (rather than two) degenerate flavors $ud u'd'$, the $\pi\pi'$ scattering length is positive (attractive); and (II) in QCD with only two (u,d) degenerate flavors the I=2 (say, $\pi^+\pi^+$ hadronic) scattering length is, in the large $N_C$ limit, repulsive. $\pi(\pi')$ are the lowest physical states coupling to $J^p = \bar{u}(x)\gamma_5d(x)$ and $J^{p'} = \bar{u}'(x)\gamma_5d'(x),$ respectively.
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arxiv:hep-th/0010250
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