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Cold Molecular Ions at the Quantum Limit

Final Report Summary - COMIQ (Cold Molecular Ions at the Quantum Limit)


The EU Initial Training Network Cold Molecular Ions at the Quantum limit (COMIQ), figure F1, was initiated in November 2013 with 10 full beneficiaries and one associated partner. The partners of the network have been composed of experts with complementary background and expertise for optimizing the composition for the interdisciplinary endeavour at the border between physics, chemistry, engineering and numerics. The coordinating node has been Aarhus University, Denmark, with Prof. Michael Drewsen being the scientific coordinator. The research of the network has been aimed at investigating how cooling, trapping, and control techniques applied to molecular ions can expand the realm of quantum technology, enhance precision measurements on molecular systems and lead to chemistry at the ultra-cold quantum limit. The research has been focused on molecular ions translationally cooled to temperatures just a thousandth of a degree above the absolute zero-point range, where they become part of a spatially ordered structure, a so-called Coulomb crystal, and consequently become a unique target for a wide range of investigations. Building on prior landmark studies for various advanced applications such as ultra-sensitive mass spectrometry, ultrahigh-resolution spectroscopy to test fundamental physical concepts, cooling of macromolecular ions in the gas phase and chemical processes at very low temperatures, as well as recent developments of cooling and state preparation of the internal molecular degrees of freedom (rotation, vibration, spin) and laser-cooled atomic ions coupled to ultracold atomic gases by members of COMIQ, important new results demonstrating the enormous potential of this research field have been obtained within COMIQ the past 4 years. Some of most spectacular results include the introduction of cryogenically cooled ion traps which have led to the coldest internally cooled molecular ions reached so-far by buffer gas cooling and to the demonstration of sympathetical cooling of multiple charged ions, first demonstration of laser excitation of dipole-forbidden transitions in a cold molecular ion, record-high resolution in molecular vibrational spectroscopy, demonstration of three-body state-to-state chemistry, and the study of rotational-state changing collisions at low temperatures.

Through the state-of-the-art research, the partners of COMIQ have secured a new generation of young scientists within cold molecular ion research by in total have trained one Experienced Researcher (ER) and 16 Early Stage Researchers (ERSs) of which 6 have already earned their doctor’s degree (PhD), and the 9 others will in the near future. Following a training-through-research philosophy, the fellows have been trained through a network-based, highly interdisciplinary training program comprised of chemistry and physics, experiment and theory, complementary skills and technology. The innovative scientific training program included joint technological developments with private-sector partners, which were experts in the innovative technologies required for the experiments. Care has been taking to secure that the ERSs have developed the skills and expertise needed for a future research career in the scientific field of cold molecular ions and its technological spin-offs. Each of the fellows has been enrolled in a challenging research project at a host institute, and through secondments to collaborators, they have in addition received training in a complementary academic or industrial environment. The high quality of these projects is documented by the scientific and technological outcome achieved during the existence of COMIQ. Technological highlights complementing the scientific ones mentioned above, include the development of a digital ion trap, a damped cosine trap ejection methodologies, development of high-voltage frequency generator, a new technique for all-electrical stabilization of semiconductor lasers without the need for an optical reference, building of a frequency stabilized laser source in the Mid-IR region. The fellows have experienced a network-wide training through schools, workshops, and meetings, which combined have broadened the follows’ perspective, provided the possibility of fruitful exchange of ideas, and finally the acquisition of expertise in both experimental methods and theoretical concepts. An essential aspect for the career advancement of the fellows have been their access to a wide range of state-of-the-art technological diversity of experimental methods: ion trapping, manipulation of cold atoms, laser techniques, precision chemical dynamics and quantum control of ultracold molecular ion reactions etc.

Three schools were organized, which were not only attended by the COMIQ partners, but also by external scientists and students. The first school introduced the fellows to a series of scientific, practical and complementary skills e.g. ion trapping and cooling methods, molecular physics, laser techniques, good lab practice, and practical training in molecular dynamics. The second school organized introduced the fellows to quantum information, precision chemical dynamics and quantum control of ultracold molecular ion reactions, internal quantum-state preparation, Quantum Cascade Lasers (QCLs), generation and application of cold molecules and theory on ion-molecular reaction and electronic structure. The third school included topics such as laser quantum control, quantum information science, ultracold collision theory, ultracold gases and their interactions with ions, microstructured ion traps, precision spectroscopy.

These topics are increasingly important in todays advanced experiments and simulations. The fellows also received practical training in radiofrequency techniques and complementary training in presentation skills, management, safety practice, communication, founding a spin-off company, commercialisation. The schools further encompassed public engagement workshops.

A Final Network Conference was held with 27 expert talks within the scientific field of COMIQ. From this meeting it was clear that the field is now growing into an actual scientific community instead of “just” a network of research groups working on these topics, a fact we to a large extent attribute to COMIQ.

The COMIQ research methodology and method is presented in four research packages entitled; Quantum state preparation, Precision measurements, Quantum controlled chemistry and Molecular quantum technology, figure F2. The private sector partners actively participated in the network management and training program, and played an important role in each work package. Network-wide meetings and conferences strengthened existing links between COMIQ partners and intensified the exchange between academia and the private sector. Results and benefits of the network-induced collaborations have been shared and diffused within Europe by network events open to external researchers and by publications in high-profile high-impact peer-reviewed scientific journals. 70 publications have been published in peer-review journals, and more are currently in preparation.

Several key aspects illustrated in figure F4, highlight the impact of COMIQ with respect to societal and economic matters. The COMIQ network have educated young researchers at the highest level with the aim of promoting their careers within the science community as well as for strengthen the European economy through work in the private sector. The collaboration between academic experimental groups and industrial partners have already resulted in new products for the European high-tech industry thus expanding Europe’s high-tech landscape and strengthen European leadership in the marked.

More information about COMIQ, contact information and logo (F1) can be found at The coordinator, Prof. Michael Drewsen, can be contacted at