A uniform model of the massive spinning particle in any dimension

The general model of an arbitrary spin massive particle in any dimensional space-time is derived on the basis of Kirillov - Kostant - Souriau approach. It is shown that the model allows consistent coupling to an arbitrary background of electromagnetic and gravitational fields.Comment: Latex, revised version of hep-th/981100

Radiation reaction and renormalization in classical electrodynamics of point particle in any dimension

The effective equations of motion for a point charged particle taking account of radiation reaction are considered in various space-time dimensions. The divergencies steaming from the pointness of the particle are studied and the effective renormalization procedure is proposed encompassing uniformly the cases of all even dimensions. It is shown that in any dimension the classical electrodynamics is a renormalizable theory if not multiplicatively beyond d=4. For the cases of three and six dimensions the covariant analogs of the Lorentz-Dirac equation are explicitly derived.Comment: minor changes in concluding section, misprints corrected, LaTeX2e, 15 page

BRST theory without Hamiltonian and Lagrangian

We consider a generic gauge system, whose physical degrees of freedom are obtained by restriction on a constraint surface followed by factorization with respect to the action of gauge transformations; in so doing, no Hamiltonian structure or action principle is supposed to exist. For such a generic gauge system we construct a consistent BRST formulation, which includes the conventional BV Lagrangian and BFV Hamiltonian schemes as particular cases. If the original manifold carries a weak Poisson structure (a bivector field giving rise to a Poisson bracket on the space of physical observables) the generic gauge system is shown to admit deformation quantization by means of the Kontsevich formality theorem. A sigma-model interpretation of this quantization algorithm is briefly discussed.Comment: 19 pages, minor correction

On the Minimal Model of Anyons

We present new geometric formulations for the fractional spin particle models on the minimal phase spaces. New consistent couplings of the anyon to background fields are constructed. The relationship between our approach and previously developed anyon models is discussed.Comment: 17 pages, LaTex, no figure

General method for including Stueckelberg fields

A systematic procedure is proposed for inclusion of Stueckelberg fields. The procedure begins with the involutive closure when the original Lagrangian equations are complemented by all the lower order consequences. The involutive closure can be viewed as Lagrangian analogue of complementing constrained Hamiltonian system with secondary constraints. The involutively closed form of the field equations allows for explicitly covariant degree of freedom number count, which is stable with respect to deformations. If the original Lagrangian equations are not involutive, the involutive closure will be a non-Lagrangian system. The Stueckelberg fields are assigned to all the consequences included into the involutive closure of the Lagrangian system. The iterative procedure is proposed for constructing the gauge invariant action functional involving Stueckelberg fields such that Lagrangian equations are equivalent to the involutive closure of the original theory. The generators of the Stueckelberg gauge symmetry begin with the operators generating the closure of original Lagrangian system. These operators are not assumed to be a generators of gauge symmetry of any part of the original action, nor are they supposed to form an on shell integrable distribution. With the most general closure generators, the consistent Stueckelberg gauge invariant theory is iteratively constructed, without obstructions at any stage. The Batalin-Vilkovisky form of inclusion the Stueckelberg fields is worked out and existence theorem for the Stueckelberg action is proven.Comment: 30 pages, minor corrections in the abstrac