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arXiv · 2307.16098

Cosmological Bounces Induced by a Fermion Condensate

Giorgi Tukhashvili·Paul J. Steinhardt
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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 $\langle \bar{\Psi}\Psi \rangle$ -- 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.

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BibTeXRIS

Giorgi Tukhashvili, Paul J. Steinhardt. 2023-07-30. Cosmological Bounces Induced by a Fermion Condensate. https://doi.org/10.1103/physrevlett.131.091001

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