Quintessence dissipative superattractor cosmology

Abstract

We investigate the simplest quintessence dissipative dark matter attractor cosmology characterized by a constant quintessence baryotropic index and a power-law expansion. We show that a class of accelerated coincidence-solving attractor solutions converge into this asymptotic behavior. Despite of its simplicity, such "superattractor" regime provides a model of the recent universe that also exhibits an excellent fit to supernovae luminosity observations and no age conflict. Our best fit gives α = 1.71 ± 0.29 for the power-law exponent. We calculate for this regime the evolution of density and entropy fluctuations. PACS number(s): 98.80.Hw, 04.20Jb 1

Transition redshift: new kinematic constraints from supernovae

“…Among a number of possibilities to describe this dark energy component, the simplest and most theoretically appealing way is by means of a positive cosmological constant Λ. Other possible candidates are: a vacuum decaying energy density, or a time varying Λ‐term (Ozer & Taha 1987; Freese et al 1987; Carvalho, Lima & Waga 1992; Lima & Maia 1993; Maia & Lima 1999, 2002; Lima 1996; Overduin & Cooperstock 1998; Cunha, Lima & Alcaniz 2002a; Cunha, Lima & Pires 2002b; Cunha & Santos 2004; Alcaniz & Lima 2005; Carneiro & Lima 2005; Fabris, Shapiro & Sola 2007), a time varying relic scalar field slowly rolling down its potential (Ratra & Peebles 1988; Frieman et al 1995; Caldwell, Dave & Steinhardt 1998; Saini et al 2000; Caldwell 2000; Carvalho et al 2006), the so‐called ‘X‐matter’, an extra component simply characterized by an equation of state p x =ωρ x (Chiba, Sugiyama & Nakamura 1997; Turner & White 1997; Alcaniz & Lima 1999, 2001; Kujat et al 2002; Alcaniz, Lima & Cunha 2003), and the Chaplygin gas whose equation of state is given by p =− A /ρ where A is a positive constant (Kamenshchik, Moschella & Pasquier 2001; Bento, Bertolami & Sen 2002; Dev, Jain & Alcaniz 2003; Bento, Bertolami & Sen 2003; Cunha, Alcaniz & Lima 2004; Lima, Cunha & Alcaniz 2006a,b), among others (Lima & Alcaniz 1999; Chimento, Jakubi & Zuccala 2001; Freese & Lewis 2002; Pavon & Zimdahl 2005). For scalar field and XCDM scenarios, the ω parameter may be a function of the redshift (see, for example, Efstathiou 1999; Cunha, Marassi & Santos 2007), or still, as has been recently discussed, it may violate the dominant energy condition and assume values <−1 when the extra component is called phantom energy (Caldwell 2002; Lima, Cunha & Alcaniz 2003; Perivolaropoulos 2005; Gonzalez‐Diaz & Siguenza 2004; Lima & Alcaniz 2004; Santos & Lima 2008).…”

Interacting quintessence solution to the coincidence problem

“…Formally it looks as if we were dealing with a noninteracting dissipative matter fluid (cf. [12,14]). …”

“…We will assume that all the quantities in Γ ≡ γ (e) m − γ (e) φ can be expressed in terms of the ratio r. Then, according to Eq. (14), stationarity requires Γ(r s ) = 0. Let us look at the stability of these constant solutions.…”

Dark energy, dissipation, and the coincidence problem

“…This "superattractor" regime provides a model of the recent universe that also exhibits an excellent fit to the high redshift supernovae data luminosity and no age conflict [8].…”