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"Precision Spectroscopy of Atomic Hydrogen"

Dr. Thomas Udem
Max-Planck Institute for Quantum Optics
Garching, Germany


Precise determination of transition frequencies in atomic hydrogen provides one of the most critical confrontations of experimental data with the theory of quantum electrodynamics (QED). The sharpest transition in atomic hydrogen occurs between the metastable 2S state and the 1S ground state. It's transition frequency has now been measured with almost 15 digits uncertainty using an optical frequency comb and a cesium atomic clock as a reference [1]. In combinations with other measured transition frequencies one can determine the value of the Rydberg constant and the proton charge radius, that enter the QED description as parameters. The hydrogen data has been self-consistent in this analysis.

A recent measurement of the Lamb shift in muonic hydrogen has allowed to determin the proton charge radius with a largely reduced uncertainty [2]. However, this value contradicts results obtained with ordinary hydrogen. We hope that we can shed light on this discrepancy by providing additional experimental input with increased accuracy.

[1] C.Parthey et al. Phys. Rev. Lett. 79, 052505 (2009).
[2] R.Pohl et al. Nature. 466, 213 (2010).

Wednesday, October 30, 2013
IQSE 578, 11:00 AM
Mitchell Physics Building

Institute for Quantum Science and Engineering
Texas A&M University

Host: Dr. Hans Schuessler