http://arxiv.org/abs/1901.10959
Models of inflation with antisymmetric tensor studied in the past are plagued with ghost instability even in an unperturbed FRW background. We show that it is possible to avoid ghosts by considering the most general kinetic term for antisymmetric tensor. The kinetic part acquires a new gauge symmetry violating term whose effect on perturbed modes is to prevent the appearance of nondynamical modes, and thus avoid ghosts. For completeness, we also perform a check for gradient instability when this new kinetic term is dominant and find that the perturbations are free of gradient instability.
S. Aashish, A. Padhy and S. Panda
Thu, 31 Jan 19
35/59
Comments: 11 pages