ERC FUNDED PROJECTS

Understanding the many-body physics of strongly correlated systems has always been a major challenge for theoretical and experimental physics. The recent advances in the field of ultracold quantum gases have opened a completely new way to study such strongly correlated systems. It is now feasible to use ultracold gases as quantum simulators for such diverse systems such as the Hubbard model or the BCS-BEC crossover. The objective of this project is to study a three-component Fermi gas in an optical lattice, a system with rich many-body physics. With our experiments we aim to contribute to the understanding of exotic phases which are discussed in the context of QCD and condensed matter physics.

1 469 040 €

Start date: 2011-08-01, End date: 2016-07-31

Many Gram-positive (pathogenic) bacteria are dependent on the uptake of vitamins from the environment or from the infected host. We have recently discovered the long-elusive family of membrane protein complexes catalyzing such transport. The vitamin transporters have an unprecedented modular architecture consisting of a single multipurpose energizing module (the Energy Coupling Factor, ECF) and multiple exchangeable membrane proteins responsible for substrate recognition (S-components). The S-components have characteristics of ion-gradient driven transporters (secondary active transporters), whereas the energizing modules are related to ATP-binding cassette (ABC) transporters (primary active transporters). The aim of the proposal is threefold: First, we will address the question how properties of primary and secondary transporters are combined in ECF transporters to obtain a novel transport mechanism. Second, we will study the fundamental and unresolved question how protein-protein recognition takes place in the hydrophobic environment of the lipid bilayer. The modular nature of the ECF proteins offers a natural system to study the driving forces used for membrane protein interaction. Third, we will assess whether the ECF transport systems could become targets for antibacterial drugs. ECF transporters are found exclusively in prokaryotes, and their activity is often essential for viability of Gram-positive pathogens. Thus they could turn out to be an Achilles’ heel for the organisms. Structural and mechanistic studies (X-ray crystallography, microscopy, spectroscopy and biochemistry) will reveal how the different transport modes are combined in a single protein complex, how transport is energized and catalyzed, and how protein-protein recognition takes place. Microbiological screens will be developed to search for compounds that inhibit prokaryote-specific steps of the mechanism of ECF transporters.

1 500 000 €

Start date: 2012-01-01, End date: 2017-12-31

"An important driver of scientific progress has always been the envisioning of applications far beyond existing technological capabilities. Such thinking creates new challenges for physicists, driven by the groundbreaking nature of the anticipated application. In the case of laser physics, one of these applications is laser wake-field particle acceleration and possible future uses thereof, such as in collider experiments, or for medical applications such as cancer treatment. To accelerate electrons and positrons to TeV-energies, a laser architecture is required that allows for the combination of high efficiency, Petawatt peak powers, and Megawatt average powers. Developing such a laser system would be a challenging task that might take decades of aggressive research, development, and, most important, revolutionary approaches and innovative ideas. The goal of the ACOPS project is to develop a compact, efficient, scalable, and cost-effective high-average and high-peak power ultra-short pulse laser concept. The proposed approach to this goal relies on the spatially and temporally separated amplification of ultrashort laser pulses in waveguide structures, followed by coherent combination into a single train of pulses with increased average power and pulse energy. This combination can be realized through the coherent addition of the output beams of spatially separated amplifiers, combined with the pulse stacking of temporally separated pulses in passive enhancement cavities, employing a fast-switching element as cavity dumper. Therefore, the three main tasks are the development of kW-class high-repetition-rate driving lasers, the investigation of non-steady state pulse enhancement in passive cavities, and the development of a suitable dumping element. If successful, the proposed concept would undoubtedly provide a tool that would allow researchers to surpass the current limits in high-field physics and accelerator science."

1 881 040 €

Start date: 2014-02-01, End date: 2019-01-31

"The proposed research program has three main objectives. The first and second objectives are to seek extreme precisions in optical atomic spectroscopy and optical clocks, and to use this quest as a mean of exploration in atomic physics. The third objective is to explore new possibilities that stem from extreme precision. These goals will be pursued via three complementary activities: #1: Search for extreme precisions with an Hg optical lattice clock. #2: Explore and exploit the rich Hg system, which is essentially unexplored in the cold and ultra-cold regime. #3: Identify new applications of clocks with extreme precision to Earth science. Clocks can measure directly the gravitational potential via Einstein’s gravitational redshift, leading to the idea of “clock-based geodesy”. The 2 first activities are experimental and build on an existing setup, where we demonstrated the feasibility of an Hg optical lattice clock. Hg is chosen for its potential to surpass competing systems. We will investigate the unexplored physics of the Hg clock. This includes interactions between Hg atoms, lattice-induced light shifts, and sensitivity to external fields which are specific to the atomic species. Beyond, we will explore the fundamental limits of the optical lattice scheme. We will exploit other remarkable features of Hg associated to the high atomic number and the diversity of stable isotopes. These features enable tests of fundamental physical laws, ultra-precise measurements of isotope shifts, measurement of collisional properties toward evaporative cooling and quantum gases of Hg, investigation of forbidden transitions promising for measuring the nuclear anapole moment of Hg. The third activity is theoretical and is aimed at initiating collaborations with experts in modelling Earth gravity. With this expertise, we will identify the most promising and realistic approaches for clocks and emerging remote comparison methods to contribute to geodesy, hydrology, oceanography, etc."

1 946 432 €

Start date: 2014-04-01, End date: 2019-03-31