Cosmology with hybrid expansion law: scalar field reconstruction of cosmic history and observational constraints

TL;DR

This paper introduces a hybrid expansion law model for cosmic history, combining power-law and exponential functions, and reconstructs scalar field potentials to match observational data on universe acceleration.

Contribution

It proposes a novel hybrid expansion law framework and reconstructs scalar field potentials, connecting theoretical models with observational constraints.

Findings

Hybrid expansion law models cosmic transition from deceleration to acceleration.

Scalar field potentials can reproduce the hybrid expansion law.

Model aligns with late-time acceleration and early universe nucleosynthesis constraints.

Abstract

In this paper, we consider a simple form of expansion history of Universe referred to as the hybrid expansion law - a product of power-law and exponential type of functions. The ansatz by construction mimics the power-law and de Sitter cosmologies as special cases but also provides an elegant description of the transition from deceleration to cosmic acceleration. We point out the Brans-Dicke realization of the cosmic history under consideration. We construct potentials for quintessence, phantom and tachyon fields, which can give rise to the hybrid expansion law in general relativity. We investigate observational constraints on the model with hybrid expansion law applied to late time acceleration as well as to early universe a la nucleosynthesis.