Spinors, Inflation, and Non-Singular Cyclic Cosmologies

C. Armendáriz-Picón, Patrick B. Greene

Research output: Contribution to journalArticlepeer-review

120 Scopus citations


We consider toy cosmological models in which a classical, homogeneous, spinor field provides a dominant or sub-dominant contribution to the energy-momentum tensor of a flat Friedmann-Robertson-Walker universe. We find that, if such a field were to exist, appropriate choices of the spin or self-interaction would generate a rich variety of behaviors, quite different from their widely studied scalar field counterparts. We first discuss solutions that incorporate a stage of cosmic inflation and estimate the primordial spectrum of density perturbations seeded during such a stage. Inflation driven by a spinor field turns out to be unappealing as it leads to a blue spectrum of perturbations and requires considerable fine-tuning of parameters. We next find that, for simple, quartic spinor self-interactions, non-singular cyclic cosmologies exist with reasonable parameter choices. These solutions might eventually be incorporated into a successful past- and future-eternal cosmological model free of singularities. In an Appendix, we discuss the classical treatment of spinors and argue that certain quantum systems might be approximated in terms of such fields.

Original languageEnglish (US)
Pages (from-to)1637-1658
Number of pages22
JournalGeneral Relativity and Gravitation
Issue number9
StatePublished - Sep 2003


  • Cosmology
  • Inflation
  • Spinor field

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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