Integration of multi-junction absorbers and catalysts for efficient solar-driven artificial leaf structures : a physical and materials science perspective. - In: Solar RRL, ISSN 2367-198X, Bd. 0 (2024), 0, S. 1-88
Artificial leaves could be the breakthrough technology to overcome the limitations of storage and mobility through the synthesis of chemical fuels from sunlight, which will be an essential component of a sustainable future energy system. However, the realization of efficient solar-driven artificial leaf structures requires integrated specialized materials such as semiconductor absorbers, catalysts, interfacial passivation, and contact layers. To date, no competitive system has emerged due to a lack of scientific understanding, knowledge-based design rules, and scalable engineering strategies. Here, we will discuss competitive artificial leaf devices for water splitting, focusing on multi-absorber structures to achieve solar-to-hydrogen conversion efficiencies exceeding 15%. A key challenge is integrating photovoltaic and electrochemical functionalities in a single device. Additionally, optimal electrocatalysts for intermittent operation at photocurrent densities of 10-20 mA cm^-2 must be immobilized on the absorbers with specifically designed interfacial passivation and contact layers, so-called buried junctions. This minimizes voltage and current losses and prevents corrosive side reactions. Key challenges include understanding elementary steps, identifying suitable materials, and developing synthesis and processing techniques for all integrated components. This is crucial for efficient, robust, and scalable devices. Here, we discuss and report on corresponding research efforts to produce green hydrogen with unassisted solar-driven (photo-)electrochemical devices. This article is protected by copyright. All rights reserved.
https://doi.org/10.1002/solr.202301047
Reducing reservoir computer hyperparameter dependence by external timescale tailoring. - In: Neuromorphic computing and engineering, ISSN 2634-4386, Bd. 4 (2024), 1, 014001, S. 1-16
Task specific hyperparameter tuning in reservoir computing is an open issue, and is of particular relevance for hardware implemented reservoirs. We investigate the influence of directly including externally controllable task specific timescales on the performance and hyperparameter sensitivity of reservoir computing approaches. We show that the need for hyperparameter optimisation can be reduced if timescales of the reservoir are tailored to the specific task. Our results are mainly relevant for temporal tasks requiring memory of past inputs, for example chaotic timeseries prediction. We consider various methods of including task specific timescales in the reservoir computing approach and demonstrate the universality of our message by looking at both time-multiplexed and spatially-multiplexed reservoir computing.
https://doi.org/10.1088/2634-4386/ad1d32
Enhancing the performance of quantum reservoir computing and solving the time-complexity problem by artificial memory restriction. - In: Physical review research, ISSN 2643-1564, Bd. 6 (2024), 1, 013051, S. 013051-1-013051-11
We propose a scheme that can enhance the performance and reduce the computational cost of quantum reservoir computing. Quantum reservoir computing is a computing approach which aims at utilizing the complexity and high dimensionality of small quantum systems, together with the fast trainability of reservoir computing, in order to solve complex tasks. The suitability of quantum reservoir computing for solving temporal tasks is hindered by the collapse of the quantum system when measurements are made. This leads to the erasure of the memory of the reservoir. Hence, for every output, the entire input signal is needed to reinitialize the reservoir, leading to quadratic time complexity. Another critical issue for the hardware implementation of quantum reservoir computing is the need for an experimentally accessible means of tuning the nonlinearity of the quantum reservoir. We present an approach which addresses both of these issues. We propose artificially restricting the memory of the quantum reservoir by only using a small number inputs to reinitialize the reservoir after measurements are performed. This strongly influences the nonlinearity of the reservoir response due to the influence of the initial reservoir state, while also substantially reducing the number of quantum operations needed to perform time-series prediction tasks due to the linear rather than quadratic time complexity. The reinitialization length therefore provides an experimental accessible means of tuning the nonlinearity of the response of the reservoir, which can lead to significant task-specific performance improvement. We numerically study the linear and quadratic algorithms for a fully connected transverse Ising model and a quantum processor model.
https://doi.org/10.1103/PhysRevResearch.6.013051
Photonic reservoir computing for energy efficient and versatile machine learning application. - In: Proceedings of the Royal Society of Victoria, Bd. 135 (2023), 2, S. 38-40
Time-multiplexed reservoir computing is a machine learning concept which can be realised in photonic hardware systems using only one physical node. The concept can be used for various problems, ranging from classification problems to time-series prediction tasks, while being fast and energy efficient. Here, a theoretical analysis of a reservoir computer realised via delay-coupled semiconductor lasers is presented and the role of the internal system time-scales and the bifurcation structure is discussed. It is further shown that optimal performance can be reached by tailoring the coupling delays to the specific memory requirements of the given task.
https://doi.org/10.1071/rs23006
Delay-based reservoir computing with spin-VCSELs: interplay between internal dynamics and performance. - In: 2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), (2023), insges. 1 S.
Machine learning setups that are able to process data in the optical domain are ideal for on -chip hardware implementations [1]. Due to the fact that the training of hardware based solutions is complicated, a delay-based reservoir computing (RC) realization, where only the output weights need to be trained via linear regression, is very promising [2]. In this paper we investigate vertical cavity surface emitting laser with two mode emission (spin-VCSEL) as the nonlinear node for a delay-based RC setup. These lasers have the ability to exibit reprodicible and high speed dynamics [3] and are thus ideal candidates to increase the data injection rates which are limited by the clocktime [4], [5]. The focus of our numerical investigations is on the interplay between the internal charge carrier dynamics of the spin-VCSEL and its performance when operated in a delay-based RC setup with optically-injected phase-modulated data injection.
https://doi.org/10.1109/CLEO/Europe-EQEC57999.2023.10232555
Uncovering vulnerable connections in the aging brain using reservoir computing. - In: Emerging Topics in Artificial Intelligence (ETAI) 2023, (2023), PC1265508
We used reservoir computing to explore the changes in the connectivity patterns of whole-brain anatomical networks derived by diffusion-weighted imaging, and their impact on cognition during aging. The networks showed optimal performance at small densities. This performance decreased with increasing density, with the rate of decrease being strongly associated with age and performance on behavioural tasks measuring cognitive function. This suggests that a network core of anatomical hubs is crucial for optimal functioning, while weaker connections are more susceptible to aging effects. This study highlights the potential utility of reservoir computing in understanding age-related changes in cognitive function.
https://doi.org/10.1117/12.2677364
Self-induced ultrafast electron-hole-plasma temperature oscillations in nanowire lasers. - In: Physical review applied, ISSN 2331-7019, Bd. 20 (2023), 3, S. 034045-1-034045-12
Nanowire lasers can be monolithically and site-selectively integrated onto silicon photonic circuits. To assess their full potential for ultrafast optoelectronic devices, a detailed understanding of their lasing dynamics is crucial. However, the roles played by their resonator geometry and the microscopic processes that mediate energy exchange between the photonic, electronic, and phononic subsystems are largely unexplored. Here, we study the dynamics of GaAs-AlGaAs core-shell nanowire lasers at cryogenic temperatures using a combined experimental and theoretical approach. Our results indicate that these NW lasers exhibit sustained intensity oscillations with frequencies ranging from 160GHz to 260GHz. As the underlying physical mechanism, we have identified self-induced electron-hole plasma temperature oscillations resulting from a dynamic competition between photoinduced carrier heating and cooling via phonon scattering. These dynamics are intimately linked to the strong interaction between the lasing mode and the gain material, which arises from the wavelength-scale dimensions of these lasers. We anticipate that our results could lead to optimised approaches for ultrafast intensity and phase modulation of chip-integrated semiconductor lasers at the nanoscale.
https://doi.org/10.1103/PhysRevApplied.20.034045
Data-informed reservoir computing for efficient time-series prediction. - In: Chaos, ISSN 1089-7682, Bd. 33 (2023), 7, 073109, S. 073109-1-073109-11
We propose a new approach to dynamical system forecasting called data-informed-reservoir computing (DI-RC) that, while solely being based on data, yields increased accuracy, reduced computational cost, and mitigates tedious hyper-parameter optimization of the reservoir computer (RC). Our DI-RC approach is based on the recently proposed hybrid setup where a knowledge-based model is combined with a machine learning prediction system, but it replaces the knowledge-based component by a data-driven model discovery technique. As a result, our approach can be chosen when a suitable knowledge-based model is not available. We demonstrate our approach using a delay-based RC as the machine learning component in conjunction with sparse identification of nonlinear dynamical systems for the data-driven model component. We test the performance on two example systems: the Lorenz system and the Kuramoto-Sivashinsky system. Our results indicate that our proposed technique can yield an improvement in the time-series forecasting capabilities compared with both approaches applied individually, while remaining computationally cheap. The benefit of our proposed approach, compared with pure RC, is most pronounced when the reservoir parameters are not optimized, thereby reducing the need for hyperparameter optimization.
https://doi.org/10.1063/5.0152311
Data-driven forecasting of nonequilibrium solid-state dynamics. - In: Physical review, ISSN 2469-9969, Bd. 107 (2023), 18, 184306, S. 184306-1-184306-18
We present a data-driven approach to efficiently approximate nonlinear transient dynamics in solid-state systems. Our proposed machine-learning model combines a dimensionality reduction stage with a nonlinear vector autoregression scheme. We report an outstanding time-series forecasting performance combined with an easy-to-deploy model and an inexpensive training routine. Our results are of great relevance as they have the potential to massively accelerate multiphysics simulation software and thereby guide the future development of solid-state-based technologies.
https://doi.org/10.1103/PhysRevB.107.184306
Spontaneous emission noise resilience of coupled nanolasers. - In: Frontiers in photonics, ISSN 2673-6853, Bd. 4 (2023), 1169988, S. 01-06
We investigate the spontaneous emission noise resilience of the phase-locked operation of two delay-coupled nanolasers. The system is modeled by semi-classical Maxwell-Bloch rate equations with stochastic Langevin-type noise sources. Our results reveal that a polarization dephasing time of two to three times the cavity photon lifetime maximizes the system’s ability to remain phase-locked in the presence of noise-induced perturbations. The Langevin noise term is caused by spontaneous emission processes which change both the intensity auto-correlation properties of the solitary lasers and the coupled system. In an experimental setup, these quantities are measurable and can be directly compared to our numerical data. The strong parameter dependence of the noise tolerance that we find may show possible routes for the design of robust on-chip integrated networks of nanolasers.
https://doi.org/10.3389/fphot.2023.1169988
Multiplexed random-access optical memory in warm cesium vapor. - In: Optics express, ISSN 1094-4087, Bd. 31 (2023), 6, S. 10150-10158
The ability to store large amounts of photonic quantum states is regarded as substantial for future optical quantum computation and communication technologies. However, research for multiplexed quantum memories has been focused on systems that show good performance only after an elaborate preparation of the storage media. This makes it generally more difficult to apply outside a laboratory environment. In this work, we demonstrate a multiplexed random-access memory to store up to four optical pulses using electromagnetically induced transparency in warm cesium vapor. Using a Λ-System on the hyperfine transitions of the Cs D1 line, we achieve a mean internal storage efficiency of 36% and a 1/e lifetime of 3.2 µs. In combination with future improvements, this work facilitates the implementation of multiplexed memories in future quantum communication and computation infrastructures.
https://doi.org/10.1364/OE.483642
Deriving task specific performance from the information processing capacity of a reservoir computer. - In: Nanophotonics, ISSN 2192-8614, Bd. 12 (2023), 5, S. 937-947
In the reservoir computing literature, the information processing capacity is frequently used to characterize the computing capabilities of a reservoir. However, it remains unclear how the information processing capacity connects to the performance on specific tasks. We demonstrate on a set of standard benchmark tasks that the total information processing capacity correlates poorly with task specific performance. Further, we derive an expression for the normalized mean square error of a task as a weighted function of the individual information processing capacities. Mathematically, the derivation requires the task to have the same input distribution as used to calculate the information processing capacities. We test our method on a range of tasks that violate this requirement and find good qualitative agreement between the predicted and the actual errors as long as the task input sequences do not have long autocorrelation times. Our method offers deeper insight into the principles governing reservoir computing performance. It also increases the utility of the evaluation of information processing capacities, which are typically defined on i.i.d. input, even if specific tasks deliver inputs stemming from different distributions. Moreover, it offers the possibility of reducing the experimental cost of optimizing physical reservoirs, such as those implemented in photonic systems.
https://doi.org/10.1515/nanoph-2022-0415
Photonic reservoir computing with non-linear memory cells: interplay between topology, delay and delayed input. - In: Emerging Topics in Artificial Intelligence (ETAI) 2022, (2022), 1220408, S. 1220408-1-1220408-7
Photonic reservoir computing is an emerging topic due to the possibility to realize very fast devices with minimal training effort. We will discuss the reservoir computing performance of memory cells with a focus on the impact of delay lines and the interplay between coupling topology and performance for various benchmark tasks. We will further show that additional delayed input can be beneficial for reservoir computing setups in general, as it provides an easy tuning parameter, which can improve the performance of a reservoir on a range of tasks.
https://doi.org/10.1117/12.2633339
Optimizing the cavity-arm ratio of V-shaped semiconductor disk lasers. - In: Physical review applied, ISSN 2331-7019, Bd. 18 (2022), 6, S. 064070
Passively mode-locked semiconductor disk lasers have received tremendous attention from both science and industry. Their relatively inexpensive production combined with excellent pulse performance and great emission-wavelength flexibility make them suitable laser candidates for applications ranging from frequency-comb tomography to spectroscopy. However, due to the interaction of the active medium dynamics and the device geometry, emission instabilities occur at high pump powers and thereby limit their performance potential. Hence, understanding those instabilities becomes critical for an optimal laser design. Using a delay-differential equation model, we are able to detect, understand, and classify three distinct instabilities that limit the maximum achievable pump power for the fundamental mode-locking state and link them to characteristic positive-net-gain windows. We furthermore derive a simple analytic approximation in order to quantitatively describe the stability boundary. Our results enable us to predict the optimal laser-cavity configuration with respect to positive-net-gain instabilities and therefore may be of great relevance for the future development of passively mode-locking semiconductor disk lasers.
https://doi.org/10.1103/PhysRevApplied.18.064070
Master memory function for delay-based reservoir computers with single-variable dynamics. - In: IEEE transactions on neural networks and learning systems, ISSN 2162-2388, Bd. 0 (2022), 0, S. 1-14
We show that many delay-based reservoir computers considered in the literature can be characterized by a universal master memory function (MMF). Once computed for two independent parameters, this function provides linear memory capacity for any delay-based single-variable reservoir with small inputs. Moreover, we propose an analytical description of the MMF that enables its efficient and fast computation. Our approach can be applied not only to single-variable delay-based reservoirs governed by known dynamical rules, such as the Mackey-Glass or Stuart-Landau-like systems, but also to reservoirs whose dynamical model is not available.
https://doi.org/10.1109/TNNLS.2022.3220532
Role of delay-times in delay-based photonic reservoir computing. - In: Optical materials express, ISSN 2159-3930, Bd. 12 (2022), 3, S. 1214-1231
Delay-based reservoir computing has gained a lot of attention due to the relative simplicity with which this concept can be implemented in hardware. However, unnecessary constraints are commonly placed on the relationship between the delay-time and the input clock-cycle, which can have a detrimental effect on the performance. We review the existing literature on this subject and introduce the concept of delay-based reservoir computing in a manner that demonstrates that no predefined relationship between the delay-time and the input clock-cycle is required for this computing concept to work. Choosing the delay-times independent of the input clock-cycle, one gains an important degree of freedom. Consequently, we discuss ways to improve the computing performance of a reservoir formed by delay-coupled oscillators and show the impact of delay-time tuning in such systems.
https://doi.org/10.1364/OME.451016
Connecting reservoir computing with statistical forecasting and deep neural networks. - In: Nature Communications, ISSN 2041-1723, Bd. 13 (2022), 227, S. 1-3
Among the existing machine learning frameworks, reservoir computing demonstrates fast and low-cost training, and its suitability for implementation in various physical systems. This Comment reports on how aspects of reservoir computing can be applied to classical forecasting methods to accelerate the learning process, and highlights a new approach that makes the hardware implementation of traditional machine learning algorithms practicable in electronic and photonic systems.
https://doi.org/10.1038/s41467-021-27715-5
Three-dimensional optical microcavities: from geometric phases to tailored far-field emission. - Ilmenau : Universitätsbibliothek, 2021. - 1 Online-Ressource (iii, 204 Seiten)
Technische Universität Ilmenau, Dissertation 2021
Diese Arbeit behandelt dreidimensionale optische Mikrokavitäten in Bezug auf ihre Resonanzmoden. Die optischen Mikrokavitäten reichen dabei von Möbiusband-Kavitäten über zylindrische und kegelförmige Ringkavitäten sowie kegelförmige Tube-Kavitäten bis hin zu Arrays von Lima¸con-Kavitäten. Im ersten Teil werden flüstergalerieartige Moden von dielektrischen Möbiusband-Kavitäten mit Hilfe von FDTD-Simulationen untersucht. Die Topologie des Möbiusbands erlaubt die Entstehung einer geometrischen Phase und zwar der Pancharatnam-Phase. Darauf aufbauend wird untersucht, wie die Pancharatnam-Phase durch Verkürzung der Länge des verdrehten Anteils oder durch Erhöhung der Dicke des Möbiusbands manipuliert werden kann. Dabei untersuchen wir, wie die Polarisation und die Fernfelder der flüstergalerieartigen Moden beeinflusst werden. Außerdem wird die Nonagon-Möbiusband-Kavität - eine Möbiusband-Kavität mit Querschnittsform dreifacher Rotationssymmetrie - eingeführt, die ebenfalls eine Manipulation der Pancharatnam-Phase ermöglicht. Im zweiten Teil werden propagierende flüstergalerieartige Moden in zylindrischen Ringkavitäten, konischen Ringkavitäten und konischen Tube-Kavitäten mittels FDTD-Simulationen und vektorieller Beugungstheorie untersucht. Der propagierende Charakter der Moden ermöglicht die sogenannte Spin-Richtungs-Wechselwirkung des Lichts. Darauf aufbauend wird untersucht, wie die Fernfeldpolarisation durch die axiale Morphologie der flüstergalerieartigen Moden und durch geometrische Eigenschaften der Kavitäten wie die Öffnungswinkel von konischen Ring- und Tube-Kavitäten beeinflusst wird. Mit Hilfe vektorieller Beugungstheorie wird ein qualitativer Zusammenhang zwischen den lokalen Eigenschaften der Moden im Inneren der Kavität und der Fernfeldpolarisation beschrieben. Dabei wird die Rolle von Beugung und Präzession des elektrischen Feldvektors um die Kavitätenachse diskutiert. Es wird gezeigt, dass elliptische und zirkulare Polarisationszustände im Fernfeld unmittelbar durch propagierende flüstergalerieartige Moden auftreten, auch ohne inhomogenes oder anisotropes Kavitätenmaterial. Im dritten Teil wird die Fernfeldabstrahlung von linearen Arrays bestehend aus Lima¸con-Kavitäten mithilfe von FDTD-Simulationen untersucht. Während das Fernfeld einer einzelnen Lima¸con-Kavität gerichtete Emission aufweist, wird untersucht, wie sich diese gerichtete Emission in Abhängigkeit der Arrayeigenschaften wie dem Abstand zwischen den Kavitäten und der Anzahl der Kavitäten ändert. Es wird gezeigt, dass die Abstrahlung des Arrays entweder weiter verstärkt (Superdirektionalität) oder sogar umgekehrt Kavitäten werden kann (Richtungsumkehr).
https://nbn-resolving.org/urn:nbn:de:gbv:ilm1-2021000314
Reservoir computing with delayed input for fast and easy optimisation. - In: Entropy, ISSN 1099-4300, Bd. 23 (2021), 12, 1560, S. 1-13
Reservoir computing is a machine learning method that solves tasks using the response of a dynamical system to a certain input. As the training scheme only involves optimising the weights of the responses of the dynamical system, this method is particularly suited for hardware implementation. Furthermore, the inherent memory of dynamical systems which are suitable for use as reservoirs mean that this method has the potential to perform well on time series prediction tasks, as well as other tasks with time dependence. However, reservoir computing still requires extensive task-dependent parameter optimisation in order to achieve good performance. We demonstrate that by including a time-delayed version of the input for various time series prediction tasks, good performance can be achieved with an unoptimised reservoir. Furthermore, we show that by including the appropriate time-delayed input, one unaltered reservoir can perform well on six different time series prediction tasks at a very low computational expense. Our approach is of particular relevance to hardware implemented reservoirs, as one does not necessarily have access to pertinent optimisation parameters in physical systems but the inclusion of an additional input is generally possible.
https://doi.org/10.3390/e23121560
Husimi functions for coupled optical resonators. - In: Journal of the Optical Society of America, ISSN 1520-8532, Bd. 38 (2021), 4, S. 573-578
Phase-space analysis has been widely used in the past for the study of optical resonant systems. While it is usually employed to analyze the far-field behavior of resonant systems, we focus here on its applicability to coupling problems. By looking at the phase-space description of both the resonant mode and the exciting source, it is possible to understand the coupling mechanisms as well as to gain insights and approximate the coupling behavior with reduced computational effort. In this work, we develop the framework for this idea and apply it to a system of an asymmetric dielectric resonator coupled to a waveguide.
https://doi.org/10.1364/JOSAA.422740
Deformed microcavities with very high Q-factors and directional farfield emission. - In: EOS Annual Meeting (EOSAM 2020), (2020), 01006, S. 1-2
We report the design and optimized fabrication of deformed whispering gallery mode resonators in silica with solely ICP-RIE. This allows us to control the morphology of the resonators more freely and results in low surface roughness. The light was coupled into the resonator using a state of the art tapered fiber approach and we determined the Q-factor in the range of 10^5
https://doi.org/10.1051/epjconf/202023801006
Optische Systeme im Phasenraumbild. - In: DGaO-Proceedings, ISSN 1614-8436, Bd. 121 (2020), B29, insges. 2 S.
https://nbn-resolving.org/urn:nbn:de:0287-2020-B029-0
Spin-orbit interaction of light in three-dimensional microcavities. - In: Physical review, ISSN 2469-9934, Bd. 102 (2020), 4, 043524
We investigate the spin-orbit coupling of light in three-dimensional cylindrical and tubelike whispering gallery mode resonators. We show that its origin is the transverse confinement of light in the resonator walls, even in the absence of inhomogeneities or anisotropies. The spin-orbit interaction results in elliptical far-field polarization (spin) states and causes spatial separation of polarization handedness in the far field. The ellipticity and spatial separation are enhanced for whispering gallery modes with higher excitation numbers along the resonator height. We analyze the asymmetry of the ellipticity and the tilt of the polarization orientation in the far field of conelike microcavities. Furthermore, we find a direct relationship between the tilt of the polarization orientation in the far field and the local inclination of the resonator wall. Our findings are based on finite-difference time-domain simulations and are supported by three-dimensional diffraction theory.
https://doi.org/10.1103/PhysRevA.102.043524
Moist Rayleigh-Bérnard Convection in conditionally unstable environments. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section (SKM) together with the DPG Division Environmental Physics and the Working Groups Accelerator Physics; Equal Opportunities; Energy; Industry and Business; Physics, Modern IT and Artificial Intelligence, Young DPG, (2020), DY 16.3
Fabrication and characterization of deformed microdisk cavities in silicon dioxide with high Q-factor. - In: Applied optics, ISSN 2155-3165, Bd. 59 (2020), 26, S. 7893-7899
We demonstrate the excitation and characterization of whispering gallery modes in a deformed optical microcavity. To fabricate deformed microdisk microresonators we established a fabrication process relying on dry plasma etching tools for many degrees of freedom and a shape-accurate morphology. This approach allowed us to fabricate resonators of different sizes with a controlled sidewall angle and underetching in large quantities with reproducible properties such as a surface roughness RQ ≤ 2nm. The excitation and characterization of these modes were achieved by using a state-of-the-art tapered fiber coupling setup with a narrow linewidth tunable laser source. The conducted measurements in shortegg resonators showed at least two modes within a spectral range of about 237 pm. The highest Q-factors measured were in the range of 105. Wave optical eigenmode and frequency domain simulations were conducted that could partially reproduce the observed behavior and therefore allow us to compare the experimental results.
https://doi.org/10.1364/AO.398108
Splitting and combining of exceptional points. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section (SKM) together with the DPG Division Environmental Physics and the Working Groups Accelerator Physics; Equal Opportunities; Energy; Industry and Business; Physics, Modern IT and Artificial Intelligence, Young DPG, (2020), KFM 7.5
Nonhermitian defect states from lifetime differences. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section (SKM) together with the DPG Division Environmental Physics and the Working Groups Accelerator Physics; Equal Opportunities; Energy; Industry and Business; Physics, Modern IT and Artificial Intelligence, Young DPG, (2020), KFM 7.4
Far-field polarization states of 3D-whispering-gallery-mode resonators. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section (SKM) together with the DPG Division Environmental Physics and the Working Groups Accelerator Physics; Equal Opportunities; Energy; Industry and Business; Physics, Modern IT and Artificial Intelligence, Young DPG, (2020), KFM 7.3
Super-directional light emission and emission reversal from micro cavity arrays. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section (SKM) together with the DPG Division Environmental Physics and the Working Groups Accelerator Physics; Equal Opportunities; Energy; Industry and Business; Physics, Modern IT and Artificial Intelligence, Young DPG, (2020), KFM 7.1
Sources and coupling in billiards for light. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section (SKM) together with the DPG Division Environmental Physics and the Working Groups Accelerator Physics; Equal Opportunities; Energy; Industry and Business; Physics, Modern IT and Artificial Intelligence, Young DPG, (2020), DY 53.3
Ray-wave correspondence in graphene billiards with sources. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section (SKM) together with the DPG Division Environmental Physics and the Working Groups Accelerator Physics; Equal Opportunities; Energy; Industry and Business; Physics, Modern IT and Artificial Intelligence, Young DPG, (2020), DY 57.18
Augmentation of absorption channels induced by wave-chaos effects in free-standing nanowire arrays. - In: Optics express, ISSN 1094-4087, Bd. 28 (2020), 16, S. 23569-23583
Plenty of issues on quantal features in chaotic systems have been raised since chaos was accepted as one of the intrinsic properties of nature. Through intensive studies, it was revealed that resonance spectra in chaotic systems exhibit complicated structures, which is deeply concerned with sophisticated resonance dynamics. Motivated by these phenomena, we investigate light absorption characteristics of chaotic nanowires in an array. According to our results, a chaotic cross-section of a nanowire induces a remarkable augmentation of absorption channels, that is, an increasing number of absorption modes leads to substantial light absorption enhancement, as the deformation of cross-section increases. We experimentally demonstrate the light absorption enhancement with free-standing Si-nanowire polydimethylsiloxane (PDMS) composites. Our results are applicable not only to transparent solar cells but also to complementary metal-oxide-semiconductor (CMOS) image sensors to maximize absorption efficiency.
https://doi.org/10.1364/OE.398687
Analytical Fresnel laws for curved dielectric interfaces. - In: Journal of optics, ISSN 2040-8986, Volume 22 (2020), number 1, 015605, Seite 1-6
https://doi.org/10.1088/2040-8986/ab5c42
Quantenchaos. - In: Vielfältige Physik, (2019), S. 253-262
https://doi.org/10.1007/978-3-662-58035-6_23
Hybridization of different types of exceptional points. - In: Photonics research, ISSN 2327-9125, Bd. 7 (2019), 12, S. 1473-1478
https://doi.org/10.1364/PRJ.7.001473
Non-Hermitian defect states from lifetime differences. - In: Physical review, ISSN 2469-9934, Bd. 100 (2019), 6, 063801, insges. 8 S.
https://doi.org/10.1103/PhysRevA.100.063801
Superdirectional light emission and emission reversal from microcavity arrays. - In: Physical review research, ISSN 2643-1564, Bd. 1 (2019), 3, S. 033171-1-033171-5
Optical microdisk cavities with certain asymmetric shapes are known to possess unidirectional far-field emission properties. Here, we investigate arrays of these dielectric microresonators with respect to their emission properties resulting from the coherent behavior of the coupled constituents. This approach is inspired by electronic mesoscopic physics where the additional interference effects are known to enhance the properties of the individual system. As an example, we study the linear arrangement of nominally identical Lima¸con-shaped cavities and find mostly an increase of the portion of directional emitted light while its angular spread is largely diminished from 20 deg for the single cavity to about 3 deg for a linear array of 10 Lima¸con resonators, in fair agreement with a simple array model. Moreover, by varying the intercavity distance, we observe windows of reversion of the emission directionality and superdirectionality that can be interesting for applications like optical sensing or interconnects. We introduce a generalized array factor model that takes the coupling into account.
https://doi.org/10.1103/PhysRevResearch.1.033171
Mesoskopische Flüstergaleriemodenresonatoren im sichtbaren Spektrum auf Basis von Silizium Mikrostrukturierung. - In: MikroSystemTechnik Kongress 2019, (2019), S. 178-181
Untersuchung deformierter optischer Mikrokavitäten anhand des abgestrahlten Fernfelds. - In: DGaO-Proceedings, ISSN 1614-8436, Bd. 120 (2019), B17, insges. 2 S.
https://nbn-resolving.org/urn:nbn:de:0287-2019-B017-3
Super-directional light emission from arrays of deformed microcavities. - In: DPG-Frühjahrstagung 2019 (DPG Spring Meeting 2019) of the Condensed Matter Section (SKM) together with the Division Radiation and Medical Physics and the Working Groups Equal Opportunities, Industry and Business, Young DPG; Symposia, exhibition of scientific instruments and literature, (2019), KFM 4.10
The optical Möbius strip cavity: tailoring geometric phases and far fields. - In: DPG-Frühjahrstagung 2019 (DPG Spring Meeting 2019) of the Condensed Matter Section (SKM) together with the Division Radiation and Medical Physics and the Working Groups Equal Opportunities, Industry and Business, Young DPG; Symposia, exhibition of scientific instruments and literature, (2019), KFM 4.9
Hamiltonian matrix elements of the stadium billiard. - In: DPG-Frühjahrstagung 2019 (DPG Spring Meeting 2019) of the Condensed Matter Section (SKM) together with the Division Radiation and Medical Physics and the Working Groups Equal Opportunities, Industry and Business, Young DPG; Symposia, exhibition of scientific instruments and literature, (2019), DY 42.7
Analytical Fresnel laws at convex and concave non-planar interfaces from a transfer matrix approach. - In: DPG-Frühjahrstagung 2019 (DPG Spring Meeting 2019) of the Condensed Matter Section (SKM) together with the Division Radiation and Medical Physics and the Working Groups Equal Opportunities, Industry and Business, Young DPG; Symposia, exhibition of scientific instruments and literature, (2019), DY 37.4
Non-Hermitian degeneracies of internal-external mode pairs in dielectric microdisks. - In: Photonics research, ISSN 2327-9125, Bd. 7 (2019), 4, S. 464-472
https://dx.doi.org/10.1364/PRJ.7.000464
Mesoscopic optics. - In: Mikro-Nano-Integration, (2018), S. 55-57
Single-photon-single-electron transition for interpretation of optical spectra of nonspherical metal nanoparticles in aqueous colloidal solutions. - In: Journal of nanomaterials, ISSN 1687-4129, Bd. 2018 (2018), 1781389, S. 1-8
https://doi.org/10.1155/2018/1781389
Transport in disordered optical systems. - In: Joint Meeting of the DPG and EPS Condensed Matter Divisions together with the Statistical and Nonlinear Physics Division of the EPS and the Working Groups: Equal Opportunities, Industry and Business, Young DPG, Philosophy of Physics, (all DPG) EPS Young Minds, EPS History of Physics Group, (2018), DY 69.13
Whispering-gallery-like modes in two and three dimensional microcavities. - In: Joint Meeting of the DPG and EPS Condensed Matter Divisions together with the Statistical and Nonlinear Physics Division of the EPS and the Working Groups: Equal Opportunities, Industry and Business, Young DPG, Philosophy of Physics, (all DPG) EPS Young Minds, EPS History of Physics Group, (2018), KFM 5.1
Ray-wave correspondence in optical and graphene Billiards. - In: Joint Meeting of the DPG and EPS Condensed Matter Divisions together with the Statistical and Nonlinear Physics Division of the EPS and the Working Groups: Equal Opportunities, Industry and Business, Young DPG, Philosophy of Physics, (all DPG) EPS Young Minds, EPS History of Physics Group, (2018), DY 23.4
Signatures of multiple exceptional points in optical microdisk cavities. - In: Joint Meeting of the DPG and EPS Condensed Matter Divisions together with the Statistical and Nonlinear Physics Division of the EPS and the Working Groups: Equal Opportunities, Industry and Business, Young DPG, Philosophy of Physics, (all DPG) EPS Young Minds, EPS History of Physics Group, (2018), DY 69.8
Optical microcavities for nanoparticle sensing. - In: Joint Meeting of the DPG and EPS Condensed Matter Divisions together with the Statistical and Nonlinear Physics Division of the EPS and the Working Groups: Equal Opportunities, Industry and Business, Young DPG, Philosophy of Physics, (all DPG) EPS Young Minds, EPS History of Physics Group, (2018), DY 69.16
An analytical approach to extend Fresnel laws to concave shaped interfaces. - In: Joint Meeting of the DPG and EPS Condensed Matter Divisions together with the Statistical and Nonlinear Physics Division of the EPS and the Working Groups: Equal Opportunities, Industry and Business, Young DPG, Philosophy of Physics, (all DPG) EPS Young Minds, EPS History of Physics Group, (2018), DY 69.15
Exceptional points of third-order in a layered optical microdisk cavity. - In: New journal of physics, ISSN 1367-2630, Bd. 20 (2018), 083016, insges. 10 S.
https://doi.org/10.1088/1367-2630/aad594
The optical Möbius strip cavity: tailoring geometric phases and far fields. - In: epl, ISSN 1286-4854, Bd. 121 (2018), 2, S. 24001, insges. 6 S.
https://doi.org/10.1209/0295-5075/121/24001
Perturbation theory for asymmetric deformed optical microdisk cavities. - In: 21. Deutsche Physikerinnentagung, (2017), S. 110
Ray-wave correspondence in optical and graphene Billiards. - In: 21. Deutsche Physikerinnentagung, (2017), S. 109
Extended ray dynamics for integrable and chaotic optical microcavities. - In: 21. Deutsche Physikerinnentagung, (2017), S. 108
Three-dimensional description of optical microcavities. - In: 21. Deutsche Physikerinnentagung, (2017), S. 107
Consequences of a wave-correction extended ray dynamics for integrable and chaotic optical microcavities. - In: Journal of optics, ISSN 2040-8986, Bd. 19 (2017), 12, S. 125603, insges. 13 S.
https://doi.org/10.1088/2040-8986/aa93c2
Polarization evolution in 3D micro-cavities. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section (SKM), (2017), DY 32.8
Interplay of geometry and dynamics in mesoscopic model systems. - Ilmenau : Universitätsbibliothek, 2017. - 1 Online-Ressource (182 Seiten)
Technische Universität Ilmenau, Dissertation 2017
Diese Arbeit behandelt anhand verschiedenener mesoskopischer Modellsysteme das Zusammenspiel von Geometrie und Form eines Systems mit seinen Eigenschaften und seiner Dynamik. Im ersten Teil wird ein erweitertes strahlenoptisches Modell für dielektrische optische Mikrokavitäten untersucht. Strahlenoptik ist eine effiziente Methode, um die Fernfeldabstrahlung dieser Systeme vorherzusagen. Werden allerdings Systeme betrachtet, deren Abmessungen nur wenige Lichtwellenlängen betragen, können Korrekturen der geometrischen Optik notwendig werden, um Welleneffekte zu berücksichtigen. Diese Korrekturen sind die Goos-Hänchen-Verschiebung, eine seitliche Verschiebung des Strahls entlang der Grenzfläche, und der Effekt des Fresnel-Filterns, eine Korrektur des Winkels, die das Reflexions- und das Brechungsgesetz der Strahlenoptik und das Prinzip der Umkehrbarkeit des Strahlengangs bricht. Diese Strahlverschiebungen werden für ebene und gekrümmte Grenzflächen diskutiert, außerdem werden die Einflüsse verschiedener Parameter auf die Korrekturterme untersucht. Ein wichtiges Resultat ist, dass die Krümmung der Grenzfläche den Effekt des Fresnel-Filterns verstärkt, wohingegen sie die Goos-Hänchen-Verschiebung abschwächt. Anschließend wird das strahlenoptische Modell auf verschiedene Beispiele angewendet, nämlich Mikrokavitäten in der Form von deformierten Kreisscheiben, also Systeme mit gekrümmten Grenzflächen, und dreieckige Kavitäten, also Systeme mit ausschließlich ebenen Grenzflächen. Sowohl für Systeme mit gekrümmten als auch mit ebenen Grenzflächen kann es wichtig sein, die auf endlichen Wellenlängen beruhenden Korrekturen miteinzubeziehen, um eine gute Übereinstimmung zwischen der Strahlenbeschreibung und Ergebnissen aus Experimenten oder Wellensimulationen zu erhalten. Die Systeme können aber nicht nur durch ihre Grenzfläche charakterisiert werden, sondern auch dadurch, ob ihre klassische Dynamik chaotisch oder nicht-chaotisch ist. Für Systeme mit chaotischer Dynamik ist bekannt, dass die Fernfeldabstrahlung durch die instabile Mannigfaltigkeit des chaotischen Sattels bestimmt wird. Als Beispiele für nicht-chaotische Systeme werden deformierte Kreisscheiben mit kleinen Verformungen und Dreiecke betrachtet. Für diese Systeme wird erörtert, dass die Abstrahlung durch die Trajektorien mit den kleinsten, nichtverschwindenden Zerfallsraten bestimmt wird. Darüber hinaus kann es notwendig sein, Intensitätsverstärkung im Strahlenbild zu berücksichtigen, um verlässliche Ergebnisse für stark verlustbehaftete Lasersysteme zu erhalten. Im zweiten Teil werden graphenartige Systeme diskutiert. An diesen wird zuerst der Einfluss von einachsigen Verformungen in einem tight-binding-Modell des hexagonalen Gitters untersucht. Einachsige Stauchung des Gitters führt zu einem Phasenübergang und zur Ausbildung von Randzuständen senkrecht zur Verzerrungsrichtung. Diese Randzustände sind unabhängig von der genauen Terminierung des Gitters. Als zweites wird ein Strahlenmodell eingeführt, das eine Beschreibung von Graphen-Bauelementen ermöglichen könnte, die genauso effizient ist wie die Strahlenbeschreibung von optischen Systemen.
http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017000059
Amended ray-optical description of dielectric optical microcavities. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section (SKM), (2017), DY 61.7
Three-dimensional lima¸con: properties and applications. - In: Physical review, ISSN 2469-9934, Bd. 95 (2017), 1, 011801, insges. 6 S.
https://doi.org/10.1103/PhysRevA.95.011801
Whispering gallery modes in graphene billiards. - In: 80th Annual Meeting of the DPG and DPG-Frühjahrstagung (Spring Meeting) of the Condensed Matter Section (SKM), (2016), DY 26.7, insges. 1 S.
Distance dependence of fluctuations in mesoscopic transport: from branched flow to UCFs. - In: 80th Annual Meeting of the DPG and DPG-Frühjahrstagung (Spring Meeting) of the Condensed Matter Section (SKM), (2016), DY 26.5, insges. 1 S.
Three-dimensional description of optical microcavities. - In: 80th Annual Meeting of the DPG and DPG-Frühjahrstagung (Spring Meeting) of the Condensed Matter Section (SKM), (2016), DY 41.5, insges. 1 S.
Triangular microlasers in the ray picture. - In: 80th Annual Meeting of the DPG and DPG-Frühjahrstagung (Spring Meeting) of the Condensed Matter Section (SKM), (2016), DY 41.6, insges. 1 S.
Ray picture and ray-wave correspondence in triangular microlasers. - In: Journal of optics, ISSN 2040-8986, Bd. 18 (2016), 12, S. 125605, insges. 7 S.
http://dx.doi.org/10.1088/2040-8978/18/12/125605
Nonlinear dynamical tunneling of optical whispering gallery modes in the presence of a Kerr nonlinearity. - In: Physical review, ISSN 2469-9934, Bd. 94 (2016), 5, 053849, insges. 8 S.
http://dx.doi.org/10.1103/PhysRevA.94.053849
Spin-orbit coupling of light in asymmetric microcavities. - In: Nature Communications, ISSN 2041-1723, Bd. 7 (2016), 10938, S. 1-6
https://doi.org/10.1038/ncomms10983
Ray-wave correspondence in triangular microlasers. - In: 19. Deutsche Physikerinnentagung, (2015), S. 45
Chaotic microlasers. - In: Scholarpedia journal, ISSN 1941-6016, Bd. 10 (2015), 9, S. 30923
Accepted on: 2015-09-15, last modified on 28 November 2015
http://dx.doi.org/10.4249/scholarpedia.30923
Wave-inspired corrections for an efficient ray-optical description of micro-optics devices. - In: PIERS 2015, [Progress in Electromagnetics Research Symposium], (2015), S. 1647-1651
Directional emission from chaotic microdisk lasers and the role of boundary imperfections. - In: PIERS 2015, [Progress in Electromagnetics Research Symposium], (2015), S. 1637-1641
3D emission profiles of disk-limacon-coupled resonators. - In: 79th Annual Meeting of the DPG and DPG-Frühjahrstagung (Spring Meeting) of the Condensed Matter Section (SKM) together with the Divisions: History of Physics, Gravitation and Relativity, Microprobes, Theoretical and Mathematical Physics, and Working Groups: Energy, Equal Opportunities, Information, Philosophy of Physics, Physics and Disarmament, young DPG ; March, 15 - 20, 2015, Technische Universität Berlin, 2015, DY 55.4
Quantum-classical correspondence in electronic transport through quantum point contacts. - In: 79th Annual Meeting of the DPG and DPG-Frühjahrstagung (Spring Meeting) of the Condensed Matter Section (SKM) together with the Divisions: History of Physics, Gravitation and Relativity, Microprobes, Theoretical and Mathematical Physics, and Working Groups: Energy, Equal Opportunities, Information, Philosophy of Physics, Physics and Disarmament, young DPG ; March, 15 - 20, 2015, Technische Universität Berlin, 2015, DY 24.6
Ray-path reversal and Loschmidt echo for light beams. - In: 79th Annual Meeting of the DPG and DPG-Frühjahrstagung (Spring Meeting) of the Condensed Matter Section (SKM) together with the Divisions: History of Physics, Gravitation and Relativity, Microprobes, Theoretical and Mathematical Physics, and Working Groups: Energy, Equal Opportunities, Information, Philosophy of Physics, Physics and Disarmament, young DPG ; March, 15 - 20, 2015, Technische Universität Berlin, 2015, DY 24.5
Curvature dependence of semiclassical corrections to ray optics: how Goos-Hänchen shift and Fresnel filtering deviate from the planar case result. - In: epl, ISSN 1286-4854, Bd. 107 (2014), 6, S. 64001, insges. 5 S.
http://dx.doi.org/10.1209/0295-5075/107/64001
Abnormal high-Q modes of coupled stadium-shaped microcavities. - In: Optics letters, ISSN 1539-4794, Bd. 39 (2014), 14, S. 4196-4199
http://dx.doi.org/10.1364/OL.39.004196
Goos-Hänchen shift and Fresnel filtering at curved interfaces - analytic and numeric results. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section [SKM] together with the DPG Divisions: Microprobes, the Working Groups: Industry and Business, young DPG as well as the Committee Accelerator Physics ; March 30 - April 4, 2014, Technical University of Dresden, 2014, DY 23.7
The mesoscopic X-ray edge problem: boundary effects enhance photoabsorption in quantum dots. - In: The European physical journal, ISSN 1434-6036, Bd. 87 (2014), 1, 12, S. 1-6
https://doi.org/10.1140/epjb/e2013-41013-4
Edge-independent formation of localized states in manipulated honeycomb lattices. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section [SKM], with its Divisions: Biological Physics, Chemical and Polymer Physics, Crystallography, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Physics of Socio-Economic Systems, Semiconductor Physics, Surface Science, Thin Fils, Vacuum Science and Technology, together with the Divisions: Microprobes, and Radiation and Medical Physics as well as the Working Groups: Industry and Business, and "Young DPG" ; March 10 - 15, 2013, University of Regensburg, 2013, DY 30.1
Are Fresnel filtering and the angular Goos-Hänchen shift the same?. - In: DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section [SKM], with its Divisions: Biological Physics, Chemical and Polymer Physics, Crystallography, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Physics of Socio-Economic Systems, Semiconductor Physics, Surface Science, Thin Fils, Vacuum Science and Technology, together with the Divisions: Microprobes, and Radiation and Medical Physics as well as the Working Groups: Industry and Business, and "Young DPG" ; March 10 - 15, 2013, University of Regensburg, 2013, DY 30.4
Phase-space analysis of lasing modes in a chaotic microcavity. - In: Physical review. Atomic, molecular, and optical physics / American Physical Society. - College Park, Md., 1970-2015 , ISSN: 1094-1622 , ZDB-ID: 1472694-4, ISSN 1094-1622, Bd. 88 (2013), 2, S. 023855, insges. 7 S.
http://dx.doi.org/10.1103/PhysRevA.88.023855
Numerical investigations of shallow moist convection, 2013. - Online-Ressource (PDF-Datei: V, 128 S., 5,30 MB) : Ilmenau, Techn. Univ., Diss., 2013
Parallel als Druckausg. erschienen
Atmosphärische Konvektion ist ein sehr aktives Forschungsfeld mit vielen Richtungen, etwa Messtechnik, Laborexperimente und numerische Simulationen. Ein Großteil dieser Simulationen sind sogennante Large-Eddy-Simulationen, bei denen nur die großskaligen Strömungsstrukturen aufgelöst werden und kleinere Strukturen der Turbulenz modelliert sind. Jedoch spielen genau diese kleineren Strukturen eine wichtige Rolle für das Verständnis physikalischer Prozesse innerhalb von Wolken. Deshalb werden in dieser Arbeit bevorzugt direkte numerische Simulationen durchgeführt, die alle turbulenten Längenskalen auflösen. Die höhere Auflösung geht aber auf Kosten der physikalischen Komplexität und der erreichbaren Turbulenzstärke. Die Arbeit beginnt mit einer kurzen Einführung in die Gebiete thermische und atmosphärische Konvektion. Besondere Beachtung erhält dabei das komplexe Zusammenspiel zwischen turbulenter Strömung und physikalischer Prozesse auf sehr kleinen Größenskalen. Auch wie Wolken auf das Klima der Erde einwirken wird diskutiert. Anschließend wird das Modell für feuchte Rayleigh-Benard Konvektion vorgestellt. Im Hauptteil der Dissertation werden Resultate der numerischen und analytischen Untersuchungen präsentiert. Zu Beginn liegt der Fokus auf dem Übergang zur Turbulenz. Einige Eigenschaften dieses Übergangs sind ähnlich derer einfacher Scherströmungen. Folglich können Methoden, die für die Untersuchung des Turbulenzübergangs solcher Strömungen entwickelt wurden, in abgwandelter Form hier genutzt werden. Im weiteren werden Ergebnisse direkter numerischer Simulationen diskutiert. Geometrische Eigenschaften der simulierten Wolken sowie der Einfluss der thermischen Randbedingungen sind Inhalt der folgenden Abschnitte. über die ganze Arbeit hinweg werden die Resultate mit Erkenntnissen aus trockener Rayleigh-Benard und atmosphärischer Konvektion verglichen. Das Hauptaugenmerk der Arbeit liegt auf der Erforschung des Effekts latenter Wärmefreisetzung auf atmosphärische konvektive Prozesse, ohne Berücksichtigung anderer relevanter Prozesse, wie zum Beispiel Niederschlag.
http://www.db-thueringen.de/servlets/DocumentServlet?id=22190
How curvature affects the far-field emission from deformed optical microcavities. - In: Journal of optics, ISSN 2040-8986, Bd. 15 (2013), 1, S. 014010, insges. 6 S.
http://dx.doi.org/10.1088/2040-8978/15/1/014010
Are Fresnel filtering and the angular Goos-Hänchen shift the same?. - In: Journal of optics, ISSN 2040-8986, Bd. 15 (2013), 1, S. 014009, insges. 8 S.
http://dx.doi.org/10.1088/2040-8978/15/1/014009
Diffusion on edges of insulating graphene with intravalley and intervalley scattering. - In: Physical review. Condensed matter and materials physics / American Physical Society. - College Park, Md. : APS, 1970-2015 , ISSN: 1550-235X , ZDB-ID: 1473011-X, ISSN 1550-235X, Bd. 86 (2012), 20, S. 205414, insges. 7 S.
http://dx.doi.org/10.1103/PhysRevB.86.205414
Sub-bandgap absorption in polymer-fullerene solar cells studied by temperature-dependent external quantum efficiency and absorption spectroscopy. - In: Chemical physics letters, Bd. 542 (2012), S. 70-73
http://dx.doi.org/10.1016/j.cplett.2012.05.063
Quasiattractors in coupled maps and coupled dielectric cavities. - In: Physical review. Statistical, nonlinear, and soft matter physics / American Physical Society. - College Park, Md. : APS, January 1993-December 2015 , ISSN: 1550-2376 , ZDB-ID: 1472725-0, ISSN 1550-2376, Bd. 85 (2012), 5, S. 056213, insges. 6 S.
http://dx.doi.org/10.1103/PhysRevE.85.056213
Correlation between near infrared-visible absorption, intrinsic local and global sheet resistance of poly(3,4-ethylenedioxy-thiophene) poly(styrene sulfonate) thin films. - In: Applied physics letters, ISSN 1077-3118, Bd. 100 (2012), 15, S. 253301, insges. 3 S.
http://dx.doi.org/10.1063/1.3697402
Investigation of the structures of sodium borophosphate glasses by reverse Monte Carlo modeling to examine the origins of the mixed glass former effect. - In: The journal of physical chemistry. Energy, materials, and catalysis / American Chemical Society. - Washington, DC : Soc., 2007- , ISSN: 1932-7455 , ZDB-ID: 2256522-X, ISSN 1932-7455, Bd. 116 (2012), 1, S. 1503-1511
http://dx.doi.org/10.1021/jp2085654
Interaction of pacemakers as generating mechanism of atrial fibrillation. - In: 2011 computing in cardiology (CinC 2011), (2011), S. 229-232
LAMMPS CUDA - a general purpose MD code. - In: 75th Annual Meeting of the DPG and combined DPG Spring Meeting of the Condensed Matter Section and the Section AMOP, 2011, MM 12.27
Evaluation of MD force fields for ion transport in glassy materials. - In: 75th Annual Meeting of the DPG and combined DPG Spring Meeting of the Condensed Matter Section and the Section AMOP, 2011, DY 20.5
Network forming units in alkali borate and borophosphate glasses and the mixed glass former effect. - In: RSC Advances, ISSN 2046-2069, Bd. 1 (2011), 7, S. 1370-1382
http://dx.doi.org/10.1039/C1RA00583A
The development of Mellanox/NVIDIA GPUDirect over InfiniBand - a new model for GPU to GPU communications. - In: Computer science, research + development, ISSN 1865-2042, Bd. 26 (2011), 3/4, S. 267-273
http://dx.doi.org/10.1007/s00450-011-0157-1
LAMMPSCuda - a new GPU accelerated molecular dynamics simulations package and its application to ion-conduting glasses, 2011. - Online-Ressource (PDF-Datei: 107 S., 1328 KB) : Ilmenau, Techn. Univ., Diss., 2011
Parallel als Druckausg. erschienen
Computersimulationen sind heute ein fundamentaler Bestandteil von Forschung und Entwicklung. In den letzten Dekaden wurden die Grenzen dessen, was modelliert werden kann, durch die kontinuierliche Steigerung der verfügbaren Rechenleistung dramatisch erweitert. Aufgrund der stagnierenden seriellen Rechenleistung heutiger Prozessoren müssen zukünftige Leistungsgewinne mittels Parallelisierung erreicht werden. Insbesondere heterogene Hardware-Architekturen werden immer wichtiger, da sie inhärente Vorteile im Bereich der Energieeffizienz aufweisen. Zur Zeit wird dieser Bereich durch von Grafikkarten beschleunigte Systeme dominiert. Aufgrund ihres fünf- bis zehnfachen Energie- und Kosteneffizienz haben auf Grafikkarten basierte Supercomputer seit ihrer Einführung im Jahr 2008 schnelle Verbreitung gefunden. Mittlerweile beziehen drei der fünf schnellsten Computer der Welt einen Großteil ihrer Rechenleistung aus Grafikkarten. Um derartige Systeme effizient zu nutzen sind jedoch neue Programmierungsansätze notwendig. In dieser Arbeit wird ein neuer Molekular-Dynamik-Code namens LAMMPScuda vorgestellt. LAMMPScuda verwendet Grafikkarten um Simulationen verschiedenster Materialklassen zu beschleunigen. Dazu gehören biologische Systeme, Halbleiter, Metalle, inorganische Gläser und Polymersysteme. Es werden sowohl Details der Implementierung vorgestellt als auch umfangreiche Leistungsuntersuchungen präsentiert. Diese zeigen, dass LAMMPScuda sowohl auf einzelnen PCs als auch auf Großrechnern mit hunderten Grafikkarten effizient laufen kann. Im zweiten Teil der Arbeit wird LAMMPScuda verwendet, um ein neues Potential für ionenleitende Gläser der Zusammensetzung xLi2O-yB2O3-zSi2O4-wP2O5 zu entwickeln. Wie sich zeigt, kann das neue Potential - das mit BC-U bezeichnet wird - nicht nur strukturelle sondern auch dynamische experimentelle Daten verschiedener binärer Gläser über den gesamten Kompositionsbereich besser reproduzieren als zum Vergleich herangezogene etablierte Potentiale. Zudem tritt in Simulationen von Borophosphaten der sogenannte Mischnetzwerkformer-Effekt auf. Damit ist das BC-U Potential prädestiniert dafür, zur Verifizierung von Theorien der mikroskopischen Ursachen dieses Effektes eingesetzt zu werden.
http://www.db-thueringen.de/servlets/DocumentServlet?id=19880
Time-dependent density functional theory for driven lattice gas systems with interactions. - In: epl, ISSN 1286-4854, Bd. 93 (2011), 5, S. 50003, insges. 5 S.
http://dx.doi.org/10.1209/0295-5075/93/50003
Influence of dispersion interactions on the adsorption of PTCDA on Ag(110). - In: Physica status solidi, ISSN 1610-1642, Bd. 7 (2010), 2, S. 236-239
The interaction of PTCDA with Ag(110) is analysed with second order Møller-Plesset perturbation theory (MP2), including the main part of the dispersion interactions at an ab initio level. On rigid substrate clusters, the optimized adsorbate geometry consists of a nearly flat perylene core, surrounded by carboxylic oxygens closer to the substrate, but with anhydride atoms at a larger height. The average height of the carbon core is found at 2.68 Å, in excellent agreement with the value of 2.59 Ädetermined in recent X-ray standing wave measurements. In sharp contrast to the rather flat MP2 geometry, the lack of dispersion interactions in density functional theory (DFT) results in an unrealistic bent adsorbate geometry. The calculated core level shifts and the vibrational fingerprint reproduce the observed trends.
https://doi.org/10.1002/pssc.200982500
Numerical calculation of the filter efficiency of fibrous aerosol filters. - In: DPG Spring Meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Crystallography, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Physics of Socio-Economic Systems, Radiation and Medical Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working group: Industry and Business, 2010, DY 6.25
Self-organized growth of helicenes on calcite (104) surfaces: Monte Carlo simulations and experiments. - In: DPG Spring Meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Crystallography, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Physics of Socio-Economic Systems, Radiation and Medical Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working group: Industry and Business, 2010, MM 26.79
Bucky ball island morphologies on CaF 2: theory and experiment. - In: DPG Spring Meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Crystallography, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Physics of Socio-Economic Systems, Radiation and Medical Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working group: Industry and Business, 2010, MM 26.74
Excitation patterns in inhomogeneous media from the FitzHugh-Nagumo equations and the Belousov-Zhabotinsky reaction. - In: DPG Spring Meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Crystallography, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Physics of Socio-Economic Systems, Radiation and Medical Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working group: Industry and Business, 2010, DY 15.1
Assessing the predictive power of the Reverse Monte Carlo Method for amorphous systems. - In: DPG Spring Meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Crystallography, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Physics of Socio-Economic Systems, Radiation and Medical Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working group: Industry and Business, 2010, DY 25.3
Harnessing the power of modern GPUs with LAMMPS. - In: DPG Spring Meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Crystallography, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Physics of Socio-Economic Systems, Radiation and Medical Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working group: Industry and Business, 2010, DY 30.9
Generating mechanism for fibrillatory states. - In: DPG Spring Meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Crystallography, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Physics of Socio-Economic Systems, Radiation and Medical Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working group: Industry and Business, 2010, DY 30.34
Varying coulomb trapping of network forming units and the mixed glass former effect. - In: DPG Spring Meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Crystallography, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Physics of Socio-Economic Systems, Radiation and Medical Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working group: Industry and Business, 2010, DY 30.10
Wavefront-obstacle and wavefront-wavefront interactions as mechanisms for atrial fibrillation: a study based on the FitzHugh-Nagumo equations. - In: Computing in cardiology, 2010, ISBN 978-1-4244-7318-2, (2010), S. 525-528
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5738000
Reverse Monte Carlo modeling of ion conducting network glasses: an evaluation based on molecular dynamics simulations. - In: Physical chemistry, chemical physics, ISSN 1463-9084, Bd. 12 (2010), 35, S. 10444-10451
http://dx.doi.org/10.1039/C003472J
Island size distributions in submonolayer growth : prediction by mean field theory with coverage dependent capture numbers. - In: Physical review. Condensed matter and materials physics / American Physical Society. - College Park, Md. : APS, 1970-2015 , ISSN: 1550-235X , ZDB-ID: 1473011-X, ISSN 1550-235X, Bd. 82 (2010), 20, S. 201401, insges. 4 S.
http://dx.doi.org/10.1103/PhysRevB.82.201401
Unidirectional hopping transport of interacting particles on a finite chain. - In: The journal of chemical physics, ISSN 1089-7690, Bd. 133 (2010), 5, 054102, insges. 3 S.
https://doi.org/10.1063/1.3463000
Thermodynamics of two-stroke engine based on periodically driven two-level system. - In: Physica. Low-dimensional systems & nanostructures. - Amsterdam [u.a.] : North-Holland, Elsevier Science, 1998- , ISSN: 1386-9477 , ZDB-ID: 1466595-5, ISSN 1386-9477, Bd. 42 (2010), 3, S. 472-476
Publ. entstand im Rahmen der Veranst.: Proceedings of the International Conference Frontiers of Quantum and Mesoscopic Thermodynamics, FQMT '08
http://dx.doi.org/10.1016/j.physe.2009.06.031
Energetics and performance of a microscopic heat engine based on exact calculations of work and heat distributions. - In: Journal of statistical mechanics: theory and experiment, ISSN 1742-5468, 2010, 03, P03002, insges. 21 S.
http://dx.doi.org/10.1088/1742-5468/2010/03/P03002
Nonlinear hopping transport in ring systems and open channels. - In: Physical chemistry, chemical physics, ISSN 1463-9084, Bd. 12 (2010), 3, S. 645-654
http://dx.doi.org/10.1039/b916827c
Numerical calculation of single fiber efficiency for fibrous filters. - In: Frühjahrstagung 2009 der Sektion AMOP, 73. Jahrestagung der DPG mit Ordentlicher Mitgliederversammlung der DPG, mit den Fachverbänden Atomphysik, Massenspektrometrie, Molekülphysik, Quantenoptik und Photonik, Umweltphysik sowie den Arbeitskreisen Chancengleichheit, Energie und den Arbeitsgruppen Junge DPG, Information und Physik und Abrüstung, 2009, UP 10.10
Atrial fibrillation induced by interference of regular wave fronts with fronts emanating from a spiral wave. - In: DPG spring meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working groups: Industry and Business, Physics of Socio-Economic Systems, 2009, DY 9.4
Coverage dependence of capture numbers in kinetic thin film growth and its impact on island size distributions. - In: DPG spring meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working groups: Industry and Business, Physics of Socio-Economic Systems, 2009, O 27.34
Dynamical phase diagrams for spiral waves attached to obstacles and suppression of spiral waves by boundary effects. - In: DPG spring meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working groups: Industry and Business, Physics of Socio-Economic Systems, 2009, DY 27.17
Models for the mixed glass former effect in ion-conducting glasses. - In: DPG spring meeting of the Condensed Matter Section with the divisions: Biological Physics, Chemical and Polymer Physics, Dielectric Solids, Dynamics and Statistical Physics, Low Temperature Physics, Magnetism, Metal and Material Physics, Semiconductor Physics, Surface Science, Thin Films, Vacuum Science and Technology as well as the working groups: Industry and Business, Physics of Socio-Economic Systems, 2009, DY 26.5
Time series analysis and modeling of the statistical properties of heart beat dynamics during atrial fibrillation, 2009. - Online-Ressource (PDF-Datei: 148 S., 2162 KB) : Ilmenau, Techn. Univ., Diss., 2009
Parallel als Druckausg. erschienen
Die vorliegende Arbeit diskutiert die Frage, ob und inwieweit es möglich ist, die Rate des Vorhofflimmerns allein auf Basis der statistischen Eigenschaften ventrikulärer Interbeatintervalle zu bestimmen. Sie konzentriert sich zunächst auf die statistische Analyse von EKG-Signalen im Allgemeinen und ventrikulären Tachogrammen im Besondern. Dabei wird ein neues Verfahren - die statistische Analyse so genannter Morphogramme - vorgestellt, mit dessen Hilfe sich die gesamte in einem EKG enthaltene Information, ohne aufwendige Mustererkennungsverfahren auswerten lässt. Es wird gezeigt, dass dieses Verfahren geeignet ist verschiedene Gesundheitszustände zu identifizieren. Anschließend konzentriert sich die Arbeit auf die statistische Analyse von ventrikulären Interbeatintervallen die in Gegenwart von Vorhofflimmern beobachtet werden. Dabei wird eine neue, bisher nicht beschriebene charakteristische, statistische Eigenschaft dieser Intervalle - ein exponentieller Abfall der Verteilungsfunktion im Bereich langer Intervalle - präsentiert. Im Weiteren wird gezeigt, dass verschiedene charakteristische Eigenschaften dieser Intervalle nicht unabhängig voneinander beobachtet werden, sondern zueinander in Beziehung stehen. Im Folgenden konzentriert sich die Arbeit auf die mathematische Beschreibung der physikalischen Prozesse bei der Überleitung atrialer Impulse über den AV-Knoten. Im Besonderen konzentriert sie sich dabei auf das Überleitungsmodell von Jorgensen et al.. Es wird gezeigt, dass sich dieses Modell vollständig analytisch beschreiben lässt. Auf Basis der allgemeinen Diskussion dieses Modells und den, unter gegebenen Randbedingungen abgeleiteten speziellen Lösungen des Überleitungsmodells, werden zwei Verfahren zur Bestimmung der Vorhofflimmerrate präsentiert. Auf Basis klinischen Daten werden beide Verfahren validiert und hinsichtlich ihrer Performance diskutiert. Die vorliegende Arbeit zeigt, dass eine Bestimmung der Vorhofflimmerrate allein auf Basis der statistischen Eigenschaften der ventrikulären Interbeatintervalle möglich ist.
http://www.db-thueringen.de/servlets/DocumentServlet?id=15677
Ab initio calculation of the dispersion interaction between a polyaromatic molecule and a noble metal substrate: PTCDA on Ag(110). - In: The journal of physical chemistry, ISSN 1932-7455, Bd. 113 (2009), 46, S. 19897-19904
http://dx.doi.org/10.1021/jp902370b
Work distributions for Ising chains in a time-dependent magnetic field. - In: Physical review. Statistical, nonlinear, and soft matter physics / American Physical Society. - College Park, Md. : APS, January 1993-December 2015 , ISSN: 1550-2376 , ZDB-ID: 1472725-0, ISSN 1550-2376, Bd. 80 (2009), 2, S. 020101, insges. 4 S.
http://dx.doi.org/10.1103/PhysRevE.80.020101
Constant dielectric loss in disordered ionic conductors: theoretical aspects. - In: Solid state ionics, ISSN 0167-2738, Bd. 180 (2009), 6/8, S. 446-450
http://dx.doi.org/10.1016/j.ssi.2008.09.027
Mixed barrier model for the mixed glass former effect in ion conducting glasses. - In: Physical review letters, ISSN 1079-7114, Bd. 102 (2009), 14, 145902, insges. 4 S.
https://doi.org/10.1103/PhysRevLett.102.145902
Automated synchrogram analysis applied to heartbeat and reconstructed respiration. - In: Chaos, ISSN 1089-7682, Bd. 19 (2009), 1, 015106, S. 015106-1-015106-8
https://doi.org/10.1063/1.3096415
Fundamental questions relating to ion conduction in disordered solids. - In: Reports on progress in physics, ISSN 1361-6633, Bd. 172 (2009), 4, S. 046501, insges. 15 S.
http://dx.doi.org/10.1088/0034-4885/72/4/046501
Binding energies between unlike atoms determined from island densities. - In: Journal of applied physics, ISSN 1089-7550, Bd. 105 (2009), 5, 054312, insges. 3 S.
https://doi.org/10.1063/1.3086315
Aging, rejuvenation and memory effects in systems far from equilibrium. - In: AIP conference proceedings, ISSN 1551-7616, Bd. 982 (2008), S. 684-689
http://dx.doi.org/10.1063/1.2897878
Fluctuation effects in kinetic thin film growth. - In: Anomalous fluctuation phenomena in complex systems, (2008), S. 211-244
Stability and numerical simulation of the liquid metal pinch using the shallow water approximation. - In: New trends in fluid mechanics research, (2008), S. 717
Stochastic theories and scaling relations for early-stage surface growth. - In: European physical journal special topics, ISSN 1951-6401, Bd. 161 (2008), 1, S. 151-165
http://dx.doi.org/10.1140/epjst/e2008-00757-0
Dipolar interactions and constant dielectric loss spectra. - In: European physical journal special topics, ISSN 1951-6401, Bd. 161 (2008), 1, S. 79-96
http://dx.doi.org/10.1140/epjst/e2008-00752-5
Theoretical and numerical stability analysis of the liquid metal pinch using the shallow water approximation. - In: Journal of thermal science, ISSN 1993-033X, Bd. 17 (2008), 3, S. 261-266
http://dx.doi.org/10.1007/s11630-008-0261-0
Constrained flow around a magnetic obstacle. - In: Journal of fluid mechanics, ISSN 1469-7645, Bd. 610 (2008), S. 131-156
https://doi.org/10.1017/S0022112008002590
Structure of glassy lithium sulfate films sputtered in nitrogen: insight from Raman spectroscopy and ab initio calculations. - In: Physical review. Condensed matter and materials physics / American Physical Society. - College Park, Md. : APS, 1970-2015 , ISSN: 1550-235X , ZDB-ID: 1473011-X, ISSN 1550-235X, Bd. 77 (2008), 9, S. 094116, insges. 5 S.
http://dx.doi.org/10.1103/PhysRevB.77.094116
Aging in the shear-transformation-zone theory of plastic deformation. - In: Physical review. Statistical, nonlinear, and soft matter physics / American Physical Society. - College Park, Md. : APS, January 1993-December 2015 , ISSN: 1550-2376 , ZDB-ID: 1472725-0, ISSN 1550-2376, Bd. 78 (2008), 5, S. 056109, insges. 11 S.
http://dx.doi.org/10.1103/PhysRevE.78.056109
The wake of a magnetic obstacle. - In: 72nd annual meeting and DPG spring meeting of the Condensed Matter Section and the divisions: Physics Education, History of Physics, Radiation and Medical Physics as well as the working groups: Equal Opportunities, Industry and Business, Information, Physics and Disarmament, Physics of Socio-Economic Systems, Young DPG, 2008, DY 25.4
Role of ion-ion interaction for diffusion paths and residence sites in glassy electrolytes. - In: 72nd annual meeting and DPG spring meeting of the Condensed Matter Section and the divisions: Physics Education, History of Physics, Radiation and Medical Physics as well as the working groups: Equal Opportunities, Industry and Business, Information, Physics and Disarmament, Physics of Socio-Economic Systems, Young DPG, 2008, DY 29.72
Thin film growth of binary alloys. - In: 72nd annual meeting and DPG spring meeting of the Condensed Matter Section and the divisions: Physics Education, History of Physics, Radiation and Medical Physics as well as the working groups: Equal Opportunities, Industry and Business, Information, Physics and Disarmament, Physics of Socio-Economic Systems, Young DPG, 2008, DY 29.48
Interaction effects and work theorems. - In: 72nd annual meeting and DPG spring meeting of the Condensed Matter Section and the divisions: Physics Education, History of Physics, Radiation and Medical Physics as well as the working groups: Equal Opportunities, Industry and Business, Information, Physics and Disarmament, Physics of Socio-Economic Systems, Young DPG, 2008, DY 28.3
Investigation of atrial fibrillation generating mechanisms. - In: 72nd annual meeting and DPG spring meeting of the Condensed Matter Section and the divisions: Physics Education, History of Physics, Radiation and Medical Physics as well as the working groups: Equal Opportunities, Industry and Business, Information, Physics and Disarmament, Physics of Socio-Economic Systems, Young DPG, 2008, DY 17.37
Nonlinear hopping conduction in open channels. - In: 72nd annual meeting and DPG spring meeting of the Condensed Matter Section and the divisions: Physics Education, History of Physics, Radiation and Medical Physics as well as the working groups: Equal Opportunities, Industry and Business, Information, Physics and Disarmament, Physics of Socio-Economic Systems, Young DPG, 2008, DY 17.24
1D lattice model for binary growth and surface relaxation. - In: New journal of physics, ISSN 1367-2630, Bd. 10 (2008), 103008, insges. 9 S.
https://doi.org/10.1088/1367-2630/10/10/103008
Neue Wirbelstrukturen der Kanalströmung eines Flüssigmetalls in inhomogenen Magnetfeldern. - In: Workshop Elektroprozesstechnik, (2008), 13, insges. 8 S.
Transition to turbulence in the Hartmann boundary layer. - In: GAMM-Mitteilungen, ISSN 1522-2608, Bd. 30 (2007), 1, S. 125-132
https://doi.org/10.1002/gamm.200790002
Submonolayer growth of binary alloys. - In: 71st annual meeting of the DPG and spring meeting of the Condensed Matter Division and the sections: Biological Physics, Environmental Physics, Extraterrestrial Physics, History of Physics, Physics Education, Radiation and Medical Physics as well as the working groups: Energy Matters, Equal Opportunities, Industry and Economy, Information, Physics and Disarmament, Physics of Socio-Economic Systems, 2007, DY 10.4
Influence of inhomogenous magnetic field on the electric potential distribution in liquid metal channel flow. - In: 71st annual meeting of the DPG and spring meeting of the Condensed Matter Division and the sections: Biological Physics, Environmental Physics, Extraterrestrial Physics, History of Physics, Physics Education, Radiation and Medical Physics as well as the working groups: Energy Matters, Equal Opportunities, Industry and Economy, Information, Physics and Disarmament, Physics of Socio-Economic Systems, 2007, DY 14.2
Ab-inito calculations of atomic cluster configurations for ion conducting glasses. - In: 71st annual meeting of the DPG and spring meeting of the Condensed Matter Division and the sections: Biological Physics, Environmental Physics, Extraterrestrial Physics, History of Physics, Physics Education, Radiation and Medical Physics as well as the working groups: Energy Matters, Equal Opportunities, Industry and Economy, Information, Physics and Disarmament, Physics of Socio-Economic Systems, 2007, DY 13.10
Evaluation of effective one-particle potentials for the identification of ion conduction pathways in glasses. - In: 71st annual meeting of the DPG and spring meeting of the Condensed Matter Division and the sections: Biological Physics, Environmental Physics, Extraterrestrial Physics, History of Physics, Physics Education, Radiation and Medical Physics as well as the working groups: Energy Matters, Equal Opportunities, Industry and Economy, Information, Physics and Disarmament, Physics of Socio-Economic Systems, 2007, DY 13.11
Driven transport through channels: interaction effects. - In: 71st annual meeting of the DPG and spring meeting of the Condensed Matter Division and the sections: Biological Physics, Environmental Physics, Extraterrestrial Physics, History of Physics, Physics Education, Radiation and Medical Physics as well as the working groups: Energy Matters, Equal Opportunities, Industry and Economy, Information, Physics and Disarmament, Physics of Socio-Economic Systems, 2007, BP 16.48
Spatio-temporal dynamics of the action potential during atrial fibrillation. - In: 71st annual meeting of the DPG and spring meeting of the Condensed Matter Division and the sections: Biological Physics, Environmental Physics, Extraterrestrial Physics, History of Physics, Physics Education, Radiation and Medical Physics as well as the working groups: Energy Matters, Equal Opportunities, Industry and Economy, Information, Physics and Disarmament, Physics of Socio-Economic Systems, 2007, DY 24.22
Theoretical description of the statistics of ventricular beat intervals during atrial fibrillation. - In: 71st annual meeting of the DPG and spring meeting of the Condensed Matter Division and the sections: Biological Physics, Environmental Physics, Extraterrestrial Physics, History of Physics, Physics Education, Radiation and Medical Physics as well as the working groups: Energy Matters, Equal Opportunities, Industry and Economy, Information, Physics and Disarmament, Physics of Socio-Economic Systems, 2007, DY 28.9
Mean field theory for relaxation in random dipolar systems. - In: 71st annual meeting of the DPG and spring meeting of the Condensed Matter Division and the sections: Biological Physics, Environmental Physics, Extraterrestrial Physics, History of Physics, Physics Education, Radiation and Medical Physics as well as the working groups: Energy Matters, Equal Opportunities, Industry and Economy, Information, Physics and Disarmament, Physics of Socio-Economic Systems, 2007, DY 30.46
Magnetfelder machen Wirbel in Metallen : TU Ilmenau: neue Wirbelstrukturen bei der Flüssigmetallströmung entdeckt. - In: Stahl + Eisen, ISSN 0340-4803, Bd. 127 (2007), 6/7, S. 147
New advances in susceptibility weighted MRI to determine physiological parameters, 2007. - Online-Ressource (PDF-Datei: 174 S., 5484 KB) : Ilmenau, Techn. Univ., Diss., 2007
Parallel als Druckausg. erschienen
Die Magnetresonanztomographie bietet die Möglichkeit der Bestimmung des Blutoxygenierungsgrades kleiner venöser Gefäße und damit lokaler Hirnareale mit Hilfe einer Multiecho-Gradientenecho-Sequenz. Mit dieser Sequenz kann der Signalzerfall in einem Voxel, welches von einer einzelnen Vene bzw. von Blutkapillaren durchzogen ist, bestimmt werden. Der Signalzerfall ist charakteristisch für die von der Vene oder den Kapillaren erzeugten Feldinhomogenitäten, so dass sich Aussagen über den Blutoxygenierungsgrad und Blutvolumenanteil treffen lassen. Durch Fitten simulierter Signalverläufe an gemessene Phantom- und Probandendaten konnte gezeigt werden, dass es mit der hier vorgestellten Methode möglich ist, den venösen Blutoxygenierungsgrad zu quantifizieren. Weiterhin konnte eine durch gezielte Modulation des zerebralen Blutflusses hervorgerufene Änderung der Blutoxygenierung in vivo nachgewiesen werden. Die Erweiterung des Modells eines einzelnen Gefäßes auf ein Gefäßnetzwerk diente als Grundlage zur theoretischen Beschreibung der Blutkapillaren, die das Hirngewebe durchziehen und mit Sauerstoff versorgen. Dieses Netzwerkmodel konnte in Phantomexperimenten verifiziert werden. Dagegen zeigte sich bei einer Probandenmessung, dass es nicht möglich ist einzig anhand des gemessenen Signalverlaufs valide Werte für die Blutoxygenierung und den Blutvolumenanteil eindeutig zu bestimmen. Die hohe Korrelation zwischen beiden Parametern bewirkt, dass mehrere Paare von Oxygenierungs- und Volumenwerten passende Signalkurven liefern. Eine unabhängige Quantifizierung oder Abschätzung des venösen Blutvolumens kann hier helfen eindeutige Oxygenierungswerte zu erhalten. Im Rahmen der vorliegenden Dissertation konnte das Signalverhalten von suszeptibilitätssensitiven Messungen in der Magnetresonanztomographie genauer untersucht und eine Methode zur nicht-invasiven Bestimmung der venösen Blutoxygenierung an einzelnen Gefäßen entwickelt werden. Erste in vivo Ergebnisse des Gefäßnetzwerkes verdeutlichen, dass für eine genaue Quantifizierung der Blutoxygenierung weitere Parameter, wie das Blutvolumen, unabhängig bestimmt werden müssen. Dennoch ist es möglich, die Methode am einzelnen Blutgefäß zur besseren Charakterisierung von Pathologien sowie physiologischen Änderungen,z.B. bei der funktionellen Magnetresonanztomographie, einzusetzen.
http://www.db-thueringen.de/servlets/DerivateServlet/Derivate-13751/ilm1-2007000258.pdf
Turbulent magnetohydrodynamic channel flow : results of direct numerical simulations. - In: Complex effects in MHD: from astrophysics to liquid metals, (2007), S. 3-14
Simulation of MBE-growth of alloy nanoclusters in a magnetic field. - In: Materials science & engineering, ISSN 1873-0191, Bd. 27 (2007), 5/8, S. 1325-1327
http://dx.doi.org/10.1016/j.msec.2006.07.006
Soft particle model for block copolymers. - In: The journal of chemical physics, ISSN 1089-7690, Bd. 127 (2007), 13, 134905, insges. 11 S.
https://doi.org/10.1063/1.2787007
Numerical study of liquid metal flow in a rectangular duct under the influence of a heterogeneous magnetic field. - In: Fluid dynamics & materials processing, ISSN 1555-256X, Bd. 3 (2007), 2, S. 94-114
Scaling of island densities in submonolayer growth of binary alloys. - In: Physical review letters, ISSN 1079-7114, Bd. 99 (2007), 1, 016106, insges. 4 S.
https://doi.org/10.1103/PhysRevLett.99.016106
Structure of the wake of a magnetic obstacle. - In: Physical review letters, ISSN 1079-7114, Bd. 98 (2007), 14, 144504, insges. 4 S.
https://doi.org/10.1103/PhysRevLett.98.144504
Modeling epitaxial growth of binary alloy nanostructures on a weakly interacting substrate. - In: Physical review. Condensed matter and materials physics / American Physical Society. - College Park, Md. : APS, 1970-2015 , ISSN: 1550-235X , ZDB-ID: 1473011-X, ISSN 1550-235X, Bd. 75 (2007), 8, S. 085437, insges. 10 S.
http://dx.doi.org/10.1103/PhysRevB.75.085437
Influence of external magnetic fields on the growth of alloy nanoclusters. - In: Journal of physics. Condensed matter. - Bristol : IOP Publ., 1989- , ISSN: 1361-648X , ZDB-ID: 1472968-4, ISSN 1361-648X, Bd. 19 (2007), 8, S. 086227, insges. 8 S.
http://dx.doi.org/10.1088/0953-8984/19/8/086227
Numerical study of turbulent magnetohydrodynamic channel flow. - In: Journal of fluid mechanics, ISSN 1469-7645, Bd. 572 (2007), S. 179-188
http://dx.doi.org/10.1017/S0022112006003673
Comparison of ion sites and diffusion paths in glasses obtained by molecular dynamics simulations and bond valence analysis. - In: Physical review. Condensed matter and materials physics / American Physical Society. - College Park, Md. : APS, 1970-2015 , ISSN: 1550-235X , ZDB-ID: 1473011-X, ISSN 1550-235X, Bd. 75 (2007), 1, S. 014203, insges. 11 S.
http://dx.doi.org/10.1103/PhysRevB.75.014203
Nearly constant loss spectra in glasses: dipolar interaction effects. - In: AIP conference proceedings, ISSN 1551-7616, Bd. 832 (2006), S. 492-497
http://dx.doi.org/10.1063/1.2204546
Influence of atrio-ventricular conduction on the statistical properties of ventricular beat intervals during atrial fibrillation. - 5 S. = 221,1 KB, TextDruckausg.: Conference and meeting of the European Study Group on Cardiovascular Oscillations 2006, May 15 - 17, 2006, Jena, Germany. - Jena, 2006, S. 36-38
http://www.db-thueringen.de/servlets/DocumentServlet?id=7485
Long exponentially distributed interbeat intervals in the ECG of patients with atrial fibrillation show white noise behaviour in power spectrum. - 6 S. = 708,6 KB, TextDruckausg.: Conference and meeting of the European Study Group on Cardiovascular Oscillations, May 15 - 17, 2006, Jena, Germany. - Jena, 2006, S. 32-35
http://www.db-thueringen.de/servlets/DocumentServlet?id=8062
Liquid metal flow under the influence of heterogeneous magnetic field: numerical study. - In: Proceedings, (2006), S. 194-199
Numerical study of magnetohydrodynamic turbulence in channel flow. - In: Proceedings, (2006), S. 139-144
Simulation and phenomenology of turbulent magnetohydrodynamic channel flow. - In: Turbulence, heat and mass transfer 5, (2006), S. 179-182
A comparative study on the electronic structure of the 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide RT-ionic liquid by electron spectroscopy and first principles calculations. - In: Zeitschrift für physikalische Chemie, ISSN 2196-7156, Bd. 220 (2006), 10, S. 1407-1416
The near-surface electronic structure of the room-temperature ionic liquid 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide has been investigated with ultraviolet and X-ray photoelectron spectroscopy as well as metastable induced electron spectroscopy. The results have been compared with density functional theory calculations. The good agreement between the experimental and theoretical data provides detailed insight into the origin of the observed spectral features. In particular, we found that a simple composition of the spectra of the isolated ions does not suffice to fit to the experimental results, but interionic interactions have to be considered.
http://dx.doi.org/10.1524/zpch.2006.220.10.1407
Exponential distribution of long heart beat intervals during atrial fibrillation and their relevance for white noise behaviour in power spectrum. - In: Journal of biological physics, ISSN 1573-0689, Bd. 32 (2006), 5, S. 383-392
http://dx.doi.org/10.1007/s10867-006-9022-z
Transition to turbulence in magnetohydrodynamic channel flow of liquid metals. - In: NIC Symposium 2006, (2006), S. 341-348
Strong dispersion of the surface optical phonon of silicon carbide in the near vicinity of the surface Brillouin zone center. - In: Surface science, ISSN 1879-2758, Bd. 600 (2006), 14, S. 2886-2893
The surface optical or FuchsKliewer phonons of the (0 0 1) surface of 3C-SiC and the Si-terminated (0 0 0 1) surfaces of 4H- and 6H-SiC have been investigated with high resolution electron energy loss spectroscopy (HREELS). For each of the SiC polytypes the frequency of the surface optical phonon changes with surface reconstruction, indicating subtle differences in the static polarization at differently reconstructed surfaces. Due to their anisotropy, hexagonal surfaces exhibit a second, much weaker FuchsKliewer mode. For all surfaces under examination, a linear dispersion of the FuchsKliewer mode frequency has been found for wave vectors close to the Gamma-point. This dispersion can be explained by dynamical dipole coupling between atomic oscillators at the surface of the highly polar silicon carbide.
http://dx.doi.org/10.1016/j.susc.2006.05.031
Surface phonons of clean, hydrogen- and deuterium-terminated Si(0 0 1) surfaces. - In: Surface science, ISSN 1879-2758, Bd. 600 (2006), 17, S. 3446-3455
We present a comprehensive vibrational study of the clean and hydrogen- or deuterium-terminated silicon (0 0 1) surface. The modes related to the clean as well as to the H:Si, D:Si, and 2H:Si, 2D:Si surfaces are studied by means of high resolution electron energy loss spectroscopy (HREELS). We pay special attention to the modification of the phonon modes by the surface treatments and compare the data with reported experimental and theoretical results. The analysis of the relative phonon intensities of the clean, mono- and dihydride surfaces yields the assignment of the modes related to the dimer bonds. The isotopic shifts of vibrons related to the SiH and SiD bonds and to the surface phonon are discussed and applied to the characterisation of the surface excitations.
http://dx.doi.org/10.1016/j.susc.2006.06.030
Kinetic growth of nanoclusters with perpendicular magnetic anisotropy. - In: epl, ISSN 1286-4854, Bd. 75 (2006), 1, S. 167-173
The growth of binary-alloy clusters on a weakly interacting substrate through codeposition of two atomic species is studied by kinetic Monte Carlo simulation. Our model describes salient features of CoPt3 nanoclusters, as obtained recently by the molecular-beam epitaxy technique. The clusters display perpendicular magnetic anisotropy (PMA) in a temperature window of growth favorable for applications. This temperature window is found to arise from the interplay of Pt surface segregation and aspect ratio for cluster shapes. Conclusions are drawn on how to optimize growth parameters with respect to PMA.
http://dx.doi.org/10.1209/epl/i2006-10085-9
Ion diffusion and mechanical losses in mixed alkali glasses. - In: Journal of non-crystalline solids, ISSN 0022-3093, Bd. 352 (2006), 42/49, S. 5178-5187
Based on general theoretical considerations we show that the fraction cV of vacant sites for the mobile ions in glasses should be small in order to understand the peculiar behavior of the internal friction in the mixed alkali effect. Moreover, for small cV, the steep fall of the conductivity in the dilute foreign alkali region can be explained by a trapping of vacancies induced by the minority ions. To demonstrate our general analysis we study a simple hopping model and show that it allows one to recover both the typical behavior of the internal friction (shifts of single and mixed alkali peak positions with the mixing ratio and associated changes in activation energies, changes of peak heights) and the typical behavior of tracer diffusion coefficients (drastic fall of mobility of one type of ion by replacement with a second type of mobile ion and associated changes in activation energies). Reasonable values of model parameters can be estimated from measured data and predictions are made for experiments.
http://dx.doi.org/10.1016/j.jnoncrysol.2005.12.061
Parametric study of the streak breakdown mechanism in Hartmann flow. - In: Fundamental and applied MHD, (2005), S. 125-128
Surface reaction of C60 with atomic hydrogen: formation of a protecting hydrocarbon layer. - In: Fullerenes, nanotubes & carbon nanostructures, ISSN 1536-4046, Bd. 13.2005, Suppl. 1, S. 131-138
The interaction of a single domain C60/InP(0 0 1)-(2x4) film during exposure to atomic hydrogen was investigated. At low hydrogen dosing, a high reactivity of the C60 molecules was detected. Presumably, the cracking of fullerene cages follows from a fast destruction of the molecular order. High dosing leads, by chemical modification, to the formation of a stable coverage of hydrocarbons, which is promising for future technological applications.
http://dx.doi.org/10.1081/FST-200039235
Statistical analysis of fluctuations in the ECG morphology. - In: Physica, ISSN 1873-2119, Bd. 354 (2005), S. 415-431
https://doi.org/10.1016/j.physa.2005.03.019
Ionic transport in disordered materials. - In: Diffusion in condensed matter, (2005), S. 813-856
Ion diffusion in mixed alkali glasses. - In: Diffusion fundamentals, ISSN 1862-4138, Bd. 2 (2005), Seite 30.1-30.2, insges. 2 S.
http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-195485
Surface diffusion and growth of alloy nanoclusters: a Monte Carlo study. - In: Diffusion fundamentals, ISSN 1862-4138, Bd. 2 (2005), 19.1-19.2, insges. 2 S.
http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-195320
Internal friction and vulnerability of mixed alkali glasses. - In: Physical review letters, ISSN 1079-7114, Bd. 95 (2005), 11, 115901, insges. 4 S.
https://doi.org/10.1103/PhysRevLett.95.115901
MHD-channel flow of liquid metal under inhomogeneous magnetic field - Part 2: Direct numerical simulation. - In: Fundamental and applied MHD, (2005), S. 215-218
Surface phonons of clean and hydrogen terminated Si(1 1 0) surfaces. - In: Surface science, ISSN 1879-2758, Bd. 582 (2005), 1/3, S. 159-172
We report an investigation of the dynamical properties of clean and monohydride-terminated Si(1 1 0) surfaces, measured by means of high resolution electron energy loss spectroscopy (HREELS). On both surfaces a number of surface phonons is observed and successfully assigned to predicted modes. A (1 x 5) reconstruction is found to be the stable surface phase corresponding to monohydride coverage of Si(1 1 0). For the SiH stretching and bending bands of this monohydride Si(1 1 0) surface we find a relatively strong dispersion along the [1 -1 0] direction. Apparently, this is related to the coupling of oscillators along the Si chains of the (1 1 0) surface. In addition, surface vibrations induced by adsorbed residual gases are measured and analysed.
http://dx.doi.org/10.1016/j.susc.2005.03.013
Dielectric response in strongly disordered materials: analytic approaches. - In: Zeitschrift für physikalische Chemie, ISSN 2196-7156, Bd. 218 (2004), 12, S. 1375-1384
http://dx.doi.org/10.1524/zpch.218.12.1375.53829
Static and time dependent density functional theory with internal degrees of freedom: merits and limitations demonstrated for the potts model. - In: Journal of statistical physics, ISSN 1572-9613, Bd. 114 (2004), 3/4, S. 1115-1125
http://dx.doi.org/10.1023/B:JOSS.0000012518.27400.2a
Quasicrystalline order in binary dipolar systems. - In: The European physical journal, ISSN 1434-6036, Bd. 42 (2004), 1, S. 85-94
https://doi.org/10.1140/epjb/e2004-00359-6
Multi echo susceptibility weighted imaging (SWI) - phantom and in vivo measurements. - In: Beiträge zur 38. Jahrestagung der Deutschen Gesellschaft für Biomedizinische Technik im VDE - BMT 2004, 22 -24 September 2004, TU Ilmenau, (2004), S. 148-149
Transport in disordered ionic conductors. - In: Mass and charge transport in inorganic materials II, (2003), S. 159-170
Description of far-from-equilibrium processes by mean-field lattice gas models. - In: Advances in physics, ISSN 1460-6976, Bd. 52 (2003), 6, S. 523-638
http://dx.doi.org/10.1080/00018730310001615932
Spin precession in disordered systems: anomalous relaxation due to heavy-tailed field distributions. - In: epl, ISSN 1286-4854, Bd. 62 (2003), 3, S. 439-445
http://dx.doi.org/10.1209/epl/i2003-00415-5
Real space renormalization group approach to spin-glass dynamics. - In: Physical review. Condensed matter and materials physics / American Physical Society. - College Park, Md. : APS, 1970-2015 , ISSN: 1550-235X , ZDB-ID: 1473011-X, ISSN 1550-235X, Bd. 68 (2003), 6, S. 060404, insges. 4 S.
http://dx.doi.org/10.1103/PhysRevB.68.060404
Zeitenwandel : die Geschichte des Instituts für Physik von 1953 bis heute, [Teil] 6. - In: Ilmenauer Uni-Nachrichten, Bd. 46 (2003), 1, S. 20
Stochastic modeling of ion dynamics in glasses. - In: Solid state ionics: trends in the new millennium, (2002), S. 689-700
Effective medium theory of conduction in stretched polymer electrolytes. - In: The journal of physical chemistry, ISSN 1520-5207, Bd. 106 (2002), 24, S. 6149-6155
http://dx.doi.org/10.1021/jp013373a
Approaching the low-temperature limit in nucleation and two-dimensional growth of fcc (100) metal films Ag/OAg(100). - In: Physical review. Condensed matter and materials physics / American Physical Society. - College Park, Md. : APS, 1970-2015 , ISSN: 1550-235X , ZDB-ID: 1473011-X, ISSN 1550-235X, Bd. 66 (2002), 15, S. 155435, insges. 7 S.
http://dx.doi.org/10.1103/PhysRevB.66.155435
Dynamics of disordered dipolar systems. - In: Physical chemistry, chemical physics, ISSN 1463-9084, Bd. 4 (2002), 14, S. 3168-3172
http://dx.doi.org/10.1039/b110484e
Kinetics in one-dimensional lattice gas and Ising models from time-dependent density-functional theory. - In: Physical review. Statistical, nonlinear, and soft matter physics / American Physical Society. - College Park, Md. : APS, January 1993-December 2015 , ISSN: 1550-2376 , ZDB-ID: 1472725-0, ISSN 1550-2376, Bd. 65 (2002), 6, S. 066112, insges. 8 S.
http://dx.doi.org/10.1103/PhysRevE.65.066112
Gaussian ellipsoid model for confined polymer systems. - In: The journal of chemical physics, ISSN 1089-7690, Bd. 117 (2002), 9, S. 4564-4577
https://doi.org/10.1063/1.1497156
Lévy field distributions and anomalous spin relaxation in disordered magnetic systems. - In: Physica, ISSN 1873-2119, Bd. 314 (2002), 1/4, S. 200-207
https://doi.org/10.1016/S0378-4371(02)01189-5
Influence of adatom interactions on second-layer nucleation. - In: Physical review. Condensed matter and materials physics / American Physical Society. - College Park, Md. : APS, 1970-2015 , ISSN: 1550-235X , ZDB-ID: 1473011-X, ISSN 1550-235X, Bd. 66 (2002), 7, S. 073402, insges. 4 S.
http://dx.doi.org/10.1103/PhysRevB.66.073402
Non-Debye relaxations in disordered ionic solids. - In: Chemical physics, Bd. 284 (2002), 1/2, S. 439-467
http://dx.doi.org/10.1016/S0301-0104(02)00673-0
Zeitenwandel : die Geschichte des Instituts für Physik von 1953 bis heute, [Teil] 5. - In: Ilmenauer Uni-Nachrichten, Bd. 45 (2002), 5, S. 20
Zeitenwandel : die Geschichte des Instituts für Physik von 1953 bis heute, [Teil] 3. - In: Ilmenauer Uni-Nachrichten, Bd. 45 (2002), 3, S. 20
Zeitenwandel : die Geschichte des Instituts für Physik von 1953 bis heute, [Teil] 4. - In: Ilmenauer Uni-Nachrichten, Bd. 45 (2002), 4, S. 20
Zeitenwandel : die Geschichte des Instituts für Physik von 1953 bis heute, [Teil] 2. - In: Ilmenauer Uni-Nachrichten, Bd. 45 (2002), 1, S. 24
Die rätselhafte Größe Zeit. - In: Beiträge aus dem wissenschaftlichen Leben, Bd. 5 (2001), S. 45-51
Zeitenwandel : die Geschichte des Instituts für Physik von 1953 bis heute, [Teil] 1. - In: Ilmenauer Uni-Nachrichten, Bd. 44 (2001), 6, S. 16
Die Macht des Geistes ... : Universitäten in der Wissensgesellschaft. - In: Ilmenauer Uni-Nachrichten, Bd. 43 (2000), 3, S. 22-23
Phonons in group-III nitride mixed crystals. - In: Compound semiconductors 1999, (2000), S. 499-502
Phonons in ternary group-III nitride alloys. - In: Physical review, ISSN 1550-235X, Bd. 61 (2000), 9, S. 6091-6105
http://dx.doi.org/10.1103/PhysRevB.61.6091
Lattice dynamics of ternary alloys. - In: Physica status solidi, ISSN 1521-3951, Bd. 216 (1999), 1, S. 761-768
http://dx.doi.org/10.1002/(SICI)1521-3951(199911)216:1<761::AID-PSSB761>3.0.CO;2-G
Modelling of single barrier heterostructures including band bending and non-parabolicity effects of the band structure. - In: Solid state electronics, Bd. 38 (1995), 2, S. 357-365
http://dx.doi.org/10.1016/0038-1101(94)00101-K
Modellierung von Einbarrieren-Tunneldioden. - In: Vortragsreihen, (1995), S. 452-457
Selbstkonsistente Berechnung und Simulation von zylindersymmetrischen Quantum-Dot-Strukturen. - In: Vortragsreihen, (1995), S. 363-368
Untersuchung von Si-dotierten GaAs/AlGaAs Quantum Wells mittels Elektroreflexion. - In: Vortragsreihen Mikroelektronik und Schaltungstechnik, Kommunikations- und Meßtechnik, (1992), S. 74-79
Untersuchung des Einflusses einer [delta]-Dotierung im Quantengraben auf die elektronischen Eigenschaften eines GaAs/AlGaAs-HFET's. - In: Vortragsreihen Mikroelektronik und Schaltungstechnik, Kommunikations- und Meßtechnik, (1992), S. 68-73
Enveloppentheorie für schmallückige Halbleiter mit Anwendung auf Tunnelung in Heterostrukturen, 1991. - Getr. Zählung : Ilmenau, Techn. Hochsch., Diss., 1991
Enth. außerdem: Thesen
Elektronische und Transporteigenschaften des zweidimensionalen Elektronengases im starken Magnetfeld, 1990. - 83, [4] Bl. : Ilmenau, Techn. Hochsch., Diss., 1990