ERC FUNDED PROJECTS

"The A2C2 project treats two major challenges in climate and atmospheric research: the time dependence of the climate attractor to external forcings (solar, volcanic eruptions and anthropogenic), and the attribution of extreme climate events occurring in the northern extra-tropics. The main difficulties are the limited climate information, the computer cost of model simulations, and mathematical assumptions that are hardly verified and often overlooked in the literature. A2C2 proposes a practical framework to overcome those three difficulties, linking the theory of dynamical systems and statistics. We will generalize the methodology of flow analogues to multiple databases in order to obtain probabilistic descriptions of analogue decompositions. The project is divided into three workpackages (WP). WP1 embeds the analogue method in the theory of dynamical systems in order to provide a metric of an attractor deformation in time. The important methodological step is to detect trends or persisting outliers in the dates and scores of analogues when the system yields time-varying forcings. This is done from idealized models and full size climate models in which the forcings (anthropogenic and natural) are known. A2C2 creates an open source toolkit to compute flow analogues from a wide array of databases (WP2). WP3 treats the two scientific challenges with the analogue method and multiple model ensembles, hence allowing uncertainty estimates under realistic mathematical hypotheses. The flow analogue methodology allows a systematic and quasi real-time analysis of extreme events, which is currently out of the reach of conventional climate modeling approaches. The major breakthrough of A2C2 is to bridge the gap between operational needs (the immediate analysis of climate events) and the understanding long-term climate changes. A2C2 opens new research horizons for the exploitation of ensembles of simulations and reliable estimates of uncertainty."

1 491 457 €

Start date: 2014-03-01, End date: 2019-02-28

Actanthrope intends to promote a neuro-robotics perspective to explore original models of anthropomorphic action. The project targets contributions to humanoid robot autonomy (for rescue and service robotics), to advanced human body simulation (for applications in ergonomics), and to a new theory of embodied intelligence (by promoting a motion-based semiotics of the human action). Actions take place in the physical space while they originate in the –robot or human– sensory-motor space. Geometry is the core abstraction that makes the link between these spaces. Considering that the structure of actions inherits from that of the body, the underlying intuition is that actions can be segmented within discrete sub-spaces lying in the entire continuous posture space. Such sub-spaces are viewed as symbols bridging deliberative reasoning and reactive control. Actanthrope argues that geometric approaches to motion segmentation and generation as promising and innovative routes to explore embodied intelligence: - Motion segmentation: what are the sub-manifolds that define the structure of a given action? - Motion generation: among all the solution paths within a given sub-manifold, what is the underlying law that makes the selection? In Robotics these questions are related to the competition between abstract symbol manipulation and physical signal processing. In Computational Neuroscience the questions refer to the quest of motion invariants. The ambition of the project is to promote a dual perspective: exploring the computational foundations of human action to make better robots, while simultaneously doing better robotics to better understand human action. A unique “Anthropomorphic Action Factory” supports the methodology. It aims at attracting to a single lab, researchers with complementary know-how and solid mathematical background. All of them will benefit from unique equipments, while being stimulated by four challenges dealing with locomotion and manipulation actions.

2 500 000 €

Start date: 2014-01-01, End date: 2018-12-31

"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

"Massive black holes (MBHs) weighing million solar masses and above inhabit the centers of today's galaxies, weighing about a thousandth of the host bulge mass. MBHs also powered quasars known to exist just a few hundred million years after the Big Bang. Owing to observational breakthroughs and remarkable advancements in theoretical models, we do now that MBHs are out there and evolved with their hosts, but we do not know how they got there nor how, and when, the connection between MBHs and hosts was established. To have a full view of MBH formation and growth we have to look at the global process where galaxies form, as determined by the large-scale structure, on Mpc scales. On the other hand, the region where MBHs dominate the dynamics of gas and stars, and accretion occurs, is merely pc-scale. To study the formation of MBHs and their fuelling we must bridge from Mpc to pc scale in order to follow how galaxies influence MBHs and how in turn MBHs influence galaxies. BLACK aims to connect the cosmic context to the nuclear region where MBHs reside, and to study MBH formation, feeding and feedback on their hosts through a multi-scale approach following the thread of MBHs from cosmological, to galactic, to nuclear scales. Analytical work guides and tests numerical simulations, allowing us to probe a wide dynamical range. Our theoretical work will be crucial for planning and interpreting current and future observations. Today and in the near future facilities at wavelengths spanning from radio to X-ray will widen and deepen our view of the Universe, making this an ideal time for this line of research."

1 668 385 €

Start date: 2014-06-01, End date: 2019-05-31

"This project is concerned with problems that involve a very large number of variables, and whose efficient numerical treatment is challenged by the so-called curse of dimensionality, meaning that computational complexity increases exponentially in the variable dimension. The PI intend to establish in his host institution a scientific leadership on the mathematical understanding and numerical treatment of these problems, and to contribute to the development of this area of research through international collaborations, organization of workshops and research schools, and training of postdocs and PhD students. High dimensional problems are ubiquitous in an increasing number of areas of scientific computing, among which statistical or active learning theory, parametric and stochastic partial differential equations, parameter optimization in numerical codes. There is a high demand from the industrial world of efficient numerical methods for treating such problems. The practical success of various numerical algorithms, that have been developed in recent years in these application areas, is often limited to moderate dimensional setting. In addition, these developments tend to be, as a rule, rather problem specific and not always founded on a solid mathematical analysis. The central scientific objectives of this project are therefore: (i) to identify fundamental mathematical principles behind overcoming the curse of dimensionality, (ii) to understand how these principles enter in relevant instances of the above applications, and (iii) based on the these principles beyond particular problem classes, to develop broadly applicable numerical strategies that benefit from such mechanisms. The performances of these strategies should be provably independent of the variable dimension, and in that sense break the curse of dimensionality. They will be tested on both synthetic benchmark tests and real world problems coming from the afore-mentioned applications."

1 848 000 €

Start date: 2014-01-01, End date: 2018-12-31

Some of the primary questions in extragalactic astronomy concern the formation and evolution of galaxies in the distant Universe. In particular, little is known about the less luminous (and therefore less massive) galaxy populations, which are currently missed from large observing surveys and could contribute significantly to the overall star formation happening at early times. One way to overcome the current observing limitations prior to the arrival of the future James Webb Space Telescope or the European Extremely Large Telescopes is to use the natural magnification of strong lensing clusters to look at distant sources with an improved sensitivity and resolution. The aim of CALENDS is to build and study in great details a large sample of accurately-modelled, strongly lensed galaxies at high redshift (1<z<5) selected in the fields of massive clusters, and compare them with the more luminous or lower redshift populations. We will develop novel techniques in this process, in order to improve the accuracy of strong-lensing models and precisely determine the mass content of these clusters. By performing a systematic modelling of the cluster sample we will look into the relative distribution of baryons and dark matter as well as the amount of substructure in cluster cores. Regarding the population of lensed galaxies, we will study their global properties through a multiwavelength analysis covering the optical to millimeter domains, including spectroscopic information from MUSE and KMOS on the VLT, and ALMA. We will look for scaling relations between the stellar, gas and dust parameters, and compare them with known relations for lower redshift and more massive galaxy samples. For the most extended sources, we will be able to spatially resolve their inner properties, and compare the results of individual regions with predictions from simulations. We will look into key physical processes: star formation, gas accretion, inflows and outflows, in these distant sources.

1 450 992 €

Start date: 2013-09-01, End date: 2019-08-31

"Electronic spins are usually detected by their interaction with electromagnetic fields at microwave frequencies. Since this interaction is very weak, only large ensembles of spins can be detected. In circuit quantum electrodynamics (cQED) on the other hand, artificial superconducting atoms are made to interact strongly with microwave fields at the single photon level, and quantum-limited detection of few-photon microwave signals has been developed. The goal of this project is to apply the concepts and techniques of cQED to the detection and manipulation of electronic and nuclear spins, in order to reach a novel regime in which a single electronic spin strongly interacts with single microwave photons. This will lead to 1) A considerable enhancement of the sensitivity of spin detection by microwave methods. We plan to detect resonantly single electronic spins in a few milliseconds. This could enable A) to perform electron spin resonance spectroscopy on few-molecule samples B) to measure the magnetization of various nano-objects at millikelvin temperatures, using the spin as a magnetic sensor with nanoscale resolution. 2) Applications in quantum information science. Strong interaction with microwave fields at the quantum level will enable the generation of entangled states of distant individual electronic and nuclear spins, using superconducting qubits, resonators and microwave photons, as “quantum data buses” mediating the entanglement. Since spins can have coherence times in the seconds range, this could pave the way towards a scalable implementation of quantum information processing protocols. These ideas will be primarily implemented with NV centers in diamond, which are electronic spins with properties suitable for the project."

1 999 995 €

Start date: 2014-03-01, End date: 2019-02-28

"The physics of complex quantum systems with controllable interactions is emerging as a fundamental topic for a broad community, providing an opportunity to test theories of strongly correlated quantum many-body systems and opening interesting applications such as quantum simulators. Recently, in solid-state structures with effective photon-photon interactions the rich physics of quantum fluids of light has been explored, albeit not yet in the regime of strong photonic correlations. Exciting advances in cavity Quantum Electro-Dynamics (QED) and superconducting circuit QED make strong photon-photon interactions now accessible. A growing interest is focusing on lattices of coupled resonators, implementing Hubbard-like Hamiltonians for photons injected by pump driving fields. Similarly to electronic systems, the physics of large two-dimensional (2D) photonic lattices is a fundamental theoretical challenge in the regime of strong correlations. CORPHO has the ambition to develop novel scalable theoretical methods for 2D lattices of cavities, including spatially inhomogeneous driving and dissipation. The proposed methods are based on a hybrid strategy combining cluster mean-field theory and Wave Function Monte Carlo on a physical ‘Corner’ of the Hilbert space in order to calculate the steady-state density matrix and the properties of the non-equilibrium phases. We will study 2D lattices with complex unit cells and ‘fractional’ driving (only a fraction of the sites is pumped), a configuration that, according to recent preliminary studies, is expected to dramatically enhance and enrich quantum correlations. We will also investigate the interplay between driving and geometric frustration in 2D lattices with polarization-dependent interactions. Finally, the quantum control of strongly correlated photonic systems will be explored, including quantum feedback processes, cooling of thermal fluctuations and switching between multi-stable phases."

1 378 440 €

Start date: 2014-06-01, End date: 2019-05-31

"Since the first laser discovery in 1960 and the first Free Electron Laser (FEL) in 1977, Linac based fourth generation light sources provide intense coherent fs pulses in the X-ray range for multidisciplinary investigations of matter. In parallel, Laser Wakefield Accelerator (LWFA) by using intense laser beams interacting with cm long plasmas can now provide high quality electron beams of very short bunches (few fs) with high peak currents (few kA). The so-called 5th generation light source aims at reducing the size and the cost of these FELs by replacing the linac by LWFA. Indeed, spontaneous emission from LWFA has already been observed, but the presently still rather large energy spread (1 %) and divergence (mrad) prevent from the FEL amplification. In 2012, two novel schemes in the transport proposed in the community, including my SOLEIL group, predict a laser gain increase by 3 or 4 orders of magnitudes. COXINEL aims at demonstrating the first lasing of an LWFA FEL and its detailed study in close interaction with future potential users. The key concept relies on an innovative electron beam longitudinal and transverse manipulation in the transport towards an undulator: a ""demixing"" chicane sorts the electrons in energy and reduces the spread from 1 % to a slice one of 0.1%, and the transverse density is maintained constant all along the undulator (supermatching). Simulations based on the performance of the 60 TW laser of the Laboratoire d’Optique Appliquée and existing undulators from SOLEIL suggest that the conditions for lasing are fulfilled. The SOLEIL environment also possesses the engineering fabrication capability for the actual realization of these theoretical ideas, with original undulators and innovative variable permanent compact magnets for the transport. COXINEL will enable to master in Europe advanced schemes scalable to shorter wavelengths and pulses, paving the way towards FEL light sources on laboratory size, for fs time resolved experiments."

2 500 000 €

Start date: 2014-01-01, End date: 2018-12-31