Something New Under (and in) the Sun? Effective field theories for point sources and the Hydrogen atom Speaker(s): Cliff Burgess
Abstract:
This talk applies effective field theory to the backreaction of sources with finite size but infinite mass. The main tool for calculating backreaction is a general relation between a source's effective action and the boundary conditions of `bulk’ fields in the nearsource limit. As applied to the Maxwell (or Einstein) fields for point sources this boundary condition reproduces standard Gauss’ Law expressions, but the same arguments imply sourcedependent boundary conditions for the Schrodinger (or Dirac) field of an orbiting particle. As applied to the quantum mechanics of a particle interacting with a source through an inversesquare potential EFTs remove the guesswork from the (wellknown) ambiguities in the determination of boundary conditions at the origin, and provides a simple interpretation of the classical renormalization effects that are known to arise in this case. EFT arguments show why the RG evolution associated with this classical renormalization is likely universal for a great many types of point sources. The EFT boundary conditions also modify how finitesize effects alter boundstate orbits in the Coulomb problem, and in particular give them a nonstandard dependence on the mass of the orbiting particle. It is argued that this might provide a solution to the `protonradius puzzle’, in which experiments seem to indicate a different proton radius depending on whether or not it is measured using electrons or muons. Date: 10/01/2017  1:00 pm
Series: Particle Physics
