26 research outputs found
Hamiltonian Approach to Lagrangian Gauge Symmetries
We reconsider the problem of finding all local symmetries of a Lagrangian.
Our approach is completely Hamiltonian without any reference to the associated
action. We present a simple algorithm for obtaining the restrictions on the
gauge parameters entering in the definition of the generator of gauge
transformations.Comment: LaTex, 8 pages, Latex error correcte
Master Equation for Lagrangian Gauge Symmetries
Using purely Hamiltonian methods we derive a simple differential equation for
the generator of the most general local symmetry transformation of a
Lagrangian. The restrictions on the gauge parameters found by earlier
approaches are easily reproduced from this equation. We also discuss the
connection with the purely Lagrangian approach. The general considerations are
applied to the Yang-Mills theory.Comment: 14 pages, Late
Two-Dimensional Thermofield Bosonization
The main objective of this paper is to obtain an operator realization for the
bosonization of fermions in 1 + 1 dimensions, at finite, non-zero temperature
T. This is achieved in the framework of the real time formalism of Thermofield
Dynamics. Formally the results parallel those of the T = 0 case. The well known
two-dimensional Fermion-Boson correspondences at zero temperature are shown to
hold also at finite temperature. In order to emphasize the usefulness of the
operator realization for handling a large class of two-dimensional quantum
field-theoretic problems, we contrast this global approach with the cumbersome
calculation of the fermion-current two-point function in the imaginary-time
formalism and real time formalisms. The calculations also illustrate the very
different ways in which the transmutation from Fermi-Dirac to Bose-Einstein
statistics is realized.Comment: 30 pages, no figure. Submitted to Annals of Physic
Decoupled path integral formulation of chiral QCD with
We analyse the BRST constraints and corresponding Hilbert-space structure of
chiral QCD in the decoupled formulation for the case of the
Jackiw-Rajaraman parameter . We show that despite formal similarities this
theory is not equivalent to QCD, and that its extension to U(N) does not
lead to an infinite vacuum degeneracy.Comment: LaTeX, 22 page
BRST Cohomology and Hilbert Spaces of Non-Abelian Models in the Decoupled Path Integral Formulation
The existence of several nilpotent Noether charges in the decoupled
formulation of two-dimensional gauge theories does not imply that all of these
are required to annihilate the physical states. We elucidate this matter in the
context of simple quantum mechanical and field theoretical models, where the
structure of the Hilbert space is known. We provide a systematic procedure for
deciding which of the BRST conditions is to be imposed on the physical states
in order to ensure the equivalence of the decoupled formulation to the
original, coupled one.Comment: 31 pages,Late
Two-Dimensional Thermofield Bosonization II: Massive Fermions
We consider the perturbative computation of the N-point function of chiral
densities of massive free fermions at finite temperature within the thermofield
dynamics approach. The infinite series in the mass parameter for the N-point
functions are computed in the fermionic formulation and compared with the
corresponding perturbative series in the interaction parameter in the bosonized
thermofield formulation. Thereby we establish in thermofield dynamics the
formal equivalence of the massive free fermion theory with the sine-Gordon
thermofield model for a particular value of the sine-Gordon parameter. We
extend the thermofield bosonization to include the massive Thirring model.Comment: 21 pages, to be published in Annals of Physic
BFT Hamiltonian Embedding of Non-Abelian Self-Dual Model
Following systematically the generalized Hamiltonian approach of Batalin,
Fradkin and Tyutin, we embed the second-class non-abelian self-dual model of P.
K. Townsend et al into a gauge theory. The strongly involutive Hamiltonian and
constraints are obtained as an infinite power series in the auxiliary fields.
By formally summing the series we obtain a simple interpretation for the
first-class Hamiltonian, constraints and observables.Comment: LaTeX, 12 Page
Gauge Invariant Variational Approach with Fermions: the Schwinger Model
We extend the gauge invariant variational approach of Phys. Rev. D52 (1995)
3719, hep-th/9408081, to theories with fermions. As the simplest example we
consider the massless Schwinger model in 1+1 dimensions. We show that in this
solvable model the simple variational calculation gives exact results.Comment: 14 pages, 1 figur
Metafluid dynamics and Hamilton-Jacobi formalism
Metafluid dynamics was investigated within Hamilton-Jacobi formalism and the
existence of the hidden gauge symmetry was analyzed. The obtained results are
in agreement with those of Faddeev-Jackiw approach.Comment: 7 page
Induced Parity-Breaking Term at Finite Chemical Potential and Temparature
We exactly calculated the parity-odd term of the effective action induced by
the fermions in 2+1 dimensions at finite chemical potential and finite
temperature. It shows that gauge invariance is still respected. A more gerneral
class of background configurations is considered. The knowledge of the reduced
1+1 determinant is required in order to draw exact conclusions about the gauge
invariance of the parity-odd term in this latter case.Comment: 8 pages, LATEX, no figure