ERC FUNDED PROJECTS

"This proposal has two objectives. First, I propose to measure the antiproton mass relative to the electron mass with a fractional precision of 0.1 ppb by carrying out sub-Doppler two-photon laser spectroscopy of antiprotonic helium atoms. The antiproton mass would then be better known than the proton mass. The (anti)proton-to-electron mass ratio is regarded as a one of several fundamental physical constants which, like the fine structure constant α, is a dimensionless quantity of nature that can be measured to ppb-scale precision. The experiment would constitute the highest precision confirmation of CPT symmetry involving atoms containing antiprotons. A new buffer gas cooling technique will be used to cool down the atoms to temperature T<1.5 K, thereby reducing the residual Doppler width of the two-photon resonance signals caused by the thermal motion of the atom in the experimental target. A new quasi-cw laser with high peak power and narrow linewidth will be developed. In the later half of the project, high-quality antiproton beam from the new ELENA storage ring constructed at CERN will be used to reach higher precisions of 10^-11 Second, I propose to measure the pion mass to a precision of <10^-8 by carrying out the first laser spectroscopy of pionic helium atoms, where the pion occupies a Rydberg state and the electron the 1s state. This corresponds to a >300-fold improvement in precision compared to the currently known mass, and approaches the fundamental limit imposed by the 26-ns lifetime of the pion. Past measurements of mπ show a bifurcation, i.e. two groups of experimental results near 139.570 and 139.568 MeV/c^2. The laser spectroscopy of pionic helium will provide an unambiguous value for the pion mass. This will improve the limit on the muon neutrino mass obtained from laboratory experiments, and reduce the uncertainty on the Fermi coupling constant. This will be the first time an atom containing a meson has been studied by laser spectroscopy."

1 428 660 €

Start date: 2013-02-01, End date: 2018-01-31

"""The strong interaction at neutron-rich extremes"" (STRONGINT) will investigate the structure of matter at the neutron-rich frontier in the laboratory and in the cosmos based on chiral effective field theory (EFT) interactions. Chiral EFT opens up a systematic path to investigate many-body forces and provides unique constraints for three-neutron and four-neutron interactions. We will for the first time explore the predicted many-body forces in neutron matter and neutron-rich matter. One milestone will be set by the development of a systematic power counting for neutron-rich matter. This will enable us to carry out diagrammatic approaches, and to develop ground-breaking nonperturbative Monte-Carlo calculations. Our results will strongly constrain the nuclear equation of state at the extremes reached in core-collapse supernovae and neutron stars. Based on the developments for neutron-rich matter, we will investigate spin correlations and develop a systematic description of neutrino-matter interactions, which can set the new standard for supernova simulations. Our pioneering studies have revealed new facets of three-body forces in neutron-rich nuclei, such as their role in determining the location of the neutron dripline in oxygen and in elucidating the doubly-magic nature of calcium-48. We will investigate the impact of chiral three-nucleon forces on key regions in the r-process path and develop a chiral EFT for valence-shell interactions. This will open new horizons for understanding the shell structure of nuclei. Another milestone will be set by the first calculation of neutrino-less double-beta decay based on chiral EFT interactions and consistent electroweak currents. The proposed interdisciplinary problems are essential for a successful and quantitative understanding of these big science questions."

1 495 020 €

Start date: 2012-09-01, End date: 2017-08-31

Fundamental research is key important to allow us to find new, economically and ecologically attractive ways to meet current challenges. The current depletion of available phosphorus resources is a concern. Unlike oil, which is lost once used, phosphorus can be recovered and used over and over again or at least transformed into other compounds of chemical use. The intention of the present research proposal is to contribute to the field of synthetic chemistry both, inorganic and organic, by identifying and developing highly-reactive phosphorus building blocks that can be potentially regenerated. We would like to enter new avenues of phosphorus chemistry which will address fundamental questions and develop new applications. Using novel and powerful phosphorus reagents, new concepts for more efficient, selective and sustainable synthetic procedures will be developed. We also seek greener and more efficient processes and, whenever possible, to recover the phosphorus after the reaction. Phosphorus-based compounds will also be used in the recovery of industrial waste by-products such as phosphane oxides and depleted UF6, and will therefore have a positive impact on certain chemical industries and the environment. With our proposal we aim to address the following aspects: 1) Synthesis of N-heterocyclic pnictanes (Pn = P, As, Sb, Bi with emphasis on P) and related cationic derivatives 2) Exploration of N-heterocyclic phosphanes as reagents in organic synthesis. 3) Preparation of catenated, branched and cyclic polyphosphanes via a novel method for P–P bond formation – access to novel polyphosphorus-based ligand systems. 4) Alternative processes for the recycling of UF6 and related derivatives to access novel precursors for uranium chemistry and to recover fluorine based products of high economic value.

1 422 000 €

Start date: 2013-03-01, End date: 2018-02-28

Cells release neurotransmitters, hormones and other compounds stored in secretory vesicles by a process called exocytosis. In this process, the molecules are released upon stimulation by a nanomachine forming a fusion pore that connects the vesicular lumen to the extracellular space. Similar fusion events are also essential for intracellular transport mechanisms and virus-induced fusion. Here I propose a multidisciplinary approach using highly innovative techniques to determine the nanomechanical mechanism of fusion pore formation. The proposal is based on the hypothesis that the vesicle fusion nanomachine is formed by the mechanical interactions of the SNARE proteins synaptobrevin, syntaxin, and SNAP-25 and that the fusion pore is opened by intra-membrane movement of the transmembrane domains. I will combine fluorescence resonance energy transfer microscopy with detection of individual fusion events using microfabricated electrochemical detector arrays to demonstrate that fusion pore formation is produced directly by a conformational change in the SNARE complex. I will estimate the energies that are needed to pull the synaptobrevin C terminus into the hydrophobic membrane core and the forces that are generated by the SNARE complex for wild type and a set of specific mutations using molecular dynamics simulations. I will determine how these energies and forces relate to inhibition and facilitation of experimentally observed fusion, performing patch clamp capacitance measurements of vesicle fusion in chromaffin cells expressing wild type and mutated SNARE proteins. Based on these results I will develop a detailed picture of the molecular steps, the energies, and the forces exerted by the molecular nanomachine of fusion pore formation and will ultimately generate a molecular movie of this fundamental biological process. Understanding cellular and viral fusion events will likely lead to novel treatments from spasms and neurodegeneration to cancer and infectious disease

2 165 200 €

Start date: 2013-04-01, End date: 2018-03-31