ERC FUNDED PROJECTS

Macroscopic control of quantum states is a major theme in much of modern physics because quantum coherence enables study of fundamental physics and has promising applications for quantum information processing. The potential significance of quantum computing is recognized well beyond the physics community. For electron spins in GaAs quantum dots, it has become clear that decoherence caused by interactions with the nuclear spins is a major challenge. We propose to investigate and reduce hyperfine induced decoherence with two complementary approaches: nuclear spin state narrowing and nuclear spin polarization. We propose a new projective state narrowing technique: a large, Coulomb blockaded dot measures the qubit nuclear ensemble, resulting in enhanced spin coherence times. Further, mediated by an interacting 2D electron gas via hyperfine interaction, a low temperature nuclear ferromagnetic spin state was predicted, which we propose to investigate using a quantum point contact as a nuclear polarization detector. Estimates indicate that the nuclear ferromagnetic transition occurs in the sub-Millikelvin range, well below already hard to reach temperatures around 10 mK. However, the exciting combination of interacting electron and nuclear spin physics as well as applications in spin qubits give ample incentive to strive for sub-Millikelvin temperatures in nanostructures. We propose to build a novel type of nuclear demagnetization refrigerator aiming to reach electron temperatures of 0.1 mK in semiconductor nanostructures. This interdisciplinary project combines Microkelvin and nanophysics, going well beyond the status quo. It is a challenging project that could be the beginning of a new era of coherent spin physics with unprecedented quantum control. This project requires a several year commitment and a team of two graduate students plus one postdoctoral fellow.

1 377 000 €

Start date: 2008-06-01, End date: 2013-05-31

The DNA within our cells is constantly being damaged by both environmental and endogenous agents; of the many forms of DNA damage, the DNA double-strand break (DSB) is considered to be most dangerous. Correct processing of DSBs is not only essential for maintaining genomic integrity but is also required in specific biological processes, such as meiotic recombination and V(D)J recombination, in which DNA breaks are deliberately generated. In animals, defects in the proper response to DSBs can thus have different outcomes: cancer predisposition, embryonic lethality, or compromised immunity. Many genes that play a role in the processing of DSBs have been identified over the past decades, mainly by cloning genes that are responsible for specific human genomic instability or immune deficiency syndromes, and by genetic approaches using unicellular eukaryotes and rodent cell lines. It is, however, evident that many components required in higher eukaryotes are not yet known and the identification of those will be a major challenge for future research. Here, we will for the first time systematically test all genes encoded by an animals genome directly for their involvement in the cellular response to DSB in both somatic and germline tissues: we will use our recently developed transgenic animal models (C. elegans) that visualizes repair of a single localized genomic DNA break in genome wide RNAi screenings to identify (and then characterize) the complement of genes that are required to keep our genome stable, and when mutated can predispose humans to cancer. In parallel, we will study the cellular response to single DNA breaks that are artificially generated during different stages of gametogenesis, as well as address the developmental consequences of DSB induction during the earliest stages of embryonic development – an almost completely unexplored area in the field of genome instability and DNA damage responses.

1 060 000 €

Start date: 2008-05-01, End date: 2014-04-30

My project is to write a history of the formation of Islam using the vastly important but largely neglected papyri from Egypt. Until the introduction of paper in the 10th C., papyrus was the Mediterranean world’s primary writing material. Thousands of papyrus documents survive, preserving a minutely detailed transcription of daily life, as well as the only contemporary records of Islam’s rise and first wave of conquests. As an historian and papyrologist, my career has been dedicated to developing the potential of this extraordinary resource. The prevailing model of Islam’s formation is based on sources composed by a literary élite some 150 years after the events they describe. The distortions this entails are especially problematic since it was in these first two centuries that Islam’s institutional, social and religious framework developed and stabilised. To form a meaningful understanding of this development requires tackling the contemporary documentary record, as preserved in the papyri. Yet the technical difficulties presented by these mostly unpublished and uncatalogued documents have largely barred their use by historians. This project is a systematic attempt to address this critical problem. The project has three stages: 1) a stocktaking of unedited Arabic, Coptic and Greek papyri; 2) the editing of a corpus of the most significant papyri; 3) the presentation of a synthetic historical analysis through scholarly publications and a dedicated website. By examining the impact of Islam on the daily life of those living under its rule, the goal of this project is to understand the striking newness of Islamic society and its debt to the diverse cultures it superseded. Questions will be the extent, character and ambition of Muslim state competency at the time of the Islamic conquest; the steps – military, administrative and religious – by which it extended its reach and what this tells us about the origins and evolution of Muslim ideas of rulership, religion and pow

1 000 000 €

Start date: 2009-03-01, End date: 2015-02-28

Protein folding, the process by which a protein assumes its three-dimensional shape, is one of the basic unsolved problems of biophysical and biochemical research. Many of the structural changes taking place during protein folding, especially during the early stages, are as yet poorly understood. This is because high-resolution structural techniques generally lack the time resolution necessary for observation of folding dynamics, whereas methods that have the required time resolution generally lack structural specificity. We propose an experimental approach that combines the structure-sensitivity of multi-dimensional NMR with the ultrafast time resolution of optical techniques. To do this, we use two-dimensional optical spectroscopy (in particular, two-dimensional optical spectroscopy and time-resolved vibrational circular dichroism) in combination with site-specific labeling of proteins. This will make it possible to obtain a structurally and temporally resolved picture of protein folding, which can be regarded as a 'molecular movie' of the folding process. With the proposed method, we will investigate structural changes during protein folding at increasing levels of complexity: from the dynamics of alpha-helix nucleation, to the formation and structural characteristics of intermediate states in small globular proteins and complex beta-sheet topologies, to the nature of biologically functional, short-lived unfolded states in signalling proteins. At each of these levels of complexity, the proposed method will be used to unravel the mechanisms behind the respective folding events.

1 716 321 €

Start date: 2008-09-01, End date: 2014-08-31