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Precision metrology on the hydrogen atom in search for new physics
Author(s) -
Ubachs Wim,
Vassen Wim,
Salumbides Edcel J.,
Eikema Kjeld S. E.
Publication year - 2013
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.201300730
Subject(s) - physics , metrology , hydrogen atom , hydrogen , physics beyond the standard model , atom (system on chip) , atomic physics , theoretical physics , quantum mechanics , computer science , group (periodic table) , embedded system
The Hydrogen atom has been the benchmark system throughout the history of atomic physics. This year we celebrate the centennial of the Bohr model [1], proposing the first quantum description of an atom and the rationale behind the Rydberg formula. This explanation of the spectrum of the H-atom ignited the quantum revolution. With the invention of the laser and the development of laser spectroscopic techniques the accuracy of spectroscopic measurements of the 1S-2S transition of hydrogen atom (natural linewidth 1.3 Hz) has improved by many orders of magnitude as shown in Figure 1, culminating now at an impressive 10 Hz or a relative accuracy of 4×10−15 [2]. Precision metrology of the Hatom is aimed towards testing fundamental theories in physics, in particular quantum electrodynamics (QED). At the basic level there are three ingredients involved in these tests: QED calculations for the H-atom, a value for the Rydberg constant R∞, and a value for the rms proton charge radius 〈rp〉rms [3]. The effect of the proton radius is small, only contributing some 1.2 MHz on the binding energy of the 1S ground state [3], but with respect to the present-day 10-Hz experimental accuracy, this contribution is significant. The uncertainties are however intertwined, e.g. the present uncertainty in the proton charge radius from electron scattering propagates Figure 1 Display of improvement of the relative accuracy achieved in spectroscopic studies of the 1S-2S transition in atomic hydrogen. (adapted and extended from Hansch, Rev. Mod. Phys. 78, 1297 (2006)).