Evolution of perturbations in distinct classes of canonical scalar field models of dark energy - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: Dark energy must cluster in order to be consistent with the equivalenceprinciple. The background evolution can be effectively modelled by either ascalar field or by a barotropic fluid.The fluid model can be used to emulateperturbations in a scalar field model of dark energy, though this model breaksdown at large scales. In this paper we study evolution of dark energyperturbations in canonical scalar field models: the classes of thawing andfreezing models.The dark energy equation of state evolves differently in theseclasses.In freezing models, the equation of state deviates from that of acosmological constant at early times.For thawing models, the dark energyequation of state remains near that of the cosmological constant at early timesand begins to deviate from it only at late times.Since the dark energy equationof state evolves differently in these classes,the dark energy perturbations tooevolve differently. In freezing models, since the equation of state deviatesfrom that of a cosmological constant at early times, there is a significantdifference in evolution of matter perturbations from those in the cosmologicalconstant model.In comparison, matter perturbations in thawing models differfrom the cosmological constant only at late times. This difference provides anadditional handle to distinguish between these classes of models and thisdifference should manifest itself in the ISW effect.



Autor: H. K. Jassal

Fuente: https://arxiv.org/







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