Inflation by spin and torsion in Poincare gauge theory of gravity

Abstract

In Poincare gauge theory of gravity, in addition to mass-energy content, spin is also a source for gravitational interactions. Although the effects of spin are negligible at low energies, they can play a crucial role at very early universe when the spin density was very high. In this paper by choosing a suitable Lagrangian for Poincare gauge theory of gravity, and suitable energy-momentum and spin density tensors, we show that the effects of spin and torsion can lead to a inflationary phase without the need for any additional fields. No fine tuning of parameters is required in this setup. We also calculate the scalar spectral index at the end of inflation and show that it agrees with the most recent observational data.

7 pages, 8 figures, Accepted for publication in EPL

References in corpus (7)

• Planck 2015 results. XIII. Cosmological parameters
• Cosmology with torsion: An alternative to cosmic inflation
• Torsion Cosmology and the Accelerating Universe
• Poincare gauge theory of gravity: Friedman cosmology with even and odd parity modes. Analytic part
• Cosmological dynamics with propagating Lorentz connection modes of spin zero
• Regular accelerating Universe without dark energy
• Accelerating Universe with spacetime torsion but without dark matter and dark energy

Cited by in corpus (8)

• Friedmann-like universes with torsion
• Local symmetries and physical degrees of freedom in $f(T)$ gravity: a Dirac Hamiltonian constraint analysis
• Cosmological signatures of torsion and how to distinguish torsion from the dark sector
• Different types of torsion and their effect on the dynamics of fields
• Friedmann cosmology with hyperfluids
• The Role of Torsion in Trans-Planckian Physics
• Light propagation and optical scalars in torsion theories of gravity
• Twisting inflation to sub-Planckian axion decay constants