Axion gravitodynamics, Lense-Thirring effect, and gravitational waves

We investigate physical implications of a gravitational analog axion electrodynamics with parity-violating gravitoelectromagnetic theta term. This is related to the Nieh-Yan topological invariant in gravity torsion, contrast well-studied Chern-Simons term quadratic curvature, coupled via dynamical axionlike scalar field. Axion gravitodynamics corresponding linearized theory. find that potentially observable effects are over 80 orders magnitude stronger than for its counterpart and could be reach detection by experiments near future. For near-Earth scenario, we derive corrections Lense-Thirring effect compare them data from satellite-based (Gravity Probe B). waves, modified dispersion relations, polarization-dependent group phase velocities, neutron star mergers (GW170817) even bounds.