@inproceedings{LaeuterKramerRubinetal.2022, author = {L{\"a}uter, Matthias and Kramer, Tobias and Rubin, Martin and Altwegg, Kathrin}, title = {Determination of the ice composition near the surface of comet 67P/Churyumov-Gerasimenko}, booktitle = {Europlanet Science Congress}, doi = {10.5194/epsc2022-826}, pages = {EPSC2022-826}, year = {2022}, abstract = {During the apparition of comet 67P/Churyumov-Gerasimenko (67P/C-G) solar irradiation causes varying rates for sublimation of volatile species from the cometary nucleus. Because sublimation processes take place close to the cometary surface, the relative abundance of volatiles in the coma and the ice composition are related to each other. To quantify this relation we assume a model for the expansion of a collisionless gas from the surface into the surrounding space. We use an inverse model approach to relate the in situ measurements of gas densities from the two Rosetta instruments COPS (COmet Pressure Sensor) and DFMS (Double Focusing Mass Spectrometer) at the positions of the spacecraft to the locations of surface gas emissions during the Rosetta mission 2014-2016. We assume the temporally integrated gas emissions to be representative for the ice composition close to the surface. Our analysis shows characteristic differences in the ice compositions between both hemispheres of 67P/C-G. In particular CO2 ice has a reduced abundance on the northern hemisphere. In contrast to the hemispherical differences, the two lobes do not show significant differences in terms of their ice composition.}, language = {en} } @inproceedings{BrookFullerSwinburneetal.2022, author = {Brook, Glenn and Fuller, Douglas and Swinburne, John and Christgau, Steffen and L{\"a}uter, Matthias and Rodrigues Pel{\´a}, Ronaldo and Lewin, Stein and Christian, Tuma and Steinke, Thomas}, title = {An Early Scalability Study of Omni-Path Express}, address = {Hamburg}, organization = {ISC 2022 IXPUG}, doi = {10.13140/RG.2.2.21353.57442}, pages = {8}, year = {2022}, abstract = {This work provides a brief description of Omni-Path Express and the current status of its development, stability, and performance. Basic benchmarks that highlight the gains of OPX over PSM2 are provided, and the results of an initial performance and scalability study of several applications are presented.}, language = {en} } @inproceedings{KramerLaeuter2022, author = {Kramer, Tobias and L{\"a}uter, Matthias}, title = {The near nucleus gas and dust environment around comet 67P/Churyumov-Gerasimenko}, booktitle = {Europlanet Science Congress}, doi = {10.5194/epsc2022-281}, pages = {EPSC2022-281}, year = {2022}, abstract = {The Rosetta mission to comet 67P/C-G provided a detailed view of the near nucleus environment of an active Jupiter family comet. The continuous monitoring of the gas pressure with the ROSINA experiment at the location of the Rosetta spacecraft in combination with the images of the dust environment acquired by the OSIRIS cameras allows one to test different hypotheses about the origin of the dust and gas emissions. In addition the orbital elements and the rotation axis and spin rate of the nucleus are affected by the gas release.}, language = {en} } @inproceedings{BuergerGundlachBlumetal.2022, author = {B{\"u}rger, Johanna and Gundlach, Bastian and Blum, J{\"u}rgen and Hayne, Paul and L{\"a}uter, Matthias and Kramer, Tobias}, title = {Lunar regolith properties derived from LRO/Diviner data and thermophysical modelling}, booktitle = {Europlanet Science Congress}, doi = {10.5194/epsc2022-92}, pages = {EPSC2022-92}, year = {2022}, abstract = {The Moon as our nearest celestial object is one of the most important bodies for space resource exploration and planetary science. However, knowledge of the physical properties of the lunar regolith is required for the exploitation of lunar resources and for understanding the Moon's geologic history. This knowledge comes mainly from Apollo in-situ experiments and returned samples, but the global distribution of these properties is still poorly understood. Remote sensing measurements offer the opportunity to derive properties of unsampled areas with the help of models. In our study, a microphysical thermal model for the lunar regolith was developed and the simulated surface temperatures were compared with thermal emission measurements from the Diviner radiometer on board the Lunar Reconnaissance Orbiter (LRO) to derive regolith properties. This work expands upon previous investigations of lunar regolith properties using Diviner data, by more directly simulating physical properties such as particle size and porosity.}, language = {en} } @inproceedings{SikorskiRabbenChewleetal.2025, author = {Sikorski, Alexander and Rabben, Robert Julian and Chewle, Surahit and Weber, Marcus}, title = {Capturing the Macroscopic Behaviour of Molecular Dynamics with Membership Functions}, booktitle = {Mathematical Optimization for Machine Learning: Proceedings of the MATH+ Thematic Einstein Semester 2023}, editor = {Fackeldey, K.}, publisher = {De Gruyter}, arxiv = {http://arxiv.org/abs/2404.10523}, doi = {10.1515/9783111376776-004}, pages = {41 -- 58}, year = {2025}, abstract = {Markov processes serve as foundational models in many scientific disciplines, such as molecular dynamics, and their simulation forms a common basis for analysis. While simulations produce useful trajectories, obtaining macroscopic information directly from microstate data presents significant challenges. This paper addresses this gap by introducing the concept of membership functions being the macrostates themselves. We derive equations for the holding times of these macrostates and demonstrate their consistency with the classical definition. Furthermore, we discuss the application of the ISOKANN method for learning these quantities from simulation data. In addition, we present a novel method for extracting transition paths based on the ISOKANN results and demonstrate its efficacy by applying it to simulations of the 𝜇-opioid receptor. With this approach we provide a new perspective on analyzing the macroscopic behaviour of Markov systems.}, language = {en} } @article{BuergerHayneGundlachetal.2024, author = {B{\"u}rger, Johanna and Hayne, Paul and Gundlach, Bastian and L{\"a}uter, Matthias and Kramer, Tobias and Blum, J{\"u}rgen}, title = {A Microphysical Thermal Model for the Lunar Regolith: Investigating the Latitudinal Dependence of Regolith Properties}, volume = {129}, journal = {Journal of Geophysical Research: Planets}, number = {3}, doi = {10.1029/2023JE008152}, year = {2024}, abstract = {The microphysical structure of the lunar regolith provides information on the geologic history of the Moon. We used remote sensing measurements of thermal emission and a thermophysical model to determine the microphysical properties of the lunar regolith. We expand upon previous investigations by developing a microphysical thermal model, which more directly simulates regolith properties, such as grain size and volume filling factor. The modeled temperatures are matched with surface temperatures measured by the Diviner Lunar Radiometer Experiment on board the Lunar Reconnaissance Orbiter. The maria and highlands are investigated separately and characterized in the model by a difference in albedo and grain density. We find similar regolith temperatures for both terrains, which can be well described by similar volume filling factor profiles and mean grain sizes obtained from returned Apollo samples. We also investigate a significantly lower thermal conductivity for highlands, which formally also gives a very good solution, but in a parameter range that is well outside the Apollo data. We then study the latitudinal dependence of regolith properties up to ±80° latitude. When assuming constant regolith properties, we find that a variation of the solar incidence-dependent albedo can reduce the initially observed latitudinal gradient between model and Diviner measurements significantly. A better match between measurements and model can be achieved by a variation in intrinsic regolith properties with a decrease in bulk density with increasing latitude. We find that a variation in grain size alone cannot explain the Diviner measurements at higher latitudes.}, language = {en} } @inproceedings{BuergerHayneGundlachetal.2023, author = {B{\"u}rger, Johanna and Hayne, Paul and Gundlach, Bastian and L{\"a}uter, Matthias and Kramer, Tobias and Blum, J{\"u}rgen}, title = {Investigating the Latitudinal Dependence of Lunar Regolith Properties Using LRO/Diviner Data and a Microphysical Thermal Model}, volume = {55}, booktitle = {Bulletin of the AAS}, number = {8}, year = {2023}, abstract = {Regolith is formed through weathering of the local rock by meteorite bombardment, space weathering (Pieters \& Noble, 2016) and thermal erosion (Delbo et al., 2014). In the case of the Moon, the space weathering effects and diurnal temperature variations are reduced towards the poles. The aim of this study is to investigate whether the lunar regolith properties derived from the comparison of regolith temperatures measured by the Diviner radiometer (Paige et al., 2010) on board the Lunar Reconnaissance Orbiter (LRO) with simulated temperatures derived from a microphysical thermal model show a latitudinal dependence. The developed microphysical thermal model expands upon previous models by more directly simulating regolith properties, such as grain radius and volume filling factor.}, language = {en} } @inproceedings{LaeuterKramer2023, author = {L{\"a}uter, Matthias and Kramer, Tobias}, title = {Non-gravitational acceleration and torque on comet 67P/Churyumov-Gerasimenko}, volume = {55}, booktitle = {Bulletin of the AAS}, number = {8}, year = {2023}, abstract = {From August 2014 to September 2016, the ESA operated the Rosetta spacecraft mission alongside with comet 67P/Churyumov-Gerasimenko (67P). The mission provided valuable long-term data on the comet's nucleus, including its volume, mass, tensor of inertia, spatial position of the orbital trajectory, and rotational state.}, language = {en} } @article{LaeuterKramerRubinetal.2022, author = {L{\"a}uter, Matthias and Kramer, Tobias and Rubin, Martin and Altwegg, Kathrin}, title = {The ice composition close to the surface of comet 67P/Churyumov-Gerasimenko}, volume = {6}, journal = {ACS Earth and Space Chemistry}, number = {5}, arxiv = {http://arxiv.org/abs/2305.16201}, doi = {10.1021/acsearthspacechem.1c00378}, pages = {1189 -- 1203}, year = {2022}, abstract = {The relation between ice composition in the nucleus of comet 67P/Churyumov-Gerasimenko on the one hand and relative abundances of volatiles in the coma on the other hand is important for the interpretation of density measurements in the environment of the cometary nucleus. For the 2015 apparition, in situ measurements from the two ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) sensors COPS (COmet Pressure Sensor) and DFMS (Double Focusing Mass Spectrometer) determined gas densities at the spacecraft position for the 14 gas species H2O, CO2, CO, H2S, O2, C2H6, CH3OH, H2CO, CH4, NH3, HCN, C2H5OH, OCS, and CS2. We derive the spatial distribution of the gas emissions on the complex shape of the nucleus separately for 50 subintervals of the two-year mission time. The most active patches of gas emission are identified on the surface. We retrieve the relation between solar irradiation and observed emissions from these patches. The emission rates are compared to a minimal thermophysical model to infer the surface active fraction of H2O and CO2. We obtain characteristic differences in the ice composition close to the surface between the two hemispheres with a reduced abundance of CO2 ice on the northern hemisphere (locations with positive latitude). We do not see significant differences for the ice composition on the two lobes of 67P/C-G.}, language = {en} } @article{RayaMorenoDaschFarahanietal.2026, author = {Raya-Moreno, Mart{\´i} and Dasch, Noah Alexy and Farahani, Nasrin and Gonzalez Oliva, Ignacio and Gulans, Andris and Hossain, Manoar and Kleine, Hannah and Kuban, Martin and Lubeck, Sven and Maurer, Benedikt and Pavone, Pasquale and Peschel, Fabian and Popova-Gorelova, Daria and Qiao, Lu and Richter, Elias and Rigamonti, Santiago and Rodrigues Pel{\´a}, Ronaldo and Sinha, Kshitij and Speckhard, Daniel T. and Tillack, Sebastian and Tumakov, Dmitry and Hong, Seokhyun and Uzulis, Janis and Voiculescu, Mara and Vona, Cecilia and Yang, Mao and Draxl, Claudia}, title = {An exciting approach to theoretical spectroscopy}, arxiv = {http://arxiv.org/abs/2601.11388}, year = {2026}, language = {en} } @article{QiaoRodriguesPelaDraxl2026, author = {Qiao, Lu and Rodrigues Pel{\´a}, Ronaldo and Draxl, Claudia}, title = {First-principles approach to ultrafast pump-probe spectroscopy in solids}, arxiv = {http://arxiv.org/abs/2509.07612}, year = {2026}, language = {en} }