Victor O. Rivelles

A Consistent noncommutative field theory: The Wess-Zumino model

Abstract We show that the noncommutative Wess–Zumino model is renormalizable to all orders of perturbation theory. The noncommutative scalar potential by itself is non-renormalizable but the Yukawa terms demanded by supersymmetry improve the situation turning the theory into a renormalizable one. As in the commutative case, there are neither quadratic nor linear divergences. Hence, the IR/UV mixing does not give rise to quadratic infrared poles.

N=4 Superconformal Mechanics and the Potential Structure of AdS Spaces

Abstract The dynamics of an N =4 spinning particle in a curved background is described using the N =4 superfield formalism. The SU (2) local × SU (2) global N =4 superconformal symmetry of the particle action requires the background to be a real “Kahler-like” manifold whose metric is generated by a sigma-model superpotential. The anti-de-Sitter spaces are shown to belong to this class of manifolds.

Scalar field theory in the AdS/CFT correspondence revisited

Abstract We consider the role of boundary conditions in the AdSd+1/CFTd correspondence for the scalar field theory. Also a careful analysis of some limiting cases is presented. We study three possible types of boundary conditions, Dirichlet, Neumann and mixed. We compute the two-point functions of the conformal operators on the boundary for each type of boundary condition. We show how particular choices of the mass require different treatments. In the Dirichlet case we find that there is no double zero in the two-point function of the operator with conformal dimension d/2. The Neumann case leads to new normalizations for the boundary two-point functions. In the massless case we show that the conformal dimension of the boundary conformal operator is precisely the unitarity bound for scalar operators. We find a one-parameter family of boundary conditions in the mixed case. There are again new normalizations for the boundary two-point functions. For a particular choice of the mixed boundary condition and with the mass squared in the range −d2/4 [(d−2)/2, d/2] . For mass squared m2>−d2/4+1 the same choice of mixed boundary condition leads to a boundary operator whose conformal dimension is the unitarity bound.

THE NONCOMMUTATIVE SUPERSYMMETRIC NONLINEAR SIGMA MODEL

We show that the noncommutativity of space–time destroys the renormalizability of the 1/N expansion of the O(N) Gross–Neveu model. A similar statement holds for the noncommutative nonlinear sigma model. However, we show that, up to the subleading order in 1/N expansion, the noncommutative supersymmetric O(N) nonlinear sigma model becomes renormalizable in D=3. We also show that dynamical mass generation is restored and there is no catastrophic UV/IR mixing. Unlike the commutative case, we find that the Lagrange multiplier fields, which enforce the supersymmetric constraints, are also renormalized. For D=2 the divergence of the four-point function of the basic scalar field, which in D=3 is absent, cannot be eliminated by means of a counterterm having the structure of a Moyal product.

Chern-Simons theories in the AdS/CFT correspondence

Abstract We consider the AdS/CFT correspondence for theories with a Chern-Simons term in three dimensions. We find the two-point functions of the boundary conformal field theories for the Proca-Chern-Simons theory and the Self-Dual model. We also discuss particular limits where we find the two-point function of the boundary conformal field theory for the Maxwell-Chern-Simons theory. In particular our results are consistent with the equivalence between the Maxwell-Chern-Simons theory and the Self-Dual model.

Notes on β-deformations of the pure spinor superstring in AdS5×S5

We study the properties of the vertex operator for the beta-deformation of the superstring in AdS(5) x S(5) in the pure spinor formalism. We discuss the action of supersymmetry on the infinitesimal beta-deformation, the application of the homological perturbation theory, and the relation between the worldsheet description and the spacetime supergravity description.

Towards a consistent noncommutative supersymmetric Yang-Mills theory : superfield covariant analysis

Commutative four dimensional supersymmetric Yang-Mills (SYM) theory is known to be renormalizable for N=1,2, and finite for N=4. However, in the noncommutative version of the model the UV/IR mechanism gives rise to infrared divergences which may spoil the perturbative expansion. In this work we pursue the study of the consistency of the N=1,2,4 noncommutative supersymmetric Yang-Mills theory with gauge group U(N) (NCSYM). We employ the covariant superfield framework to compute the one-loop corrections to the two- and three-point functions of the gauge superfield V. It is found that the cancellation of the harmful UV/IR infrared divergences only takes place in the fundamental representation of the gauge group. We argue that this is in agreement with the low energy limit of the open superstring in the presence of an external magnetic field. As expected, the planar sector of the two-point function of the V superfield exhibits UV divergences. They are found to cancel, in the Feynman gauge, for the maximally extended N=4 supersymmetric theory. This gives support to the belief that the N=4 NCSYM theory is UV finite.

The three-dimensional noncommutative nonlinear sigma model in superspace

Abstract We study the superspace formulation of the noncommutative nonlinear supersymmetric O ( N ) invariant sigma-model in 2+1 dimensions. We prove that the model is renormalizable to all orders of 1/ N and explicitly verify that the model is asymptotically free.

Gauge theory formulations for continuous and higher spin fields

We consider a gauge theory action for continuous spin particles formulated in a spacetime enlarged by an extra coordinate recently proposed by Schuster and Toro. It requires one scalar gauge field and has two local symmetries. We show that the local symmetries are reducible in the sense that the parameters also have a local symmetry. Using reducibility we get an action which has two scalar gauge fields and a reducible but simpler local symmetry. We then show how this action and equations of motion are related to previously proposed formulations for continuous spin particles and higher spin theories. We also discuss the physical contents of each formulation to reveal the physical degrees of freedom.

Non Abelian Fields in Very Special Relativity

We study non-Abelian fields in the context of very special relativity (VSR). For this we define the covariant derivative and the gauge field gauge transformations, both of them involving a fixed null vector