Baryon asymmetry from Barrow entropy: theoretical predictions and observational constraints

Giuseppe Gaetano Luciano; Emmanuel N. Saridakis

doi:10.1140/epjc/s10052-022-10530-7

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2022) 82: 558
https://doi.org/10.1140/epjc/s10052-022-10530-7

Regular Article - Theoretical Physics

Baryon asymmetry from Barrow entropy: theoretical predictions and observational constraints

Giuseppe Gaetano Luciano¹^,2^a and Emmanuel N. Saridakis³^,4^,5

¹ Dipartimento di Fisica, Università di Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano, SA, Italy
² INFN, Sezione di Napoli, Gruppo Collegato di Salerno, Via Giovanni Paolo II, 132, 84084, Fisciano, SA, Italy
³ National Observatory of Athens, Lofos Nymfon, 11852, Athens, Greece
⁴ Department of Astronomy, School of Physical Sciences, University of Science and Technology of China, 230026, Hefei, Anhui, China
⁵ CAS Key Laboratory for Research in Galaxies and Cosmology, University of Science and Technology of China, 230026, Hefei, Anhui, China

^a gluciano@sa.infn.it

Received: 21 May 2022
Accepted: 16 June 2022
Published online: 24 June 2022

Abstract

We investigate the generation of baryon asymmetry from the corrections brought about in the Friedman equations due to Barrow entropy. In particular, by applying the gravity-thermodynamics conjecture one obtains extra terms in the Friedmann equations that change the Hubble function evolution during the radiation-dominated epoch. Hence, even in the case of standard coupling between the Ricci scalar and baryon current they can lead to a non-zero baryon asymmetry. In order to match observations we find that the Barrow exponent should lie in the interval $0.005 ≲ Δ ≲ 0.008$ $0.005\lesssim \Delta \lesssim 0.008$ , which corresponds to a slight deviation from the standard Bekenstein–Hawking entropy. The upper bound is tighter than the one of other observational constraints, however the interesting feature is that in the present analysis we obtain a non-zero lower bound. Nevertheless this lower bound would disappear if the baryon asymmetry in Barrow-modified cosmology is generated by other mechanisms, not related to the Barrow modification.

© The Author(s) 2022

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