Show simple item record Sur, Sourav Das, Saurya 2015-12-15T19:20:49Z 2015-12-15T19:20:49Z 2015-12-15
dc.identifier.citation Sur, S., & Das, S. (2009). Multiple kinetic k-essence, phantom barrier crossing and stability. Journal of Cosmology and Astroparticle Physics, 2009(01), 007.
dc.description Sherpa Romeo green journal. “This is an author-created, un-copyedited version of an article accepted for publication/published in Journal of Cosmology and Astroparticle Physics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it.” en_US
dc.description.abstract We investigate models of dark energy with purely kinetic multiple k- essence sources that allow for the crossing of the phantom divide line, without violating the conditions of stability. It is known that with more than one kinetic k-field one can possibly construct dark energy models whose equation of state parameter wX crosses −1 (the phantom barrier) at recent red-shifts, as indicated by the Supernova Ia and other observational probes. However, such models may suffer from cosmological instabilities, as the effective speed of propagation cX of the dark energy density perturbations may become imaginary while the wX = −1 barrier is crossed. Working out the expression for cX we show that multiple kinetic k-essence fields do indeed lead to a wX = −1 crossing dark energy model, satisfying the stability criterion c2 X ≥ 0 as well as the condition cX ≤ 1 (in natural units), which implies that the dark energy is not super-luminal. As a specific example, we construct a phantom barrier crossing model involving three k-fields for which cX is a constant, lying between 0 and 1. The model fits well with the latest Supernova Ia Union data, and the best fit shows that wX crosses −1 at red-shift z ∼ 0.2, whereas the dark energy density nearly tracks the matter density at higher red-shifts. en_US
dc.language.iso en_CA en_US
dc.subject Dark energy en_US
dc.subject Kinetic k-essence en_US
dc.subject Phantom barrier en_US
dc.subject Stability en_US
dc.subject Dark energy theory
dc.subject Supernova type Ia
dc.subject Cosmological perturbation theory
dc.title Multiple kinetic k-essence, phantom barrier crossing and stability en_US
dc.type Article en_US
dc.publisher.faculty Arts and Science en_US
dc.publisher.department Department of Physics en_US
dc.description.peer-review No
dc.publisher.institution University of Lethbridge en_US

Files in this item

This item appears in the following Collection(s)

Show simple item record