Generalized ghost dark energy in Brans-Dicke theory

It was argued that the vacuum energy of the Veneziano ghost field of QCD, in a time-dependent background, can be written in the general form, H + O(H²), where H is the Hubble parameter. Based on this, a phenomenological dark energy model whose energy density is of the form ρ = αH + βH² was recently proposed to explain the dark energy dominated universe. In this paper, we investigate this generalized ghost dark energy model in the setup of Brans-Dicke cosmology. We study the cosmological implications of this model. In particular, we obtain the equation of state, the deceleration parameters, and a differential equation governing the evolution of this dark energy model. It is shown that the equation of state parameter of the generalized ghost dark energy can cross the phantom line (w_D = -1) in some range of the parameters spaces. (author)