ERC FUNDED PROJECTS

Several observed anomalies in neutrino oscillation data can be explained by a hypothetical fourth neutrino separated from the three standard neutrinos by a squared mass difference of a few eV2. This hypothesis can be tested with a PBq (ten kilocurie scale) 144Ce antineutrino beta-source deployed at the center of a large low background liquid scintillator detector, such like Borexino, KamLAND, and SNO+. In particular, the compact size of such a source could yield an energy-dependent oscillating pattern in event spatial distribution that would unambiguously determine neutrino mass differences and mixing angles. The proposed program aims to perform the necessary research and developments to produce and deploy an intense antineutrino source in a large liquid scintillator detector. Our program will address the definition of the production process of the neutrino source as well as its experimental characterization, the detailed physics simulation of both signal and backgrounds, the complete design and the realization of the thick shielding, the preparation of the interfaces with the antineutrino detector, including the safety and security aspects.

1 500 000 €

Start date: 2012-10-01, End date: 2018-09-30

The emergence of life is one of the most fascinating and yet largely unsolved questions in the natural sciences, and thus a significant challenge for scientists from many disciplines. There is growing evidence that ribonucleic acid (RNA) polymers, which are capable of genetic information storage and self-catalysis, were involved in the early forms of life. But despite recent progress, RNA synthesis without biological machineries is very challenging. The current project aims at understanding how to synthesize RNA in abiotic conditions. I will solve problems associated with three critical aspects of RNA formation that I will rationalize at a molecular level: (i) accumulation of precursors, (ii) formation of a chemical bond between RNA monomers, and (iii) tolerance for alternative backbone sugars or linkages. Because I will study problems ranging from the formation of chemical bonds up to the stability of large biopolymers, I propose an original computational multi-scale approach combining techniques that range from quantum calculations to large-scale all-atom simulations, employed together with efficient enhanced-sampling algorithms, forcefield improvement, cutting-edge analysis methods and model development. My objectives are the following: 1 • To explain why the poorly-understood thermally-driven process of thermophoresis can contribute to the accumulation of dilute precursors. 2 • To understand why linking RNA monomers with phosphoester bonds is so difficult, to understand the molecular mechanism of possible catalysts and to suggest key improvements. 3 • To rationalize the molecular basis for RNA tolerance for alternative backbone sugars or linkages that have probably been incorporated in abiotic conditions. This unique in-silico laboratory setup should significantly impact our comprehension of life’s origin by overcoming major obstacles to RNA abiotic formation, and in addition will reveal significant orthogonal outcomes for (bio)technological applications.

1 497 031 €

Start date: 2018-02-01, End date: 2023-01-31

The active target and time projection chamber (ACTAR TPC) is a novel gas-filled detection system that will permit new studies into the structure and decays of the most exotic nuclei. The use of a gas volume that acts as a sensitive detection medium and as the reaction target itself (an “active target”) offers considerable advantages over traditional nuclear physics detectors and techniques. In high-energy physics, TPC detectors have found profitable applications but their use in nuclear physics has been limited. With the ACTAR TPC design, individual detection pad sizes of 2 mm are the smallest ever attempted in either discipline but is a requirement for high-efficiency and high-resolution nuclear spectroscopy. The corresponding large number of electronic channels (16000 from a surface of only 25×25 cm) requires new developments in high-density electronics and data-acquisition systems that are not yet available in the nuclear physics domain. New experiments in regions of the nuclear chart that cannot be presently contemplated will become feasible with ACTAR TPC.

1 290 000 €

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

"AIME is an inquiry to make more precise what is lumped together into the confusing word ""modernization"". The work done in the field of science studies (STS) on the progress and practice of science and technology has had the consequence of deeply modifying the definition of ""modernity"", resulting into the provocative idea that ""we (meaning the Europeans) have never been modern"". This is, however only a negative definition. To obtain a positive rendering of the European current situation, it is necessary to start an inquiry in the complex and conflicting set of values that have been invented. This inquiry is possible only if there is a clear and shareable way to judge the differences in the set of truth-conditions that make up those conflicting sets of values. AIME offers a grammar of those differences based on the key notion of modes of existence. Then it builds a procedure and an instrument to test this grammar into a selected set of situations where the definitions of the differing modes of existence is redefined and renegotiated. The result is a set of shareable definitions of what modernization has been in practice. This is important just at the moment when Europe has lost its privileged status and needs to be able to present itself in a new ways to the other cultures and civilizations which are making up the world of globalization with very different views on what it is to modernize themselves."

1 334 720 €

Start date: 2011-09-01, End date: 2015-06-30

Applied electrochemistry plays a key role in many technologies, such as batteries, fuel cells, supercapacitors or solar cells. It is therefore at the core of many research programs all over the world. Yet, fundamental electrochemical investigations remain scarce. In particular, electrochemistry is among the fields for which the gap between theory and experiment is the largest. From the computational point of view, there is no molecular dynamics (MD) software devoted to the simulation of electrochemical systems while other fields such as biochemistry (GROMACS) or material science (LAMMPS) have dedicated tools. This is due to the difficulty of accounting for complex effects arising from (i) the degree of metallicity of the electrode (i.e. from semimetals to perfect conductors), (ii) the mutual polarization occurring at the electrode/electrolyte interface and (iii) the redox reactivity through explicit electron transfers. Current understanding therefore relies on standard theories that derive from an inaccurate molecular-scale picture. My objective is to fill this gap by introducing a whole set of new methods for simulating electrochemical systems. They will be provided to the computational electrochemistry community as a cutting-edge MD software adapted to supercomputers. First applications will aim at the discovery of new electrolytes for energy storage. Here I will focus on (1) ‘‘water-in-salts’’ to understand why these revolutionary liquids enable much higher voltage than conventional solutions (2) redox reactions inside a nanoporous electrode to support the development of future capacitive energy storage devices. These selected applications are timely and rely on collaborations with leading experimental partners. The results are expected to shed an unprecedented light on the importance of polarization effects on the structure and the reactivity of electrode/electrolyte interfaces, establishing MD as a prominent tool for solving complex electrochemistry problems.

1 588 769 €

Start date: 2018-04-01, End date: 2023-03-31

I propose to use large clouds of cold Ytterbium atoms to observe Anderson localization of light in three dimensions, which has challenged theoreticians and experimentalists for many decades. After the prediction by Anderson of a disorder-induced conductor to insulator transition for electrons, light has been proposed as ideal non interacting waves to explore coherent transport properties in the absence of interactions. The development in experiments and theory over the past several years have shown a route towards the experimental realization of this phase transition. Previous studies on Anderson localization of light using semiconductor powders or dielectric particles have shown that intrinsic material properties, such as absorption or inelastic scattering of light, need to be taken into account in the interpretation of experimental signatures of Anderson localization. Laser-cooled clouds of atoms avoid the problems of samples used so far to study Anderson localization of light. Ab initio theoretical models, available for cold Ytterbium atoms, have shown that the mere high spatial density of the scattering sample is not sufficient to allow for Anderson localization of photons in three dimensions, but that an additional magnetic field or additional disorder on the level shifts can induce a phase transition in three dimensions. The role of disorder in atom-light interactions has important consequences for the next generation of high precision atomic clocks and quantum memories. By connecting the mesoscopic physics approach to quantum optics and cooperative scattering, this project will allow better control of cold atoms as building blocks of future quantum technologies. Time-resolved transport experiments will connect super- and subradiant assisted transmission with the extended and localized eigenstates of the system. Having pioneered studies on weak localization and cooperative scattering enables me to diagnostic strong localization of light by cold atoms.

2 490 717 €

Start date: 2019-10-01, End date: 2024-09-30

RNA interference (RNAi) is a conserved sequence-specific, gene-silencing mechanism that is induced by double-stranded RNA (dsRNA). One of the functions of this pathway is the defense against parasitic nucleic acids: transposons and viruses. Previous results demonstrated that viral infections in Drosophila melanogaster are fought by an antiviral RNAi response and that components of the endocytic pathway are required for dsRNA entry to initiate the RNAi response. Recently we have shown that infected insect cells spread a systemic silencing signal that elicits a protective RNAi-dependent immunity throughout the organism. This suggests that the cell-autonomous RNAi response is insufficient to control a viral infection and that flies also rely on systemic immune response to fight against such infections. As a junior group leader, I will study the mechanisms that mediate the RNAi-based antiviral response in insects. By combining biochemical, cellular, molecular and genomic approaches, both in vivo and in cell culture, I will analyze the mechanisms underlying viral tropism, systemic propagation of the antiviral signal and the basis of the persistence of the antiviral state. Furthermore, I will examine whether the dsRNA-uptake pathway is conserved in mosquitoes and its relationship with viral immunity in that host. This comprehensive approach will tackle how this nucleic acid-based immunity works in insects to generate an anti-viral stage. A better understanding of the role of RNA silencing in insects during virus infection will allow the exploitation of this pathway for improvement of public health related problems such as arbovirus infection and disease.

1 900 000 €

Start date: 2009-10-01, End date: 2014-12-31

The goal of this project is to prepare in a deterministic way, and then to characterize, various entangled states of up to 25 individual atoms held in an array of optical tweezers. Such a system provides a new arena to explore quantum entangled states of a large number of particles. Entanglement is the existence of quantum correlations between different parts of a system, and it is recognized as an essential property that distinguishes the quantum and the classical worlds. It is also a resource in various areas of physics, such as quantum information processing, quantum metrology, correlated quantum systems and quantum simulation. In the proposed design, each site is individually addressable, which enables single atom manipulation and detection. This will provide the largest entangled state ever produced and fully characterized at the individual particle level. The experiment will be implemented by combining two crucial novel features, that I was able to demonstrate very recently: first, the manipulation of quantum bits written on long-lived hyperfine ground states of single ultra-cold atoms trapped in microscopic optical tweezers; second, the generation of entanglement by using the strong long-range interactions between Rydberg states. These interactions lead to the so-called dipole blockade , and enable the preparation of various classes of entangled states, such as states carrying only one excitation (W states), and states analogous to Schrödinger s cats (GHZ states). Finally, I will also explore strategies to protect these states against decoherence, developed in the framework of fault-tolerant and topological quantum computing. This project therefore combines an experimental challenge and the exploration of entanglement in a mesoscopic system.

1 449 600 €

Start date: 2009-12-01, End date: 2014-11-30