Long-Range Atom-Wall Interactions and Mixing Terms: Metastable Hydrogen

TL;DR

This paper analyzes the long-range interactions between metastable hydrogen atoms and a conducting wall, revealing significant effects of level mixing and retardation on Casimir-Polder forces and decay rates.

Contribution

It provides a detailed quantum electrodynamic calculation of atom-wall interactions including parity-breaking mixing terms and retardation effects for metastable hydrogen.

Findings

Decay width of 2S state roughly doubled at 918 atomic units from wall.

Long-range Casimir-Polder potentials and mixing amplitudes characterized.

Effect magnitude compared to the Sokolov effect.

Abstract

We investigate the interaction of metastable 2S hydrogen atoms with a perfectly conducting wall, including parity-breaking S-P mixing terms (with full account of retardation). The neighboring 2P_1/2 and 2P_3/2 levels are found to have a profound effect on the transition from the short-range, nonrelativistic regime, to the retarded form of the Casimir-Polder interaction. The corresponding P state admixtures to the metastable 2S state are calculated. We find the long-range asymptotics of the retarded Casimir-Polder potentials and mixing amplitudes, for general excited states, including a fully quantum electrodynamic treatment of the dipole-quadrupole mixing term. The decay width of the metastable 2S state is roughly doubled even at a comparatively large distance of 918 atomic units (Bohr radii) from the perfect conductor. The magnitude of the calculated effects is compared to the unexplained Sokolov effect.