Completed projects

The detec­tion of gravi­ta­tional waves (GWs) has opened a new window on the universe, through which we can study the physics of black-hole and neutron-star mergers. By analyz­ing GWs we can infer proper­ties of the corre­spond­ing astro­phys­i­cal systems. Current analy­sis methods are however too compu­ta­tion­ally expen­sive to deal with the growing amount of data. My research is thus concerned with the devel­op­ment of more efficient methods for the GW analy­sis using power­ful machine learn­ing methods.

The central paradigm of quantum optics is the absorp­tion and emission of radia­tion by quantum emitters. When the coupling between an emitter and its environ­ment becomes strong, intrigu­ing radia­tive proper­ties can be engineered, such as direc­tional emission patterns or strongly modified emission rates. This project aims at access­ing such effects in a system of ultra­cold atoms in optical lattices where artifi­cial emitters decay by emitting matter waves rather than optical radiation.

SARS-CoV‑2 has caused a pandemic and is respon­si­ble for more than 18 million infec­tions. It is hypoth­e­sized that COVID-19 is the result of killing of infected cells and exces­sive immune activa­tion. To reveal cell types and pathways that are criti­cally involved in viral repli­ca­tion and patho­gen­e­sis, I will use transcrip­tomics and functional studies of genes likely involved in these processes. The results might inform the devel­op­ment of thera­peu­tic strate­gies and the discov­ery of biomarkers.

Several goals were pursued in the devel­op­ment of this work, includ­ing the devel­op­ment of a novel in vivo method to measure the ciliary muscle of a human subject non-invasively during accom­mo­da­tion, the charac­ter­i­za­tion of the recorded muscle signals based on the accom­moda­tive abili­ties of the subject, and the devel­op­ment of a device that would utilize the recorded muscle signals to mimic the appro­pri­ate level of accom­mo­da­tion for the user, actuated through the use of a variable refrac­tive lens.

The risk to develop posttrau­matic stress disor­der (PTSD) depends on the number of traumatic events experi­enced and individ­ual risk factors, e.g. genetic predis­po­si­tions. However, to identify causal genetic variants of this polygenic disease, trauma exposure needs to be adequately assessed.

Fossil resources are increas­ingly depleted. They have to be replaced as quickly as possi­ble by renew­able raw materi­als, so that a slow transi­tion to a new and modern produc­tion of „platform chemi­cals“ can take place.

The market’s demand for carbon fiber/epoxy compos­ite has dramat­i­cally increased due to its signif­i­cant appli­ca­tions and advan­tages in indus­try. Typical loading on the struc­tures that are made up by this mater­ial often involves tensile and lateral bending of the compos­ite laminates.

The exact position of atoms in the crystal struc­ture of lanthanum mangan­ites and cobal­tates (both anorganic ionic compounds) signif­i­cantly affects their magnetic proper­ties. The crystal struc­ture of these materi­als can be altered by pressure, substi­tu­tion of elements, or crystal­lite size: Since nanopar­ti­cles have a large surface-to-volume ratio, their surface has a dominant effect on the crystal struc­ture, leading to changes compared to bulk materials.

Metama­te­ri­als are ratio­nally designed struc­tures exhibit­ing effec­tive macro­scopic mater­ial proper­ties that go beyond those of ordinary materi­als. For instance, by intro­duc­ing so-called topolog­i­cally protected resonances it is possi­ble to locally enhance mechan­i­cal vibra­tions and make them robust against pertur­ba­tions. In this project, chiral metama­te­ri­als with topolog­i­cally protected resonances are designed and fabri­cated to realize a resonant mechan­i­cal laser-beam scanner (see Figure). Such laser-beam scanners are crucial for various appli­ca­tions such as LIDAR, confo­cal microscopy, projec­tor displays, and mater­ial processing.

A rich variety of phenom­ena in solid state systems such as quantum magnet­ism or high temper­a­ture super­con­duc­tiv­ity still pose open questions on parts of their micro­scopic expla­na­tion. Due to the complex­ity of these systems, the under­ly­ing quantum many-body dynam­ics is often not acces­si­ble to compu­ta­tional simulation.

Increased anthro­pogenic activ­i­ties and climate change are causing a global shift in patterns of water fluxes. Semi-arid river basins are charac­ter­ized by more water stresses, extreme and sporadic climatic events, and have been projected to worsen in many regions under the influ­ence of climate change.

Galac­tic archae­ol­ogy uses stars as fossils to study the evolu­tion­ary history of galax­ies like our own Milky Way. Cosmo­log­i­cal simula­tions suggest that larger galax­ies were partially formed by accret­ing smaller dwarf galax­ies. Such merger events should leave observ­able signa­tures in the form of star streams, but empir­i­cal constraints on the times, numbers, and impor­tance of such mergers are still missing.