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

14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga