Speaker : P. Taylor

Title : Self-forces and self-torques in arbitrary dimensions : Part I

Abstract : Focusing on static extended bodies in static spacetimes, I will outline a derivation of exact expressions for the scalar and electromagnetic self-forces and self-torques in arbitrary dimensions. The derivation employs a non-perturbative formalism developed by Harte, which I will briefly review. I will discuss two new insights into the renormalization process that accompanies self-interaction effects. First, I will show that there is considerable freedom to use different ``effective fields’’ in the laws of motion---a freedom which can be exploited to optimally simplify specific problems. Different choices give rise to different inertias, gravitational forces, and electromagnetic or scalar self-forces, but there is a sense in which none of these quantities are individually accessible to experiment. Certain combinations are observable, however, and these remain invariant under all possible field redefinitions. Second, I will show explicitly that the renormalizations are given by functional derivatives of a symmetric, quasi-local bi-distribution. Part II of this series, given by A. Harte, will focus on point-particle limits of the static problem, as well as extending these results to dynamical self-forces.