Yang-Mills condensate dark energy coupled with matter and radiation


The coincidence problem is studied for the dark energy model of effective Yang-Mills condensate in a flat expanding universe during the matter-dominated stage. The YMC energy ρy(t)\rho_y(t) is taken to represent the dark energy, which is coupled either with the matter, or with both the matter and the radiation components. The effective YM Lagrangian is completely determined by quantum field theory up to 1-loop order. It is found that under very generic initial conditions and for a variety of forms of coupling, the existence of the scaling solution during the early stages and the subsequent exit from the scaling regime are inevitable. The transition to the accelerating stage always occurs around a redshift z(0.30.5)z\simeq (0.3\sim 0.5). Moreover, when the Yang-Mills condensate transfers energy into matter or into both matter and radiation, the equation of state wyw_y of the Yang-Mills condensate can cross over -1 around z2z\sim 2, and takes on a current value 1.1\simeq -1.1. This is consistent with the recent preliminary observations on supernovae Ia. Therefore, the coincidence problem can be naturally solved in the effective YMC dark energy models.Comment: 24 pages, 18 figure

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    Last time updated on 04/12/2019