Direct cooling of dipolar molecules

Informations projet

coolDips

N° de convention de subvention: 746525

DOI

10.3030/746525

Projet clôturé

Date de signature de la CE 8 Mars 2017

Date de début 1 Mai 2017

Date de fin 30 Avril 2019

Financé au titre de

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Coût total

€ 159 460,80

Contribution de l’UE

€ 159 460,80

Coordonné par

UNIVERSITY OF STUTTGART
Germany

Periodic Reporting for period 1 - coolDips (Direct cooling of dipolar molecules)

Période du rapport: 2017-05-01 au 2019-04-30

Résumé du contexte et des objectifs généraux du projet

The project has focused on the cooling of dipolar molecules, specifically the barium monofluoride radical. Such cold molecules are highly sought-after because they combine complex interactions with a rich internal structure. This is expected to enable novel groundbreaking applications in precision measurement, ultracold chemistry and many-body physics. While these applications are fundamental research, cooling of molecules also sets the stage for the exploitation of molecular quantum effects in future real-life devices, very much in line with the agenda of the EU Quantum Flagship.

However, the complexity that makes molecules so interesting also makes them extraordinarily challenging to cool. The goal of the project was to investigate laser cooling, which is a powerful technique to cool atoms to ultracold temperatures. This technique relies on a closed cycling transition, on which many photons from a laser beam can be scattered to realize significant forces. Such cycling transitions naturally occur in many atoms. However, in molecules, they are much more scarce, and it is first necessary to identify and characterize suitable molecular energy levels, selection rules, and potential leakage out of the cycle.

The goal of this project was to address exactly these points. The research tasks performed were thus highly challenging and only a few groups worldwide have been able to address similar questions so far. The skills and techniques cultivated by the researcher and students on the project are thus highly valuable for European society and economy.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

We have designed and set up a new experimental apparatus for the laser cooling of barium monofluoride molecules. This setup involves a cryogenic source, which produces an intense and slow beam of internally cold molecules, as well as laser systems to optically manipulate the molecules. Using this novel apparatus, we have performed high-resolution spectroscopy to characterize the molecules and to identify suitable transitions for optical cycling and laser cooling. Based on the obtained knowledge, we have realized a quasi-closed cycling transition suitable for the laser cooling of barium monofluoride. We have also studied a unique narrow-line transition in this molecular species, which will enable powerful new cooling schemes in the future. Finally, we have investigated the use of barium monofluoride in general, and our source in particular, for novel precision measurement applications.

Our results have been disseminated to the scientific community at a large number of international conferences and meetings. Moreover, we have participated in many outreach activities to promote our research to younger physics and highschool students (e.g. through lab tours and the Quantum Futur Akademie 2018 in Stuttgart), non-expert scientists (e.g. through an article in the German “Physik Journal” or the participation in interdisciplinary meetings) and the general public (e.g. through labtours and social media).

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

On the scientific side, the work has produced a powerful source for cold and slow BaF molecules. Together with the demonstrated optical cycling this sets the stage for novel precision measurements and further cooling and trapping of this molecule. In an effort to establish a European community in the burgeoning field of cold molecules, we have collaborated with researchers in different European countries. Based on this, coordinated research efforts and joint funding applications are planned for the future.

On a wider scale, the researcher has promoted quantum science to the general public. Moreover, several students mentored by the researcher have already, or are planning to apply the skills they were able to learn to new questions in the private sector. This supports the European leadership in high-tech industrial applications, in particular with respect to the emerging industrial application of quantum effects.

Illustration of the molecular source and the lasers to probe and manipulate the molecular beam.