Unravelling the fundamental phenomena of electron motion on its intrinsic time and length scales is a vital pre-requisite for technological applications as dynamics of quantum systems are largely determined by ultrafast processes occurring on sub-picosecond time and atomic length scales. ELISTRA will gain unprecedented access to the ultrafast physics of ballistic electron transport through free-standing graphene nanoribbons (GNRs) with atomic scale control by combining for the first time scanning tunnelling microscope (STM) transport experiments with sub-cycle THz laser pulses funnelled into the STM junction (light wave STM). To achieve this, single atomically precise GNRs are positioned with sub-nanometre control in a transport configuration bridging tip and substrate of an STM. THz radiation funnelled into the tunnelling junction acts as an ultrafast bias modulation driving electronic currents by opening selective transport channels on the intrinsic time scales of electron motion and tunnelling processes. Using pump-probe schemes, the project will explore the sub-picosecond time evolution of coupling of electrons traversing the ribbon with fundamental excitations like phonon modes. These experiments reveal questions about the possibility to control and modify electronic degrees of freedom beyond electron motion by THz radiation. ELISTRA will synergistically combine light wave STM, pioneered by the host institution, and STM transport experiments, in which the applicant presents outstanding skills. The project enables the applicant gathering proficiency in the rapidly emerging field combining ultrafast with atomic-scale physics. Building upon his existing expertise, the training will sharpen the applicant’s scientific profile and improve his employment perspectives by emerging him in a host institution, that continuously drives the interdisciplinary frontier of nanoscopic measurements.

Quantum Chromodynamics (QCD) undergoes a crossover from the hadronic phase at low temperatures T to a quark-gluon plasma (QGP) phase at high T. This crossover and properties of the QGP phase are important for understanding the evolution of the early universe and are being studied by major Heavy Ion Collision (HIC) experiments at RHIC and LHC. The transition temperature and many QGP properties have been determined by Lattice QCD simulations. However, connecting these to experimental remnants of QGP fireballs produced at HICs is not straightforward. Thermal effects will modify the properties of the excitations (mesons and baryons) within the medium. We propose to investigate these in-medium changes using lattice QCD methods, shedding light onto the dynamics of HIC fireballs. Low temperature, high chemical potential phases are another region of the QCD phase diagram, interesting, e.g., for the physics of neutron stars. While this region is not accessible to numerical methods at present, we address the situation of an isospin chemical potential mu_I on the lattice, which also describes important aspects of neutron star cores. We propose to determine baryonic excitations for non-zero mu_I, which can provide a deeper understanding of possible quark matter cores in neutron stars.

Coding and non-coding RNAs are regulated at numerous levels. For example, microRNA (miRNA) expression can be influenced at various steps of biosynthesis. Furthermore, it has been reported that direct RNA methylation events can also affect gene expression in many different organisms and systems. The aim of this project is to identify and characterize factors that affect the maturation of miRNAs. We will employ biochemical pull down assays to isolate specific binding partners of different miRNA species. We will analyze the physiological role of these factors using molecular or cell biological approaches. Molecular details of pre-miRNA-protein interactions will be investigated by x-ray crystallography. In addition, we will decipher the role of the m6A methylation pathway on the regulation of coding and non-coding RNAs. Writers, readers and erasers of this modification have been identified. However, not much is known about the composition of specific protein complexes as well as the atomic structure of these factors. Thus, we will functionally and structurally characterize known and putative novel factors of the m6A methylation pathway in human cells. Furthermore, using our biochemical pull down approach employed for the identification of pre-miRNA processing factors, we will identify reader proteins of several types of RNA modification that have not been investigated so far. The proposed project will elucidate the regulation of gene expression by small RNAs or direct RNA methylation and will add so far unknown components to these important regulatory pathways.