Nonresonant corrections and limits for the accuracy of the frequency measurements in modern hydrogen experiments

Abstract

The theory of the nonresonant corrections, defining the limits of accuracy for the frequency measurements in resonance experiments, is generalized to the situation when the excitation of an atomic state is governed by one Hamiltonian Ĥin and the decay of the excited state is governed by another Hamiltonian Ĥout. The description developed here corresponds to the experimental conditions realized in most accurate modern resonance-frequency measurements of the 2s–1s transition in hydrogen. Two different variants of the theoretical description of the resonance experiments, referred to as "statistical" and "coherent" scenarios, are discussed. The criterion of how to define which scenario should be attributed to a particular resonance experiment is shown. The in and (or) out quantum electrodynamic formalism referring to different asymptotic Hamiltonians is applied. A value of 10–5 Hz, obtained for the accuracy limit in the 1s–2s experiment within the "coherent" scenario, is not so far from the accuracy already achieved experimentally (46 Hz). The accuracy limits for the Lyman-alpha frequency measurements for a "coherent" type of experiment are also obtained and shown to be comparable with recent experimental accuracy.PACS Nos.: 06.20.Jr, 31.10.+z, 32.30Bv