scholarly journals REAL OR IMAGINARY? ON PAIR CREATION IN DE SITTER SPACE

2010 ◽  
Vol 25 (33) ◽  
pp. 2815-2823 ◽  
Author(s):  
EMIL T. AKHMEDOV
Keyword(s):  
Scalar Field ◽  
Path Integral ◽  
Effective Action ◽  
Particle Production ◽  
De Sitter Space ◽  
Pair Creation ◽  
De Sitter ◽  
Feynman Propagator

Using properly defined Feynman propagator we obtain nonzero imaginary contribution to the scalar field effective action in even-dimensional de Sitter space. Such a propagator follows from the path integral in de Sitter space and obeys composition principle proposed in arXiv:0709.2899. The obtained expression for the effective action shows particle production with the Gibbons–Hawking rate.

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.

scholarly journals PROBING THE VACUUM STRUCTURE OF SPACETIME

2012 ◽  
Vol 12 ◽  
pp. 310-319 ◽  
Author(s):  
SANG PYO KIM
Keyword(s):  
Scalar Field ◽  
Effective Action ◽  
Particle Production ◽  
Constant Electric Field ◽  
Massive Scalar ◽  
De Sitter ◽  
Charged Scalar ◽  
Massive Scalar Field ◽  
Vacuum Structure ◽  
Gravitational Analog

We explore the question of how to probe the vacuum structure of space time by a massive scalar field through interaction with background gravitons. Using the Γ-regularization for the in-/out-state formalism, we find the effective action of a scalar field in a conformally, asymptotically flat spacetime and a four-dimensional de Sitter space, which is a gravitational analog of the Heisenberg-Euler and Schwinger effective action for a charged scalar in a constant electric field. The effective action is nonperturbative in that it sums all one-loop diagrams with arbitrary number of external lines of gravitons. The massive scalar field becomes unstable due to particle production, the effective action has an imaginary part that determines the decay rate of the vacuum, and the out-vacuum is unitarily inequivalent to the in-vacuum.

scholarly journals Open quantum entanglement: a study of two atomic system in static patch of de Sitter space

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Samim Akhtar ◽  
Sayantan Choudhury ◽  
Satyaki Chowdhury ◽  
Debopam Goswami ◽  
Sudhakar Panda ◽  
...  
Keyword(s):  
Scalar Field ◽  
Density Matrix ◽  
Master Equation ◽  
Quantum Entanglement ◽  
De Sitter Space ◽  
Thermal Bath ◽  
Massless Scalar Field ◽  
De Sitter ◽  
Open Quantum ◽  
Non Locality

Abstract In this work, our prime objective is to study non-locality and long range effect of two body correlation using quantum entanglement from various information theoretic measure in the static patch of de Sitter space using a two body Open Quantum System (OQS). The OQS is described by a system of two entangled atoms, surrounded by a thermal bath, which is modelled by a massless probe scalar field. Firstly, we partially trace over the bath field and construct the Gorini Kossakowski Sudarshan Lindblad (GSKL) master equation, which describes the time evolution of the reduced subsystem density matrix. This GSKL master equation is characterized by two components, these are-Spin chain interaction Hamiltonian and the Lindbladian. To fix the form of both of them, we compute the Wightman functions for probe massless scalar field. Using this result alongwith the large time equilibrium behaviour we obtain the analytical solution for reduced density matrix. Further using this solution we evaluate various entanglement measures, namely Von-Neumann entropy, R$$e'$$e′nyi entropy, logarithmic negativity, entanglement of formation, concurrence and quantum discord for the two atomic subsystem on the static patch of De-Sitter space. Finally, we have studied violation of Bell-CHSH inequality, which is the key ingredient to study non-locality in primordial cosmology.

scholarly journals Conformal scattering of the Maxwell-scalar field system on de Sitter space

2019 ◽  
Vol 16 (04) ◽  
pp. 743-791
Author(s):  
Grigalius Taujanskas
Keyword(s):  
Scalar Field ◽  
De Sitter Space ◽  
Decay Rates ◽  
Energy Estimates ◽  
Small Data ◽  
De Sitter ◽  
Null Infinity ◽  
Conformally Invariant ◽  
Field System ◽  
Gauge Fixing

We prove small data energy estimates of all orders of differentiability between past null infinity and future null infinity of de Sitter space for the conformally invariant Maxwell-scalar field system. Using these, we construct bounded and invertible, but nonlinear, scattering operators taking past asymptotic data to future asymptotic data. We deduce exponential decay rates for solutions with data having at least two derivatives, and for more regular solutions discover an asymptotic decoupling of the scalar field from the charge. The construction involves a carefully chosen complete gauge fixing condition which allows us to control all components of the Maxwell potential, and a nonlinear Grönwall inequality for higher-order estimates.

Gauge gravity in noncommutative de Sitter space and pair creation

2008 ◽  
Vol 78 (4) ◽  
pp. 045101 ◽  
Author(s):  
N Mebarki ◽  
S Zaim ◽  
L Khodja ◽  
H Aisaoui
Keyword(s):  
De Sitter Space ◽  
Pair Creation ◽  
De Sitter ◽  
Gauge Gravity

scholarly journals One-loop effective action around De Sitter space

1996 ◽  
Vol 462 (2-3) ◽  
pp. 437-452 ◽  
Author(s):  
I. Antoniadis ◽  
J. Iliopoulos ◽  
T.N. Tomaras
Keyword(s):  
Effective Action ◽  
De Sitter Space ◽  
De Sitter

scholarly journals TURBULENT INSTABILITY OF ANTI-DE SITTER SPACE–TIME

2013 ◽  
Vol 28 (22n23) ◽  
pp. 1340020 ◽  
Author(s):  
MACIEJ MALIBORSKI ◽  
ANDRZEJ ROSTWOROWSKI
Keyword(s):  
Scalar Field ◽  
Cosmological Constant ◽  
Numerical Study ◽  
De Sitter Space ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Spherically Symmetric ◽  
De Sitter ◽  
Field System ◽  
Technical Details

In these lecture notes, we discuss recently conjectured instability of anti-de Sitter space, resulting in gravitational collapse of a large class of arbitrarily small initial perturbations. We uncover the technical details used in the numerical study of spherically symmetric Einstein-massless scalar field system with negative cosmological constant that led to the conjectured instability.

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