Journal•ISSN: 1826-9877
Il Nuovo Cimento B
Springer Nature
About: Il Nuovo Cimento B is an academic journal. The journal publishes majorly in the area(s): General relativity & Theory of relativity. Over the lifetime, 5269 publications have been published receiving 47724 citations.
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2,597 citations
TL;DR: In this article, an approach to study the dynamics of thin shells of dust in general relativity is presented. But no mention of admissible or even any space-time co-ordinates is needed.
Abstract: An approach to shock waves, boundary surfaces and thin shells in general relativity is developed in which their histories are characterized in a purely geometrical way by the extrinsic curvatures of their imbeddings in space-time. There is some gain in simplicity and ease of application over previous treatments in that no mention of « admissible » or, indeed, any space-time co-ordinates is needed. The formalism is applied to a study of the dynamics of thin shells of dust.
2,347 citations
TL;DR: In this paper, the classical configuration space of a system of identical particles is examined and the effect of particle spin in the present formalism is discussed. But this is only the case in which the particles move in three- or higher-dimensional space.
Abstract: The classical configuration space of a system of identical particles is examined. Due to the identification of points which are related by permutations of particle indices, it is essentially different, globally, from the Cartesian product of the one-particle spaces. This fact is explicity taken into account in a quantization of the theory. As a consequence, no symmetry constraints on the wave functions and the observables need to be postulated. The two possibilities, corresponding to symmetric and antisymmetric wave functions, appear in a natural way in the formalism. But this is only the case in which the particles move in three- or higher-dimensional space. In one and two dimensions a continuum of possible intermediate cases connects the boson and fermion cases. The effect of particle spin in the present formalism is discussed.
1,172 citations
TL;DR: In this article, a method which allows a direct picture of phenomena involving line broadening, light shifts and many-photon transitions in the ground state of sodium atoms pumped by dye-laser is reported.
Abstract: A method which allows a direct picture of phenomena involving line broadening, light shifts and many-photon transitions in the ground state of sodium atoms pumped by dye-laser is reported. A new phenomenon due to light beats between the different dye-laser axial modes has been easily evidenced by the method.
773 citations
TL;DR: In this paper, an analytic extension of quantum electrodynamics matrix elements as (analytic) functions of the number of dimensions of space (ν) was performed, and the usual divergences appeared as poles forν integer.
Abstract: We perform an analytic extension of quantum electrodynamics matrix elements as (analytic) functions of the number of dimensions of space(ν). The usual divergences appear as poles forν integer. The renormalization of those matrix elements (forν arbitrary) leads to expressions which are free of ultraviolet divergences forν equal to 4. This shows thatν can be used as an analytic regularizing parameter with, advantages over the usual analytic regularization method. In particular, gauge invariance is mantained for anyν.
447 citations