Ghost instability in the teleparallel gravity model with parity violations

Abstract

In this paper we consider the parity violating gravity model within the framework of teleparallel gravity. The parity violations are caused by the couplings of a scalar field to the scalar invariants which are parity-odd and quadratic in the torsion tensor. Totally there are two such type independent invariants, and one of them is the Nieh-Yan density. Through investigations on the cosmological perturbations of this model, we find that in general it suffers from the difficulties of ghost instability in the scalar and vector perturbations. But in the special case only the coupling to the Nieh-Yan density exists, this model is ghost free and reduces to the Nieh-Yan modified Teleparallel Gravity model. We also analyze the severity of the ghost instability by studying the perturbations around the Minkowski background.

11 pages, 0 figure, teleparallel gravity, parity violation

References in corpus (4)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Big-bounce and future time singularity resolution in Bianchi I: the projective invariant Nieh-Yan case
• Teleparallel axions and cosmology
• Parametrized post-Newtonian limit of the Nieh-Yan modified teleparallel gravity

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• Irregular universe in the Nieh-Yan modified teleparallel gravity
• Polarized gravitational waves in the parity violating scalar-nonmetricity theory
• Scalar induced gravitational waves in symmetric teleparallel gravity with a parity-violating term
• The Gauss-Bonnet topological scalar in the Geometric Trinity of Gravity
• Parity-violating primordial gravitational waves from null energy condition violation
• Chiral Gravitational Wave Background from Audible Axion via Nieh-Yan Term
• Circularly polarized gravitational waves from parity-violating scalar-tensor theory
• Bridging inflation and reheating: chiral gravitational waves from aHz to GHz
• Generalized Chern-Pontryagin models
• Degrees of freedom of a quadratic scalar-nonmetricity theory