Cosmological Bounces Induced by a Fermion Condensate

Giorgi Tukhashvili, Paul J. Steinhardt

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


We show that it is possible for fermion condensation of the Nambu-Jona-Lasinio type to induce a nonsingular bounce that smoothly connects a phase of slow contraction to a phase of expansion. A chiral condensate - a nonzero vacuum expectation value of the spinor bilinear ψ¯ψ - 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.

Original languageEnglish (US)
Article number091001
JournalPhysical review letters
Issue number9
StatePublished - Sep 1 2023

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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