Anisotropic k-essence cosmologies

doi:10.1103/PHYSREVD.73.063502

Title: Anisotropic k-essence cosmologies

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Abstract

We investigate a Bianchi type-I cosmology with k-essence and find the set of models which dissipate the initial anisotropy. There are cosmological models with extended tachyon fields and k-essence having a constant barotropic index. We obtain the conditions leading to a regular bounce of the average geometry and the residual anisotropy on the bounce. For constant potential, we develop purely kinetic k-essence models which are dust dominated in their early stages, dissipate the initial anisotropy, and end in a stable de Sitter accelerated expansion scenario. We show that linear k-field and polynomial kinetic function models evolve asymptotically to Friedmann-Robertson-Walker cosmologies. The linear case is compatible with an asymptotic potential interpolating between V{sub l}{proportional_to}{phi}{sup -{gamma}{sub l}}, in the shear dominated regime, and V{sub l}{proportional_to}{phi}{sup -2} at late time. In the polynomial case, the general solution contains cosmological models with an oscillatory average geometry. For linear k-essence, we find the general solution in the Bianchi type-I cosmology when the k field is driven by an inverse square potential. This model shares the same geometry as a quintessence field driven by an exponential potential.

Authors:

Chimento, Luis P.; Forte, Monica ^[1]

Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina)

Publication Date:: Wed Mar 15 00:00:00 EST 2006

OSTI Identifier:: 20782606

Resource Type:: Journal Article

Resource Relation:: Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevD.73.063502; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)

Country of Publication:: United States

Language:: English

Subject:: 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANISOTROPY; COSMOLOGICAL MODELS; COSMOLOGY; DE SITTER GROUP; DUSTS; GEOMETRY; MATHEMATICAL SOLUTIONS; NONLUMINOUS MATTER; POLYNOMIALS; POTENTIALS; SHEAR

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                    Chimento, Luis P., and Forte, Monica. Anisotropic k-essence cosmologies.  United States: N. p., 2006. 
        Web.  doi:10.1103/PHYSREVD.73.063502.

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                    Chimento, Luis P., & Forte, Monica. Anisotropic k-essence cosmologies.  United States.  doi:10.1103/PHYSREVD.73.063502.

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                    Chimento, Luis P., and Forte, Monica. Wed .  
        "Anisotropic k-essence cosmologies".  United States.  
        doi:10.1103/PHYSREVD.73.063502.

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@article{osti_20782606,

  title        = {Anisotropic k-essence cosmologies},

  author       = {Chimento, Luis P. and Forte, Monica},

  abstractNote = {We investigate a Bianchi type-I cosmology with k-essence and find the set of models which dissipate the initial anisotropy. There are cosmological models with extended tachyon fields and k-essence having a constant barotropic index. We obtain the conditions leading to a regular bounce of the average geometry and the residual anisotropy on the bounce. For constant potential, we develop purely kinetic k-essence models which are dust dominated in their early stages, dissipate the initial anisotropy, and end in a stable de Sitter accelerated expansion scenario. We show that linear k-field and polynomial kinetic function models evolve asymptotically to Friedmann-Robertson-Walker cosmologies. The linear case is compatible with an asymptotic potential interpolating between V{sub l}{proportional_to}{phi}{sup -{gamma}{sub l}}, in the shear dominated regime, and V{sub l}{proportional_to}{phi}{sup -2} at late time. In the polynomial case, the general solution contains cosmological models with an oscillatory average geometry. For linear k-essence, we find the general solution in the Bianchi type-I cosmology when the k field is driven by an inverse square potential. This model shares the same geometry as a quintessence field driven by an exponential potential.},

  doi          = {10.1103/PHYSREVD.73.063502},

  journal      = {Physical Review. D, Particles Fields},

  number       = 6,

  volume       = 73,

  place        = {United States},

  year         = {Wed Mar 15 00:00:00 EST 2006},

  month        = {Wed Mar 15 00:00:00 EST 2006}

}

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DOI: 10.1103/PHYSREVD.73.063502

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The dilaton-gravity sector of the two-measures field theory (TMT) is explored in detail in the context of spatially flat Friedman-Robertson-Walker (FRW) cosmology. The model possesses scale invariance which is spontaneously broken due to the intrinsic features of the TMT dynamics. The dilaton {phi} dependence of the effective Lagrangian appears only as a result of the spontaneous breakdown of the scale invariance. If no fine-tuning is made, the effective {phi}-Lagrangian p({phi},X) depends quadratically upon the kinetic term X. Hence TMT represents an explicit example of the effective k-essence resulting from first principles without any exotic term in the underlying action intendedmore »« less
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