Optimal parameterizations for observational constraints on thawing dark energy
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arXiv
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| Hauptverfasser: | , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866916811011784704 |
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| author | Shlivko, David Steinhardt, Paul J. Steinhardt, Charles L. |
| author_facet | Shlivko, David Steinhardt, Paul J. Steinhardt, Charles L. |
| contents | Time-varying dark energy is often modeled in observational analyses through generic parameterizations of its equation of state $w(z)$, which typically use two free parameters $\{w_0, w_a\}$ to span a broad range of behaviors as a function of redshift. However, this broad range of behaviors can only approximately capture the dynamics of any given microphysical theory of dark energy. A complementary approach is to use targeted parameterizations designed to model specific classes of dynamical dark energy with greater precision. Focusing on the class of thawing dark energy, we quantify and compare the precision with which nineteen generic and targeted parameterizations can capture the dynamics of physically motivated thawing quintessence theories. We find that a targeted parameterization derived from a Padé expansion of $w$ is the most reliable of these, producing accurate reconstructions of $w(z)$, the expansion history $H(z)$, and cosmological parameters such as $H_0$ and $Ω_m$ for a broad range of microphysical theories. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_02028 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Optimal parameterizations for observational constraints on thawing dark energy Shlivko, David Steinhardt, Paul J. Steinhardt, Charles L. Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology Time-varying dark energy is often modeled in observational analyses through generic parameterizations of its equation of state $w(z)$, which typically use two free parameters $\{w_0, w_a\}$ to span a broad range of behaviors as a function of redshift. However, this broad range of behaviors can only approximately capture the dynamics of any given microphysical theory of dark energy. A complementary approach is to use targeted parameterizations designed to model specific classes of dynamical dark energy with greater precision. Focusing on the class of thawing dark energy, we quantify and compare the precision with which nineteen generic and targeted parameterizations can capture the dynamics of physically motivated thawing quintessence theories. We find that a targeted parameterization derived from a Padé expansion of $w$ is the most reliable of these, producing accurate reconstructions of $w(z)$, the expansion history $H(z)$, and cosmological parameters such as $H_0$ and $Ω_m$ for a broad range of microphysical theories. |
| title | Optimal parameterizations for observational constraints on thawing dark energy |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2504.02028 |