Resumo

BAUTISTA, Carlos A.; NAVARRO, Andrés A.  e  RODRIGUEZ, Yeinzon. Vector galileons with an SU(2) symmetry as the generators of the primordial inflation and late accelerated expansion periods. Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2020, vol.44, n.170, pp.121-132.  Epub 14-Jun-2021. ISSN 0370-3908.  https://doi.org/10.18257/raccefyn.1040.

We show in this work that the generalization of the Proca action could give account of the known periods of accelerated expansion of the universe. The vector fields associated with this action, called vector Galileons, with a SU(2) symmetry and in a cosmic triad configuration, allow us to characterize an isotropic and homogeneous universe, satisfying in turn a necessary condition for the absence of the Ostrogradski instability. On the other hand, the aforementioned generalization allows us to define two artificial fluids: the Yang-Mills fluid which corresponds to a kinetic term with positive energy density, and the vector Galileon fluid with negative energy density, offering a new scenario for the description of the accelerated expansion of the universe. In this work we study the cosmological consequences of one of the pieces of the generalized Proca action built from the Sa µv tensor, which is the symmetric version of the gauge field strength tensor Faµv.The primordial inflation is identified with a couple of saddle points of the obtained dynamical system for this model; unfortunately the length of this period is highly sensitive to the initial conditions. On the other hand, the late accelerated expansion epoch could be successfully reproduced thanks to an interesting self-fine-tuning mechanism of the dynamical system variables.

Palavras-chave : Inflation; Dark Energy; Vector Galileons.

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