Non-Abelian Born-Infeld cosmology

Abstract

We investigate homogeneous and isotropic cosmological solutions supported by the SU(2) gauge field governed by the Born-Infeld Lagrangian. In the framework of the Friedmann-Robertson-Walker cosmology with or without the cosmological constant $\ensuremath{\lambda},$ we derive dynamical systems that give a rather complete description of the space of solutions. For $\ensuremath{\lambda}=0$ the effective equation of state $\ensuremath{\varepsilon}(p)$ is shown to interpolate between $p=\ensuremath{-}\ensuremath{\varepsilon}/3$ in the regime of the strong field and $p=\ensuremath{\varepsilon}/3$ for the weak field. Correspondingly, the universe starts with zero acceleration and gradually enters the decelerating regime, asymptotically approaching the Tolman solution.