Taming the b antighost with Ramond-Ramond flux

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The role of the Roper in chiral perturbation theory

We include the Roper excitation of the nucleon in a version of heavy-baryon chiral perturbation theory recently developed for energies around the delta resonance. We find significant improvement in the P(11) channel. (C) 2011 Elsevier B.V. All rights reserved.

Finite dimensional vertex

The spectrum of linearized excitations of the Type IIB SUGRA on AdS(5) x S-5 contains both unitary and non-unitary representations. Among the non-unitary, some are finite-dimensional. We explicitly construct the pure spinor vertex operators for a family of such finite-dimensional representations. The construction can also be applied to in finite-dimensional representations, including unitary, although it becomes in this case somewhat less explicit.

Self-dual hopfions

We construct static and time-dependent exact soliton solutions with nontrivial Hopf topological charge for a field theory in 3 + 1 dimensions with the target space being the two dimensional sphere S(2). The model considered is a reduction of the so-called extended Skyrme-Faddeev theory by the removal of the quadratic term in derivatives of the fields. The solutions are constructed using an ansatz based on the conformal and target space symmetries. The solutions are said self-dual because they solve first order differential equations which together with some conditions on the coupling constants, imply the second order equations of motion. The solutions belong to a sub-sector of the theory with an infinite number of local conserved currents. The equation for the profile function of the ansatz corresponds to the Bogomolny equation for the sine-Gordon model.

Towards a Realization of the Condensed-Matter-Gravity Correspondence in String Theory via Consistent Abelian Truncation of the Aharony-Bergman-Jafferis-Maldacena Model

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Pure spinor partition function and the massive superstring spectrum

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On semiclassical analysis of pure spinor superstring in an AdS(5) x S-5 background

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Equivalence of many-gluon Green's functions in the Duffin-Kemmer-Petieu and Klein-Gordon-Fock statistical quantum field theories

We prove the equivalence of many-gluon Green's functions in the Duffin-Kemmer-Petieu and Klein-Gordon-Fock statistical quantum field theories. The proof is based on the functional integral formulation for the statistical generating functional in a finite-temperature quantum field theory. As an illustration, we calculate one-loop polarization operators in both theories and show that their expressions indeed coincide.

Relativistic deformed mean-field calculation of binding energy differences of mirror nuclei

Binding energy differences of mirror nuclei for A = 15, 17, 27, 29, 31, 33, 39 and 41 are calculated in the framework of relativistic deformed mean-field theory. To fully include the effects of the polarization of the nuclear core due to the extra particle or hole, the spatial components of the vector meson fields and the photon are taken into account in a self-consistent manner. The calculated binding energy differences are systematically smaller than the experimental values and lend support to the existency of the Okamoto-Nolen-Schiffer anomaly found decades ago in nonrelativistic calculations, For the majority of the nuclei studied, however, the results are such that the anomaly is significantly smaller than the one obtained within state-of-the-art nonrelativistic calculations.

ANOMALIES IN CURVED SPACETIME AT FINITE TEMPERATURE

We discuss the problem of the breakdown of conformal and gauge symmetries at finite temperature in curved-spacetime background, when the changes in the background are gradual, in order to have a well-defined quantum field theory at finite temperature. We obtain the expressions for Seeley's coefficients and the heat-kernel expansion in this regime. As applications, we consider the self-interacting lambdaphi4 and chiral Schwinger models in curved backgrounds at finite temperature.

Gauge-independent analysis of 2D-gravity

In this note we show that the induced 2D-gravity SL(2, ℝ) currents can be defined in a gauge-independent way although they manifest themselves as generators of residual symmetries only in some special gauges. In the Coulomb gas representation we investigate two approaches, namely one resembling string field theory and another that emphasizes the SL(2, ℝ) structure in the phase space. In the conformal gauge we propose a solution of the Liouville theory in terms of the SL(2, ℝ) currents.

Toda lattice field theories, discrete W algebras, Toda lattice hierarchies and quantum groups

In analogy with the Liouville case we study the sl3 Toda theory on the lattice and define the relevant quadratic algebra and out of it we recover the discrete W3 algebra. We define an integrable system with respect to the latter and establish the relation with the Toda lattice hierarchy. We compute the relevant continuum limits. Finally we find the quantum version of the quadratic algebra.

Confinement, solitons and the equivalence between the sine-Gordon and massive Thirring models

We consider a two-dimensional integrable and conformally invariant field theory possessing two Dirac spinors and three scalar fields. The interaction couples bilinear terms in the spinors to exponentials of the scalars. Its integrability properties are based on the sl(2) affine Kac-Moody algebra, and it is a simple example of the so-called conformal affine Toda theories coupled to matter fields. We show, using bosonization techniques, that the classical equivalence between a U(1) Noether current and the topological current holds true at the quantum level, and then leads to a bag model like mechanism for the confinement of the spinor fields inside the solitons. By bosonizing the spinors we show that the theory decouples into a sine-Gordon model and free scalars. We construct the two-soliton solutions and show that their interactions lead to the same time delays as those for the sine-Gordon solitons. The model provides a good laboratory to test duality ideas in the context of the equivalence between the sine-Gordon and Thirring theories. © 2000 Elsevier Science B.V. All rights reserved.

Spinning Hopf solitons on S3 × ℝ

We consider a field theory with target space being the two dimensional sphere S2 and defined on the space-time S3 × . The Lagrangean is the square of the pull-back of the area form on S2. It is invariant under the conformal group SO(4,2) and the infinite dimensional group of area preserving diffeomorphisms of S2. We construct an infinite number of exact soliton solutions with non-trivial Hopf topological charges. The solutions spin with a frequency which is bounded above by a quantity proportional to the inverse of the radius of S3. The construction of the solutions is made possible by an ansatz which explores the conformal symmetry and a U(1) subgroup of the area preserving diffeomorphism group. © SISSA 2006.

MHV tree amplitudes in super-Yang-Mills and in superstring theory

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)