Berlin 2014 – wissenschaftliches Programm

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SYAW: Awards Symposium

SYAW 2: Awards Symposium II

SYAW 2.2: Preisträgervortrag

Mittwoch, 19. März 2014, 17:00–17:30, Kinosaal

Metrology of atomic hydrogen: from the Rydberg constant to the size of the proton — •François Biraben — Laboratoire Kastler Brossel, ENS, CNRS, UPMC, 4 place Jussieu, 75252 Paris Cedex 05, France --- Laureate of the Gentner-Kastler-Prize

The hydrogen atom has a central position in the history of 20th-century physics and hydrogen spectroscopy is associated with the successive advances in the understanding of the atomic structure. Thanks to optical frequency measurements and Doppler free techniques, several optical frequencies of hydrogen are now known with a fractional accuracy better than 10-11 and thus it is possible to extract from these data not only the value of the Rydberg constant but also the energy shift due to the finite size of the proton. The value of the proton radius extracted from hydrogen measurements (Rp=0.8764(89)fm [1]) is in agreement with the value deduced from scattering experiments (Rp=0.8791(79) fm [2]). On the contrary these values are in disagreement with the recent result deduced from the measurement of the Lamb shift in muonic hydrogen (Rp=0.84087(39)fm [3]). This discrepancy has renewed the interest in hydrogen spectroscopy. In this lecture, we present the most recent experiments and describe the analysis of the data used to deduce the Rydberg constant, the Lamb shifts and the size of the proton. We report also the recent development of our 1S-3S experiment.

1 P.J. Mohr et al, Rev. Mod. Phys. 84, 1527 (2012).

2 J.C. Bernauer et al, Phys. Rev. Lett. 105, 242001 (2010).

3 A. Antognini et al, Science 339, 417 (2013).