Семинар на 19.09.2019 г.

На 19 септември 2019 г., четвъртък, от 13:15 ч. в зала 300 на ИЯИЯЕ ще се състои сбирка, на която гостуващият у нас проф.Стефан Шилер (Дюселдорф, Германия) ще изнесе доклад на тема:

"Rotating Molecules and Fundamental Constants".

Molecules provide exciting opportunities for precision measurements - significantly extending those offered by atoms. In recent years, it has become possible to manipulate molecules in more and more powerful ways, especially cooling them to the millikelvin range and lower and trapping them. This enables precision spectroscopic studies. Our own work focuses on the second-simplest existing molecule: HD+, one member of the family of molecular hydrogen ions (MHI). This three-body quantum system is sufficiently simple that it can be dealt with by ab initio theory, yet it still poses a significant challenge when it comes to high-precision predictions. In order to test the predictions and to determine some key fundamental constants of atomic physics using this molecule, we have developed a novel technique for rotational spectroscopy, which achieves the Lamb-Dicke regime [1]. This enabled us to observe, for the first time, ultra-narrow rotational transitions, to study the frequency shifts due to external fields and finally to determine their frequency with an uncertainty smaller than the current theoretical uncertainty. Applying a suitable analysis technique, the comparison between experiment and theory results permitted determining a combination of fundamental constants with uncertainty smaller than CODATA2018. We could also deduce a value of the proton mass, which is in excellent agreement with the directly measured one. Finally, our experiment also sets improved upper bounds for the strength of a hypothetical "fifth force" between proton and deuteron.
[1] S. Alighanbari, et al. Nature Physics 14, 555–559 (2018), doi: 10.1038/s41567-018-0074-3


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