Cosmic acceleration and geodesic deviation in chameleon scalar field model

Raziyeh Zaregonbadi; Nasim Saba; Mehrdad Farhoudi

doi:10.1140/epjc/s10052-022-10646-w

2022 Impact factor 4.4

Particles and Fields

Open Access

Eur. Phys. J. C (2022) 82: 730
https://doi.org/10.1140/epjc/s10052-022-10646-w

Regular Article - Theoretical Physics

Cosmic acceleration and geodesic deviation in chameleon scalar field model

Raziyeh Zaregonbadi¹^a, Nasim Saba² and Mehrdad Farhoudi²

¹ Department of Physics, Faculty of Science, Malayer University, Malayer, Iran
² Department of Physics, Shahid Beheshti University, Evin, 19839, Tehran, Iran

^a r.zaregonbadi@malayeru.ac.ir, r.zaregonbadi@gmail.com

Received: 6 April 2022
Accepted: 27 July 2022
Published online: 21 August 2022

Abstract

While considering the chameleon scalar field model with the spatially flat FLRW background, we investigate the late-time acceleration phase of the universe, wherein we apply the typical potential usually used in this model. Through setting some constraints on the free parameters of the model, we indicate that the non-minimal coupling between the matter and the scalar field in such a model should be strongly coupled in order to have an accelerated expansion of the universe at the late-time. We also investigate the relative acceleration of the parallel geodesics by obtaining the geodesic deviation equation in the context of chameleon model. Then, through the null deviation vector fields, we obtain the observer area-distance as a measurable quantity to compare the model with other relevant models.

© The Author(s) 2022

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