Eur. Phys. J. C (2009) 60: 135-140
https://doi.org/10.1140/epjc/s10052-008-0858-1

Regular Article - Theoretical Physics

Holographic dark energy in Brans–Dicke theory

Institute of Theoretical Physics, School of Physics & Optoelectronic Technology, Dalian University of Technology, Dalian, 116024, People’s Republic of China

^* e-mail: lxxu@dlut.edu.cn

Received: 21 August 2008
Revised: 15 December 2008
Published online: 13 January 2009

Abstract

In this paper, the holographic dark-energy model is considered in Brans–Dicke theory, where the holographic dark-energy density ρ _Λ =3c ² M _pl ² L ⁻² is replaced by ρ _h=3c ² Φ(t)L ⁻². Here is the time-variable Newton constant. With this replacement, it is found that no accelerated expansion for the universe will be achieved when the Hubble horizon is taken to play the role of an IR cut-off. When the event horizon is adopted as the IR cut-off, accelerated expansion for the universe is obtained. In this case, the equation of state of holographic dark energy, w _h, takes the modified form . In the limit α→0, the ‘standard’ holographic dark energy is recovered. In the holographic dark-energy dominated epoch, power-law and de Sitter time-space solutions are obtained.