@article{BernsYildizWinkelmannetal.2025, author = {Berns, Manon and Yildiz, Mirza and Winkelmann, Stefanie and Walter, Alexander}, title = {Independently engaging protein tethers of different length enhance synaptic vesicle trafficking to the plasma membrane}, volume = {603}, journal = {The Journal of Physiology}, number = {20}, doi = {10.1113/JP286651}, pages = {6107 -- 6134}, year = {2025}, abstract = {Synaptic vesicle (SV) trafficking toward the plasma membrane (PM) and subsequent SV maturation are essential for neurotransmitter release. These processes, including SV docking and priming, are coordinated by various proteins, such as SNAREs, Munc13, and Synaptotagmin (Syt), which connect—tether—the SV to the PM. Here, we investigated how tethers of varying lengths mediate SV docking using a simplified mathematical model. The heights of the three tether types—estimated from the structures of the SNARE complex, Munc13, and Syt—defined the SV-to-PM distance ranges for tether formation. Geometric considerations linked SV-to-PM distances to the probability and rate of tether formation. We assumed that SV tethering constrains SV motility and that multiple tethers associate by independent interactions. The model predicted that forming multiple tethers favors shorter SV-to-PM distances. Although tethers acted independently in the model, their geometrical properties often caused sequential assembly, from longer ones (Munc13/Syt), that accelerated SV movement towards the PM, to shorter ones (SNAREs) which stabilized PM-proximal SVs. Modifying tether lengths or numbers affected SV trafficking. The independent implementation of tethering proteins enabled their selective removal to mimic gene knockout situations. This showed that simulated SV-to-PM distance distributions qualitatively aligned with published EM studies upon removal of SNARE and Syt tethers, while Munc13 knockout data were best approximated when assuming additional disruption of SNARE tethers. Thus, while salient features of SV docking can be accounted for by independent tethering alone, our results suggest that functional tether interactions not yet featured in our model are crucial for biological function.}, language = {en} } @misc{BinkowskiBetzHammerschmidtetal.2024, author = {Binkowski, Felix and Betz, Fridtjof and Hammerschmidt, Martin and Zschiedrich, Lin and Burger, Sven}, title = {Source code and simulation results: Resonance modes in microstructured photonic waveguides - Efficient and accurate computation based on AAA rational approximation}, journal = {Zenodo}, doi = {10.5281/zenodo.14202408}, pages = {doi: 10.5281/zenodo.14202408}, year = {2024}, language = {en} } @article{BecksLippoldWinkleretal.2024, author = {Becks, Henrik and Lippold, Lukas and Winkler, Paul and Rohrer, Maximilian and Leusmann, Thorsten and Anton, David and Sprenger, Bjarne and K{\"a}hler, Philipp and Rudenko, Iryna and Andr{\´e}s Arcones, Daniel and Koutsourelakis, Phaedon-Stelios and Unger, J{\"o}rg F. and Weiser, Martin and Petryna, Yuri and Schnellenbach-Held, Martina and Lowke, Dirk and Wessels, Henning and Lenzen, Armin and Zabel, Volkmar and K{\"o}nke, Carsten and Claßen, Martin and Hegger, Josef}, title = {Neuartige Konzepte f{\"u}r die Zustands{\"u}berwachung und -analyse von Br{\"u}ckenbauwerken - Einblicke in das Forschungsvorhaben SPP100+}, volume = {99}, journal = {Bauingenieur}, number = {10}, doi = {10.37544/0005-6650-2024-10-63}, pages = {327 -- 338}, year = {2024}, abstract = {Die Br{\"u}ckeninfrastruktur in Deutschland und Europa steht aufgrund steigender Verkehrslasten und alternder Bauwerke vor erheblichen Herausforderungen. Das DFG-Schwerpunktprogramm 2388 „Hundert plus - Verl{\"a}ngerung der Lebensdauer komplexer Baustrukturen durch intelligente Digitalisierung" (SPP100+) strebt an, durch digitale Innovationen und pr{\"a}diktive Instandhaltungsstrategien die Nutzungsdauer bestehender Br{\"u}ckenbauwerke zu verl{\"a}ngern. Der vorliegende Beitrag fokussiert sich auf das SPP100+ zugeh{\"o}rige Cluster „Monitoring und Simulation", das sieben Teilprojekte umfasst. Die Projekte entwickeln fortschrittliche Methoden zur {\"U}berwachung und Zustandsbewertung von Br{\"u}cken mittels Digitaler Zwillinge, hochaufl{\"o}sender Sensortechnik und numerischer Simulationen. Innovative Ans{\"a}tze wie nichtlineare Modellanpassungen, stochastische Methoden und k{\"u}nstliche Intelligenz erm{\"o}glichen eine pr{\"a}zise und fr{\"u}hzeitige Identifizierung potenzieller Sch{\"a}den. Die Kombination aus kontinuierlichem Bauwerksmonitoring und effizienter Datenauswertung ist entscheidend f{\"u}r die langfristige Sicherheit und Langlebigkeit bestehender Br{\"u}cken und tr{\"a}gt dar{\"u}ber hinaus zur Ressourcenschonung bei.}, language = {de} } @article{GoebelHuynhCheginietal.2025, author = {G{\"o}bel, Fritz and Huynh, Ngoc Mai Monica and Chegini, Fatemeh and Pavarino, Luca and Weiser, Martin and Scacchi, Simone and Anzt, Hartwig}, title = {A BDDC Preconditioner for the Cardiac EMI Model in three Dimensions}, journal = {SIAM J. Sci. Comput.}, arxiv = {http://arxiv.org/abs/2502.07722}, year = {2025}, abstract = {We analyze a Balancing Domain Decomposition by Constraints (BDDC) preconditioner for the solution of three dimensional composite Discontinuous Galerkin discretizations of reaction-diffusion systems of ordinary and partial differential equations arising in cardiac cell-by-cell models like the Extracellular space, Membrane and Intracellular space (EMI) Model. These microscopic models are essential for the understanding of events in aging and structurally diseased hearts which macroscopic models relying on homogenized descriptions of the cardiac tissue, like Monodomain and Bidomain models, fail to adequately represent. The modeling of each individual cardiac cell results in discontinuous global solutions across cell boundaries, requiring the careful construction of dual and primal spaces for the BDDC preconditioner. We provide a scalable condition number bound for the precondition operator and validate the theoretical results with extensive numerical experiments.}, language = {en} } @article{BetzBinkowskiFischbachetal.2025, author = {Betz, Fridtjof and Binkowski, Felix and Fischbach, Jan David and Feldman, Nick and Zschiedrich, Lin and Rockstuhl, Carsten and Koenderink, A. Femius and Burger, Sven}, title = {Uncovering hidden resonances in non-Hermitian systems with scattering thresholds}, volume = {19}, journal = {Laser Photonics Rev.}, arxiv = {http://arxiv.org/abs/2503.03549}, doi = {10.1002/lpor.202500811}, pages = {e00811}, year = {2025}, language = {en} } @misc{BetzBinkowskiFischbachetal.2025, author = {Betz, Fridtjof and Binkowski, Felix and Fischbach, Jan David and Feldman, Nick and Rockstuhl, Carsten and Koenderink, A. Femius and Burger, Sven}, title = {Source code and simulation results: Hidden resonances in non-Hermitian systems with scattering thresholds}, journal = {Zenodo}, doi = {10.5281/zenodo.14651612}, pages = {doi: 10.5281/zenodo.14651612}, year = {2025}, language = {en} } @article{MukherjeeBurgerSiefkeetal.2025, author = {Mukherjee, Deshabrato and Burger, Sven and Siefke, Thomas and Gour, Jeetendra and Bodermann, Bernd and Petrik, Peter}, title = {Spectroscopic Ellipsometry of Plasmonic Gratings─Ideal Parameters for Sensing and Subpicometer Measurement Uncertainty}, volume = {10}, journal = {ACS Omega}, number = {14}, doi = {10.1021/acsomega.5c00951}, pages = {14466 -- 14473}, year = {2025}, language = {en} } @article{BlaskovicConradKlusetal.2025, author = {Blaskovic, Filip and Conrad, Tim and Klus, Stefan and Djurdjevac Conrad, Natasa}, title = {Random walk based snapshot clustering for detecting community dynamics in temporal networks}, volume = {15}, journal = {Scientific Reports}, arxiv = {http://arxiv.org/abs/2412.12187}, doi = {10.1038/s41598-025-09340-0}, pages = {24414}, year = {2025}, abstract = {The evolution of many dynamical systems that describe relationships or interactions between objects can be effectively modeled by temporal networks, which are typically represented as a sequence of static network snapshots. In this paper, we introduce a novel random walk based approach that can identify clusters of time-snapshots in which network community structures are stable. This allows to detect significant structural shifts over time, such as the splitting, merging, birth, or death of communities. We also provide a low-dimensional representation of entire snapshots, placing those with similar community structure close to each other in the feature space. To validate our approach, we develop an agent-based algorithm that generates synthetic datasets with the desired characteristic properties, enabling thorough testing and benchmarking. We further demonstrate the effectiveness and broad applicability of our technique by testing it on various social dynamics models and real-world datasets and comparing its performance to several state-of-the-art algorithms. Our findings highlight the strength of our approach to correctly capture and analyze the dynamics of complex systems.}, language = {en} } @phdthesis{Ernst2024, author = {Ernst, Ariane}, title = {Mathematical modeling and analysis of neurotransmission}, year = {2024}, abstract = {Modeling and simulation of neurotransmission plays a central role in the scientific investigation of synaptic functioning and neuronal communication. Understanding the neurotransmission process is crucial due to its fundamental significance in cognitive function, with impairments in this process potentially giving rise to severe pathological conditions. Existing modeling approaches capture the dynamic behavior and the probabilistic properties of the synaptic machinery utilizing results from stochastic chemical kinetics. However, the underlying mathematical theory rarely receives detailed consideration. In this thesis, we explore the neurotransmission process from a mathematical perspective and provide important insights that improve efficiency in its modeling and simulation. We introduce a new method for the direct and exact computation of first- and second-order moments of the postsynaptic current for the case of linear reaction networks, circumventing previously employed stochastic simulations. The approach hinges on the computation of the cross-correlation functions for the associated Markov jump process and their characterization by a partial differential equation. Our method can be applied to efficiently compare coarse-graining strategies for neurotransmission models, which we demonstrate for a significant recent model of synaptic vesicle release. We also numerically analyze the feasibility of reducing this particular model and show that a reduction can preserve the characteristics of the mean output current and its standard deviation to a satisfactory degree under typical stimulation conditions, where the approximation error can even be neglected depending on release site position. As the dependency on the local calcium concentration is preserved in the reduced model, it can be subjected to arbitrary types of signals in future studies. Moreover, we investigate the recovery processes of synaptic vesicles and release sites by introducing a nonlinear model with explicit recovery reactions. A sensitivity analysis provides the novel insight that the widely debated identity of the limiting recovery process during sustained stimulation is time-dependent. For our model, the output current's first-order moment and its deterministic approximation show an exceptionally high level of agreement. We determine this to be an inherent consequence of the model structure due to the independence of the two recovery processes, supporting future use of the deterministic approximation. Parameter estimations confirm our model's capability of reproducing experimental data.}, language = {en} } @article{delRazoDelleSite2025, author = {del Razo, Mauricio and Delle Site, Luigi}, title = {Dynamics of systems with varying number of particles: from Liouville equations to general master equations for open systems}, volume = {18, 001}, journal = {SciPost Physics}, doi = {10.21468/SciPostPhys.18.1.001}, year = {2025}, abstract = {A varying number of particles is one of the most relevant characteristics of systems of interest in nature and technology, ranging from the exchange of energy and matter with the surrounding environment to the change of particle number through internal dynamics such as reactions. The physico-mathematical modeling of these systems is extremely challenging, with the major difficulty being the time dependence of the number of degrees of freedom and the additional constraint that the increment or reduction of the number and species of particles must not violate basic physical laws. Theoretical models, in such a case, represent the key tool for the design of computational strategies for numerical studies that deliver trustful results. In this manuscript, we review complementary physico-mathematical approaches of varying number of particles inspired by rather different specific numerical goals. As a result of the analysis on the underlying common structure of these models, we propose a unifying master equation for general dynamical systems with varying number of particles. This equation embeds all the previous models and can potentially model a much larger range of complex systems, ranging from molecular to social agent-based dynamics.}, language = {en} } @article{AndresArconesWeiserKoutsourelakisetal.2024, author = {Andr{\´e}s Arcones, Daniel and Weiser, Martin and Koutsourelakis, Phaedon-Stelios and Unger, J{\"o}rg F.}, title = {Bias Identification Approaches for Model Updating of Simulation-based Digital Twins of Bridges}, volume = {2}, journal = {Structural Health Monitoring in the Light of Climate Impact and Data Science. Research and Review Journal of Nondestructive Testing}, number = {2}, doi = {10.58286/30524}, year = {2024}, abstract = {Simulation-based digital twins of bridges have the potential not only to serve as monitoring devices of the current state of the structure but also to generate new knowledge through physical predictions that allow for better-informed decisionmaking. For an accurate representation of the bridge, the underlying models must be tuned to reproduce the real system. Nevertheless, the necessary assumptions and simplifications in these models irremediably introduce discrepancies between measurements and model response. We will show that quantifying the extent of the uncertainties introduced through the models that lead to such discrepancies provides a better understanding of the real system, enhances the model updating process, and creates more robust and trustworthy digital twins. The inclusion of an explicit bias term will be applied to a representative demonstrator case based on the thermal response of the Nibelungenbr{\"u}cke of Worms. The findings from this work are englobed in the initiative SPP 100+, whose main aim is the extension of the service life of structures, especially through the implementation of digital twins.}, language = {en} } @article{BinkowskiBetzHammerschmidtetal.2025, author = {Binkowski, Felix and Betz, Fridtjof and Hammerschmidt, Martin and Zschiedrich, Lin and Burger, Sven}, title = {Resonance modes in microstructured photonic waveguides: Efficient and accurate computation based on AAA rational approximation}, volume = {14}, journal = {Nanophotonics}, arxiv = {http://arxiv.org/abs/2412.13826}, doi = {10.1515/nanoph-2024-0755}, pages = {1665}, year = {2025}, language = {en} } @inproceedings{SchaibleWinartoSkorjancetal.2025, author = {Schaible, Jonas and Winarto, Hanifah and Skorjanc, Victor and Yoo, Danbi and Zimmermann, Lea and Wessels, Andreas and J{\"a}ger, Klaus and Sekulic, Ivan and Schneider, Philipp-Immanuel and Bl{\"a}si, Benedikt and Burger, Sven and Becker, Christiane}, title = {Optimization strategies for colorful thin film solar cells}, volume = {PC13361}, booktitle = {Proc. SPIE}, doi = {10.1117/12.3041408}, pages = {PC133610E}, year = {2025}, language = {en} } @article{JaegerAeberhardAlarconLladoetal.2025, author = {J{\"a}ger, Klaus and Aeberhard, Urs and Alarcon Llado, Esther and Bl{\"a}si, Benedikt and Burger, Sven and Ehrler, Bruno and Favre, Wilfried and Fejfar, Anton{\´i}n and Gageot, Tristan and Gordon, Ivan and Helmers, Henning and H{\"o}hn, Oliver and Isabella, Olindo and Jošt, Marko and Ledinsk{\´y}, Martin and Mandal, Jyotirmoy and Manley, Phillip and Mu{\~n}oz, Delfina and Omair, Zunaid and Ortiz Lizcano, Juan Camilo and Paetzold, Ulrich W. and Raman, Aaswath P. and Sai, Hitoshi and Saive, Rebecca and Schmid, Martina and Yablonovitch, Eli and Becker, Christiane}, title = {Optics for terawatt-scale photovoltaics: review and perspectives}, volume = {17}, journal = {Adv. Opt. Photonics}, number = {1}, publisher = {Optica Publishing Group}, issn = {1943-8206}, doi = {10.1364/AOP.530556}, pages = {185 -- 294}, year = {2025}, abstract = {Photovoltaics, a mature technology, is set to play a vital role in achieving a carbon-free energy system. This article examines the pivotal role of optics in advancing photovoltaics. We identify key scientific research areas where the optics community can make significant contributions. We are guided by the central question: How can optics facilitate the large-scale deployment of photovoltaics necessary for decarbonizing our societies?}, language = {en} } @article{delRazoKostre2025, author = {del Razo, Mauricio and Kostr{\´e}, Margarita}, title = {Open reaction-diffusion systems: bridging probabilistic theory and simulations across scales}, volume = {58}, journal = {Journal of Physics A: Mathematical and Theoretical}, number = {14}, doi = {10.1088/1751-8121/adc520}, year = {2025}, abstract = {Reaction-diffusion processes are the foundational model for a diverse range of complex systems, ranging from biochemical reactions to social agent-based phenomena. The underlying dynamics of these systems occur at the individual particle/agent level, and in realistic applications, they often display interaction with their environment through energy or material exchange with a reservoir. This requires intricate mathematical considerations, especially in the case of material exchange since the varying number of particles/agents results in ``on-the-fly'' modification of the system dimension. In this work, we first overview the probabilistic description of reaction-diffusion processes at the particle level, which readily handles varying number of particles. We then extend this model to consistently incorporate interactions with macroscopic material reservoirs. Based on the resulting expressions, we bridge the probabilistic description with macroscopic concentration-based descriptions for linear and nonlinear reaction-diffusion systems, as well as for an archetypal open reaction-diffusion system. Using these mathematical bridges across scales, we finally develop numerical schemes for open reaction-diffusion systems, which we implement in two illustrative examples. This work establishes a methodological workflow to bridge particle-based probabilistic descriptions with macroscopic concentration-based descriptions of reaction-diffusion in open settings, laying the foundations for a multiscale theoretical framework upon which to construct theory and simulation schemes that are consistent across scales.}, language = {en} } @article{BetzBinkowskiHammerschmidtetal.2023, author = {Betz, Fridtjof and Binkowski, Felix and Hammerschmidt, Martin and Zschiedrich, Lin and Burger, Sven}, title = {Cover Picture: Resonance Expansion of Quadratic Quantities with Regularized Quasinormal Modes}, volume = {220}, journal = {Phys. Status Solidi A}, doi = {10.1002/pssa.202370013}, pages = {2370013}, year = {2023}, language = {en} } @inproceedings{KuenBetzBinkowskietal.2023, author = {Kuen, Lilli and Betz, Fridtjof and Binkowski, Felix and Schneider, Philipp-Immanuel and Hammerschmidt, Martin and Heermeier, Niels and Rodt, Sven and Reitzenstein, Stephan and Burger, Sven}, title = {Applying a Riesz-projection-based contour integral eigenvalue solver to compute resonance modes of a VCSEL}, volume = {12575}, booktitle = {Proc. SPIE}, arxiv = {http://arxiv.org/abs/2306.02926}, doi = {10.1117/12.2665490}, pages = {125750J}, year = {2023}, language = {en} } @article{MikheevaColomAchourietal.2023, author = {Mikheeva, Elena and Colom, R{\´e}mi and Achouri, Karim and Overvig, Adam and Binkowski, Felix and Duboz, Jean-Yves and Cueff, S{\´e}bastien and Fan, Shanhui and Burger, Sven and Al{\`u}, Andrea and Genevet, Patrice}, title = {Asymmetric phase modulation with light with parity-symmetry broken metasurfaces}, volume = {10}, journal = {Optica}, doi = {10.1364/OPTICA.495681}, pages = {1287}, year = {2023}, language = {en} } @article{StraubeHoefling2024, author = {Straube, Arthur and H{\"o}fling, Felix}, title = {Depinning transition of self-propelled particles}, volume = {110}, journal = {Physical Review E}, number = {6}, arxiv = {http://arxiv.org/abs/2306.09150}, doi = {10.1103/PhysRevE.110.L062601}, pages = {L062601}, year = {2024}, abstract = {For self-propelled particles in a corrugated potential landscape, we describe a discontinuous change of the classical depinning transition and a host of unique behaviors sensitive to the persistence of the propulsion direction. Exact and semianalytic results for active Brownian particles corroborate a creep regime with a superexponentially suppressed drift velocity upon lowering the force towards the threshold value. This unusual nonlinear response emerges from the competition of two critical scaling laws with exponents of 1/2 for rapidly reorienting particles and 𝑑/2 for particles with a persistent orientation; the latter case depends on the dimensionality 𝑑 of rotational motion and also includes run-and-tumble particles. Additionally, different giant diffusion phenomena occur in the two regimes. Our findings extend to random dynamics with bounded noise near a saddle-node bifurcation and have potential applications in various nonequilibrium problems, including arrested active matter and cell migration.}, language = {en} } @article{MontefuscoHelfmannOkunolaetal.2024, author = {Montefusco, Alberto and Helfmann, Luzie and Okunola, Toluwani and Winkelmann, Stefanie and Sch{\"u}tte, Christof}, title = {Partial mean-field model for neurotransmission dynamics}, volume = {369}, journal = {Mathematical Biosciences}, arxiv = {http://arxiv.org/abs/2307.01737}, doi = {10.1016/j.mbs.2024.109143}, year = {2024}, abstract = {This article addresses reaction networks in which spatial and stochastic effects are of crucial importance. For such systems, particle-based models allow us to describe all microscopic details with high accuracy. However, they suffer from computational inefficiency if particle numbers and density get too large. Alternative coarse-grained-resolution models reduce computational effort tremendously, e.g., by replacing the particle distribution by a continuous concentration field governed by reaction-diffusion PDEs. We demonstrate how models on the different resolution levels can be combined into hybrid models that seamlessly combine the best of both worlds, describing molecular species with large copy numbers by macroscopic equations with spatial resolution while keeping the stochastic-spatial particle-based resolution level for the species with low copy numbers. To this end, we introduce a simple particle-based model for the binding dynamics of ions and vesicles at the heart of the neurotransmission process. Within this framework, we derive a novel hybrid model and present results from numerical experiments which demonstrate that the hybrid model allows for an accurate approximation of the full particle-based model in realistic scenarios.}, language = {en} } @article{NiemannKlusConradetal.2024, author = {Niemann, Jan-Hendrik and Klus, Stefan and Conrad, Natasa Djurdjevac and Sch{\"u}tte, Christof}, title = {Koopman-Based Surrogate Models for Multi-Objective Optimization of Agent-Based Systems}, volume = {460}, journal = {Physica D: Nonlinear Phenomena}, arxiv = {http://arxiv.org/abs/2306.17666}, doi = {https://doi.org/10.1016/j.physd.2024.134052}, pages = {134052}, year = {2024}, abstract = {Agent-based models (ABMs) provide an intuitive and powerful framework for studying social dynamics by modeling the interactions of individuals from the perspective of each individual. In addition to simulating and forecasting the dynamics of ABMs, the demand to solve optimization problems to support, for example, decision-making processes naturally arises. Most ABMs, however, are non-deterministic, high-dimensional dynamical systems, so objectives defined in terms of their behavior are computationally expensive. In particular, if the number of agents is large, evaluating the objective functions often becomes prohibitively time-consuming. We consider data-driven reduced models based on the Koopman generator to enable the efficient solution of multi-objective optimization problems involving ABMs. In a first step, we show how to obtain data-driven reduced models of non-deterministic dynamical systems (such as ABMs) that depend on potentially nonlinear control inputs. We then use them in the second step as surrogate models to solve multi-objective optimal control problems. We first illustrate our approach using the example of a voter model, where we compute optimal controls to steer the agents to a predetermined majority, and then using the example of an epidemic ABM, where we compute optimal containment strategies in a prototypical situation. We demonstrate that the surrogate models effectively approximate the Pareto-optimal points of the ABM dynamics by comparing the surrogate-based results with test points, where the objectives are evaluated using the ABM. Our results show that when objectives are defined by the dynamic behavior of ABMs, data-driven surrogate models support or even enable the solution of multi-objective optimization problems.}, language = {en} } @article{LueckeWinkelmannHeitzigetal.2024, author = {L{\"u}cke, Marvin and Winkelmann, Stefanie and Heitzig, Jobst and Molkenthin, Nora and Koltai, P{\´e}ter}, title = {Learning interpretable collective variables for spreading processes on networks}, volume = {109}, journal = {Physical Review E}, number = {2}, arxiv = {http://arxiv.org/abs/2307.03491}, doi = {10.1103/PhysRevE.109.L022301}, pages = {L022301}, year = {2024}, abstract = {Collective variables (CVs) are low-dimensional projections of high-dimensional system states. They are used to gain insights into complex emergent dynamical behaviors of processes on networks. The relation between CVs and network measures is not well understood and its derivation typically requires detailed knowledge of both the dynamical system and the network topology. In this Letter, we present a data-driven method for algorithmically learning and understanding CVs for binary-state spreading processes on networks of arbitrary topology. We demonstrate our method using four example networks: the stochastic block model, a ring-shaped graph, a random regular graph, and a scale-free network generated by the Albert-Barab{\´a}si model. Our results deliver evidence for the existence of low-dimensional CVs even in cases that are not yet understood theoretically.}, language = {en} } @misc{BinkowskiBetzColometal.2023, author = {Binkowski, Felix and Betz, Fridtjof and Colom, Remi and Genevet, Patrice and Burger, Sven}, title = {Source code and simulation results: Poles and zeros of electromagnetic quantities in photonic systems}, journal = {Zenodo}, doi = {10.5281/zenodo.8063931}, pages = {8063931}, year = {2023}, language = {en} } @article{BinkowskiBetzColometal.2024, author = {Binkowski, Felix and Betz, Fridtjof and Colom, Remi and Genevet, Patrice and Burger, Sven}, title = {Poles and zeros in non-Hermitian systems: Application to photonics}, volume = {109}, journal = {Phys. Rev. B}, arxiv = {http://arxiv.org/abs/2307.04654}, doi = {10.1103/PhysRevB.109.045414}, pages = {045414}, year = {2024}, language = {en} } @article{ZonkerPadillaIglesiasDjurdjevacConrad2023, author = {Zonker, Johannes and Padilla-Iglesias, Cecilia and Djurdjevac Conrad, Natasa}, title = {Insights into drivers of mobility and cultural dynamics of African hunter-gatherers over the past 120 000 years}, volume = {10}, journal = {Royal Society Open Science}, number = {11}, doi = {10.1098/rsos.230495}, year = {2023}, abstract = {Humans have a unique capacity to innovate, transmit and rely on complex, cumulative culture for survival. While an important body of work has attempted to explore the role of changes in the size and interconnectedness of populations in determining the persistence, diversity and complexity of material culture, results have achieved limited success in explaining the emergence and spatial distribution of cumulative culture over our evolutionary trajectory. Here, we develop a spatio-temporally explicit agent-based model to explore the role of environmentally driven changes in the population dynamics of hunter-gatherer communities in allowing the development, transmission and accumulation of complex culture. By modelling separately demography- and mobility-driven changes in interaction networks, we can assess the extent to which cultural change is driven by different types of population dynamics. We create and validate our model using empirical data from Central Africa spanning 120 000 years. We find that populations would have been able to maintain diverse and elaborate cultural repertoires despite abrupt environmental changes and demographic collapses by preventing isolation through mobility. However, we also reveal that the function of cultural features was also an essential determinant of the effects of environmental or demographic changes on their dynamics. Our work can therefore offer important insights into the role of a foraging lifestyle on the evolution of cumulative culture.}, language = {en} } @article{DjurdjevacConradChemnitzKostreetal.2024, author = {Djurdjevac Conrad, Natasa and Chemnitz, Robin and Kostre, Margarita and Schweigart, Fleur and Fless, Friederike and Sch{\"u}tte, Christof and Ducke, Benjamin}, title = {A Mathematical perspective on Romanisation: Modelling the Roman road activation process in ancient Tunisia}, volume = {19}, journal = {PLoS ONE}, number = {9}, doi = {10.1371/journal.pone.0309752}, year = {2024}, abstract = {Romanisation is a multi-faceted historical phenomenon with profound and lasting cultural impact on the ancient world. In the modern-day territory of Tunisia, this is particularly manifest during the first four centuries AD, under the reign of the Roman Empire. We derive a reduced, operational concept of Romanisation as a cultural diffusion process that is observable in the archaeological remains of the Roman era settlement system. We then introduce a novel mathematical model that computes spatio-temporal approximations for the Romanisation of the settlement system. The model is based on the concept of temporal road activation and makes minimal assumptions regarding input data quality. The results of our study contribute to the understanding of the time dynamics of the region's road network, under the influence of Romanisation. Our model can be applied in similar archaeological research scenarios, to generate spatio-temporal backbones for the analysis of otherwise intractably complex social processes.}, language = {en} } @misc{BetzBinkowskiBurger2023, author = {Betz, Fridtjof and Binkowski, Felix and Burger, Sven}, title = {RPExpand (Version 1)}, journal = {Zenodo}, doi = {10.5281/zenodo.7840116}, pages = {doi: 10.5281/zenodo.7840116}, year = {2023}, language = {en} } @article{ErnstBankowskiJusyteetal.2025, author = {Ernst, Ariane and Bankowski, Anastasia and Jusyte, Meida and Okunola, Toluwani and Petrov, Tino and Walter, Alexander and Winkelmann, Stefanie}, title = {Parameter Optimization for a Neurotransmission Recovery Model}, volume = {87}, journal = {Bulletin of Mathematical Biology}, publisher = {Bulletin of Mathematical Biology}, doi = {10.1007/s11538-025-01486-2}, year = {2025}, abstract = {We assess the empirical applicability of a simplified model for neurotransmitter release that incorporates maturation, fusion, and recovery of both release sites and vesicles. Model parameters are optimized by fitting the model to experimental data obtained from neuromuscular junction synapses of 3rd-instar Drosophila melanogaster larvae. In particular, the mean-squared error between the local extrema of the simulated total junction current and its experimental counterpart is minimized. We compare three estimation approaches, differing in the choice of optimized parameters and the fusion rate function. Despite the model's minimalistic structure, it demonstrates a compelling ability to replicate experimental data, yielding plausible parameter estimates for five different animals. An additional identifiability analysis based on the profile likelihood reveals practical non-identifiabilities for several parameters, highlighting the need for additional constraints or data to improve estimation accuracy.}, language = {en} } @inproceedings{SekulicSchneiderHammerschmidtetal.2025, author = {Sekulic, Ivan and Schneider, Philipp-Immanuel and Hammerschmidt, Martin and Schaible, Jonas and Burger, Sven}, title = {Physics informed Bayesian optimization for inverse design of diffractive optical elements}, volume = {PC13573}, booktitle = {Proc. SPIE}, doi = {10.1117/12.3064372}, pages = {PC135730R}, year = {2025}, language = {en} } @inproceedings{HammerschmidtPlockBurgeretal.2025, author = {Hammerschmidt, Martin and Plock, Matthias and Burger, Sven and Truong, Vinh and Soltwisch, Victor and Schneider, Philipp-Immanuel}, title = {Machine learning approach for full Bayesian parameter reconstruction}, volume = {13568}, booktitle = {Proc. SPIE}, doi = {10.1117/12.3062268}, pages = {1356806}, year = {2025}, language = {en} } @article{BinkowskiKoulasSimosBetzetal.2025, author = {Binkowski, Felix and Koulas-Simos, Aris and Betz, Fridtjof and Plock, Matthias and Sekulic, Ivan and Manley, Phillip and Hammerschmidt, Martin and Schneider, Philipp-Immanuel and Zschiedrich, Lin and Munkhbat, Battulga and Reitzenstein, Stephan and Burger, Sven}, title = {High Purcell enhancement in all-TMDC nanobeam resonator designs with active monolayers for nanolasers}, volume = {112}, journal = {Phys. Rev. B}, arxiv = {http://arxiv.org/abs/2508.05333}, doi = {10.1103/nxh9-dhvx}, pages = {235410}, year = {2025}, language = {en} } @misc{BinkowskiKoulasSimosBetzetal.2025, author = {Binkowski, Felix and Koulas-Simos, Aris and Betz, Fridtjof and Plock, Matthias and Sekulic, Ivan and Manley, Phillip and Hammerschmidt, Martin and Schneider, Philipp-Immanuel and Zschiedrich, Lin and Munkhbat, Battulga and Reitzenstein, Stephan and Burger, Sven}, title = {Source code and simulation results: High Purcell enhancement in all-TMDC nanobeam resonator designs with active monolayers for nanolasers}, journal = {Zenodo}, doi = {10.5281/zenodo.16533803}, year = {2025}, language = {en} } @article{StraubeOliconMendezWinkelmannetal.2025, author = {Straube, Arthur and Olic{\´o}n M{\´e}ndez, Guillermo and Winkelmann, Stefanie and H{\"o}fling, Felix and Engel, Maximilian}, title = {Unfolding the geometric structure and multiple timescales of the urea-urease pH oscillator}, arxiv = {http://arxiv.org/abs/2508.07275}, year = {2025}, abstract = {We study a two-variable dynamical system modeling pH oscillations in the urea-urease reaction within giant lipid vesicles - a problem that intrinsically contains multiple, well-separated timescales. Building on an existing, deterministic formulation via ordinary differential equations, we resolve different orders of magnitude within a small parameter and analyze the system's limit cycle behavior using geometric singular perturbation theory (GSPT). By introducing two different coordinate scalings - each valid in a distinct region of the phase space - we resolve the local dynamics near critical fold points, using the extension of GSPT through such singular points due to Krupa and Szmolyan. This framework enables a geometric decomposition of the periodic orbits into slow and fast segments and yields closed-form estimates for the period of oscillation. In particular, we link the existence of such oscillations to an underlying biochemical asymmetry, namely, the differential transport across the vesicle membrane.}, language = {en} } @article{KourovSamoilovaStraube2025, author = {Kourov, Mikhail N. and Samoilova, Anna E. and Straube, Arthur}, title = {Dynamics of a chain of interacting magnetic particles in a one-dimensional periodic energy landscape}, volume = {89}, journal = {Bull. Russ. Acad. Sci. Phys.}, number = {7}, issn = {1062-8738}, doi = {10.1134/S1062873825711742}, pages = {1086 -- 1092}, year = {2025}, abstract = {We explore the dynamics of a one-dimensional chain of paramagnetic colloidal particles in a periodic potential. The model accounts for a constant external force, along with magnetic dipolar attraction and hard-core repulsive interactions between particles. Numerical simulations reveal the emergence of a traveling kink - a chain defect propagating along the chain. We show that the kink emerges beyond a critical force threshold and identify parameter regimes corresponding to distinct dynamic modes such as a pinned kink, a running kink, a cluster kink, and chain drift.}, language = {en} } @misc{OPUS4-10176, title = {Mathematical Optimization for Machine Learning}, editor = {Fackeldey, Konstantin and Kannan, Aswin and Pokutta, Sebastian and Sharma, Kartikey and Walter, Daniel and Walter, Andrea and Weiser, Martin}, publisher = {De Gruyter}, isbn = {9783111376776}, doi = {10.1515/9783111376776}, year = {2025}, abstract = {Mathematical optimization and machine learning are closely related. This proceedings volume of the Thematic Einstein Semester 2023 of the Berlin Mathematics Research Center MATH+ collects recent progress on their interplay in topics such as discrete optimization, nonlinear programming, optimal control, first-order methods, multilevel optimization, machine learning in optimization, physics-informed learning, and fairness in machine learning.}, language = {en} } @inproceedings{SchneiderSekulicPlocketal.2025, author = {Schneider, Philipp-Immanuel and Sekulic, Ivan and Plock, Matthias and Hammerschmidt, Martin and Rodt, Sven and Reitzenstein, Stephan and Burger, Sven}, title = {Physics-informed Bayesian optimization of nanophotonic devices}, volume = {IPRSN}, booktitle = {Advanced Photonics Congress}, doi = {10.1364/IPRSN.2025.ITu1A.2}, pages = {ITu1A.2}, year = {2025}, language = {en} } @inproceedings{JaegerMandalRandetal.2025, author = {J{\"a}ger, Klaus and Mandal, Jyotirmoy and Rand, Barry P. and Meggers, Forrest and Becker, Christiane}, title = {Thermal Management of Solar Modules with Infrared-Antireflective Coatings}, volume = {SOLITH}, booktitle = {Advanced Photonics Congress}, doi = {10.1364/SOLITH.2025.SM4E.2}, pages = {SM4E.2}, year = {2025}, language = {en} } @article{TillmannBlaesiBurgeretal.2021, author = {Tillmann, Peter and Bl{\"a}si, Benedikt and Burger, Sven and Hammerschmidt, Martin and H{\"o}hn, Oliver and Becker, Christiane and J{\"a}ger, Klaus}, title = {Optimizing metal grating back reflectors for III-V-on-silicon multijunction solar cells}, volume = {29}, journal = {Opt. Express}, doi = {10.1364/OE.426761}, pages = {22517}, year = {2021}, language = {en} } @misc{RaharinirinaWeberBirketal.2021, author = {Raharinirina, N. Alexia and Weber, Marcus and Birk, Ralph and Fackeldey, Konstantin and Klasse, Sarah M. and Richter, Tonio Sebastian}, title = {Different Tools and Results for Correspondence Analysis}, doi = {10.12752/8257}, year = {2021}, abstract = {This is a list of codes generated from ancient egyptian texts. The codes are used for a correspondence analysis (CA). Codes and CA software are available from the linked webpage.}, language = {en} } @article{PlockBurgerSchneider2021, author = {Plock, Matthias and Burger, Sven and Schneider, Philipp-Immanuel}, title = {Recent advances in Bayesian optimization with applications to parameter reconstruction in optical nano-metrology}, volume = {11783}, journal = {Proc. SPIE}, arxiv = {http://arxiv.org/abs/2107.05499}, doi = {10.1117/12.2592266}, pages = {117830J}, year = {2021}, language = {en} } @article{WinkelmannZonkerSchuetteetal.2021, author = {Winkelmann, Stefanie and Zonker, Johannes and Sch{\"u}tte, Christof and Djurdjevac Conrad, Natasa}, title = {Mathematical modeling of spatio-temporal population dynamics and application to epidemic spreading}, volume = {336}, journal = {Mathematical Biosciences}, publisher = {Elsevier}, arxiv = {http://arxiv.org/abs/2205.05000}, doi = {10.1016/j.mbs.2021.108619}, year = {2021}, abstract = {Agent based models (ABMs) are a useful tool for modeling spatio-temporal population dynamics, where many details can be included in the model description. Their computational cost though is very high and for stochastic ABMs a lot of individual simulations are required to sample quantities of interest. Especially, large numbers of agents render the sampling infeasible. Model reduction to a metapopulation model leads to a significant gain in computational efficiency, while preserving important dynamical properties. Based on a precise mathematical description of spatio-temporal ABMs, we present two different metapopulation approaches (stochastic and piecewise deterministic) and discuss the approximation steps between the different models within this framework. Especially, we show how the stochastic metapopulation model results from a Galerkin projection of the underlying ABM onto a finite-dimensional ansatz space. Finally, we utilize our modeling framework to provide a conceptual model for the spreading of COVID-19 that can be scaled to real-world scenarios.}, language = {en} } @article{AndrleHoenickeGwaltetal.2021, author = {Andrle, Anna and H{\"o}nicke, Philipp and Gwalt, Grzegorz and Schneider, Philipp-Immanuel and Kayser, Yves and Siewert, Frank and Soltwisch, Victor}, title = {GIXRF and machine learning as metrological tools for shape and element sensitive reconstructions of periodic nanostructures}, volume = {11611}, journal = {Proc. SPIE}, doi = {10.1117/12.2586082}, pages = {116110R}, year = {2021}, language = {en} } @article{NitzkeFackeldeyVrabec2021, author = {Nitzke, Isabel and Fackeldey, Konstantin and Vrabec, Jadran}, title = {Long range corrections for inhomogeneous fluids containing a droplet or a bubble}, journal = {Molecular Simulation}, doi = {https://doi.org/10.1080/08927022.2021.1954639}, pages = {1 -- 14}, year = {2021}, abstract = {Long range corrections for molecular simulations of inhomogeneous fluids with a spherical interface are presented. Correction terms for potential energy, force and virial are derived for the monatomic Lennard-Jones fluid. The method is generalised to the Mie potential and arbitrary molecular structures, employing a numerically efficient centre of mass cut-off scheme. The results are validated by a series of droplet simulations for one-centre and two-centre Lennard-Jones fluids with different cut-off radii rc. Systems with rc=8σ provide a check of self-consistence. Further, a system containing a bubble is investigated for the one-centre Lennard-Jones fluid. The equilibrium properties are almost completely independent on the cut-off radius. In comparison with vapour-liquid equilibrium data for systems without a curved interface, all properties show the expected behaviour. Simulation data are used to approximate the surface tension, which is in good agreement with the findings for planar interfaces, thus verifying the present corrections.}, language = {en} } @article{AndrleHoenickeGwaltetal.2021, author = {Andrle, Anna and H{\"o}nicke, Philipp and Gwalt, Grzegorz and Schneider, Philipp-Immanuel and Kayser, Yves and Siewert, Frank and Soltwisch, Victor}, title = {Shape- and Element-Sensitive Reconstruction of Periodic Nanostructures with Grazing Incidence X-ray Fluorescence Analysis and Machine Learning}, volume = {11}, journal = {Nanomaterials}, doi = {10.3390/nano11071647}, pages = {1647}, year = {2021}, language = {en} } @article{TiernoJohansenStraube2021, author = {Tierno, Pietro and Johansen, Tom H. and Straube, Arthur}, title = {Thermally active nanoparticle clusters enslaved by engineered domain wall traps}, volume = {12}, journal = {Nature Commun.}, doi = {10.1038/s41467-021-25931-7}, pages = {5813}, year = {2021}, abstract = {The stable assembly of fluctuating nanoparticle clusters on a surface represents a technological challenge of widespread interest for both fundamental and applied research. Here we demonstrate a technique to stably confine in two dimensions clusters of interacting nanoparticles via size-tunable, virtual magnetic traps. We use cylindrical Bloch walls arranged to form a triangular lattice of ferromagnetic domains within an epitaxially grown ferrite garnet film. At each domain, the magnetic stray field generates an effective harmonic potential with a field tunable stifness. The experiments are combined with theory to show that the magnetic confinement is effectively harmonic and pairwise interactions are of dipolar nature, leading to central, strictly repulsive forces. For clusters of magnetic nanoparticles, the stationary collective states arise from the competition between repulsion, confinement and the tendency to fill the central potential well. Using a numerical simulation model as a quantitative map between the experiment and theory we explore the field-induced crystallization process for larger clusters and unveil the existence of three different dynamical regimes. The present method provides a model platform for investigations of the collective phenomena emerging when strongly confined nanoparticle clusters are forced to move in an idealized, harmonic-like potential.}, language = {en} } @article{OehmeMoewisBoethetal.2022, author = {Oehme, Stephan and Moewis, Philippe and Boeth, Heide and Bartek, Benjamin and Lippert, Annika and von Tycowicz, Christoph and Ehrig, Rainald and Duda, Georg and Jung, Tobias}, title = {PCL insufficient patients with increased translational and rotational passive knee joint laxity have no increased range of anterior-posterior and rotational tibiofemoral motion during level walking}, volume = {12}, journal = {Scientific Reports}, number = {1}, doi = {10.1038/s41598-022-17328-3}, pages = {1 -- 11}, year = {2022}, language = {en} } @inproceedings{TillmannJaegerKatzetal.2021, author = {Tillmann, Peter and J{\"a}ger, Klaus and Katz, Eugene and Becker, Christiane}, title = {Relaxed current-matching constraints by bifacial operation and luminescent coupling in perovskite/silicon tandem solar cells}, booktitle = {2021 IEEE 48th Photovoltaic Specialists Conference (PVSC)}, doi = {10.1109/PVSC43889.2021.9518891}, pages = {1086}, year = {2021}, language = {en} } @misc{BetzBinkowskiBurger2021, author = {Betz, Fridtjof and Binkowski, Felix and Burger, Sven}, title = {RPExpand: Software for Riesz projection expansion of resonance phenomena [Source Code]}, doi = {10.24433/CO.2372084.v1}, year = {2021}, language = {de} } @article{WuArrivaultDurufleetal.2021, author = {Wu, Tong and Arrivault, Denis and Durufl{\´e}, Marc and Gras, Alexandre and Binkowski, Felix and Burger, Sven and Yan, Wei and Lalanne, Philippe}, title = {Efficient hybrid method for the modal analysis of optical microcavities and nanoresonators}, volume = {38}, journal = {J. Opt. Soc. Am. A}, doi = {10.1364/JOSAA.428224}, pages = {1224}, year = {2021}, language = {en} } @article{BetzBinkowskiBurger2021, author = {Betz, Fridtjof and Binkowski, Felix and Burger, Sven}, title = {RPExpand: Software for Riesz projection expansion of resonance phenomena}, volume = {15}, journal = {SoftwareX}, doi = {10.1016/j.softx.2021.100763}, pages = {100763}, year = {2021}, language = {en} } @article{NegrinMonteceloMovsesyanGaoetal.2022, author = {Negrin-Montecelo, Yoel and Movsesyan, Artur and Gao, Jie and Burger, Sven and Wang, Zhiming and Nlate, Sylvain and Pouget, Emilie and Oda, Reiko and Comesana-Hermo, Miguel and Govorov, Alexander O. and Correa-Duarte, Miguel}, title = {Chiral Generation of Hot Carriers for Polarization-Sensitive Plasmonic Photocatalysis with Hybrid Nanostructures}, volume = {144}, journal = {J. Am. Chem. Soc.}, doi = {10.1021/jacs.1c10526}, pages = {1663}, year = {2022}, language = {en} }