Rastall introduced an stress-energy tensor whose divergence is proportional to the gradient of the Ricci scalar. This proposal leads to a change in the form of the field equations of General Relativity, but it preserves the number of degrees of freedom. Rastall’s field equations can be either interpreted as GR with a redefined SET, or it can imply different physical consequences inside the matter sector. We investigate limits under which the Rastall field equations can be directly derived from an action, in particular from two f (R)-gravity extensions: f ( R , Lm ) and f (R, T ). We show that there are similarities between these theories, but the Rastall SET cannot be fully recovered from them, apart from certain particular cases here discussed. It is remarkable that a simple, covariant and invertible redefinition of the SET, as the one proposed by Rastall, is hard to be directly implemented in the action.

On rastall gravity formulation as a $$f(R,\mathcal {L}_m)$$ and a f(R, T) theory

Piattella, Oliver F.
;
2023-01-01

Abstract

Rastall introduced an stress-energy tensor whose divergence is proportional to the gradient of the Ricci scalar. This proposal leads to a change in the form of the field equations of General Relativity, but it preserves the number of degrees of freedom. Rastall’s field equations can be either interpreted as GR with a redefined SET, or it can imply different physical consequences inside the matter sector. We investigate limits under which the Rastall field equations can be directly derived from an action, in particular from two f (R)-gravity extensions: f ( R , Lm ) and f (R, T ). We show that there are similarities between these theories, but the Rastall SET cannot be fully recovered from them, apart from certain particular cases here discussed. It is remarkable that a simple, covariant and invertible redefinition of the SET, as the one proposed by Rastall, is hard to be directly implemented in the action.
2023
2023
https://doi.org/10.1140/epjp/s13360-023-03845-1
Fabris, Júlio C.; Piattella, Oliver F.; Rodrigues, Davi C.
File in questo prodotto:
File Dimensione Formato  
s13360-023-03845-1.pdf

accesso aperto

Descrizione: Articolo in rivista
Tipologia: Versione Editoriale (PDF)
Licenza: Creative commons
Dimensione 399.55 kB
Formato Adobe PDF
399.55 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/2148839
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 10
  • ???jsp.display-item.citation.isi??? 10
social impact