The Rh = ct universe and quintessence

Abstract

Over the last few years the Rh = ct universe has received a lot of attention, particularly when observational evidence seems to favour this over the standard ∧ cold dark matter (∧CDM) universe. Like the ∧CDM, the Rh = ct universe is based on a Friedmann-Robertson-Walker (FRW) cosmology where the total energy density ρ and pressure p of the cosmic fluid contain a dark energy component besides the usual (dark and baryonic) matter and radiation components. However, unlike the∧CDMthis model has the simple equation of state ρ +3p=0, i.e. its total active gravitational mass vanishes, which would therefore exclude a cosmological constant as the source of its dark energy component. Faced with this issue, in this paper, we examine various possible sources for the dark energy component of the Rh = ct universe and show that quintessence which has been used in other various dynamical dark energy models could also be a possible source in this case.