MBI Colloquium
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Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie
Max-Born-Straße 2a,
12489 Berlin
Max Born Hall
Precision measurements on molecular hydrogen in search for new physics
Prof. Dr. Wim Ubachs | Vrije Universiteit Amsterdam, The Netherlands
Modern laser spectroscopic and metrology methods, involving atomic clocks and frequency comb lasers, allow for ever more refined and accurate determination of the quantum level structure of the smallest molecules, the hydrogen molecule. At the same time advanced quantum calculations, including non-adiabatic, relativistic and QED-effects on these small systems have become possible at a high level of accuracy.
A comparison between experiment and theory for the benchmark dissociation energy reveals that both are in agreement at the sub-MHz level. This result can be interpreted as a test of QED in molecules, but also constraints on possible 5th forces or higher dimensions can be deduced. The abundancy and observation of H2 in quasar radiation can be used for searching possible variations of the proton-electron mass ratio, a phenomenon that surpasses known physics.
Currently the focus of research is shifting to the measurement of vibrational transitions in hydrogen; in view of the long lifetimes of those quantum states, that opens up a new avenue for precision metrology on molecules and the search for new physics.