ERC FUNDED PROJECTS

Quantum chemistry provides two approaches to molecular electronic-structure calculations: the systematically refinable but expensive many-body wave-function methods and the inexpensive but not systematically refinable Kohn Sham method of density-functional theory (DFT). The accuracy of Kohn Sham calculations is determined by the quality of the exchange correlation functional, from which the effects of exchange and correlation among the electrons are extracted using the density rather than the wave function. However, the exact exchange correlation functional is unknown—instead, many approximate forms have been developed, by fitting to experimental data or by satisfying exact relations. Here, a new approach to density-functional analysis and construction is proposed: the Lieb variation principle, usually regarded as conceptually important but impracticable. By invoking the Lieb principle, it becomes possible to approach the development of approximate functionals in a novel manner, being directly guided by the behaviour of exact functional, accurately calculated for a wide variety of chemical systems. In particular, this principle will be used to calculate ab-initio adiabatic connection curves, studying the exchange correlation functional for a fixed density as the electronic interactions are turned on from zero to one. Pilot calculations have indicated the feasibility of this approach in simple cases—here, a comprehensive set of adiabatic-connection curves will be generated and utilized for calibration, construction, and analysis of density functionals, the objective being to produce improved functionals for Kohn Sham calculations by modelling or fitting such curves. The ABACUS approach will be particularly important in cases where little experimental information is available—for example, for understanding and modelling the behaviour of the exchange correlation functional in electromagnetic fields.

2 017 932 €

Start date: 2011-03-01, End date: 2016-02-29

The two fundamental challenges of this project are the integration of medieval Jewries and their histories within the framework of European history without undermining their distinct communal status and the creation of a history of everyday medieval Jewish life that includes those who were not part of the learned elite. The study will focus on the Jewish communities of northern Europe (roughly modern Germany, northern France and England) from 1100-1350. From the mid-thirteenth century these medieval Jewish communities were subject to growing persecution. The approaches proposed to access daily praxis seek to highlight tangible dimensions of religious life rather than the more common study of ideologies to date. This task is complex because the extant sources in Hebrew as well as those in Latin and vernacular were written by the learned elite and will require a broad survey of multiple textual and material sources. Four main strands will be examined and combined: 1. An outline of the strata of Jewish society, better defining the elites and other groups. 2. A study of select communal and familial spaces such as the house, the synagogue, the market place have yet to be examined as social spaces. 3. Ritual and urban rhythms especially the annual cycle, connecting between Jewish and Christian environments. 4. Material culture, as objects were used by Jews and Christians alike. Aspects of material culture, the physical environment and urban rhythms are often described as “neutral” yet will be mined to demonstrate how they exemplified difference while being simultaneously ubiquitous in local cultures. The deterioration of relations between Jews and Christians will provide a gauge for examining change during this period. The final stage of the project will include comparative case studies of other Jewish communities. I expect my findings will inform scholars of medieval culture at large and promote comparative methodologies for studying other minority ethnic groups

1 941 688 €

Start date: 2016-11-01, End date: 2021-10-31

Digital signal processing (DSP) is a revolutionary paradigm shift enabling processing of physical data in the digital domain where design and implementation are considerably simplified. However, state-of-the-art analog-to-digital convertors (ADCs) preclude high-rate wideband sampling and processing with low cost and energy consumption, presenting a major bottleneck. This is mostly due to a traditional assumption that sampling must be performed at the Nyquist rate, that is, twice the signal bandwidth. Modern applications including communications, medical imaging, radar and more use signals with high bandwidth, resulting in prohibitively large Nyquist rates. Our ambitious goal is to introduce a paradigm shift in ADC design that will enable systems capable of low-rate, wideband sensing and low-rate DSP. While DSP has a rich history in exploiting structure to reduce dimensionality and perform efficient parameter extraction, current ADCs do not exploit such knowledge. We challenge current practice that separates the sampling stage from the processing stage and exploit structure in analog signals already in the ADC, to drastically reduce the sampling and processing rates. Our preliminary data shows that this allows substantial savings in sampling and processing rates --- we show rate reduction of 1/28 in ultrasound imaging, and 1/30 in radar detection. To achieve our overreaching goal we focus on three interconnected objectives -- developing the 1) theory 2) hardware and 3) applications of sub-Nyquist sampling. Our methodology ties together two areas on the frontier of signal processing: compressed sensing (CS), focused on finite length vectors, and analog sampling. Our research plan also inherently relies on advances in several other important areas within signal processing and combines multi-disciplinary research at the intersection of signal processing, information theory, optimization, estimation theory and hardware design.

2 400 000 €

Start date: 2015-08-01, End date: 2020-07-31

The overall objective is to fully understand the Chiral Induced Spin Selectivity (CISS) effect, which was discovered recently. It was found that the transmission or conduction of electrons through chiral molecules is spin dependent. The CISS effect is a change in the pradigm that assumed that any spin manipulation requiers magnetic materials or materials with high spin-orbit coupling. These unexpected new findings open new possibilities for applying chiral molecules in spintronics applications and may provide new insights on electron transfer processes in Biology. The specific goals of the proposed research are (i) To establish the parameters that affect the magnitude of the CISS effect. (ii) To demonstrate spintronics devices (memory and transistors) that are based on the CISS effect. (iii) To investigate the role of CISS in electron transfer in biology related systems. The experiments will be performed applying a combination of experimental methods including photoelectron spectroscopy, single molecule conduction, light-induced electron transfer, and spin specific conduction through magneto-electric devices. The project has a potential to have very large impact on various fields from Physics to Biology. It will result in the establishment of chiral organic molecules as a new substrate for wide range of spintronics related applications including magnetic memory, and in determining whether spins play a role in electron transfer processes in biology.

2 499 998 €

Start date: 2013-10-01, End date: 2018-09-30