J. Vines, AEI

Title: “Elastic scattering of spinning black holes at one-loop order: progress and questions”

Abstract: a growing research program seeks to obtain new results concerning the classical gravitational dynamics of black holes from advanced techniques for computing scattering amplitudes in quantum field theories.  At least perturbatively, a non-spinning black hole is well described by an effective point-particle worldline action coupled with the Hilbert action, and it is well established that this corresponds to a classical limit of a massive scalar field/particle minimally coupled to the graviton.  Spinning black holes seem to similarly correspond to higher-spin (indeed infinite-spin) massive fields/particles.  I will discuss the nature of this observed but unexplained correspondence and the evidence for it, pointing out the current frontiers of understanding.

Certain “minimally coupled” amplitudes for higher-spin massive particles exchanging gravitons can be matched to results from classical spinning-black-hole effective actions (matched to the Kerr solution), finding remarkable agreement for arbitrary (infinite) spins at tree level and for lower spins at one-loop order.  However, at current understanding, ambiguities arise on both sides of the correspondence for sufficiently high spins at one-loop order, in the form of yet undetermined Wilson coefficients.  The exploration of these and related issues presents rich opportunities for cross-pollination of ideas and techniques between the fields of amplitudes and classical gravity.