@article{50148, abstract = {{We develop a general decomposition of an ensemble of initial density profiles in terms of an average state and a basis of modes that represent the event-by-event fluctuations of the initial state. The basis is determined such that the probability distributions of the amplitudes of different modes are uncorrelated. Based on this decomposition, we quantify the different types and probabilities of event-by-event fluctuations in Glauber and Saturation models and investigate how the various modes affect different characteristics of the initial state. We perform simulations of the dynamical evolution with KoMPoST and MUSIC to investigate the impact of the modes on final-state observables and their correlations.}}, author = {{Borghini, Nicolas and Borrell, Marc and Feld, Nina and Roch, Hendrik and Schlichting, Sören and Werthmann, Clemens}}, journal = {{Phys. Rev. C 107 (2023) 034905}}, title = {{{Statistical analysis of initial state and final state response in heavy-ion collisions}}}, doi = {{10.1103/PhysRevC.107.034905}}, year = {{2022}}, } @article{50149, abstract = {{Abstract RNA editing processes are strikingly different in animals and plants. Up to thousands of specific cytidines are converted into uridines in plant chloroplasts and mitochondria whereas up to millions of adenosines are converted into inosines in animal nucleo-cytosolic RNAs. It is unknown whether these two different RNA editing machineries are mutually incompatible. RNA-binding pentatricopeptide repeat (PPR) proteins are the key factors of plant organelle cytidine-to-uridine RNA editing. The complete absence of PPR mediated editing of cytosolic RNAs might be due to a yet unknown barrier that prevents its activity in the cytosol. Here, we transferred two plant mitochondrial PPR-type editing factors into human cell lines to explore whether they could operate in the nucleo-cytosolic environment. PPR56 and PPR65 not only faithfully edited their native, co-transcribed targets but also different sets of off-targets in the human background transcriptome. More than 900 of such off-targets with editing efficiencies up to 91%, largely explained by known PPR-RNA binding properties, were identified for PPR56. Engineering two crucial amino acid positions in its PPR array led to predictable shifts in target recognition. We conclude that plant PPR editing factors can operate in the entirely different genetic environment of the human nucleo-cytosol and can be intentionally re-engineered towards new targets.}}, author = {{Lesch, Elena and Schilling, Maximilian T and Brenner, Sarah and Yang, Yingying and Gruss, Oliver J and Knoop, Volker and Schallenberg-Rüdinger, Mareike}}, issn = {{0305-1048}}, journal = {{Nucleic Acids Research}}, keywords = {{Genetics}}, number = {{17}}, pages = {{9966--9983}}, publisher = {{Oxford University Press (OUP)}}, title = {{{Plant mitochondrial RNA editing factors can perform targeted C-to-U editing of nuclear transcripts in human cells}}}, doi = {{10.1093/nar/gkac752}}, volume = {{50}}, year = {{2022}}, } @unpublished{50224, abstract = {{We study the influence of fringing magnetic fields on turbulent thermal convection in a horizontally extended rectangular domain. The magnetic field is created in the gap between two semi-infinite planar magnetic poles, with the convection layer located near the edge of the gap. We employ direct numerical simulations in this setup for fixed Rayleigh and small Prandtl numbers, but vary the fringe-width by controlling the gap between the magnetic poles and the convection cell. The magnetic field generated by the magnets is strong enough to cease the flow in high magnetic flux region of the convection cell. We observe that as the local vertical magnetic field strength increases, the large scale structures become thinner and align themselves perpendicular to the longitudinal sidewalls. We determine the local Nusselt and Reynolds numbers as functions of the local Hartmann number (based on the vertical component of the magnetic field) and estimate the global heat and momentum transport. We show that the global heat transport decreases with increasing fringe-width for strong magnetic fields but increases with increasing fringe-width for weak magnetic fields. In the regions of large vertical magnetic fields, the convective motion becomes confined to the vicinity of the sidewalls. The amplitudes of these wall modes show a non-monotonic dependence on the fringe-width.}}, author = {{Bhattacharya, Shashwat and Boeck, Thomas and Krasnov, Dmitry and Schumacher, Jörg}}, booktitle = {{arXiv:2211.00559}}, title = {{{Effects of strong fringing magnetic fields on turbulent thermal convection}}}, year = {{2022}}, } @article{54849, abstract = {{The third‐order susceptibility of lithium niobate (LiNbO3) is calculated within a Berry‐phase formulation of the dynamical polarization based on the electronic structure obtained within density‐functional theory (DFT). Maximum values of the order of  m V are calculated for photon energies between 1.2 and 2 eV, i.e., in the lower half of the optical bandgap of lithium niobate. Both free and bound electron (bi)polarons are found to lead to a remarkable enhancement of the third‐order susceptibility for photon energies below 1 eV.}}, author = {{Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero}}, issn = {{0370-1972}}, journal = {{physica status solidi (b)}}, number = {{2}}, publisher = {{Wiley}}, title = {{{Third‐Order Susceptibility of Lithium Niobate: Influence of Polarons and Bipolarons}}}, doi = {{10.1002/pssb.202200453}}, volume = {{260}}, year = {{2022}}, } @article{28413, abstract = {{Optical traveling wave antennas offer unique opportunities to control and selectively guide light into a specific direction, which renders them excellent candidates for optical communication and sensing. These applications require state-of-the-art engineering to reach optimized functionalities such as high directivity and radiation efficiency, low sidelobe levels, broadband and tunable capabilities, and compact design. In this work, we report on the numerical optimization of the directivity of optical traveling wave antennas made from low-loss dielectric materials using full-wave numerical simulations in conjunction with the particle swarm optimization algorithm. The antennas are composed of a reflector and a director deposited on a glass substrate, and an emitter placed in the feed gap between them serves as an internal source of excitation. In particular, we analyze antennas with rectangular- and horn-shaped directors made of either hafnium dioxide or silicon. The optimized antennas produce highly directional emissions due to the presence of two dominant guided TE modes in the director in addition to leaky modes. These guided modes dominate the far-field emission pattern and govern the direction of the main lobe emission, which predominately originates from the end facet of the director. Our work also provides a comprehensive analysis of the modes, radiation patterns, parametric influences, and bandwidths of the antennas, which highlights their robust nature.}}, author = {{Farheen, Henna and Leuteritz, Till and Linden, Stefan and Myroshnychenko, Viktor and Förstner, Jens}}, issn = {{0740-3224}}, journal = {{Journal of the Optical Society of America B}}, keywords = {{tet_topic_opticalantenna}}, number = {{1}}, pages = {{83}}, title = {{{Optimization of optical waveguide antennas for directive emission of light}}}, doi = {{10.1364/josab.438514}}, volume = {{39}}, year = {{2022}}, } @article{29075, abstract = {{We study a double-scattering coherent mechanism of negative polarization (NP) near opposition that is observed for powder-like surfaces. The problem is solved numerically for absorbing structures with irregular constituents, cubes, spheres, and ellipsoids larger than the wavelength of incident light. Our simulations show that double scattering between two random irregular particles shows weak NP. Adding one more particle significantly increases the relative contribution of double scattering which enhances NP. Simulations with regular shapes and controlled geometric parameters show that the interference mechanism is sensitive to the geometry of the scattering system and can also result in no polarization or even strong enhancement of positive polarization at backscattering.}}, author = {{Alhaddad, Samer and Grynko, Yevgen and Farheen, Henna and Förstner, Jens}}, issn = {{0146-9592}}, journal = {{Optics Letters}}, keywords = {{tet_topic_scattering}}, number = {{1}}, pages = {{58}}, title = {{{Numerical analysis of the coherent mechanism producing negative polarization at backscattering from systems of absorbing particles}}}, doi = {{10.1364/ol.444953}}, volume = {{47}}, year = {{2022}}, } @article{31329, abstract = {{Highly directive antennas with the ability of shaping radiation patterns in desired directions are essential for efficient on-chip optical communication with reduced cross talk. In this paper, we design and optimize three distinct broadband traveling-wave tantalum pentoxide antennas exhibiting highly directional characteristics. Our antennas contain a director and reflector deposited on a glass substrate, which are excited by a dipole emitter placed in the feed gap between the two elements. Full-wave simulations in conjunction with global optimization provide structures with an enhanced linear directivity as high as 119 radiating in the substrate. The high directivity is a result of the interplay between two dominant TE modes and the leaky modes present in the antenna director. Furthermore, these low-loss dielectric antennas exhibit a near-unity radiation efficiency at the operational wavelength of 780 nm and maintain a broad bandwidth. Our numerical results are in good agreement with experimental measurements from the optimized antennas fabricated using a two-step electron-beam lithography, revealing the highly directive nature of our structures. We envision that our antenna designs can be conveniently adapted to other dielectric materials and prove instrumental for inter-chip optical communications and other on-chip applications.}}, author = {{Farheen, Henna and Yan, Lok-Yee and Quiring, Viktor and Eigner, Christof and Zentgraf, Thomas and Linden, Stefan and Förstner, Jens and Myroshnychenko, Viktor}}, issn = {{1094-4087}}, journal = {{Optics Express}}, keywords = {{tet_topic_opticalantenna}}, number = {{11}}, pages = {{19288}}, publisher = {{Optica Publishing Group}}, title = {{{Broadband optical Ta2O5 antennas for directional emission of light}}}, doi = {{10.1364/oe.455815}}, volume = {{30}}, year = {{2022}}, } @article{34065, author = {{Kirchgässner, Wilhelm and Wallscheid, Oliver and Böcker, Joachim}}, issn = {{0952-1976}}, journal = {{Engineering Applications of Artificial Intelligence}}, publisher = {{Elsevier BV}}, title = {{{Thermal neural networks: Lumped-parameter thermal modeling with state-space machine learning}}}, doi = {{10.1016/j.engappai.2022.105537}}, volume = {{117}}, year = {{2022}}, } @inproceedings{32859, author = {{Kirchgässner, Wilhelm and Wallscheid, Oliver and Böcker, Joachim}}, booktitle = {{2022 International Power Electronics Conference (IPEC-Himeji 2022- ECCE Asia)}}, publisher = {{IEEE}}, title = {{{Learning Thermal Properties and Temperature Models of Electric Motors with Neural Ordinary Differential Equations}}}, doi = {{10.23919/ipec-himeji2022-ecce53331.2022.9807209}}, year = {{2022}}, } @inproceedings{31183, author = {{Dechert, Christopher and Kenig, Eugeny}}, location = {{Frankfurt am Main}}, title = {{{Untersuchung von kleinskaligen Flüssigkeitselementen auf mikrostrukturierten Packungsoberflächen}}}, year = {{2022}}, } @article{37318, abstract = {{Abstract The interaction between quantum light and matter is being intensively studied for systems that are enclosed in high-Q cavities which strongly enhance the light–matter coupling. Cavities with low Q-factors are generally given less attention due to their high losses that quickly destroy quantum systems. However, bad cavities can be utilized for several applications, where lower Q-factors are required, e.g., to increase the spectral width of the cavity mode. In this work, we demonstrate that low-Q cavities can be beneficial for preparing specific electronic steady states when certain quantum states of light are applied. We investigate the interaction between quantum light with various statistics and matter represented by a Λ-type three-level system in lossy cavities, assuming that cavity losses are the dominant loss mechanism. We show that cavity losses lead to non-trivial electronic steady states that can be controlled by the loss rate and the initial statistics of the quantum fields. We discuss the mechanism of the formation of such steady states on the basis of the equations of motion and present both analytical expressions and numerical simulations for such steady states.}}, author = {{Rose, Hendrik and Tikhonova, O V and Meier, Torsten and Sharapova, Polina}}, issn = {{1367-2630}}, journal = {{New Journal of Physics}}, keywords = {{General Physics and Astronomy}}, number = {{6}}, publisher = {{IOP Publishing}}, title = {{{Steady states of Λ-type three-level systems excited by quantum light with various photon statistics in lossy cavities}}}, doi = {{10.1088/1367-2630/ac74d8}}, volume = {{24}}, year = {{2022}}, } @article{37319, author = {{Grisard, S. and Rose, Hendrik and Trifonov, A. V. and Reichhardt, R. and Reiter, D. E. and Reichelt, Matthias and Schneider, C. and Kamp, M. and Höfling, S. and Bayer, M. and Meier, Torsten and Akimov, I. A.}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, number = {{20}}, publisher = {{American Physical Society (APS)}}, title = {{{Multiple Rabi rotations of trions in InGaAs quantum dots observed by photon echo spectroscopy with spatially shaped laser pulses}}}, doi = {{10.1103/physrevb.106.205408}}, volume = {{106}}, year = {{2022}}, } @inproceedings{37329, author = {{Trautmann, Alexander and Zuo, Ruixin and Wang, Guifang and Hannes, Wolf-Rüdiger and Yang, Shidong and Thong, Le Huu and Ngo, Cong and Steiner, Johannes and Ciappina, Marcelo and Reichelt, Matthias and Duc, Huynh Thanh and Song, Xiaohong and Yang, Weifeng and Meier, Torsten}}, booktitle = {{Ultrafast Phenomena and Nanophotonics XXVI}}, editor = {{Betz, Markus and Elezzabi, Abdulhakem Y.}}, title = {{{Microscopic simulations of high harmonic generation from semiconductors}}}, doi = {{10.1117/12.2607447}}, volume = {{11999}}, year = {{2022}}, } @inproceedings{37327, author = {{Rose, Hendrik and Tikhonova, Olga V. and Meier, Torsten and Sharapova, Polina}}, booktitle = {{Ultrafast Phenomena and Nanophotonics XXVI}}, editor = {{Betz, Markus and Elezzabi, Abdulhakem Y.}}, title = {{{Theoretical analysis of correlations between two quantum fields exciting a three-level system using the cluster-expansion approach}}}, doi = {{10.1117/12.2608528}}, volume = {{11999}}, year = {{2022}}, } @article{37323, author = {{Paul, J. and Rose, Hendrik and Swagel, E. and Meier, Torsten and Wahlstrand, J. K. and Bristow, A. D.}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, number = {{11}}, publisher = {{American Physical Society (APS)}}, title = {{{Coherent contributions to population dynamics in a semiconductor microcavity}}}, doi = {{10.1103/physrevb.105.115307}}, volume = {{105}}, year = {{2022}}, } @unpublished{37325, author = {{Meier, Torsten and Ali, Usman}}, booktitle = {{Condensed Matter}}, title = {{{Super-Bloch oscillations with parametric modulation of a parabolic trap}}}, year = {{2022}}, } @article{40523, abstract = {{AbstractTailored nanoscale quantum light sources, matching the specific needs of use cases, are crucial building blocks for photonic quantum technologies. Several different approaches to realize solid-state quantum emitters with high performance have been pursued and different concepts for energy tuning have been established. However, the properties of the emitted photons are always defined by the individual quantum emitter and can therefore not be controlled with full flexibility. Here we introduce an all-optical nonlinear method to tailor and control the single photon emission. We demonstrate a laser-controlled down-conversion process from an excited state of a semiconductor quantum three-level system. Based on this concept, we realize energy tuning and polarization control of the single photon emission with a control-laser field. Our results mark an important step towards tailored single photon emission from a photonic quantum system based on quantum optical principles.}}, author = {{Jonas, B. and Heinze, Dirk Florian and Schöll, E. and Kallert, P. and Langer, T. and Krehs, S. and Widhalm, A. and Jöns, Klaus and Reuter, Dirk and Schumacher, Stefan and Zrenner, Artur}}, issn = {{2041-1723}}, journal = {{Nature Communications}}, keywords = {{General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}}, number = {{1}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Nonlinear down-conversion in a single quantum dot}}}, doi = {{10.1038/s41467-022-28993-3}}, volume = {{13}}, year = {{2022}}, } @article{40431, author = {{Praschan, Tom and Heinze, Dirk and Breddermann, Dominik and Zrenner, Artur and Walther, Andrea and Schumacher, Stefan}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, number = {{4}}, publisher = {{American Physical Society (APS)}}, title = {{{Pulse shaping for on-demand emission of single Raman photons from a quantum-dot biexciton}}}, doi = {{10.1103/physrevb.105.045302}}, volume = {{105}}, year = {{2022}}, } @misc{40428, author = {{Jonas, Björn and Heinze, Dirk Florian and Schöll, Eva and Kallert, Patricia and Langer, Timo and Krehs, Sebastian and Widhalm, Alex and Jöns, Klaus and Reuter, Dirk and Zrenner, Artur}}, publisher = {{LibreCat University}}, title = {{{Nonlinear down-conversion in a single quantum dot}}}, doi = {{10.5281/ZENODO.6024228}}, year = {{2022}}, } @article{37711, abstract = {{AbstractPolarons influence decisively the performance of lithium niobate for optical applications. In this work, the formation of (defect) bound polarons in lithium niobate is studied by ab initio molecular dynamics. The calculations show a broad scatter of polaron formation times. Rising temperature increases the share of trajectories with long formation times, which leads to an overall increase of the average formation time with temperature. However, even at elevated temperatures, the average formation time does not exceed the value of 100 femtoseconds, i.e., a value close to the time measured for free, i.e., self-trapped polarons. Analyzing individual trajectories, it is found that the time required for the structural relaxation of the polarons depends sensitively on the excitation of the lithium niobate high-frequency phonon modes and their phase relation.}}, author = {{Krenz, Marvin and Gerstmann, Uwe and Schmidt, Wolf Gero}}, issn = {{0947-8396}}, journal = {{Applied Physics A}}, keywords = {{General Materials Science, General Chemistry}}, pages = {{480}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Bound polaron formation in lithium niobate from ab initio molecular dynamics}}}, doi = {{10.1007/s00339-022-05577-y}}, volume = {{128}}, year = {{2022}}, }