Effective Field Theory in Classical Physics



Effective Field Theory (EFT) was developed starting in the 1970’s by high-energy particle physicists as a systematic way to calculate quantities in quantum field theory that could be measured in particle accelerator experiments. EFT has provided deep physical insights into the nature of elementary particles (and other phenomena) and has since become a standard tool for the high-energy physicist and, more generally, for the quantum field theorist.

More than a theory, EFT is a paradigm or a way of approaching certain types of problems. This suggests that EFT can be applied also to classical physics problems. To my knowledge, the first people to fully realize and apply this observation were Walter Goldberger (Yale) and Ira Rothstein (Carnegie Mellon Univ) who made an EFT to describe the conservative dynamics of a pair of orbiting black holes and/or neutron stars (which is called a “compact binary”) when they orbit each other slowly relative to the speed of light.

EFT practitioners have quickly made strides to reproduce results in gravitational wave physics that were derived using traditional approaches over the course of decades. Soon after, wholly new results followed that will be useful for observing gravitational waves with detectors like LIGO.

I am currently writing a Topical Review for the journal Classical & Quantum Gravity that should be published in Summer 2014. The title, at least for now, is “Effective Field Theory and Gravity”. The article will contain a somewhat pedagogical overview of EFT for classical physics problems in gravity, will review some of the major results with gravitational wave applications, and will present some directions in astrophysics and cosmology to which I think EFT might be useful.

My contributions to EFT in classical physics are summarized below (in some kind of order) from a select set of papers I’ve published.

Finite size corrections to radiation reaction in classical electrodynamics

(Description in progress)

Gravitational self-force for compact binaries with small mass ratios

(Description in progress)

Scalar self-force effects at high orders in the mass ratio

(Description in progress)

Gravitational self-force in the ultra-relativistic regime

(Description in progress)