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Physical Review D
Article
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Physical Review D
Article . 2009 . Peer-reviewed
License: APS Licenses for Journal Article Re-use
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https://dx.doi.org/10.48550/ar...
Article . 2009
License: arXiv Non-Exclusive Distribution
Data sources: Datacite
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de Sitter nonlinear sigma model and accelerating universe

Authors: Lee, Joohan; Lee, Tae Hoon; Moon, Taeyoon; Oh, Phillial;

de Sitter nonlinear sigma model and accelerating universe

Abstract

We consider a cosmology with a non-compact nonlinear sigma model.The target space is of de-Sitter type and four scalar fields are introduced.The potential is absent but cosmological constant term $Λ$ is added. One of the scalar fields is time dependent and the remaining three fields have no time dependence but only spatial dependence. We show that a very simple ansatz for the scalar fields results in the accelerating universe with an exponential expansion at late times. It is pointed out that the presence of the energy density and pressure coming from the spatial variation of the three scalar fields plays an essential role in our analysis which includes $Λ=0$ as a special case and it discriminate from the standard $Λ$-dominated acceleration. We perform a stability analysis of the solutions and find that some solutions are classically stable and attractor. We also present a non-perturbative solution which asymptotically approaches an exponential acceleration and discusspossible cosmological implications in relation with dark energy. It turns out that the equation of state approaches asymptotically $ω=-1$ both from above and below, but the crossing does not occur. It predicts present value of $ω\sim -1\mp 0.07$, which is within the region allowed by the oservational data. This solution also exhibits a power law expansion at early times, and the energy density of the scalar fields mimics that of the stiff matter.

9 pages

Related Organizations
Keywords

High Energy Physics - Theory, Cosmology and Nongalactic Astrophysics (astro-ph.CO), High Energy Physics - Theory (hep-th), FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), General Relativity and Quantum Cosmology, Astrophysics - Cosmology and Nongalactic Astrophysics

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    popularity
    This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
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    influence
    This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
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    This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
13
Average
Average
Average
Green
bronze