68 citations · 765 across the 90 of their papers we have counts for
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New charged dynamical particles in spatially flat FLRW space-times
Ion I. Cotaescu
New time-dependent metric tensors with spherical symmetry satisfying the Einstein-Maxwell equations in space-times with FLRW asymptotic behaviour are derived here for the first tim…
Masses dynamics during black hole evaporation in spatially flat FLRW universes
Ion I. Cotaescu, Ion Cotaescu
The new dynamical solutions of Einstein's equations with perfect fluid in space-times with FLRW asymptotic behaviour, derived recently \cite{Cot,Cot1,Cot2}, may describe evaporatin…
New one-parameter models of dynamical particles in spatially flat FLRW space-times
Ion I. Cotaescu
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 behav…
Conserved spin operator of Dirac's theory in spatially flat FLRW spacetimes
Ion I. Cotaescu
New conserved spin and orbital angular momentum operators of Dirac's theory on spatially flat FLRW spacetimes are proposed generalizing thus recent results concerning the role of P…
Discrete symmetries of Dirac's theory in the de Sitter manifold
Ion I. Cotaescu, Ion Cotaescu
The discrete symmetries of the Dirac 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, name…
Quantum theory of redshift in de Sitter expanding universe
Ion I. Cotaescu
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 th…
Kinematics in spatially flat FLRW space-time
Ion I. Cotaescu
The kinematics on spatially flat FLRW space-times is presented for the first time in co-moving local charts with physical coordinates, i. e. the cosmic time and Painlev\' e-type Ca…
Light from Reissner-Nordstrom-de Sitter black holes
Ion I. Cotaescu
We derive for the first time the form of the spiral null geodesics around the photon sphere of the Reissner-Nordstrom black hole in the de Sitter expanding universe. Moreover, we o…
Light from Schwarzschild Black Holes in de Sitter expanding universe
Ion I. Cotaescu
A new method is applied for deriving the redshift and shadow of a Schwarzschild black hole moving freely in the de Sitter expanding universe as recorded by a co-moving remote obser…
Longitudinal Doppler effect in de Sitter expanding universe
Ion I. Cotaescu
A new redshift formula is obtained considering the longitudinal Doppler effect in the de Sitter expanding universe where the relative geodesic motion is governed by the Lorenzian i…
Time evolution of the free Dirac field in spatially flat FLRW space-times
Ion I. Cotaescu
The framework of the relativistic quantum mechanics on spatially flat FLRW space-times is considered for deriving the analytical solutions of the Dirac equation in different local…
Flat limit of the de Sitter QFT in the rest frame vacuum
Ion I. Cotaescu
The problem of the flat limits of the scalar and spinor fields on the de Sitter expanding universe is considered in the rest frame vacuum where the frequencies are separated in res…
Rest frame vacuum of the Proca field on the de Sitter expanding universe
Ion I. Cotaescu
The general plane wave solutions of the Proca field in conformal charts of the de Sitter expanding universe are derived for arbitrary polarizations showing how the frequencies can…
Rest frame vacua of massive Klein-Gordon fields on spatially flat FLRW spacetimes
Ion I. Cotaescu
We propose a method of projecting the quantum states from a state space of a given geometry into another state space generated by a different geometry, taking care on the correct n…
Rest frame vacuum of the Dirac field on spatially flat FLRW spacetimes
Ion I. Cotaescu
In quantum theory of the free Dirac field on spatially flat FLRW spacetimes we introduce a new type of vacuum able to separate the positive and negative frequencies in the rest fra…
Aharonov-Bohm rings in de Sitter expanding universe
Ion I. Cotaescu
The -dimensional Dirac equation of the fermions moving in ideal Aharonov-Bohm rings in the de Sitter expanding universe is used for deriving the exact expressions of the gen…
First order QED effects on a spatially flat FLRW spacetime with a Milne-type scale factor
Ion I. Cotaescu, Diana Popescu
The quantum electrodynamics (QED) on a spatially flat -dimensional Friedmann-Lema\^ itre-Robertson-Walker (FLRW) spacetime with a Milne-type scale factor is outlined focusin…
Integral representation of the scalar propagators on the de Sitter expanding universe
Ion I. Cotaescu, Ion Cotaescu
A new type of integral representation is proposed for the propagators of the massive Klein-Gordon field minimally coupled to the gravity of the de Sitter expanding universe. This r…
Scattering of Dirac fermions by spherical massive bodies
Ion I. Cotaescu, Ciprian A. Sporea
The asymptotic form of Dirac spinors in the field of a Schwarzschild black hole is used for deriving analytically for the first time the phase shifts of the partial wave analysis o…
Integral representation of the Feynman propagators of the Dirac fermions on the de Sitter expanding universe
Ion I. Cotaescu
The propagators of the Dirac fermions on the expanding portion of the (1+3)-dimensional de Sitter spacetime are considered as mode sums in momentum representation with a fixed vacu…
Propagators of the Dirac fermions on spatially flat FLRW spacetimes
Ion I. Cotaescu
The general formalism of the free Dirac fermions on spatially flat -dimensional Friedmann-Lema\^ itre-Robertson-Walker (FLRW) spacetimes is developed in momentum representat…
Propagators of the Dirac fermions in de Sitter expanding universe
Ion I. Cotaescu
The propagators of the Dirac fermions are studied in the configuration representation on the expanding portion of the -dimensional de Sitter spacetime considering a fixed va…
Collective classical motion on hyperbolic spacetimes of any dimensions
Ion I. Cotaescu
The geodesics equations on de Sitter and anti-de Sitter spacetimes of any dimensions, are the starting point for deriving the general form of the Boltzmann equation in terms of con…
de Sitter geodesics in stereographic charts
Ion I. Cotaescu
It is shown that the stereographic coordinates on the -dimensional de Sitter spacetime induce, in the parametric equations of all the timelike geodesics, artificial singular…