Eur. Phys. J. Plus (2019) 134: 5
https://doi.org/10.1140/epjp/i2019-12382-y

Regular Article

Hubble drift in Palatini theories

¹ Dipartimento di Matematica, University of Torino, via Carlo Alberto 10, 10123, Torino, Italy
² Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Torino, via P. Giuria 1, 10125, Torino, Italy
³ Dipartimento di Fisica, University of Napoli “Federico II”, via Cinthia, I-80126, Napoli, Italy
⁴ Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Napoli, via Cinthia 9, I-80126, Napoli, Italy
⁵ Gran Sasso Science Institute (GSSI), via F. Crispi 7, I-67100, L’Aquila, Italy
⁶ Physics Department, Lancaster University, LA1 4YB, Lancaster, UK
⁷ Dipartimento di Fisica, University of Torino, via P. Giuria 1, 10125, Torino, Italy
⁸ INAF, Osservatorio Astrofisico di Torino, strada osservatorio 20, 10025, Pino Torinese, Italy

^* e-mail: lorenzo.fatibene@unito.it

Received: 29 October 2018
Accepted: 7 November 2018
Published online: 8 January 2019

Abstract

In a Palatini model, we define chronodynamical effects due to the choice of atomic clocks as standard reference clocks and we develop a formalism able to quantitatively separate them from the usual effective dark sources one has in extended theories, namely the ones obtained by recasting field equations for in the form of Einstein equations. We apply the formalism to Hubble drift and briefly discuss the issue about the physical frame. In particular, we shall argue that there is not one single physical frame, for example, in the sense one defines measure in one frame while test particles goes along geodesics in the other frame. That is the physical characteristic of extended gravity. As an example, we discuss how the Jordan frame may be well suited to discuss cosmology, though it fails within the solar system.