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arXiv · 2608.19392

Action-level characterization of gravitational-wave propagation in dynamical Barbero--Immirzi gravity

Zhi-Fu Gao·Hui Wang·Luiz Carlos Garcia de Andrade·Na Wang·Guo-Qiang Jin·Zhou-Jian Cao
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Abstract

We investigate which operators in first-order dynamical Barbero--Immirzi (BI) gravity control cosmological tensor propagation at the action level. Within a bosonic, two-derivative, curvature-linear Einstein--Cartan class, eliminating the algebraic Lorentz connection reveals a separation between the scalar sector and the tensor kinetic normalization. In particular, the Holst-to-Palatini ratio determines the scalar kinetic structure, whereas the transverse-traceless tensor mode is normalized by the parity-even Hilbert--Palatini coefficient. As a consequence, a minimal dynamical Holst sector with fixed parity-even normalization remains exactly on the general-relativistic tensor-propagation surface and does not generate anomalous gravitational-wave friction. We then construct a regular nonminimal parity-even realization in which the tensor normalization evolves cosmologically, derive the corresponding standard-siren observable, and apply current GWTC-3, GWTC-4.0, and GWTC-5.0 information as an observational test of this action-level tensor sector. The resulting constraints should therefore be interpreted as limits on the evolution of the tensor kinetic normalization rather than direct constraints on minimal BI torsion dynamics.

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Zhi-Fu Gao, Hui Wang, Luiz Carlos Garcia de Andrade, Na Wang, Guo-Qiang Jin, Zhou-Jian Cao. 2026-09-19. Action-level characterization of gravitational-wave propagation in dynamical Barbero--Immirzi gravity. https://arxiv.org/abs/2608.19392

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