Cardassian expansion: a model in which the universe is flat, matter dominated, and accelerating

By K. Freese, Matthew J. Lewis. 2002

393 citations recorded by the source corpus.

Abstract A modification to the Friedmann–Robertson–Walker equation is proposed in which the universe is flat, matter dominated, and accelerating. An additional term, which contains only matter or radiation (no vacuum contribution), becomes the dominant driver of expansion at a late epoch of the universe. During the epoch when the new term dominates, the universe accelerates; we call this period of acceleration the Cardassian era. The universe can be flat and yet consist of only matter and radiation, and still be compatible with observations. The energy density required to close the universe is much smaller than in a standard cosmology, so that matter can be sufficient to provide a flat geometry. The new term required may arise, e.g., as a consequence of our observable universe living as a 3-dimensional brane in a higher-dimensional universe. The Cardassian model survives several observational tests, including the cosmic background radiation, the age of the universe, the cluster baryon fraction, and structure formation.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/3851e39425ba3c378be2bf5ead128ce7fb907028

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Citations in the corpus

Generalized Chaplygin gas as a unified scenario of dark matter/energy: Observational constraints (2004, background): “…also proposed for acceleration of the universe, such as brane world cosmologies (Randall and Sundrum 1999a,b; Alcaniz, Jain and Dev 2002; Deffayet, Dvali and Gabadadze 2002; Jain, Dev and Alcaniz 2002, 2003), and Cardassian expansion model (Freese and Lewis 2002; Zhu and Fujimoto 2002,2003,2004).”
Ghost condensation and a consistent infrared modification of gravity (2003, background): “Such attempts have been made in the past [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11].”
Robust Dark Energy Constraints from Supernovae, Galaxy Clustering, and 3 yr Wilkinson Microwave Anisotropy Probe Observations (2006, background): “…can be explained by an unknown energy component (Freese et al. 1987;Linde 1987; Peebles &Ratra 1988;Wetterich 1988; Frieman et al. 1995; Caldwell et al. 1998), or amodification of general relativity (Sahni&Habib 1998; Parker&Raval 1999; Dvali et al. 2000;Mersini et al. 2001; Freese & Lewis 2002).”
The Cardassian expansion revisited: constraints from updated Hubble parameter measurements and type Ia supernova data (2017, methodology): “The original Cardassian model was introduced by Freese & Lewis (2002) to explain the accelerated expansion of the Universe without DE. Motivated by braneworld theory, this model modifies the Friedmann equation as H2 = 8πGρt 3 +Bρnt , (1) where H = ȧ/a is the Hubble parameter, a is the scale factor…”
Smoothing supernova data to reconstruct the expansion history of the universe (2005, background): “…that it is possible to obtain an accelerating universe through modifying the gravity sector (see, for instance, Deffayet, Dvali & Gabadadze (2002); Freese & Lewis (2002); Sahni & Shtanov (2003); Carroll, Hoffman & Trodden (2003); Capozziello, Carloni & Troisi (2003); Nojiri & Odintsov (2003);…”
A Bird's Eye View of f (R)-Gravity (2009, background): “Interesting examples of this kind are the Cardassian expansion [41] and DGP gravity [42].”
Probing Dark Energy with Baryonic Acoustic Oscillations from Future Large Galaxy Redshift Surveys (2003, background): “…models (Caldwell et al. 1998) and other theories (Zlatev et al. 1999; Bucher & Spergel 1999; Armendariz-Picon et al. 2000; Boyle et al. 2001; Gu & Hwang 2001; Kasuya 2001; Bilic et al. 2002; Deffayet et al. 2002; Freese & Lewis 2002) typically allow equations of state with a redshift dependence.”
Scrutinizing Exotic Cosmological Models Using ESSENCE Supernova Data Combined with Other Cosmological Probes (2007, methodology): “Cardassian Expansion Cardassian models (Freese & Lewis 2002) involve a modification of the Friedmann equation which allows for an acceleration in a flat, matter-dominated universe.”
Imperfect Dark Energy from Kinetic Gravity Braiding (2010, neutral): “[91].”
What Do We Really Know about Cosmic Acceleration? (2005, background): “Given that state of affairs, it is not unreasonable to think more broadly, even entertaining the possibility that the explanationmay well have to do with gravity theory itself (Carroll et al. 2004; Capozziello et al. 2003; Freese & Lewis 2002; Arkani-Hamed et al. 2002; Dvali & Turner 2003).”
Cosmic dynamics in the era of Extremely Large Telescopes (2008, methodology): “The case q = 1 corresponds to the original Cardassian model (Freese & Lewis 2002) which is, however, as far as the Hubble expansion is concerned, exactly equivalent to a flat quintessence model with wX = n − 1.”
Observational probes of cosmic acceleration (2012, background): “Alternatively, one can simply postulate a modified Friedmann equation without specifying a complete gravitational theory, e.g., by replacing ρ on the right hand side of H2 ∝ ρ with a parameterized function H2 ∝ g(ρ) (Freese and Lewis, 2002; Freese, 2005).”