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Title: | Imprints of cosmic strings on the cosmological gravitational wave background |
Author: | Kleidis, Kostas Papadopoulos, Demetrios B. Verdaguer Oms, Enric, 1950- Vlahos, L. (Loukas), 1949- |
Keywords: | Teoria de camps (Física) Ones gravitacionals Models de corda Cordes còsmiques Field theory (Physics) Gravitational waves String models Cosmic strings |
Issue Date: | 2008 |
Publisher: | The American Physical Society |
Abstract: | The equation which governs the temporal evolution of a gravitational wave (GW) in curved space-time can be treated as the Schrodinger equation for a particle moving in the presence of an effective potential. When GWs propagate in an expanding Universe with constant effective potential, there is a critical value (k_c) of the comoving wave-number which discriminates the metric perturbations into oscillating (k > k_c) and non-oscillating (k < k_c) modes. As a consequence, if the non-oscillatory modes are outside the horizon they do not freeze out. The effective potential is reduced to a non-vanishing constant in a cosmological model which is driven by a two-component fluid, consisting of radiation (dominant) and cosmic strings (sub-dominant). It is known that the cosmological evolution gradually results in the scaling of a cosmic-string network and, therefore, after some time (\Dl \ta) the Universe becomes radiation-dominated. The evolution of the non-oscillatory GW modes during \Dl \ta (while they were outside the horizon), results in the distortion of the GW power spectrum from what it is anticipated in a pure radiation-model, at present-time frequencies in the range 10^{-16} Hz < f < 10^5 Hz. |
Note: | Reproducció digital del document publicat en format paper, proporcionada per PROLA i http://dx.doi.org/10.1103/PhysRevD.78.024027 |
It is part of: | Physical Review D, 2008, vol. 78, núm. 2, p. 024027-1-024027-8 |
URI: | http://hdl.handle.net/2445/12387 |
Related resource: | http://doi.org/10.1103/PhysRevD.78.024027 |
ISSN: | 0556-2821 |
Appears in Collections: | Articles publicats en revistes (Física de la Matèria Condensada) |
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