Resumen de Infrared-finite algorithms in QED II. The expansion of the groundstate of an atom interacting with the quantized radiation field

Volker Bach, Jürg Fröhlich, Alessandro Pizzo

• In this paper, we present an explicit and constructive algorithm enabling us to calculate the groundstate and the groundstate energy of a non-relativistic atom minimally coupled to the quantized radiation field up to an error of arbitrary finite order in the fine structure constant. Because of infrared divergences, which invalidate a straightforward Taylor expansion, an iterative construction is employed to remove the infrared cut-off in photon momentum space and to produce a convergent algorithm