Gravitational waves in a spatially closed de Sitter spacetime

Abbassi, Amir H.; Khodagholizadeh, Jafar; Abbassi, Amir M.

doi:10.1140/epjc/s10052-013-2592-6

Cited by 8 publications

(4 citation statements)

References 18 publications

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“…Even though in WMAP nine-year data report the results have been interpreted as an evidence in the support of flat universe, in no way do the data rule out the case of K = 1 [5]. By choosing the maximally extended de-Sitter metric as unperturbed background, we found the evolution of tensor modes fluctuation in curved spacetime [6] . We compute only the tensor mode fluctuation between the time of inflation and present specially from a temperature ≈ 10 10 K when electron positron annihilation is substantially complete and neutrinos have decoupled from matter and radiation.…”

Section: Introductionmentioning

confidence: 71%

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Damping of tensor mode in spatially closed cosmology

2014

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We derive an integro-differential equation for propagation of cosmological gravitation waves in spatially closed cosmology whereas the traceless transverse tensor part of the anisotropic stress tensor is free streaming neutrinos (including antineutrinos), which have been traveling essentially without collision since temperature dropped below about $ 10^{10} K$. We studied the short wavelengths and long wavelengths of gravitational waves (GWs) that enter the horizon in closed spacetime. The solution shows that the anisotropic stress reduces the squared amplitude by 76% for wavelengths that enter the horizon during radiation-dominated phase and this reduction is less for the wavelength that enter the horizon at later times. At the end we compare the results to theComment: 10 pages, 1 figur

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Section: Introductionmentioning

confidence: 71%

“…We found a complete solution of differential equation for tensor perturbation in the closed universe [6]. We begin by neglecting the anisotropic inertia tensor Π T ij and then we consider x 1 so with this approximation, the field equation (2) governing the Fourier components of the tensor components of D ij becomes…”

Section: Short Wavelengthsmentioning

confidence: 99%

Damping of tensor mode in spatially closed cosmology

2014

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“…It is also possible to express the tensor spherical harmonics in terms of the Chebyshev polynomials of the first kind [31]. It can be shown that…”

Section: Tensor Perturbations and Tensor Random Fieldsmentioning

confidence: 99%

“…It is also possible to express the tensor harmonics on S 3 (a) in terms of the Chebyshev polynomials of the first kind [31] which constitute the tensor Cartesian harmonics. It can be shown…”

Section: Tensor Perturbations and Tensor Random Fieldsmentioning

confidence: 99%

On the perturbation theory in spatially closed background

2014

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In this article, we investigate some features of the perturbation theory in a spatially closed universe. We will show that the perturbative field equations in a spatially closed universe always have two independent adiabatic solutions provided that the wavelengths of perturbation modes are very much longer than the Hubble horizon. It will be revealed that these adiabatic solutions do not depend on the curvature directly. We also propose a new interpretation for the curvature perturbation in terms of the unperturbed background geometry.

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