scholarly journals REDUCTION FORMALISM FOR DIRAC FERMIONS ON DE SITTER SPACE–TIME

2008 ◽  
Vol 23 (07) ◽  
pp. 1075-1087 ◽  
Author(s):  
COSMIN CRUCEAN ◽  
RADU RACOCEANU
Keyword(s):  
Perturbation Theory ◽  
Dirac Equation ◽  
Exact Solutions ◽  
Scattering Amplitude ◽  
De Sitter Space ◽  
Space Time ◽  
Green Functions ◽  
Dirac Fermions ◽  
De Sitter

The reduction formulas for Dirac fermions is derived using the exact solutions of free Dirac equation on de Sitter space–time. In the framework of the perturbation theory one studies the Green functions and derives the scattering amplitude in the first orders of perturbation theory.

scholarly journals COULOMB SCATTERING OF THE DIRAC FERMIONS ON DE SITTER EXPANDING UNIVERSE

2007 ◽  
Vol 22 (34) ◽  
pp. 2573-2585 ◽  
Author(s):  
COSMIN CRUCEAN
Keyword(s):  
Dirac Equation ◽  
Exact Solutions ◽  
Cross Section ◽  
Dirac Field ◽  
Coulomb Scattering ◽  
De Sitter Spacetime ◽  
Dirac Fermions ◽  
Final States ◽  
De Sitter ◽  
Sitter Spacetime

The lowest order contribution of the amplitude of the Dirac–Coulomb scattering in de Sitter spacetime is calculated assuming that the initial and final states of the Dirac field are described by exact solutions of the free Dirac equation on de Sitter spacetime with a given momentum and helicity. One studies the difficulties that arises when one passes from the amplitude to cross section.

scholarly journals NEW DIRAC QUANTUM MODES IN MOVING FRAMES OF THE DE SITTER SPACE–TIME

2008 ◽  
Vol 23 (22) ◽  
pp. 3707-3720 ◽  
Author(s):  
ION I. COTĂESCU ◽  
COSMIN CRUCEAN
Keyword(s):  
Quantum Mechanics ◽  
Dirac Equation ◽  
Complete System ◽  
Plane Waves ◽  
De Sitter Space ◽  
Space Time ◽  
Principal Result ◽  
Moving Frames ◽  
De Sitter ◽  
Schrödinger Picture

Recently a new time-evolution picture of the Dirac quantum mechanics was defined in charts with spatially flat Robertson–Walker metrics, under the name of Schrödinger picture (I. I. Cotăescu, Mod. Phys. Lett. A22, 2965 (2007)). In the present paper, new Dirac quantum modes are found in moving charts of the de Sitter space–time using the technical advantages offered by this picture. The principal result is a new set of energy eigenspinors which behave as polarized plane waves and form a complete system of orthonormalized solutions of the free Dirac equation.

scholarly journals SPINOR TWO-POINT FUNCTIONS AND PEIERLS BRACKET IN DE SITTER SPACE

2009 ◽  
Vol 06 (07) ◽  
pp. 1069-1088 ◽  
Author(s):  
GIAMPIERO ESPOSITO ◽  
RAJU ROYCHOWDHURY
Keyword(s):  
Symmetric Spaces ◽  
De Sitter Space ◽  
Space Time ◽  
Green Functions ◽  
De Sitter ◽  
Geometric Objects ◽  
Two Component ◽  
Component Spinor

This paper studies spinor two-point functions for spin-1/2 and spin-3/2 fields in maximally symmetric spaces such as de Sitter (dS) space–time, by using intrinsic geometric objects. The Feynman, positive- and negative-frequency Green functions are then obtained for these cases, from which we eventually display the supercommutator and the Peierls bracket under such a setting in two-component-spinor language.

scholarly journals TACHYONS IN DE SITTER SPACE AND ANALYTICAL CONTINUATION FROM dS/CFT TO AdS/CFT

2004 ◽  
Vol 19 (29) ◽  
pp. 4985-5001 ◽  
Author(s):  
M. CADONI ◽  
P. CARTA
Keyword(s):  
Analytic Continuation ◽  
De Sitter Space ◽  
Space Time ◽  
Analytical Continuation ◽  
Green Functions ◽  
De Sitter ◽  
Field Equations ◽  
Scalar Particles

We discuss analytic continuation from d-dimensional Lorentzian de Sitter ( dS d) to d-dimensional Lorentzian anti-de Sitter ( AdS d) space–time. We show that AdS d, with opposite signature of the metric, can be obtained as analytic continuation of a portion of dS d. This implies that the dynamics of (positive square-mass) scalar particles in AdS d can be obtained from the dynamics of tachyons in dS d. We discuss this correspondence both at the level of the solution of the field equations and of the Green functions. The AdS / CFT duality is obtained as analytic continuation of the dS / CFT duality.

scholarly journals DIRAC–COULOMB SCATTERING WITH PLANE WAVE ENERGY EIGENSPINORS ON DE SITTER EXPANDING UNIVERSE

2008 ◽  
Vol 23 (09) ◽  
pp. 1351-1359 ◽  
Author(s):  
ION I. COTĂESCU ◽  
COSMIN CRUCEAN
Keyword(s):  
Dirac Equation ◽  
Plane Wave ◽  
Wave Energy ◽  
De Sitter Space ◽  
Space Time ◽  
Dirac Field ◽  
Coulomb Scattering ◽  
Final States ◽  
De Sitter ◽  
Scattering Process

The lowest order contribution of the amplitude of Dirac–Coulomb scattering in de Sitter space–time is calculated assuming that the initial and final states of the Dirac field are described by exact solutions of the free Dirac equation on de Sitter space–time with a given energy and helicity. We find that the total energy is conserved in the scattering process.

scholarly journals Exact solutions in (2+1)-dimensional anti-de Sitter space-time admitting a linear or non-linear equation of state

2014 ◽  
Vol 355 (2) ◽  
pp. 353-359 ◽  
Author(s):  
Ayan Banerjee ◽  
Farook Rahaman ◽  
Kanti Jotania ◽  
Ranjan Sharma ◽  
Mosiur Rahaman
Keyword(s):  
Equation Of State ◽  
Exact Solutions ◽  
Linear Equation ◽  
De Sitter Space ◽  
Space Time ◽  
De Sitter ◽  
Non Linear Equation ◽  
Non Linear

scholarly journals Exact solutions to Einstein–Maxwell theory on Eguchi–Hanson space

2017 ◽  
Vol 32 (17) ◽  
pp. 1750098 ◽  
Author(s):  
A. M. Ghezelbash ◽  
V. Kumar
Keyword(s):  
Cosmological Constant ◽  
Exact Solutions ◽  
De Sitter Space ◽  
Space Time ◽  
De Sitter ◽  
Maxwell Theory ◽  
Analytical Functions ◽  
Higher Dimensional ◽  
All Solutions ◽  
Metric Functions

In this paper, we construct explicit analytical exact solutions to the six and higher-dimensional Einstein–Maxwell theory. In all solutions, a subspace of the metric is the Eguchi–Hanson space where the metric functions are completely determined in terms of known analytical functions. Moreover, we find the solutions can be extended from nonstationary exact solutions to Einstein–Maxwell theory with cosmological constant. We show that the solutions are asymptotically expanding patches of de Sitter space–time.

LIFETIME OF A DE SITTER PARTICLE

2008 ◽  
Vol 05 (08) ◽  
pp. 1243-1254
Author(s):  
HENRI EPSTEIN
Keyword(s):  
Perturbation Theory ◽  
Minkowski Space ◽  
Principal Series ◽  
De Sitter Space ◽  
Space Time ◽  
De Sitter ◽  
Complementary Series ◽  
First Order ◽  
Interaction Terms ◽  
Minkowski Space Time

The familiar rule which, in Minkowski space-time, forbids the decay of a particle into heavier products, does not hold in de Sitter space-time. We study, in first order of perturbation theory, the decay of a particle of the "principal series" and show that it may decay into two particles of any of the "principal" or "complementary" series (with suitable interaction terms). Spectral conditions reappear in the decay of a "complementary" particle: but its lifetime is 0.

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