Hamiltonian BRST Research Articles

Hamiltonian and Lagrangian BRST Quantization in Riemann Manifold II

We have previously developed the BRST quantization on the hypersurface V N − 1 embedded in N -dimensional Euclidean space R N in both Hamiltonian and Lagrangian formulation. We generalize the formalism in the case of L -dimensional manifold V L embedded in R N with 1 ≤ L < N . The result is essentially the same as the previous one. We have also verified the results obtained here using a simple example of particle motion on a torus knot.

Hamiltonian and Lagrangian BRST Quantization in Riemann Manifold

The BRST quantization of particle motion on the hypersurface V N − 1 embedded in Euclidean space R N is carried out both in Hamiltonian and Lagrangian formalism. Using Batalin-Fradkin-Fradkina-Tyutin (BFFT) method, the second class constraints obtained using Hamiltonian analysis are converted into first class constraints. Then using BFV analysis the BRST symmetry is constructed. We have given a simple example of these kind of system. In the end we have discussed Batalin-Vilkovisky formalism in the context of this (BFFT modified) system.

Hamiltonian BRST-invariant deformations in Abelian gauge theory with higher derivative matter fields

We construct the consistent interactions among the Abelian gauge fields and various higher derivative matter fields within the framework of the Hamiltonian BRST formalism. To achieve this, we mainly investigate a set of iterative equations with respect to the free model under study by using the cohomological technique. Concretely, it is shown that the second-order and the other higher-order deformations of the BRST charge are supposed to be zero. While for the BRST-invariant Hamiltonian, the third-order as well as the corresponding higher-order deformation terms vanish completely for scalar fields. In special, the deformation of BRST-invariant Hamiltonian for the spinor field model terminates at order one as we can imagine. Furthermore, after plugging these deformed quantities into the original Hamiltonian and exploiting the ghost-independent terms, we recover the usual local gauge symmetries of the resulting interacting theory which can be interpreted as the gaugings of the rigid invariance of the uncoupled system.

BRST quantization of cosmological perturbations

BRST quantization is an elegant and powerful method to quantize theories with local symmetries. In this article we study the Hamiltonian BRST quantization of cosmological perturbations in a universe dominated by a scalar field, along with the closely related quantization method of Dirac. We describe how both formalisms apply to perturbations in a time-dependent background, and how expectation values of gauge-invariant operators can be calculated in the in-in formalism. Our analysis focuses mostly on the free theory. By appropriate canonical transformations we simplify and diagonalize the free Hamiltonian. BRST quantization in derivative gauges allows us to dramatically simplify the structure of the propagators, whereas Dirac quantization, which amounts to quantization in synchronous gauge, dispenses with the need to introduce ghosts and preserves the locality of the gauge-fixed action.

Quantum 3D tensionless string in light-cone gauge

We discuss the quantization of a tensionless closed string in light-cone gauge. It is known that by using a Hamiltonian BRST scheme the tensionless p-branes have no Lorentz anomaly in any space-time dimensions and no anomaly of space-time conformal symmetry in two dimensions. In this paper, we show that tensionless 3d strings in light-cone gauge also have no anomaly of space-time conformal symmetry. We also study the spectrum of a tensionless 3d closed string.

A first look at Weyl anomalies in shape dynamics

One of the more popular objections towards shape dynamics is the suspicion that anomalies in the spatial Weyl symmetry will arise upon quantization. The purpose of this short paper is to establish the tools required for an investigation of the sort of anomalies that can possibly arise. The first step is to adapt to our setting Barnich and Henneaux's formulation of gauge cohomology in the Hamiltonian setting, which serve to decompose the anomaly into a spatial component and time component. The spatial part of the anomaly, i.e., the anomaly in the symmetry algebra itself ([Ω, Ω] ∝ ℏ instead of vanishing) is given by a projection of the second ghost cohomology of the Hamiltonian BRST differential associated to Ω, modulo spatial derivatives. The temporal part, [Ω, H] ∝ ℏ is given by a different projection of the first ghost cohomology and an extra piece arising from a solution to a functional differential equation. Assuming locality of the gauge cohomology groups involved, this part is always local. Assuming locality for the gauge cohomology groups, using Barnich and Henneaux's results, the classification of Weyl cohomology for higher ghost numbers performed by Boulanger, and following the descent equations, we find a complete characterizations of anomalies in 3+1 dimensions. The spatial part of the anomaly and the first component of the temporal anomaly are always local given these assumptions even in shape dynamics. The part emerging from the solution of the functional differential equations explicitly involves the shape dynamics Hamiltonian, and thus might be non-local. If one restricts this extra piece of the temporal anomaly to be also local, then overall no Weyl anomalies, either temporal or spatial, emerge in the 3+1 case.

MULTISYMPLECTIC BRST

After briefly describing Hamiltonian BRST methods and the multisymplectic approach to field theory, a symmetric geometric Lagrangian is studied by extending the BRST method to the multisymplectic setting. This work uses ideas first introduced by Hrabak [On the multisymplectic origin of the nonabelian deformation algebra of pseudoholomorphic embeddings in strictly almost Kähler ambient manifolds, and the corresponding BRST algebra, preprint (1999), arXiv: math-ph/9904026].

GAUGE ALGEBRA OF IRREDUCIBLE THEORIES IN THE Sp(2)-SYMMETRIC BRST FORMALISM

An explicit solution to classical master equations of the Sp(2)-symmetric Hamiltonian BRST quantization scheme is presented in the case of irreducible gauge theories. A realization of the observable algebra is constructed.

A New Construction for Hamiltonian BRST Operators

In this paper, we describe a precise contracting homotopy which provides a new construction of Hamiltonian BRST operators with only three summands.

Hamiltonian BRST and Batalin-Vilkovisky Formalisms for Second Quantization of Gauge Theories

Gauge theories that have been first quantized using the Hamiltonian BRST operator formalism are described as classical Hamiltonian BRST systems with a BRST charge of the form <\Psi,\Omega\Psi>_{even} and with natural ghost and parity degrees for all fields. The associated proper solution of the classical Batalin-Vilkovisky master equation is constructed from first principles. Both of these formulations can be used as starting points for second quantization. In the case of time reparametrization invariant systems, the relation to the standard <\Psi,\Omega\Psi>_{odd} master action is established.

QUANTIZATION OF BOSONIC STRING MODEL IN (26+2)-DIMENSIONAL SPACE–TIME

We investigate the quantization of the bosonic string model which has a local U (1)V× U (1)Agauge invariance as well as the general coordinate and Weyl invariance on the world-sheet. The model is quantized by Lagrangian and Hamiltonian BRST formulations á la Batalin, Fradkin and Vilkovisky and noncovariant light-cone gauge formulation. Upon the quantization the model turns out to be formulated consistently in (26+2)-dimensional background space–time involving two time-like coordinates.

Hamiltonian BRST quantization of a noncommutative non-Abelian gauge theory and its Seiberg-Witten map

We consider the Hamiltonian BRST quantization of a noncommutative non-Abelian gauge theory. The Seiberg-Witten map of all phase-space variables, including multipliers, ghosts, and their momenta, is given in first order in the noncommutative parameter $\ensuremath{\theta}.$ We show that there exists a complete consistency between the gauge structures of the original and mapped theories, derived in a canonical way, once we appropriately choose the map solutions.

Hamiltonian BRST deformation of a class ofn-dimensional BF-type theories

Consistent Hamiltonian interactions that can be added to an abelian free BF-type class of theories in any n greater or equal to 4 spacetime dimensions are constructed in the framework of the Hamiltonian BRST deformation based on cohomological techniques. The resulting model is an interacting field theory in higher dimensions with an open algebra of on-shell reducible first-class constraints. We argue that the Hamiltonian couplings are related to a natural structure of Poisson manifold on the target space.

HAMILTONIAN COHOMOLOGICAL DERIVATION OF FOUR-DIMENSIONAL NONLINEAR GAUGE THEORIES

Consistent couplings among a set of scalar fields, two types of one-forms and a system of two-forms are investigated in the light of the Hamiltonian BRST cohomology, giving a four-dimensional nonlinear gauge theory. The emerging interactions deform the first-class constraints, the Hamiltonian gauge algebra, as well as the reducibility relations.

NOTE ON THE DUAL BRST SYMMETRY IN GAUGE THEORY

We analyze the relation between the Lagrangian and Hamiltonian BRST symmetry generators for a recently proposed two-dimensional symmetry. In particular it is shown that this symmetry may be obtained from a canonical transformation in the ghost sector in a gauge-independent way.

Nonabelian interactions from Hamiltonian BRST cohomology

Consistent Hamiltonian couplings between a set of vector fields and a system of matter fields are derived by means of BRST cohomological techniques.

Poisson structures in BRST–antiBRST invariant Lagrangian formalism

We show that the specific operators V^a appearing in the triplectic formalism can be viewed as the anti-Hamiltonian vector fields generated by a second rank irreducible Sp(2) tensor. This allows for an explicit realization of the triplectic algebra being constructed from an arbitrary Poisson bracket on the space of the fields only, equipped by the flat Poisson connection. We show that the whole space of fields and antifields can be equipped with an even supersymplectic structure when this Poisson bracket is non-degenerate. This observation opens the possibility to provide the BRST/antiBRST path integral by a well-defined integration measure, as well as to establish a direct link between the Sp(2) symmetric Lagrangian and Hamiltonian BRST quantization schemes.

Hamiltonian BRST interactions in Abelian theories

Consistent couplings between an Abelian gauge field and three types of matter fields are investigated by means of the Hamiltonian BRST deformation theory based on cohomological techniques. In this manner, scalar electrodynamics, the Stuckelberg theory for Abelian zero- and one-forms, respectively, spinor electrodynamics, are inferred.

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.

Freedman-Townsend vertex from Hamiltonian BRST cohomology

Consistent interactions among a set of 2-form gauge fields in four dimensions are derived along a Hamiltonian cohomological procedure. It is shown that the deformation of the BRST charge and BRST-invariant Hamiltonian for the free model leads to the Freedman-Townsend interaction vertex. The resulting interaction deforms both the gauge transformations and reducibility relations, but not the algebra of gauge transformations.