28 research outputs found
No interactions for a collection of Weyl gravitons intermediated by a scalar field
The cross-couplings among several Weyl gravitons (described in the free limit
by a sum of linearized Weyl actions) in the presence of a scalar field are
studied with the help of the deformation theory based on local BRST cohomology.
Under the hypotheses of locality, smoothness of the interactions in the
coupling constant, Poincare invariance, (background) Lorentz invariance, and
the preservation of the number of derivatives on each field, together with the
supplementary assumption that the internal metric defined by the sum of Weyl
lagrangians is positively defined, we prove that there are no consistent
cross-interactions among different Weyl gravitons in the presence of a scalar
field. The couplings of a single Weyl graviton to a scalar field are also
discussed.Comment: 53 page
Irreducible Hamiltonian BRST symmetry for reducible first-class systems
An irreducible Hamiltonian BRST quantization method for reducible first-class
systems is proposed. The general theory is illustrated on a two-stage reducible
model, the link with the standard reducible BRST treatment being also
emphasized.Comment: Latex 2.09, 23 pages, to appear in Int. J. Mod. Phys.
First-Class Approaches to Massive 2-Forms
Massive 2-forms are analyzed from the point of view of the Hamiltonian
quantization using the gauge-unfixing approach and respectively the
Batalin--Fradkin method. Both methods finally output the manifestly Lorentz
covariant path integral for 1- and 2-forms with Stueckelberg coupling.Comment: 14 page
Two-dimensional interactions between a BF-type theory and a collection of vector fields
Consistent interactions that can be added to a two-dimensional, free abelian
gauge theory comprising a special class of BF-type models and a collection of
vector fields are constructed from the deformation of the solution to the
master equation based on specific cohomological techniques. The deformation
procedure modifies the Lagrangian action, the gauge transformations, as well as
the accompanying algebra of the interacting model.Comment: LaTeX 2e, 31 page
Irreducible Hamiltonian BRST-anti-BRST symmetry for reducible systems
An irreducible Hamiltonian BRST-anti-BRST treatment of reducible first-class
systems based on homological arguments is proposed. The general formalism is
exemplified on the Freedman-Townsend model.Comment: LaTeX 2.09, 35 page
No multi-graviton theories in the presence of a Dirac field
The cross-couplings among several massless spin-two fields (described in the
free limit by a sum of Pauli-Fierz actions) in the presence of a Dirac field
are investigated in the framework of the deformation theory based on local BRST
cohomology. Under the hypotheses of locality, smoothness of the interactions in
the coupling constant, Poincare invariance, (background) Lorentz invariance and
the preservation of the number of derivatives on each field, we prove that
there are no consistent cross-interactions among different gravitons in the
presence of a Dirac field. The basic features of the couplings between a single
Pauli-Fierz field and a Dirac field are also emphasized.Comment: 48 page
Cohomological BRST aspects of the massless tensor field with the mixed symmetry (k,k)
The main BRST cohomological properties of a free, massless tensor field that
transforms in an irreducible representation of GL(D,R), corresponding to a
rectangular, two-column Young diagram with k>2 rows are studied in detail. In
particular, it is shown that any non-trivial co-cycle from the local BRST
cohomology group H(s|d) can be taken to stop either at antighost number (k+1)
or k, its last component belonging to the cohomology of the exterior
longitudinal derivative H(gamma) and containing non-trivial elements from the
(invariant) characteristic cohomology H^{inv}(delta|d).Comment: Latex, 50 pages, uses amssym
BRST cohomological results on the massless tensor field with the mixed symmetry of the Riemann tensor
The basic BRST cohomological properties of a free, massless tensor field with
the mixed symmetry of the Riemann tensor are studied in detail. It is shown
that any non-trivial co-cycle from the local BRST cohomology group can be taken
to stop at antighost number three, its last component belonging to the
cohomology of the exterior longitudinal derivative and containing non-trivial
elements from the (invariant) characteristic cohomology.Comment: 39 page
Consistent interactions of dual linearized gravity in D=5: couplings with a topological BF model
Under some plausible assumptions, we find that the dual formulation of
linearized gravity in D=5 can be nontrivially coupled to the topological BF
model in such a way that the interacting theory exhibits a deformed gauge
algebra and some deformed, on-shell reducibility relations. Moreover, the
tensor field with the mixed symmetry (2,1) gains some shift gauge
transformations with parameters from the BF sector.Comment: 63 pages, accepted for publication in Eur. Phys. J.