516 research outputs found

    Non-Locality and Ellipticity in a Gauge-Invariant Quantization

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    The quantum theory of a free particle in two dimensions with non-local boundary conditions on a circle is known to lead to surface and bulk states. Such a scheme is here generalized to the quantized Maxwell field, subject to mixed boundary conditions. If the Robin sector is modified by the addition of a pseudo-differential boundary operator, gauge-invariant boundary conditions are obtained at the price of dealing with gauge-field and ghost operators which become pseudo-differential. A good elliptic theory is then obtained if the kernel occurring in the boundary operator obeys certain summability conditions, and it leads to a peculiar form of the asymptotic expansion of the symbol. The cases of ghost operator of negative and positive order are studied within this framework.Comment: 17 pages, plain Te

    Workmen\u27s Compensation at Sea

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    At the present time there are three possible remedies available to seamen who are injured in the course of their employment. In order to maintain any of these actions, the injured party must of course qualify as a seaman. The traditional tests used to determine whether a maritime worker is a seaman are as follows: 1) the vessel must be in navigation, 2) the worker must have a more or less permanent connection with the vessel, and 3) the worker must be aboard the vessel primarily to aid in navigation. These standards have been somewhat modified by Offshore Company v. Robinson. In that case, the court stated that there is an evidentiary basis for holding a person to be a seaman if: 1) there is evidence that the worker was assigned permanently to a vessel, or performed a substantial part of his work aboard a vessel, and 2) his duties contributed to the function of the vessel or to the accomplishment of its mission. Therefore, it seems that it does not matter whether the vessel is actually in navigation or if the maritime worker is aboard primarily in aid of navigation so long as he performs a substantial part of his work on the vessel. Furthermore, the definition of vessel has been extended to cover almost any floating object that is capable of being moved from one place to another

    Relativistically Covariant Symmetry in QED

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    We construct a relativistically covariant symmetry of QED. Previous local and nonlocal symmetries are special cases. This generalized symmetry need not be nilpotent, but nilpotency can be arranged with an auxiliary field and a certain condition. The Noether charge generating the symmetry transformation is obtained, and it imposes a constraint on the physical states.Comment: Latex file, 9 page

    Boundary Operators in Quantum Field Theory

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    The fundamental laws of physics can be derived from the requirement of invariance under suitable classes of transformations on the one hand, and from the need for a well-posed mathematical theory on the other hand. As a part of this programme, the present paper shows under which conditions the introduction of pseudo-differential boundary operators in one-loop Euclidean quantum gravity is compatible both with their invariance under infinitesimal diffeomorphisms and with the requirement of a strongly elliptic theory. Suitable assumptions on the kernel of the boundary operator make it therefore possible to overcome problems resulting from the choice of purely local boundary conditions.Comment: 23 pages, plain Tex. The revised version contains a new section, and the presentation has been improve

    UV-finite scalar field theory with unitarity

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    In this paper we show how to define the UV completion of a scalar field theory such that it is both UV-finite and perturbatively unitary. In the UV completed theory, the propagator is an infinite sum of ordinary propagators. To eliminate the UV divergences, we choose the coefficients and masses in the propagator to satisfy certain algebraic relations, and define the infinite sums involved in Feynman diagram calculation by analytic continuation. Unitarity can be proved relatively easily by Cutkosky's rules. The theory is equivalent to infinitely many particles with specific masses and interactions. We take the Ď•4\phi^4 theory as an example and demonstrate our idea through explicit Feynman diagram computation.Comment: 14 pages, references adde

    Nonlocal regularization of abelian models with spontaneous symmetry breaking

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    We demonstrate how nonlocal regularization is applied to gauge invariant models with spontaneous symmetry breaking. Motivated by the ability to find a nonlocal BRST invariance that leads to the decoupling of longitudinal gauge bosons from physical amplitudes, we show that the original formulation of the method leads to a nontrivial relationship between the nonlocal form factors that can appear in the model.Comment: 11 pages, uses amsart. To appear in Mod. Phys. Lett

    Hamilton-Jacobi formalism for Linearized Gravity

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    In this work we study the theory of linearized gravity via the Hamilton-Jacobi formalism. We make a brief review of this theory and its Lagrangian description, as well as a review of the Hamilton-Jacobi approach for singular systems. Then we apply this formalism to analyze the constraint structure of the linearized gravity in instant and front-form dynamics.Comment: To be published in Classical and Quantum Gravit
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