Volume 129, Number 2, January 2020
|Number of page(s)||6|
|Published online||26 February 2020|
A connection between Rastall-type and f(R, T) gravities
1 Physics Department, Faculty of Sciences, University of Sistan and Baluchestan - Zahedan, Iran
2 Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), University of Maragheh P. O. Box 55136-553, Maragheh, Iran
Received: 24 December 2019
Accepted: 7 February 2020
Recently a Lagrangian formulation for Rastall Gravity (RG) has been proposed in the framework of f(R, T) gravity. In the present work we obtain Lagrangian formulation for the standard Rastall theory assuming the matter content is a perfect fluid with linear Equation of State (EoS). We therefore find a relation between the coupling constant of the Lagrangian, the Rastall gravitational coupling constant and the EoS parameter. We also propose a Lagrangian for the Generalized Rastall Gravity (GRG). In this case the Rastall parameter which is a constant is replaced by a variable one. More exactly, it appears as a function of the Ricci scalar and the trace of the Energy Momentum Tensor (EMT). In both mentioned models, the Lagrangians are constructed by a linear function of R and T.
PACS: 04.20.Fy – Canonical formalism, Lagrangians, and variational principles / 04.50.Kd – Modified theories of gravity
© EPLA, 2020
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