2,852 research outputs found
Hamilton - Jacobi treatment of front-form Schwinger model
The Hamilton-Jacobi formalism was applied to quantize the front-form
Schwinger model. The importance of the surface term is discussed in detail. The
BRST-anti-BRST symmetry was analyzed within Hamilton-Jacobi formalism.Comment: 11 pages, to be published in Int. Journ. Mod. Phys.
Inibição do crescimento de fungos do gênero Aspergillus produtores de ocratoxina a por extratos aquosos de erva-mate.
Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos
Multi Hamilton-Jacobi quantization of O(3) nonlinear sigma model
The O(3) non-linear sigma model is investigated using multi Hamilton-Jacobi
formalism. The integrability conditions are investigated and the results are in
agreement with those obtained by Dirac's method. By choosing an adequate
extension of phase space we describe the transformed system by a set of three
Hamilton-Jacobi equations and calculate the corresponding action.Comment: 10 pages, LaTeX, to be published in Mod. Phys. Lett.
An analysis of cosmological perturbations in hydrodynamical and field representations
Density fluctuations of fluids with negative pressure exhibit decreasing time
behaviour in the long wavelength limit, but are strongly unstable in the small
wavelength limit when a hydrodynamical approach is used. On the other hand, the
corresponding gravitational waves are well behaved. We verify that the
instabilities present in density fluctuations are due essentially to the
hydrodynamical representation; if we turn to a field representation that lead
to the same background behaviour, the instabilities are no more present. In the
long wavelength limit, both approachs give the same results. We show also that
this inequivalence between background and perturbative level is a feature of
negative pressure fluid. When the fluid has positive pressure, the
hydrodynamical representation leads to the same behaviour as the field
representation both at the background and perturbative levels.Comment: Latex file, 18 page
On Equivalence of Duffin-Kemmer-Petiau and Klein-Gordon Equations
A strict proof of equivalence between Duffin-Kemmer-Petiau (DKP) and
Klein-Gordon (KG) theories is presented for physical S-matrix elements in the
case of charged scalar particles interacting in minimal way with an external or
quantized electromagnetic field. First, Hamiltonian canonical approach to DKP
theory is developed in both component and matrix form. The theory is then
quantized through the construction of the generating functional for Green
functions (GF) and the physical matrix elements of S-matrix are proved to be
relativistic invariants. The equivalence between both theories is then proved
using the connection between GF and the elements of S-matrix, including the
case of only many photons states, and for more general conditions - so called
reduction formulas of Lehmann, Symanzik, Zimmermann.Comment: 23 pages, no figures, requires macro tcilate
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