Zobrazeno 1 - 10
of 103
pro vyhledávání: '"Ion I. Cotaescu"'
Autor:
Ion I. Cotăescu
Publikováno v:
European Physical Journal C: Particles and Fields, Vol 84, Iss 8, Pp 1-8 (2024)
Abstract New one-parameter models of non-rotating dynamical particles are derived as isotropic solutions of Einstein’s equations with perfect fluid in space-times with FLRW asymptotic behaviour, thus generalizing the models recently proposed by Cot
Externí odkaz:
https://doaj.org/article/c389a4c74aff4f74a97adb5a2dd5c489
Autor:
Ion I. Cotăescu
Publikováno v:
European Physical Journal C: Particles and Fields, Vol 84, Iss 5, Pp 1-13 (2024)
Abstract New conserved spin and orbital angular momentum operators of Dirac’s theory on spatially flat FLRW space-times are proposed generalizing thus the recent results concerning the role of Pryce’s spin operator in the flat case (Cotăescu in
Externí odkaz:
https://doaj.org/article/a5881bd57afd43d3879fa961423ff43c
Autor:
Ion I. Cotăescu, Ion Cotăescu
Publikováno v:
European Physical Journal C: Particles and Fields, Vol 83, Iss 10, Pp 1-10 (2023)
Abstract The discrete symmetries of Dirac’s free field on the de Sitter manifold are studied, taking into account that this has two portions that can play the role of physical space-times, namely an expanding and a collapsing universe. The proper d
Externí odkaz:
https://doaj.org/article/cb4f40d0bcb04db5bcd30a35d60f9d45
Autor:
Ion I. Cotăescu
Publikováno v:
European Physical Journal C: Particles and Fields, Vol 82, Iss 11, Pp 1-16 (2022)
Abstract It is shown that the components of Pryce’s spin operator of Dirac’s theory are SU(2) generators of a representation carried by the space of Pauli’s spinors determining the polarization of the plane wave solutions of Dirac’s equation.
Externí odkaz:
https://doaj.org/article/3fef3e38172f4f26b55499b0a493058e
Autor:
Ion I. Cotăescu
Publikováno v:
European Physical Journal C: Particles and Fields, Vol 82, Iss 8, Pp 1-15 (2022)
Abstract The processes in the first order of perturbations of de Sitter quantum electrodynamics (QED) in Coulomb gauge are studied but setting our recently proposed rest frame vacuum of the Dirac field instead of the traditional adiabatic one. This v
Externí odkaz:
https://doaj.org/article/5526ffcd61dc4645bfa9653f7e7ebb5e
Autor:
Ion I. Cotăescu
Publikováno v:
European Physical Journal C: Particles and Fields, Vol 82, Iss 1, Pp 1-10 (2022)
Abstract The propagation of the packets of left-handed plane wave solutions of the massless Dirac equation is studied in spatially flat Friedmann–Lemaître–Robertson–Walker (FLRW) space-times. Assuming that the observations are performed in phy
Externí odkaz:
https://doaj.org/article/df26c59dd820457ab02e7accd0e13f05
Autor:
Ion I. Cotăescu
Publikováno v:
European Physical Journal C: Particles and Fields, Vol 82, Iss 1, Pp 1-9 (2022)
Abstract Metrics of dynamical point particles embedded in spatially flat FLRW space-times are derived as isotropic solutions of the Einstein equations with the energy–momentum tensor of a perfect fluid. These particles are produced by central singu
Externí odkaz:
https://doaj.org/article/78a1262cfe744ab9b8b7d44c86a36de2
Autor:
Ion I. Cotăescu
Publikováno v:
European Physical Journal C: Particles and Fields, Vol 81, Iss 10, Pp 1-20 (2021)
Abstract The classical and quantum theory of the Maxwell free field (or perturbation) minimally coupled to the gravity of local-Minkowskian spatially flat Friedmann–Lemaître–Robertson–Walker (FLRW) space-times is constructed in conformal local
Externí odkaz:
https://doaj.org/article/30efaaf4f0a845798cabb9ee5a9d37dd
Autor:
Ion I. Cotăescu, Ion Cotăescu
Publikováno v:
European Physical Journal C: Particles and Fields, Vol 81, Iss 7, Pp 1-10 (2021)
Abstract We study for the first time the propagation of the packets of plane waves of the Maxwell free field in the de Sitter expanding universe as detected by an observer staying at rest in his proper frame with physical de Sitter–Painlevé coordi
Externí odkaz:
https://doaj.org/article/8b088f5322574e9b94f7600e9e798c09
Autor:
Ion I. Cotăescu
Publikováno v:
European Physical Journal C: Particles and Fields, Vol 81, Iss 6, Pp 1-13 (2021)
Abstract The quantum theory of the Maxwell free field in Coulomb gauge on the de Sitter expanding universe is completed with the technical elements needed for building a coherent quantum theory of redshift. Paying special attention to the conserved o
Externí odkaz:
https://doaj.org/article/fd8f24c5c9f34a4c9daaab96aaccb3e8