Torsion, Gravity Induced Chiral Symmetry Breaking and Cosmological Bounce

Abstract

In this paper, we elaborate and extend our proposal arXiv:2307.16098 of the cosmological bouncing model in which a chiral condensate violates the null energy condition and induces a bounce. The condensate formation is caused by the gravitational effects that arise in the effective action when the curvature of space-time is non-zero. As the chiral condensation is a vacuum effect, the symmetries of the FRW space-time are not violated. We explicitly calculate the spinor effective action in the presence of a background gravitational field up to second order in curvature and with derivative corrections and also derive the initial conditions of the condensate. In addition, a new interaction term between the condensate and the scalar field is introduced that might be relevant for producing the adiabatic perturbations during the contraction phase. The curvature/energy density stays far from Planckian values throughout this evolution.

26 pages, 12 figures; v2: references added; typos corrected;

References in corpus (12)

• Towards a Nonsingular Bouncing Cosmology
• Anisotropy in a Nonsingular Bounce
• Supersmoothing through Slow Contraction
• The cosmological BCS mechanism and the Big Bang Singularity
• Robustness of slow contraction to cosmic initial conditions
• Fermi-bounce cosmology and the fermion curvaton mechanism
• Ultralocality and Slow Contraction
• Cosmological Bounces Induced by a Fermion Condensate
• Spinor driven cosmic bounces and their cosmological perturbations
• Sourcing curvature modes with entropy perturbations in non-singular bouncing cosmologies
• The Effects of Multiple Modes and Reduced Symmetry on the Rapidity and Robustness of Slow Contraction
• Nearly scale-invariant curvature modes from entropy perturbations during graceful exit