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VOL. 11, ISSUE 1 (2026)
Bianchi Type-V dark energy cosmological model with a nonminimally coupled scalar field in general relativity
Authors
Dr. R K Dubey, Anoop Kumar Pandey
Abstract
This investigation examines the cosmological
dynamics of a spatially homogeneous, anisotropic Bianchi Type-V (BV) universe.
The accelerating expansion observed at late times is attributed to dark energy
(DE) modeled by a real scalar field (𝜙) non-minimally
coupled to the Ricci scalar (𝑅) within the framework of General Relativity (GR). The non-minimal
coupling (NMC) is introduced via the Jordan Frame action, 𝑆 ∝ 𝐹(𝜙)𝑅, where 𝐹(𝜙) = 𝑀 + 𝜉𝜙.
The methodology involves deriving the coupled modified Einstein Field Equations
(EFE) and the Klein-Gordon (KG) equation for the BV metric.[1] To
facilitate analytical solutions and ensure compatibility with current
observations, a kinematic constraint is applied: the shear scalar (𝜎) is assumed
proportional to the expansion scalar (𝜃), which dictates
rapid late-time isotropization.[2] Exact solutions are obtained
using a combined exponential and power-law ansatz for the average scale factor,
𝑎(𝑡) = (𝑡 exp(𝜆𝑡)) /, which naturally describes a transition from an early
decelerated phase to the current accelerated phase.[4] Key results
demonstrate that the non-minimal coupling constant (𝜉) plays a critical
role in determining the effective Equation of State parameter (𝑤 ), allowing for
dynamic evolution and potentially facilitating transient phantom crossing (𝑤 < −1), a
feature supported by certain recent observational constraints.[6]
Furthermore, the model successfully exhibits efficient shear dilution, ensuring
that the Universe achieves the observed low levels of anisotropy today. It is
concluded that the NMC Bianchi V model offers a theoretically rich, dynamical
alternative to the isotropic ΛCDM model, addressing both early-time anisotropy
and observationally relevant late-time acceleration, although strict
constraints on the local effects of 𝜉 remain a critical
challenge.[8]
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Pages:109-114
How to cite this article:
Dr. R K Dubey, Anoop Kumar Pandey "Bianchi Type-V dark energy cosmological model with a nonminimally coupled scalar field in general relativity". International Journal of Advanced Research and Development, Vol 11, Issue 1, 2026, Pages 109-114
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