Eur. Phys. J. C (2015) 75: 149
https://doi.org/10.1140/epjc/s10052-015-3371-3

Regular Article - Theoretical Physics

Unified dark fluid in Brans–Dicke theory

¹ Department of Physics, Indira Gandhi Institute of Technology, Sarang, Dhenkanal, 759146, Odisha, India
² Department of Physics, Government College of Engineering, Kalahandi, Bandopala, Risigaon, Bhawanipatna, Kalahandi, 766002, Odisha, India
³ Department of Mathematics, Birla Institute of Technology and Science-Pilani, Hyderabad Campus, Hyderabad, 500078, India

^* e-mail: sktripathy@igitsarang.ac.in
^** e-mail: tripathy_sunil@rediffmail.com

Received: 5 February 2015
Accepted: 24 March 2015
Published online: 9 April 2015

Abstract

Anisotropic dark energy cosmological models are constructed in the frame work of generalised Brans–Dicke theory with a self-interacting potential. A unified dark fluid characterised by a linear equation of state is considered as the source of dark energy. The shear scalar is considered to be proportional to the expansion scalar simulating an anisotropic relationship among the directional expansion rates. The dynamics of the universe in the presence of a unified dark fluid in anisotropic background have been discussed. The presence of an evolving scalar field makes it possible to get an accelerating phase of expansion even for a linear relationship among the directional Hubble rates. It is found that the anisotropy in expansion rates does not affect the scalar field, the self-interacting potential, but it controls the non-evolving part of the Brans–Dicke parameter.