ERC FUNDED PROJECTS

This project aims at designing novel hybrid nanophotonic devices comprising metallic nanostructures and active elements such as dye molecules or colloidal quantum dots. Three core objectives, each going far beyond the state of the art, shall be tackled: (i) Metamaterials containing gain materials: Metamaterials introduce magnetism to the optical frequency range and hold promise to create entirely novel devices for light manipulation. Since present day metamaterials are extremely absorptive, it is of utmost importance to fight losses. The ground-breaking approach of this proposal is to incorporate fluorescing species into the nanoscale metallic metastructures in order to compensate losses by stimulated emission. (ii) The second objective exceeds the ansatz of compensating losses and will reach out for lasing action. Individual metallic nanostructures such as pairs of nanoparticles will form novel and unusual nanometre sized resonators for laser action. State of the art microresonators still have a volume of at least half of the wavelength cubed. Noble metal nanoparticle resonators scale down this volume by a factor of thousand allowing for truly nanoscale coherent light sources. (iii) A third objective concerns a substantial improvement of nonlinear effects. This will be accomplished by drastically sharpened resonances of nanoplasmonic devices surrounded by active gain materials. An interdisciplinary team of PhD students and a PostDoc will be assembled, each scientist being uniquely qualified to cover one of the expertise fields: Design, spectroscopy, and simulation. The project s outcome is twofold: A substantial expansion of fundamental understanding of nanophotonics and practical devices such as nanoscopic lasers and low loss metamaterials.

1 494 756 €

Start date: 2010-10-01, End date: 2015-09-30

AQSuS aims at experimentally implementing analogue quantum simulation of interacting spin models in two-dimensional geometries. The proposed experimental approach paves the way to investigate a broad range of currently inaccessible quantum phenomena, for which existing analytical and numerical methods reach their limitations. Developing precisely controlled interacting quantum systems in 2D is an important current goal well beyond the field of quantum simulation and has applications in e.g. solid state physics, computing and metrology. To access these models, I propose to develop a novel circuit quantum-electrodynamics (cQED) platform based on the 3D transmon qubit architecture. This platform utilizes the highly engineerable properties and long coherence times of these qubits. A central novel idea behind AQSuS is to exploit the spatial dependence of the naturally occurring dipolar interactions between the qubits to engineer the desired spin-spin interactions. This approach avoids the complicated wiring, typical for other cQED experiments and reduces the complexity of the experimental setup. The scheme is therefore directly scalable to larger systems. The experimental goals are: 1) Demonstrate analogue quantum simulation of an interacting spin system in 1D & 2D. 2) Establish methods to precisely initialize the state of the system, control the interactions and readout single qubit states and multi-qubit correlations. 3) Investigate unobserved quantum phenomena on 2D geometries e.g. kagome and triangular lattices. 4) Study open system dynamics with interacting spin systems. AQSuS builds on my backgrounds in both superconducting qubits and quantum simulation with trapped-ions. With theory collaborators my young research group and I have recently published an article in PRB [9] describing and analysing the proposed platform. The ERC starting grant would allow me to open a big new research direction and capitalize on the foundations established over the last two years.

1 498 515 €

Start date: 2017-04-01, End date: 2022-03-31

This project aims at the development of a novel toolbox of ab-initio methods that approximate the true many-electron wavefunction using systematically improvable perturbation and coupled-cluster theories. The demand and prospects for these methods are excellent given that the highly-accurate coupled-cluster theories can predict atomization- and reaction energies in a wide range of solids and molecules with chemical accuracy (≈43 meV). However, the computational cost involved inhibits their widespread use in the field of materials science so far. A multitude of suggested developments in the present proposal hold the promise to reduce the computational cost beyond what is currently considered possible by the community. These include explicit correlation methods that augment the conventional wavefunction expansion with terms that depend on the electron pair correlation factors. In contrast to the widely-used homogeneous correlation factors, this proposal aims at the investigation of inhomogeneous correlation factors that can also capture van der Waals interactions. Furthermore this proposal seeks to employ a recently developed combination of atom-centered basis functions and plane wave basis sets, maximizing the compactness in the wavefunction expansion. The combination of these ideas bears the potential to reduce the computational cost of coupled-cluster calculations in solids by three orders of magnitude, leading to a breakthrough in the field of highly-accurate ab-initio simulations. As such the study of challenging solid state physics and chemistry problems forms an important part of this proposal. We seek to investigate molecular adsorption and reactions in zeolites and on surfaces, pressure-driven solid-solid phase transitions of two dimensional layered materials and defects in solids. These problems are paradigmatic for van der Waals interactions and strong correlation, and methods that describe their electronic structure accurately are highly sought after.

1 460 826 €

Start date: 2017-07-01, End date: 2022-06-30

The central research theme of this proposal is the study of social change (skills, productivity, attitudes and beliefs) in Europe along cohort lines and as a function of changing age composition. Using demographic methods, age-specific and cohort-specific changes shall be quantitatively disentangled. The impact of migration flows as well as fertility differentials combined with intergenerational transmissions will be taken into account. It is expected that viewed together, these analyses will result in significant new insights and represent frontier research about likely social and economic challenges associated with ageing and demographic change in Europe and the appropriate policies for coping with them. Unlike projections of long-term economic growth or energy use, demographic forecasts tend to have comparatively low margins of error, even for forecasts half a century ahead. Traits that change systematically along age or cohort lines may therefore be projected with some degree of accuracy, which in turn can allow governments and individuals to better foresee and improve policies for predictable social change. The study will investigate two major topics, the first relating to human capital, skills, and work performance; the second relating to beliefs and attitudes in Europe. Understanding age variation in productivity and how to improve senior workers skills and capacities are paramount for ageing countries. Moreover, individual-level demographic behaviour can have aggregate level implications, including changing societal values and belief structures. The binding element is how such projections will improve one s capacity to foresee and hence develop more targeted policies that relate to ageing societies.

981 415 €

Start date: 2009-10-01, End date: 2015-03-31