J. Roca

Lagrangian and Hamiltonian BRST formalisms

Abstract We establish, at the classical level, the equivalence between the standard BRST hamiltonian formalism and the lagranian BRST approach with fields and antifields for irreducible first rank theories.

Field-antifield formalism and hamiltonian BRST approach

Abstract Introducing the BRST symmetry in the space of fields and antifields a BRST charge at the lagrangian level is constructed in a gauge invariant way. For the case of irreducible first rank theories, we establish, at the classical level, the equivalence of the field-antifield formalism with the standard BRST formalism.

The anti-BRST symmetry in the field-antifield formalism

Abstract We show the existence of a generalized anti-BRST symmetry in the space of fields and antifields. The gauge-fixed symmetry and its nilpotency are studied. Explicit expressions for irreducible and off-shell reducible theories with a closed gauge algebra are given.

Zero-curvature condition in two dimensions. Relativistic particle models and finite W-transformations

In the last few years a lot of attention has been devoted to the study of W-algebras[1]. For recent update reviews see [2], [3] where extensive lists of references can befound.An interesting way to construct classical W-algebras isbythe zero-curvature method[4], [5], [6],[7] [8]. If one constraints an A

Superfield description of N=2 topological supergravity

Abstract A free-field formulation of N =2 topological supergravity is obtained with a suitable gauge fixing of two-dimensional topological Yang-Mills theory, taking as the gauge group a contraction of Osp(2|2). We also give a superfield description of the action and its symmetry currents.

Improved multidimensional scaling analysis using neural networks with distance-error backpropagation

We show that neural networks, with a suitable error function for back-propagation, can be successfully used for metric multidimensional scaling (MDS) (i.e., dimensional reduction while trying to preserve the original distances between patterns) and are in fact able to outdo the standard algebraic approach to MDS, known as classical scaling.

Quantization of a higher-order derivative spinning particle

The quantization of a higher-order derivative Lagrangian for a relativistic spinning particle is performed. The Dirac equation is recovered.

BRST structures of the spinning string

Abstract Using the field-antifield formalism and the Dirac constraint analysis we present, in a gauge independent way, the lagrangian and hamiltonian BRST structures of the spinning string.

The propagator of a free relativistic particle in a generic gauge dλ/dτ=f(λ)

The authors compute the propagator of a free spinless relativistic particle in a generic relativistic gauge d lambda d tau =f( lambda ). A criterion is given to decide whether a particular gauge fixing is valid or not.

BRST and anti-BRST symmetries for the spinning particle

Abstract We consider the open and closed gauge algebras for the spinning particle resulting from two different sets of gauge generators. Using the Batalin-Vilkovisky lagrangian formalism, the BRST and anti-BRST generators are constructed for both cases.