Leading order finite size effects with spins for inspiralling compact binaries

Understand

The leading order finite size effects due to spin, namely that of the cubic and quartic in spin interactions, are derived for the first time for generic compact binaries via the effective field theory for gravitating spinning objects.

• These corrections enter at the third and a half and fourth post-Newtonian orders, respectively, for rapidly rotating compact objects.
• Hence, we complete the leading order finite size effects with spin up to the fourth post-Newtonian accuracy.
• We arrive at this by augmenting the point particle effective action with new higher dimensional nonminimal coupling worldline operators, involving higher-order derivatives of the gravitational field, and introducing new Wilson coefficients, corresponding to constants, which describe the octupole and hexadecapole deformations of the object due to spin.