Constraining barrow entropy-based cosmology with power-law inflation

Abstract

We study the inflationary era of the Universe in a modified cosmological scenario based on the gravity-thermodynamics conjecture with Barrow entropy instead of the usual Bekenstein–Hawking one. The former arises from the effort to account for quantum gravitational effects on the horizon surface of black holes and, in a broader sense, of the Universe. First, we extract modified Friedmann equations from the first law of thermodynamics applied to the apparent horizon of a Friedmann–Robertson–Walker Universe. Assuming a power-law behavior for the scalar inflaton field, we then investigate how the inflationary dynamics is affected in Barrow cosmological setup. We find that the inflationary era may phenomenologically consist of the slow-roll phase, while Barrow entropy is incompatible with kinetic inflation. By demanding observational consistency of the scalar spectral index and tensor-to-scalar ratio with recent Planck data, we finally constrain Barrow exponent to $$\Delta \lesssim \mathcal {O}(10^{-4})$$ Δ ≲ O ( 10 - 4 ) , which is the most stringent bound in so-far literature.

Anisotropic power-law inflation for a generalized model of two scalar and two vector fields

“…It should be noted that the type of power-law inflation considered in this paper is different from that investigated in cosmological models including power-law potentials, e.g. see [71,72], in which power-law potentials show up in the context of extended cosmology based on deformed entropy-area laws. However, power-law potential(s) would be relevant to an anisotropic hyperbolic inflation model proposed in [65].…”

Lagrangian Reconstruction of Barrow Holographic Dark Energy in Interacting Tachyon Model

“…In this Section we discuss inflation in BHDE (see also [94]). For reasons that will appear clear below and following [95], here we consider the more general expression for the length scale L −2 = αH 2 + β Ḣ, where α and β are dimensionless constant.…”