Cosmological constant from quarks and torsion

TL;DR

This paper proposes a mechanism where torsion-induced fermion interactions in Riemann-Cartan spacetime naturally generate a small, positive cosmological constant consistent with observations, linking quantum field effects to cosmology.

Contribution

It introduces a novel approach connecting fermion condensates and torsion in spacetime to explain the cosmological constant's small positive value.

Findings

Torsion induces an axial-axial four-fermion interaction in Dirac fields.

This interaction acts like a cosmological constant if fermions have a nonzero vacuum expectation value.

The resulting cosmological constant from quark fields is close to the observed value, within a factor of about 8.

Abstract

We present a simple and natural way to derive the observed small, positive cosmological constant from the gravitational interaction of condensing fermions. In the Riemann-Cartan spacetime, torsion gives rise to the axial-axial four-fermion interaction term in the Dirac Lagrangian for spinor fields. We show that this nonlinear term acts like a cosmological constant if these fields have a nonzero vacuum expectation value. For quark fields in QCD, such a torsion-induced cosmological constant is positive and its energy scale is only about 8 times larger than the observed value. Adding leptons to this picture could lower this scale to the observed value.