Resummation of the divergent perturbation series for a hydrogen atom in an electric field
 Citation data:

Physical Review A, ISSN: 10502947, Vol: 64, Issue: 1, Page: 13null
 Publication Year:
 2001
 Repository URL:
 http://scholarsmine.mst.edu/phys_facwork/988
 DOI:
 10.1103/physreva.64.013403
 Author(s):
 Publisher(s):
 Tags:
 Physics and Astronomy; Approximation Theory; Conformal Mapping; Electric Field Effects; Electron Energy Levels; Hydrogen; Integration; Mathematical Transformations; Numerical Analysis; Perturbation Techniques; BorelPade Resummation Method; Quantum Chromodynamics; Stark Effect; Quantum Theory; Approximation Theory; Conformal Mapping; Electric Field Effects; Electron Energy Levels; Hydrogen; Integration; Mathematical Transformations; Numerical Analysis; Perturbation Techniques; BorelPade Resummation Method; Quantum Chromodynamics; Stark Effect; Quantum Theory; Physics
article description
We consider the resummation of the perturbation series describing the energy displacement of a hydrogenic bound state in an electric field (known as the Stark effect or the LoSurdoStark effect), which constitutes a divergent formal power series in the electricfield strength. The perturbation series exhibits a rich singularity structure in the Borel plane. Resummation methods are presented that appear to lead to consistent results even in problematic cases where isolated singularities or branch cuts are present on the positive and negative real axis in the Borel plane. Two resummation prescriptions are compared: (i) a variant of the BorelPadé resummation method, with an additional improvement due to utilization of the leading renormalon poles, and (ii) a contourimproved combination of the Borel method with an analytic continuation by conformal mapping, and Padé approximations in the conformal variable. The singularity structure in the case of the LoSurdoStark effect in the complex Borel plane is shown to be similar to (divergent) perturbative expansions in quantum chromodynamics. © 2001 The American Physical Society.