Remarks on Barbero-Immirzi parameter as a field

Abstract

We revisit a propagating torsion gravity theory obtained by introducing a field coupled to the Holst term in the first-order Einstein-Cartan action. The resulting theory has second order field equations, no adjustable coupling constants, and one more propagating degree of freedom as compared to general relativity. When no fermions are present the theory is known to be equivalent to that of a single massless scalar field canonically coupled to gravity. We extend this result to the case with fermions and obtain an effective interaction between the scalar field and the fermionic currents. We also describe a version of the theory with a potential for the scalar field and discuss whether it can be interpreted as the inflaton.

(v1) 5 pages (v2) 6 pages, title changed to avoid misreadings, references and further comments added (v3) 10 pages, treatment of fermions added (v4) published version

References in corpus (7)

• Real Ashtekar Variables for Lorentzian Signature Space-times
• Barbero's Hamiltonian derived from a generalized Hilbert-Palatini action
• Quantum Gravity, Torsion, Parity Violation and all that
• Physical effects of the Immirzi parameter
• The Barbero-Immirzi Parameter as a Scalar Field: K-Inflation from Loop Quantum Gravity?
• Fermions in Ashtekar-Barbero Connections Formalism for Arbitrary Values of the Immirzi Parameter
• Brans-Dicke geometry

Cited by in corpus (27)

• Interaction of the Barbero--Immirzi Field with Matter and Pseudo-Scalar Perturbations
• Peccei--Quinn mechanism in gravity and the nature of the Barbero--Immirzi parameter
• Higgs inflation with the Holst and the Nieh-Yan term
• Big Bounce cosmology for Palatini $R^2$ gravity with a Nieh-Yan term
• Cosmological Bardeen-Cooper-Schrieffer condensate as dark energy
• Coupling Metric-Affine Gravity to a Higgs-Like Scalar Field
• Matter matters in Einstein-Cartan gravity
• Parity Violating Metric-Affine Gravity Theories
• Einstein-Cartan gravity, matter, and scale-invariant generalization
• Scale and Weyl Invariance in Einstein-Cartan Gravity
• Coupling Metric-Affine Gravity to the Standard Model and Dark Matter Fermions
• Big-Bounce cosmology in the presence of Immirzi field
• Torsion in string-inspired cosmologies and the universe dark sector
• Dark matter candidate from torsion
• Super-entropic black hole with Immirzi hair
• Implications of the Holst term in a $f(R)$ theory with torsion
• Torsion at different scales: from materials to the Universe
• Cosmological signature change in Cartan Gravity with dynamical symmetry breaking
• Noncommutative gravity with self-dual variables
• $f(R)$ gravity with Torsion and the Immirzi field: signature for GW detection
• Gauge invariant coupling of fields to torsion: a string inspired model
• Generalized Chern-Simons Modified Gravity in First-Order Formalism
• An introduction to the physics of Cartan gravity
• Barbero-Immirzi Value from Experiment
• Comments On Torsion and MacDowell-Mansouri gravity
• On the Generalized Einstein-Cartan Action with Fermions
• Possibility of Spontaneous Symmetry Breaking in the Nambu-Jona-Lasinio model with torsion