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arXiv · 2407.14378

New simple and accurate quintessence approximations

Artur Alho·Claes Uggla
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Abstract

We derive new approximations for quintessence solutions that are simpler and an order of magnitude more accurate than anything available in the literature, which from an observational perspective \emph{makes numerical calculations superfluous}. For example, our tracking quintessence approximation yields $\sim 0.1\%$ maximum relative errors of $H(z)/H_0$ and $\Omega_\mathrm{m}(z)$ for the observationally viable inverse power law scalar field potentials, and similarly for viable thawing quintessence models using two slow-roll parameters. The approximations are trivially computed from the scalar field potential and as an application we give \emph{analytic} expressions for the CPL parameters calculated from an arbitrary scalar field potential for thawing and tracking quintessence models.

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Artur Alho, Claes Uggla. 2024-07-19. New simple and accurate quintessence approximations. https://doi.org/10.1103/physrevd.111.083549

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