ERC FUNDED PROJECTS

State-of-the-art microscopy and diffraction imaging provides insight into the atomic and sub-atomic structure of matter. They permit determination of the positions of atoms in a crystal lattice or in a molecule as well as the distribution of electrons inside atoms. State-of-the-art time-resolved spectroscopy with femtosecond and attosecond resolution provides access to dynamic changes in the atomic and electronic structure of matter. Our proposal aims at combining these two frontier techniques of XXI century science to make a long-standing dream of scientist come true: the direct observation of atoms and electrons in their natural state: in motion. Shifts in the atoms positions by tens to hundreds of picometers can make chemical bonds break apart or newly form, changing the structure and/or chemical composition of matter. Electronic motion on similar scales may result in the emission of light, or the initiation of processes that lead to a change in physical or chemical properties, or biological function. These motions happen within femtoseconds and attoseconds, respectively. To make them observable, we need a 4-dimensional (4D) imaging technique capable of recording freeze-frame snapshots of microscopic systems with picometer spatial resolution and femtosecond to attosecond exposure time. The motion can then be visualized by slow-motion replay of the freeze-frame shots. The goal of this project is to develop a 4D imaging technique that will ultimately offer picometer resolution is space and attosecond resolution in time.

2 500 000 €

Start date: 2010-03-01, End date: 2015-02-28

New insight into ever smaller microscopic units of matter as well as in ever faster evolving chemical, physical or atomic processes pushes the frontiers in many fields in science. Pump/probe experiments turned out to be the most direct approach to time-domain investigations of fast-evolving microscopic processes. Accessing atomic and molecular inner-shell processes directly in the time-domain requires a combination of short wavelengths in the few hundred eV range and sub-femtosecond pulse duration. The concept of light-field-controlled XUV photoemission employs an XUV pulse achieved by High-order Harmonic Generation (HHG) as a pump and the light pulse as a probe or vice versa. The basic prerequisite, namely the generation and measurement of isolated sub-femtosecond XUV pulses synchronized to a strong few-cycle light pulse with attosecond precision, opens up a route to time-resolved inner-shell atomic and molecular spectroscopy with present day sources. Studies of attosecond electronic motion (1 as = 10-18 s) in solids and on surfaces and interfaces have until now remained out of reach. The unprecedented time resolution of the aforementioned technique will enable for the first time monitoring of sub-fs dynamics of such systems in the time domain. These dynamics – of electronic excitation, relaxation, and wave packet motion – are of broad scientific interest and pertinent to the development of many modern technologies including semiconductor and molecular electronics, optoelectronics, information processing, photovoltaics, and optical nano-structuring. The purpose of this project is to investigate phenomena like the temporal evolution of direct photoemission, interference effects in resonant photoemission, fast adsorbate-substrate charge transfer, and electronic dynamics in supramolecular assemblies, in a series of experiments in order to overcome the temporal limits of measurements in solid state physics and to better understand processes in microcosm.

1 296 000 €

Start date: 2008-10-01, End date: 2013-09-30

In quantum electrodynamics a range of fundamental processes are driven by omnipresent vacuum fluctuations. Photonic crystals can control vacuum fluctuations and thereby the fundamental interaction between light and matter. We will conduct experiments on quantum dots in photonic crystals and observe novel quantum electrodynamics effects including fractional decay and the modified Lamb shift. Furthermore, photonic crystals will be explored for shielding sensitive quantum-superposition states against decoherence. Defects in photonic crystals allow novel functionalities enabling nanocavities and waveguides. We will use the tight confinement of light in a nanocavity to entangle a quantum dot and a photon, and explore the scalability. Controlled ways of generating scalable and robust quantum entanglement is the essential missing link limiting quantum communication and quantum computing. A single quantum dot coupled to a slowly propagating mode in a photonic crystal waveguide will be used to induce large nonlinearities at the few-photon level. Finally we will explore a novel route to enhanced light-matter interaction employing controlled disorder in photonic crystals. In disordered media multiple scattering of light takes place and can lead to the formation of Anderson-localized modes. We will explore cavity quantum electrodynamics in Anderson-localized random cavities considering disorder a resource and not a nuisance, which is the traditional view. The main focus of the project will be on optical experiments, but fabrication of photonic crystals and detailed theory will be carried out as well. Several of the proposed experiments will constitute milestones in quantum optics and may pave the way for all-solid-state quantum communication with quantum dots in photonic crystals.

1 199 648 €

Start date: 2010-12-01, End date: 2015-11-30

I propose a program of research that may forever change the way that we understand and use quantum field theory to make predictions for experiment. This will be achieved through the advancement of new, constructive frameworks to determine and represent scattering amplitudes in perturbation theory in terms that depend only on observable quantities, make manifest (all) the symmetries of the theory, and which can be efficiently evaluated while minimally spoiling the underlying simplicity of predictions. My research has already led to the discovery and development of several approaches of this kind. This proposal describes the specific steps required to extend these ideas to more general theories and to higher orders of perturbation theory. Specifically, the plan of research I propose consists of three concrete goals: to fully characterize the discontinuities of loop amplitudes (`on-shell functions') for a broad class of theories; to develop powerful new representations of loop amplitude {\it integrands}, making manifest as much simplicity as possible; and to develop new techniques for loop amplitude {integration} that are compatible with and preserve the symmetries of observable quantities. Progress toward any one of these objectives would have important theoretical implications and valuable practical applications. In combination, this proposal has the potential to significantly advance the state of the art for both our theoretical understanding and our computational reach for making predictions for experiment. To achieve these goals, I will pursue a data-driven, `phenomenological' approach—involving the construction of new computational tools, developed in pursuit of concrete computational targets. For this work, my suitability and expertise is amply demonstrated by my research. I have not only played a key role in many of the most important theoretical developments in the past decade, but I have personally built the most powerful computational tools for their

1 499 695 €

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

The main goal of ASTRUm is to employ stored and cooled radioactive ions for forefront nuclear astrophysics research. Four key experiments are proposed to be conducted at GSI in Darmstadt, which holds the only facility to date capable of storing highly charged radionuclides in the required element and energy range. The proposed experiments can hardly be conducted by any other technique or method. The weak decay matrix element for the transition between the 2.3 keV state in 205Pb and the ground state of 205Tl will be measured via the bound state beta decay measurement of fully ionized 205Tl81+. This will provide the required data to determine the solar pp-neutrino flux integrated over the last 5 million years and will allow us to unveil the astrophysical conditions prior to the formation of the solar system. The measurements of the alpha-decay width of the 4.033 MeV excited state in 19Ne will allow us to constrain the conditions for the ignition of the rp-process in X-ray bursters. ASTRUm will open a new field by enabling for the first time measurements of proton- and alpha-capture reaction cross-sections on radioactive nuclei of interest for the p-process of nucleosynthesis. Last but not least, broad band mass and half-life measurements in a ring is the only technique to precisely determine these key nuclear properties for nuclei with half-lives as short as a millisecond and production rates of below one ion per day. To accomplish these measurements with highest efficiency, sensitivity and precision, improved detector systems will be developed within ASTRUm. Possible applications of these systems go beyond ASTRUm objectives and will be used in particular in accelerator physics. The instrumentation and experience gained within ASTRUm will be indispensable for planning the future, next generation storage ring projects, which are launched or proposed at several radioactive ion beam facilities.

1 874 750 €

Start date: 2016-04-01, End date: 2021-03-31

We propose to investigate hybrid quantum systems composed of ultracold atoms and ions. The mutual interaction of the cold neutral atoms and the trapped ion offers a wealth of interesting new physical problems. They span from ultracold quantum chemistry over new concepts for quantum information processing to genuine quantum many-body physics. We plan to explore aspects of quantum chemistry with ultracold atoms and ions to obtain a full understanding of the interactions in this hybrid system. We will investigate the regime of low energy collisions and search for Feshbach resonances to tune the interaction strength between atoms and ions. Moreover, we will study collective effects in chemical reactions between a Bose-Einstein condensate and a single ion. Taking advantage of the extraordinary properties of the atom-ion mixture quantum information processing with hybrid systems will be performed. In particular, we plan to realize sympathetic ground state cooling of the ion with a Bose-Einstein condensate. When the ion is immersed into the ultracold neutral atom environment the nature of the decoherence will be tailored by tuning properties of the environment: A dissipative quantum phase transition is predicted when the ion is coupled to a one-dimensional Bose gas. Moreover, we plan to realize a scalable hybrid quantum processor composed of a single ion and an array of neutral atoms in an optical lattice. The third direction we will pursue is related to impurity effects in quantum many-body physics. We plan to study transport through a single impurity or atomic quantum dot with the goal of realizing a single atom transistor. A single atom transistor transfers the quantum state of the impurity coherently to a macroscopic neutral atom current. Finally, we plan to observe Anderson s orthogonality catastrophe in which the presence of a single impurity in a quantum gas orthogonalizes the quantum many-body function of a quantum state with respect to the unperturbed one.

1 405 000 €

Start date: 2009-10-01, End date: 2014-09-30

Collective electron motion can unfold on attosecond time scales in nanoplasmonic systems, as defined by the inverse spectral bandwidth of the plasmonic resonant region. Similarly, in dielectrics or semiconductors, the laser-driven collective motion of electrons can occur on this characteristic time scale. Until now, such collective electron dynamics has not been directly observed on its natural, attosecond timescale. In ATTOCO, the attosecond, sub-cycle dynamics of strong-field driven collective electron dynamics in clusters and nanoparticles will be explored. Moreover, we will explore field-dependent processes induced by strong laser fields in nanometer sized matter, such as the metallization of dielectrics, which has been recently proposed theoretically. In order to map the collective electron motion we will apply the attosecond nanoplasmonic streaking technique, which has been proposed and developed theoretically. In this approach, the temporal resolution is achieved by limiting the emission of high energetic, direct photoelectrons to a sub-cycle time window using attosecond XUV pulses phase-locked to a driving few-cycle near-infrared field. Kinetic energy spectra of the photoelectrons recorded for different delays between the excitation field and the ionizing XUV pulse will allow extracting the spatio-temporal electron dynamics. ATTOCO offers the capability to measure field-induced material changes in real-time and to gain novel insight into collective electron dynamics. In particular, we aim to learn from ATTOCO in detail, how the collective electron motion is established, how the collective motion is driven by the strong external field and over which pathways and timescale the collective motion decays. ATTOCO provides also a major step in the development of lightwave (nano-)electronics, which may push the frontiers of electronics from multi-gigahertz to petahertz frequencies. If successfully accomplished, this development will herald the potential scalability of electron-based information technologies to lightwave frequencies, surpassing the speed of current computation and communication technology by many orders of magnitude.

1 498 500 €

Start date: 2013-06-01, End date: 2018-05-31

Embedded Control software plays a critical role in many safety-critical applications. For instance, modern vehicles use interacting software and hardware components to control steering and braking. Control software forms the main core of autonomous transportation, power networks, and aerospace. These applications are examples of cyber-physical systems (CPS), where distributed software systems interact tightly with spatially distributed physical systems with complex dynamics. CPS are becoming ubiquitous due to rapid advances in computation, communication, and memory. However, the development of core control software running in these systems is still ad hoc and error-prone and much of the engineering costs today go into ensuring that control software works correctly. In order to reduce the design costs and guaranteeing its correctness, I aim to develop an innovative design process, in which the embedded control software is synthesized from high-level correctness requirements in a push-button and formal manner. Requirements for modern CPS applications go beyond conventional properties in control theory (e.g. stability) and in computer science (e.g. protocol design). Here, I propose a compositional methodology for automated synthesis of control software by combining compositional techniques from computer science (e.g. assume-guarantee rules) with those from control theory (e.g. small-gain theorems). I will leverage decomposition and abstraction as two key tools to tackle the design complexity, by either breaking the design object into semi-independent parts or by aggregating components and eliminating unnecessary details. My project is high-risk because it requires a fundamental re-thinking of design techniques till now studied in separate disciplines. It is high-gain because a successful method for automated synthesis of control software will make it finally possible to develop complex yet reliable CPS applications while considerably reducing the engineering cost.

1 470 800 €

Start date: 2019-02-01, End date: 2024-01-31

The most energetic electromagnetic phenomena in the Universe are believed to be powered by the collision of two neutron stars, the smallest and densest stars on which surface gravity is about 2 billion times stronger than gravity on Earth. However, a definitive identification of neutron star mergers as central engines for short-gamma-ray bursts and kilonovae transients is possible only by direct gravitational-wave observations. The latter provide us with unique information on neutron stars' masses, radii, and spins, including the possibility to set the strongest observational constraints on the unknown equation-of-state of matter at supranuclear densities. Neutron stars binary mergers are among the main targets for ground-based gravitational-wave interferometers like Advanced LIGO and Virgo, which start operations this year. The astrophysical data analysis of the signals emitted by these sources requires the availability of accurate waveform models, which are missing to date. Hence, the theoretical understanding of the gravitational spectrum is a necessary and urgent step for the development of a gravitational-based astrophysics in the next years. This project aims at developing, for the first time, a precise theoretical model for the complete gravitational spectrum of neutron star binaries, including the merger and postmerger stages of the coalescence process. Building on the PI's unique expertise and track record, the proposed research exploits synergy between analytical and numerical methods in General Relativity. Results from state of the art nonlinear 3D numerical relativity simulations will be combined with the most advanced analytical framework for the relativistic two-body problem. The model developed here will be used in the first gravitational-wave observations and will dramatically impact multimessenger astrophysics.

1 432 301 €

Start date: 2017-10-01, End date: 2022-09-30

Wireless communication networks are the essential connectivity tissue of the modern digital age. Wireless data traffic is predicted to increase by almost three orders of magnitude in the next five years. It is unlikely that such increase can be tackled by an incremental “more-of-the-same” approach. This proposal stems from the observation that the killer application for wireless networks is on-demand access to Internet content. CARENET advocates a novel content-aware approach to wireless networks design that can provably solve the scalability problem of current systems, thus supporting the paradigmatic shift “from Gigabits per second for a few to Terabytes per month for all”. CARENET’s vision is to serve an arbitrarily large number of users with bounded transmission resources (bandwidth, number of transmit antennas, and power). The fundamental question is: how can such a per-user throughput scalability be achieved in the presence of on-demand requests, for which users do not access simultaneously the same content? CARENET builds on a novel information theoretic formulation of content-aware networks and on several recent results in information theory, network coding, channel coding, and protocol design, stimulated by the PI’s recent work. Key elements of the proposed content-aware architectures are new caching strategies, where content is stored across the wireless network nodes. These strategies are supported by the ever-growing on-board memory of wireless devices and by the new features of the forthcoming 5G-like technology. Our thesis is that scalability is possible through the novel content-aware design, while it is information-theoretically impossible otherwise. Our overarching goal envisions the delivery of one Terabyte per month to each user at an affordable cost and good Quality of Experience, rather than the traditional Gigabit per second peak rates targeted by conventional technology development.

2 497 500 €

Start date: 2018-10-01, End date: 2023-09-30

Synthetic biology is the bottom-up engineering of new molecular functionality inside a biological cell. Although it aims at a quantitative and compositional approach, most of today’s implementations of synthetic circuits are based on inefficient trial-and-error runs. This approach to circuit design does not scale well with circuit complexity and is against the basic paradigm of synthetic biology. This unsatisfactory state of affairs is partly due to the lack of the right computational methodology that can support the quantitative characterization of circuits and their significant context dependency, i.e., their change in behavior upon interactions with the host machinery and with other circuit elements. CONSYN will contribute computational methodology to overcome the trial-and-error approach and to ultimately turn synthetic circuit design into a rational bottom-up process that heavily relies on computational analysis before any actual biomolecular implementation is considered. In order to achieve this goal, we will work on the following agenda: (i) develop biophysical and statistical models of biomolecular contexts into which the synthetic circuit or synthetic part can be embedded in silico; (ii) devise new statistical inference methods that can deliver accurate characterization of circuits and their context dependency by making use of cutting-edge single-cell experimental data; (iii) derive new context-insensitive circuit designs through in silico sensitivity analysis and application of filtering theory; (iv) optimize protocols and measurement infrastructure using model-based experimental design yielding a better circuit and context characterization; (v) experimentally build synthetic circuits in vivo and in cell-free systems in order to validate and bring to life the above theoretical investigations. We are in the unique position to also address (v) in-house due to the experimental wetlab facilities in our group.

1 996 579 €

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

"A measurement of the 2S-2P transition frequencies (Lamb shift) in the muonic helium-3 and 4 ions by means of laser spectroscopy is proposed. This will lead to a ten times more accurate determination of the root-mean-square (rms) charge radii of the He-3 and He-4 nuclei. The radius of the magnetic moment distribution inside the He-3 nucleus will result from the hyperfine structure in muonic 3He. In the muonic helium ion, a single negative muon orbits the helium nucleus. The muon is a point-like lepton, just as the electron, except it is about 200 times heavier. This gives a factor of 200^3 = 10^7 enhancement of nuclear finite size effects on the energy levels of muonic vs. regular (electonic) Helium ions. Muonic helium is the ideal sytem to study the He nuclear size. The CREMA project has four main aims: (1) Solve the ""proton size puzzle"" created by our recently completed muonic hydrogen project [R. Pohl et al., ""The size of the proton"", Nature 466, 213 (2010)]. Our tenfold improvement of the proton charge radius resulted in a five sigma discrepancy with the 2006 CODATA value, which is mostly based on hydrogen spectroscopy. This poses a serious challenge to bound-state QED, and may even point towards new physics. CREMA will help to clarify this. (2) Absolute nuclear charge radii of all helium isotopes He-3,4,6,8 will result from CREMA. The charge radius differences are precisely known, but the absolute size of the He-4 anchor nucleus can best be measured in muonic helium. Absolute charge radii are a more stringent benchmark for few-nucleon nuclear models than the radius difference. (3) Test of bound-state QED: Spectroscopy of regular He+ ions is underway. He+ (Z=2) is more sensitive than hydrogen (Z=1) to higher-order QED contributions which scale as Z^5. An accurate He charge radius from CREMA is mandatory for this. (4) An improved value of the Rydberg constant will result from the He+ spectroscopy only with the improved charge radius from CREMA."

1 499 976 €

Start date: 2011-11-01, End date: 2016-10-31

The generation of a movement is the combination of discrete events (action potentials) generated in the brain, spinal cord, nerves, and muscles. These discrete events are the result of ion exchanges across membranes, electrochemical mechanisms, and active ion pumping through energy expenditure. The ensemble of spike trains discharged in the various parts of the neuromuscular system constitutes the neural code for movements. Recording and interpretation of this code provides the means for decoding the motor system. The main limitation in the investigation of the motor system is the current impossibility of detecting and processing in the intact human, during natural movements, the activity of a sufficiently large number of motor neurons and sensory afferents (neural code) to associate a functional meaning to the cellular mechanisms that ultimately determine a movement. This limitation in turn impedes to answer to many fundamental questions on the control of human movements. These questions have tremendous implications in the development of man-machine interface systems. In this project, we propose the development of advanced electrode systems for in-vivo electrophysiological recordings from nerves and muscles in humans and new computational methods/models for extracting functionally significant information on human movement from these recordings. The highly innovative focus is that of providing the link between the cellular mechanisms and the behavior of the whole motor system in the intact human, i.e. to build the bridge between the neural and functional understanding of movement. On the basis of these new technologies, we aim at answering open questions in movement neuroscience and using novel principles for man-machine interaction. Specific applications in man-machine interaction will be related to neurorehabilitation technologies, such as functional electrical stimulation, myoelectric and peripheral neural prostheses.

2 431 473 €

Start date: 2011-07-01, End date: 2016-06-30

Understanding the quantum many-particle problem is one of the grand challenges of modern physics. While tremendous progresses have been made over the past decades in thermodynamic equilibrium, nonequilibrium many-body quantum physics is still in its infancy. Strong motivation for addressing this challenge comes from recent experimental developments in diverse areas, ranging from cold atomic gases over light-driven semiconductors to microcavity arrays. This moves systems into the focus, which are located on the interface of quantum optics, many-body physics and statistical mechanics. They share in common that coherent and driven-dissipative quantum dynamics occur on an equal footing, creating scenarios without immediate counterpart in traditional condensed matter systems. This project has the goal of pushing forward the understanding of such driven open quantum systems. To this end, we follow a combined approach structured around three key challenges. (i) We aim to identify novel macroscopic phenomena, which manifestly witness microscopic non-equilibrium conditions. This concerns non-thermal stationary states, where we will shape an understanding of non-equilibrium phase diagrams and the associated phase transitions, in particular constructing a notion of driven quantum criticality. But it also encompasses the identification of new universal regimes in open system time evolution. Finally, we will extend the concept of topological order to a broader non-equilibrium context, motivated by quantum information applications. (ii) We will create new theoretical tools, in particular advancing a flexible Keldysh dynamical quantum field theory for driven open quantum systems. (iii) We will address a broad spectrum of cutting edge experimental platforms in view of exploring our theoretical scenarios, and to foster mutual cross-fertilization. With an emphasis on cold atomic gases, this program also comprises exciton-polariton condensates and coupled circuit QED architectures.

1 676 424 €

Start date: 2016-02-01, End date: 2021-01-31

In this project I will develop and exploit experimental methods, based on short and intense laser pulses, to control the spatial orientation of molecules dissolved in liquid helium nanodroplets. This idea is, so far, completely unexplored but it has the potential to open a multitude of new opportunities in physics and chemistry. The main objectives are: 1) Complete control and real time monitoring of molecular rotation inside liquid helium droplets, exploring superfluidity of the droplets, the possible formation of quantum vortices, and rotational dephasing due to interaction of the dissolved molecules with the He solvent. 2) Ultrafast imaging of molecules undergoing chemical reaction dynamics inside liquid helium droplets, exploring rapid energy dissipation from reacting molecules to the helium solvent, transition between mirror forms of chiral molecules, strong laser field processes in He-solvated molecules, and structure determination of non crystalizable proteins by electron or x-ray diffraction. I will achieve the objectives by combining liquid helium droplet technology, ultrafast laser pulse methods and advanced electron and ion imaging detection. The experiments will both rely on existing apparatus in my laboratories and on new vacuum and laser equipment to be set up during the project. The ability to control how molecules are turned in space is of fundamental importance because interactions of molecules with other molecules, atoms or radiation depend on their spatial orientation. For isolated molecules in the gas phase laser based methods, developed over the past 12 years, now enable very refined and precise control over the spatial orientation of molecules. By contrast, orientational control of molecules in solution has not been demonstrated despite the potential of being able to do so is enormous, notably because most chemistry occurs in a solvent rather than in a gas of isolated molecules.

2 409 773 €

Start date: 2013-05-01, End date: 2018-04-30

Optical imaging has exceptional potential for medical diagnosis, because it can provide high spatial resolution and molecular contrast. However, for in vivo imaging in humans, the poor penetration of only a few millimetres is a major obstacle. Optical endoscopes solve this problem, but currently most of them only perform non-advanced, classical white light imaging. Also, the speed of current devices is not sufficient to comprehensively scan entire organs at microscopic resolution. Hence, medical imaging is still dominated by non-optical techniques like X-ray, ultrasound and magnetic resonance imaging. The objective of ENCOMOLE-2i is to push the performance of advanced optical in vivo imaging techniques to cross the application threshold for clinical research and practice. An endoscopic multi-modal molecular imaging platform will be developed with unprecedented capabilities for the diagnosis of disease. The hardware technology development includes three novel imaging modalities. Optical coherence tomography with line rates of several Megahertz will be used for comprehensive structural imaging over large areas. Time encoded stimulated Raman sensing, supported by a new type of two photon microscopy, will be used for guided and referenced molecular imaging. Combining these techniques into one system and interfacing it with a newly developed endoscope will generate great synergy. Moreover, the unique synchronization capabilities of these modalities enable a radically new strategy for more efficient data acquisition: The concept of adaptive “Intelligent Imaging”. The goal is to develop a universal endoscopy platform which can then be specifically tailored to the individual application. In the project the focus is on gastrointestinal imaging. The synergy between technological and algorithmic advances in ENCOMOLE-2i will break ground for more optical in vivo imaging in clinical research and routine, which can finally lead to improved diagnosis of many types of disease.

1 998 530 €

Start date: 2016-01-01, End date: 2020-12-31

Entanglement plays a central role for strongly correlated quantum many-body systems and is considered to be the root for a number of surprising emergent phenomena in solids such as high-temperature superconductivity or fractional Quantum Hall states. Entanglement detection in these systems is an important target of current research, but has so far remained elusive owing to the fine control required and high demands on statistical sampling. The goal of this project is to realize strongly correlated quantum systems close to the ground state using quantum annealing of ultracold fermionic atoms, and to study the character, strength and role of entanglement. We will construct a novel type of cold atom experiment, which makes use of optical tweezers and Raman sideband cooling. This will allow a 100-fold improvement in the experimental repetition rate compared to conventional experiments and allow reaching the ground state in systems of up to 7x7 sites. The flexibility of the moving optical tweezers will facilitate implementing entanglement measures, including concurrence, quantum-state tomography and entanglement entropy. Our primary research objective is studying entanglement in the doped Hubbard model, where a variety of strongly correlated systems are expected, as well as the role of entanglement in thermalizing out-of-equilibrium samples. In a later stage we will focus on frustrated systems in triangular lattices and honeycomb geometries, and also interacting topological states. Our experiments will have a far-reaching impact on condensed matter research, as it will be the first platform for experimental exploration of the role of entanglement in strongly correlated fermionic many-body systems. Our insights will be beyond the capabilities of numerical simulations and we envision that the project will lead to a better understanding of complex quantum phenomena, and may ultimately drive the discovery of novel quantum materials.

1 787 564 €

Start date: 2019-08-01, End date: 2024-07-31

Motivated by the overwhelming success of symmetry concepts in formulating basic laws of physics, the present proposal (eQG) seeks to develop a new symmetry based approach to the problem of reconciling Quantum Mechanics and Einstein’s General Relativity into a consistent theory of Quantum Gravity, regarded by many as the greatest challenge of contemporary theoretical physics. The need for such a theory is most pressing for the resolution of black hole singularities and the Big Bang, but it is equally crucial to the search for a consistent UV completion of the Standard Model of Particle Physics and the unification of the fundamental interactions. eQG aims to tackle this problem from a new perspective, bringing together very different strands of development: on the one hand, by paying particular attention to recent advances in our understanding of cosmological singularities and the evidence for novel infinite-dimensional duality symmetries near the singularity that has emerged in supergravity and string theory, and to recent progress in formulating ‘exceptional geometries’ transcending Riemannian geometry; on the other hand, by exploiting insights from modern canonical quantisation towards a better understanding of the basic degrees of freedom and the dynamics of quantum space-time. The main focus of eQG will be the ‘maximally extended’ exceptional hyperbolic Kac–Moody symmetry E10, whose uniquely distinguished status makes it a prime candidate symmetry for unifying the known dualities of string and M theory, for a conceptually precise scenario of emergent (quantum) space and time near the singularity, and finally, for replacing supersymmetry as a guiding principle for unification. Consequently, the principal goal of eQG will be to explore how this symmetry can define a theory of quantum gravity, how it acts on its fundamental degrees of freedom, what the special features are of the quantised theory, and what physical predictions can be derived from it.

1 918 750 €

Start date: 2017-12-01, End date: 2022-11-30

Where in the universe are heavy elements synthesized? How are these elements produced? These are two exciting and interdisciplinary questions in nuclear astrophysics today and will be investigated in my ERC project EUROPIUM. The favored astrophysical sites are neutrino-driven winds following core-collapse supernovae and neutron star mergers, where extreme conditions enable the rapid neutron capture process (r-process). We will perform long-time multidimensional simulations of these two scenarios and combine them with nucleosynthesis calculations. In neutron star mergers, the radioactive decay of neutron-rich nuclei triggers an electromagnetic signal known as kilonova. This was potentially observed in 2013 after a short gamma ray burst, associated with a neutron star merger. We will simulate the neutrino- and viscous-driven ejecta from the disk that forms after the merger around the central compact object. In addition, we will investigate supernova neutrino-driven winds that produce lighter heavy elements from strontium to silver. We will explore the impact of rotation, improved microphysics, and magnetic fields on the wind evolution and nucleosynthesis. Because the synthesis of lighter heavy elements elements occurs closer to stability, the nuclear physics uncertainties will be reduced by experiments in the near future. This will uniquely allow us to combine observations and nucleosynthesis calculations to constrain the astrophysical conditions and gain new insights into core-collapse supernovae. In nuclear physics, a new era for extreme neutron-rich isotopes is starting with new experimental facilities. Based on our simulations, we will study the impact of the nuclear physics input (nuclear masses, beta decays, neutron captures, and fission) going beyond the state-of-the-art by providing r-process abundances with uncertainties. Comparing our results with forefront observations of the oldest stars will in turn provide new insights about the origin of heavy elements.

1 446 875 €

Start date: 2016-05-01, End date: 2021-04-30

A new class of devices exploiting Fano resonances and with important applications in information technology is suggested. Typically, the resonance of a system is described by a frequency and a lifetime, leading to a Lorentzian lineshape function. If the system instead involves interference between a discrete resonance and a continuum, a Fano lineshape appears with fundamentally different characteristics. Here, the Fano resonance is used to make a novel integrated mirror, enabling realization of Fano lasers, Fano switches and quantum Fano devices. These devices challenge well-accepted paradigms for photonic devices. The goals of the project are to demonstrate a laser with modulation bandwidth greatly exceeding all existing lasers; a nanolaser with linewidth three orders of magnitude smaller than existing nanocavity lasers; and a switch that operates at femtojoule energies and provides gain. Such devices are important for realizing high-speed optical interconnects and networks between and within chips. An increasing fraction of the global energy consumption is being used for data communication, and photonics operating at very high data rates with ultra-low energy per bit has been identified as a key technology to enable a sustainable growth of capacity demands. Existing device designs, however, cannot just be scaled down to reach the goals for next-generation integrated devices. The Fano mirror will also be used to demonstrate control at the single-photon level, which will enable high-quality on-demand single-photon sources, which are much demanded devices in photonic quantum technology. These devices all rely on the unique properties of the Fano mirror, which provides a new resource for ultrafast dynamic control, noise suppression and ultra-low energy operation. Using photonic crystal technology the project will achieve its goals in a concerted effort involving development of new theory, new nanofabrication techniques and advanced experiments.

2 500 000 €

Start date: 2019-09-01, End date: 2024-08-31

In the last decade, Silicon Photonics has been a rapidly growing field fueled by the promise of highly scalable, ultra-low power, high bandwidth and low cost silicon based optical communication systems. The last few years have seen the emergence of several dedicated world-class research groups, a dedicated international conference, heavy investments by the semiconductor industry giants, multiple private equity funded start-ups, as well as dedicated multi-user foundry services. Nevertheless, several critical roadblocks remain that have so far prevented the field from displacing older optical technologies, the resolution of which presents extremely challenging scientific challenges, requiring highly innovative devices and system architectures as well as bleeding edge process development. In a nutshell, state-of-the-art Silicon Photonics remains marginally too expensive for ultra-short distance links, too low performance for long haul communications, and still has too high a power consumption to displace electrical interconnects at the circuit board level. It is the goal of this proposal to reach three key milestones that in the applicant’s opinion are critical enablers for the field on its path towards becoming a truly disruptive technology.

1 917 080 €

Start date: 2011-10-01, End date: 2017-09-30

Six quarks and six leptons of different kinds, referred to as flavours, form the modern periodic table of the fundamental building blocks of matter. The Standard Model of particle physics successfully describes these elementary particles and the forces between them. A deeper understanding of the flavour structure of quarks and leptons, of their masses and couplings, is however still missing. Decisive new experiments are about to start in particle physics (LHC, high-intensity flavour facilities). They will test existing theoretical concepts and inspire new ideas. This should allow us to make substantial steps forwards in the construction of the fundamental Theory of Flavour, which is the main goal of this project. Such a theory should allow us to address the following fundamental questions: what is the underlying dynamics differentiating quarks and leptons of different flavour? Is this dynamics related to a new symmetry? How can this new dynamics be tested at low and high energies? These questions are of utmost importance in the context of our search for a new, more fundamental, theory of elementary interactions. They are also key ingredients to understand the strucutre of our Universe. Reaching this goal requires substantial efforts in model building, precision calculations, and phenomenological studies. These different lines of research will be joined in a novel way by the collaboration of the principal investigator with four younger team members. All team members have made, mostly independently, important and often pioneering contributions to the different aspects of this project. The combination of their different expertise in a joint effort is a unique feature of the present proposal.

1 578 400 €

Start date: 2011-05-01, End date: 2016-04-30

Motivation The enormous growth in the Internet of Things and server farms for cloud services has increased the strain on the optical communication infrastructure. By 2025, our society will require data rates that are physically impossible to implement using current state-of-the-art optical communication technologies. This is because fibre-optic communication systems are rapidly approaching their fundamental capacity limits imposed by the Kerr nonlinearity of the fibre. Nonlinear distortion limits the ability to transport and detect the information stream. This is a very critical problem for increasing the data rates of any optical fibre communication system. Proposed research The only physical quantities not affected by the nonlinearity are eigenvalues, associated with the optical fibre propagation equation. Eigenvalues are thereby ideal candidates for information transport. The concept of eigenvalues is derived under the assumption that the fibre is lossless and that there is no noise in the system which is not strictly correct. Therefore, novel methodologies and concepts for the design of a noise mitigating receiver and a noise robust transmitter are needed to reap the full benefits of optical communication systems employing eigenvalues. This proposal will develop such strategies. This will be achieved by combining, for the first time, the fields of nonlinear optics, optical communication and nonlinear digital signal processing. The results from the project will be verified experimentally, and will form the basis for a new generation of commercial optical communication systems. Preliminary results Our proof-of-concept results demonstrate, for the first time, that noise can be handled by employing novel receiver concepts. An order of magnitude improvement compared to the state-of-the-art is demonstrated. Environment The research will be carried out in close cooperation with leading groups at Stanford University and Technical University of Munich.

2 000 000 €

Start date: 2018-03-01, End date: 2023-02-28

"Functional Renormalization provides a bridge from fundamental microphysical laws to macroscopic complexity and observations. Acting like a ""theoretical microscope"" with variable resolution, it includes in a stepwise procedure the fluctuation effects which are responsible for the emergence of complexity. It describes macroscopic phenomena that are not directly visible on the microscopic level as order, phase transitions and spontaneous symmetry breaking , and is flexible enough to accommodate the change of effective degrees of freedom and associated effective laws. The laws of Nature become dependent on the length scale. We propose to develop non-perturbative flow equations into a precision tool for the understanding of many body physics, that can be tested by experiments with ultracold atoms. Fundamental questions as a formulation of quantum gravity as a non-perturbatively renormalizable quantum field theory, the emergence of fundamental length scales or the origin of dark energy will be tackled with this method. We also will address specific applications as the non-linear growth of structure in cosmology or the phase diagram of models for strongly correlated electrons."

1 955 400 €

Start date: 2012-04-01, End date: 2017-03-31