On the stability of self-accelerating Universe in modified gravity with dynamical torsion

Abstract

We consider the model of modified gravity with dynamical torsion. This model was previously found to have promising stability properties about various backgrounds. Here we study the stability of linear perturbations about the self-accelerating solution. We apply the $(3+1)$-decomposition and consider the scalar sector of perturbations. We find that the number of degrees of freedom is equal to 2, which is the same as in Minkowski background. However, there is at least one instability in the scalar sector, if the value of background torsion is large enough. This does not rule out the possibility of stable self-acceleration with torsion of the order of the effective cosmological constant.

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Cited by in corpus (7)

• Infrared modified gravity with propagating torsion: instability of torsionfull de Sitter-like solutions
• Different types of torsion and their effect on the dynamics of fields
• Spherically symmetric solutions in torsion bigravity
• Black holes in torsion bigravity
• Stability of self-accelerating Universe in modified gravity with dynamical torsion: the case of small background torsion
• Dynamical torsion gravity backgrounds
• Spherically symmetric perturbations of a Schwarzschild black hole in torsion bigravity