2025/03/04 by Wilson-Gerow, Jordan · 5 citations
#FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.2503.02867
We study the conservative dynamics of spinless compact objects in a general effective theory of gravity which includes a metric and an arbitrary number of scalar fields, through O(G3). Departures from Einstein gravity, which preserve general coordinate and local Lorentz invariance, are characterized by higher-derivative terms in a Lagrangian whose coupling constants scale as powers of a ``new-physics'' length scale, ℓ. For a purely metric theory we compute the contributions from the the leading and subleading higher-curvature curvature corrections. In four dimensions these are cubic and quartic curvature terms, i.e. orders ℓ4 and ℓ6. We also study a general multi-scalar-tensor theory of gravity to order ℓ4, which includes both Einstein-dilaton-Gauss-Bonnet (EdGB) and dynamical Chern-Simons (dCS) higher-order couplings. Specifically, we compute the radial action in a post-Minkowskian approximation for scattering orbits, to two-loop order. The result encodes the fully relativistic dynamics of the compact objects, and serves as a generating function for gauge-invariant orbital observables for both bound and unbound binary systems. Where overlapping post-Newtonian results are available, we've verified agreement.