Geometric perfect fluids from Extended Gravity

¹ Dipartimento di Fisica “E. Pancini”, Università “Federico II” di Napoli, and INFN Sezione di Napoli Compl. Univ. Monte S. Angelo Ed. G, Via Cinthia, I-80126 Napoli, Italy
² Scuola Superiore Meridionale - Largo S. Marcellino 10, I-80138 Napoli, Italy
³ Laboratory for Theoretical Cosmology, International Center of Gravity and Cosmos, Tomsk State University of Control Systems and Radioelectronics (TUSUR) - 634050 Tomsk Russia,
⁴ Physics Department “Aldo Pontremoli”, Università degli Studi di Milano and INFN Sezione di Milano Via Celoria 16, I-20133 Milano, Italy

^(a) capozziello@na.infn.it (corresponding author)

Received: 19 January 2022
Accepted: 7 February 2022

Abstract

A main issue in cosmology and astrophysics is whether the dark sector phenomenology originates from particle physics, then requiring the detection of new fundamental components, or it can be addressed by modifying General Relativity. Extended Theories of Gravity are possible candidates aimed at framing dark energy and dark matter in a comprehensive geometric view. Considering the concept of perfect scalars, we show that the field equations of such theories naturally contain perfect fluid terms. Specific examples are developed for the Friedman-Lemaître-Roberson-Walker metric.