Cosmological solutions and growth index of matter perturbations in gravity
Mar 15, 2021
15 pages
Published in:
- Phys.Rev.D 103 (2021) 10, 103521
- Published: May 18, 2021
e-Print:
- 2103.08372 [gr-qc]
DOI:
- 10.1103/PhysRevD.103.103521 (publication)
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Abstract: (APS)
The present work studies one of Einstein’s alternative formulations based on the nonmetricity scalar Q generalized as f(Q) theory. More specifically, we consider the power-law form of f(Q) gravity, i.e., f(Q)=Q+αQn. Here, we analyze the behavior of the cosmological model at the background and perturbation level. Using the dynamical system analysis, at the background level, we find the effective evolution of the model is the same as that of the ΛCDM for |n|<1. Interestingly, the geometric component of the theory solely determined the late-time acceleration of the Universe. We also examine the integrability of the model by employing the method of singularity analysis. In particular, we find the conditions under which field equations pass the Painlevé test and hence possess the Painlevé property. While the equations pass the Painlevé test in the presence of dust for any value of n, the test is valid after the addition of radiation fluid only for n<1. Finally, at the perturbation level, the behavior of matter growth index signifies a deviation of the model from the ΛCDM even for |n|<1.Note:
- 17 pages and 7 figs
- Cosmology
- matter: perturbation
- model: integrability
- radiation: fluid
- expansion: acceleration
- cosmological model: dust
- gravitation: model
- background
- field equations
- singularity
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Figures(7)
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