Taming the post-Newtonian expansion: Understanding (and simplifying) the structure of high-order post-Newtonian expansions for compact binaries Seminar

The terms in the post-Newtonian (PN) expansion of many quantities for compact binaries become combinatorially complex at higher orders. However, it is possibly to reduce much of this complexity by appropriate factorizations, etc., in some cases reducing it to the minimal complexity than can be expected. We illustrate these reductions in complexity using the gravitational wave energy flux at infinity from a point particle in a circular orbit around a Schwarzschild black hole, the compact binary observable whose PN expansion is currently known to the highest order. We then illustrate how one can use similar factorizations to aid in obtaining previously unknown terms in the PN expansion of the redshift observable from very high-accuracy numerical self-force results.