Cosmological Bounces Induced by a Fermion Condensate

Abstract

We show that it is possible for fermion condensation of the Nambu-Jona-Lasinio type to induce a non-singular bounce that smoothly connects a phase of slow contraction to a phase of expansion. A chiral condensate -- a non-zero vacuum expectation value of the spinor bilinear $⟨\bar{\Psi }\Psi ⟩$ -- can form spontaneously after a slow contraction phase smooths and flattens the universe and the Ricci-curvature exceeds a critical value. In this approach, a high density of spin-aligned free fermions is not required, which avoids the problem of generating a large anisotropy and initiating chaotic mixmaster behavior during the bounce phase.

5 pages, 4 figures; to appear in PRL

References in corpus (3)

• Supersmoothing through Slow Contraction
• The cosmological BCS mechanism and the Big Bang Singularity
• Robustness of slow contraction to cosmic initial conditions

Cited by in corpus (1)

• Tunnelling-induced cosmic bounce in the presence of anisotropies