scholarly journals TWO-POINT FUNCTIONS AND QUANTUM FIELDS IN DE SITTER UNIVERSE

1996 ◽  
Vol 08 (03) ◽  
pp. 327-391 ◽  
Author(s):  
JACQUES BROS ◽  
UGO MOSCHELLA
Keyword(s):  
Plane Waves ◽  
Thermal Characterization ◽  
De Sitter Space ◽  
Space Time ◽  
Space Structure ◽  
Spectral Condition ◽  
De Sitter ◽  
Type Representation ◽  
Tube Domains ◽  
De Sitter Universe

We present a theory of general two-point functions and of generalized free fields in d-dimensional de Sitter space-time which closely parallels the corresponding Minkowskian theory. The usual spectral condition is now replaced by a certain geodesic spectral condition, equivalent to a precise thermal characterization of the corresponding “vacuum” states. Our method is based on the geometry of the complex de Sitter space-time and on the introduction of a class of holomorphic functions on this manifold, called perikernels, which reproduce mutatis mutandis the structural properties of the two-point correlation functions of the Minkowskian quantum field theory. The theory contains as basic elementary case the linear massive field models in their “preferred” representation. The latter are described by the introduction of de Sitter plane waves in their tube domains which lead to a new integral representation of the two-point functions and to a Fourier-Laplace type transformation on the hyperboloid. The Hilbert space structure of these theories is then analysed by using this transformation. In particular we show the Reeh-Schlieder property. For general two-point functions, a substitute to the Wick rotation is defined both in complex space-time and in the complex mass variable, and substantial results concerning the derivation of Källen-Lehmann type representation are obtained.

THE DE SITTER UNIVERSE MODELS

1995 ◽  
Vol 04 (01) ◽  
pp. 115-159 ◽  
Author(s):  
E. ERIKSEN ◽  
Ø. GRØN
Keyword(s):  
Bianchi Type ◽  
De Sitter Space ◽  
Space Time ◽  
Analytic Extension ◽  
Coordinate Transformations ◽  
De Sitter ◽  
Type Iii ◽  
Dimensional Spacetime ◽  
De Sitter Universe ◽  
Universe Models

The kinematical properties of the de Sitter space-time are reviewed and investigated. The properties of the static sections are clarified. A deduction of the analytic extension, analogous to that of Kruskal and Szekeres for the Schwarzschild space-time, of the static section to the region outside the horizon is given. The representation of the de Sitter space-time as a four-dimensional hyperboloid in Minkowskian five-dimensional spacetime is reviewed. Coordinate transformations between different sections of the de Sitter space-time are found. By means of the transformation formulae the different sections are mapped onto each other in space-time diagrams. These mappings are interpreted kinematically. We have aimed at providing, whenever possible, an intuitive understanding of the kinematical properties of the different sections, and how they are interrelated. Among others we present real coordinate transformations between the static and the three Robertson-Walker sections of the de Sitter space-time on one hand and the vacuum dominated Bianchi type-III model on the other hand. These transformations are used to map the path of a typical Bianchi type-III reference particle into the static and the Robertson-Walker sections.

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 On Gravitational Entropy of de Sitter Universe

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
S. C. Ulhoa ◽  
E. P. Spaniol
Keyword(s):  
Phase Transition ◽  
Cosmological Constant ◽  
De Sitter Space ◽  
Teleparallel Gravity ◽  
Space Time ◽  
Gravitational Energy ◽  
De Sitter ◽  
First Law Of Thermodynamics ◽  
Gravitational Entropy ◽  
De Sitter Universe

The paper deals with the calculation of the gravitational entropy in the context of teleparallel gravity for de Sitter space-time. In such a theory it is possible to define gravitational energy and pressure; thus we use those expressions to construct the gravitational entropy. We use the temperature as a function of the cosmological constant and write the first law of thermodynamics from which we obtain the entropy. In the limit Λ≪1 we find that the entropy is proportional to volume, for a specific temperature’s choice; we find that ΔS≥0 as well. We also identify a phase transition in de Sitter space-time by analyzing the specific heat.

Noncommutative scalar field in de Sitter space–time and pair creation process

2021 ◽  
Vol 36 (02) ◽  
pp. 2150011
Author(s):  
Nabil Mehdaoui ◽  
Lamine Khodja ◽  
Salah Haouat
Keyword(s):  
Scalar Field ◽  
Chemical Potential ◽  
De Sitter Space ◽  
Space Time ◽  
Pair Creation ◽  
De Sitter ◽  
Creation Process ◽  
Scalar Particles ◽  
Constant Electromagnetic Field

In this work, we address the process of pair creation of scalar particles in [Formula: see text] de Sitter space–time in presence of a constant electromagnetic field by applying the noncommutativity on the scalar field up to first-order in [Formula: see text]. We calculate the density of particles created in the vacuum by the mean of the Bogoliubov transformations. In contrast to a previous result, we show that noncommutativity contributes to the pair creation process. We find that the noncommutativity plays the same role of chemical potential and gives an important interest for studies at high energies.

Quantum field theory in anti-de Sitter space-time

1978 ◽  
Vol 18 (10) ◽  
pp. 3565-3576 ◽  
Author(s):  
S. J. Avis ◽  
C. J. Isham ◽  
D. Storey
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
De Sitter Space ◽  
Space Time ◽  
Quantum Field ◽  
De Sitter
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