New HDE models with higher derivatives of the Hubble parameter $H$
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arXiv
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| Format: | Preprint |
| Veröffentlicht: |
2025
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| _version_ | 1866917006525071360 |
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| author | Pasqua, Antonio |
| author_facet | Pasqua, Antonio |
| contents | In this work, we investigate two Dark Energy (DE) models characterized by higher-order derivatives of the Hubble parameter $H$, which generalize previously proposed DE scenarios. Assuming a power-law form of the scale factor $a(t)$ given by $a(t)=b_0t^n$, we derive analytical expressions for the DE energy density, pressure, the Equation of State (EoS) parameter, the deceleration parameter and the evolutionary form of the fractional DE density. Both non-interacting and interacting dark sector frameworks are examined, with the interaction modeled through a coupling term proportional to the Dark Matter (DM) energy density. For specific parameter sets corresponding to power-law indices $n=2$, $n=3$, and $n=4$, we compute the present age of the Universe. The values obtained slightly deviate from the observationally inferred age of $\approx 13.8$ Gyr; moreover, a systematic trend is identified, with larger $n$ leading to higher ages. Furthermore, interacting scenarios consistently predict larger ages compared to their non-interacting counterparts. These results highlight the phenomenological viability and limitations of higher-derivative DE models in describing the cosmic evolution. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_12284 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | New HDE models with higher derivatives of the Hubble parameter $H$ Pasqua, Antonio General Relativity and Quantum Cosmology In this work, we investigate two Dark Energy (DE) models characterized by higher-order derivatives of the Hubble parameter $H$, which generalize previously proposed DE scenarios. Assuming a power-law form of the scale factor $a(t)$ given by $a(t)=b_0t^n$, we derive analytical expressions for the DE energy density, pressure, the Equation of State (EoS) parameter, the deceleration parameter and the evolutionary form of the fractional DE density. Both non-interacting and interacting dark sector frameworks are examined, with the interaction modeled through a coupling term proportional to the Dark Matter (DM) energy density. For specific parameter sets corresponding to power-law indices $n=2$, $n=3$, and $n=4$, we compute the present age of the Universe. The values obtained slightly deviate from the observationally inferred age of $\approx 13.8$ Gyr; moreover, a systematic trend is identified, with larger $n$ leading to higher ages. Furthermore, interacting scenarios consistently predict larger ages compared to their non-interacting counterparts. These results highlight the phenomenological viability and limitations of higher-derivative DE models in describing the cosmic evolution. |
| title | New HDE models with higher derivatives of the Hubble parameter $H$ |
| topic | General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2509.12284 |