The Essence of Quintessence and the Cost of Compression

By Bruce A. Bassett, Pier Stefano Corasaniti, Martin Kunz. 2004

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Standard two-parameter compressions of the infinite dimensional dark energy model space show crippling limitations even with current Type Ia supernova (SN Ia) data unless strong priors are imposed. First, they cannot cope with rapid evolution—our best fit to the latest SN Ia data shows late and very rapid evolution to w0 = -2.85. However, all of the standard parameterizations (incorrectly) claim that this best fit is ruled out at more than 2 σ primarily because they track it well only at very low redshift, z ≤ 0.2. Furthermore, they incorrectly rule out the observationally compatible region w ≪ -1 for z > 1. Second, the parameterizations give wildly different estimates for the redshift of acceleration, which vary from zacc = 0.14 to zacc = 0.59. Although these failings are largely cured by including higher order terms (≥3 parameters), this results in new degeneracies and opens up large regions of previously ruled out parameter space. All of this casts serious doubt on the usefulness of the standard two-parameter compressions in the coming era of high-precision dark energy cosmology and emphasizes the need for decorrelated compressions with at least three parameters.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/fed7ead27c8cb6797c887e4a6094a3109af1128a

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Citations in the corpus

Scrutinizing Exotic Cosmological Models Using ESSENCE Supernova Data Combined with Other Cosmological Probes (2007, result): “Giving an analytic form to the time evolution of w can act like a strong prior and may give misleading results (see Bassett et al. 2004; Riess et al. 2007, for further discussion).”
MultiNest: an efficient and robust Bayesian inference tool for cosmology and particle physics (2008, methodology): “…1996), which is extremely computationally intensive but has been used successfully in astronomical applications (see e.g. Hobson & McLachlan 2003; Marshall et al. 2003; Slosar A. et al. 2003; Niarchou et al. 2004; Bassett et al. 2004; Trotta 2007; Beltrán et al. 2005; Bridges et al. 2006).”
Detection of the Baryon Acoustic Peak in the Large-Scale Correlation Function of SDSS Luminous Red Galaxies (2005, background): “While treating w as a constant for all times may be a poor model (Maor et al. 2004; Bassett et al. 2004), it is a reasonable approximation for so short an interval.”
FIVE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE OBSERVATIONS: COSMOLOGICAL INTERPRETATION (2008, unknown): “The “Kink model” explored in Bassett et al. (2002, 2004); Corasaniti et al. (2004) also extrapolates a constant equation of state at early times to a different constant equation of state at late times.”