Results for "Dominik M. Juraschek"

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A dynamical magnetic field accompanying the motion of ferroelectric domain wallsApr 12 2019The recently proposed dynamical multiferroic effect describes the generation of magnetization from temporally varying electric polarization. Here, we show that the effect can lead to a magnetic field at moving ferroelectric domain walls, where the rearrangement ... More
Sum-frequency ionic Raman scatteringJan 18 2018Jan 29 2018In a recent report sum-frequency excitation of a Raman-active phonon was experimentally demonstrated for the first time. This mechanism is the sibling of impulsive stimulated Raman scattering, in which difference-frequency components of a light field ... More
Orbital magnetic moments of phononsDec 13 2018In ionic materials, circularly polarized phonons carry orbital magnetic moments that arise from circular motions of the ions, and which interact with other magnetic moments or fields. Here, we calculate the orbital magnetic moments of phonons in 35 different ... More
Random triangular Burnside groupsOct 03 2018We introduce a model for random groups in varieties of $n$-periodic groups as $n$-periodic quotients of triangular random groups. We show that for an explicit $d_{\mathrm{crit}}\in(1/3,1/2)$, for densities $d\in(1/3,d_{\mathrm{crit}})$ and for $n$ large ... More
The Inner Rim Structures of Protoplanetary DiscsAug 12 2009Aug 28 2009The inner boundary of protoplanetary discs is structured by the dramatic opacity changes at the transition from the dust-containing to a dust-free zone. This paper explores the variety and limits of inner rim structures in passively heated dusty discs. ... More
Full 2D radiative transfer modelling of transitional disk LkCa 15Jan 13 2010Apr 21 2010With the legacy of Spitzer and current advances in (sub)mm astronomy, a large number of 'transitional' disks has been identified which are believed to contain gaps or have developped large inner holes, some filled with dust. This may indicate that complex ... More
Ultrafast Structure Switching through Nonlinear PhononicsJul 06 2016We describe an ultrafast coherent control of the transient structural distortion arising from nonlinear phononics in ErFeO$_3$. Using density functional theory, we calculate the structural properties as input to an anharmonic phonon model that describes ... More
Magnetic tension and instabilities in the Orion A integral shaped filamentMay 17 2017Nov 15 2017The Orion nebula is a prime example of a massive star-forming region in our galaxy. Observations have shown that gravitational and magnetic energy are comparable in its integral shaped filament (ISF) on a scale of ~1 pc, and that the population of pre-main ... More
Quantum coarse-grained entropy and thermalization in closed systemsMar 02 2018Jan 15 2019We investigate the detailed properties of Observational entropy, introduced by \v{S}afr\'{a}nek et al. [Phys. Rev. A 99, 010101 (2019)] as a generalization of Boltzmann entropy to quantum mechanics. This quantity can involve multiple coarse-grainings, ... More
Dusty tails of evaporating exoplanets. I. Constraints on the dust compositionOct 13 2014Recently, two exoplanet candidates have been discovered, KIC 12557548b and KOI-2700b, whose transit profiles show evidence for a comet-like tail of dust trailing the planet, thought to be fed by the evaporation of the planet's surface. We aim to put constraints ... More
The thermal structure and the location of the snow line in the protosolar nebula: axisymmetric models with full 3-D radiative transferDec 03 2010The precise location of the water ice condensation front ('snow line') in the protosolar nebula has been a debate for a long time. Its importance stems from the expected substantial jump in the abundance of solids beyond the snow line, which is conducive ... More
Near-infrared emission from sublimating dust in collisionally active debris disksApr 12 2014Hot exozodiacal dust is thought to be responsible for excess near-infrared (NIR) emission emanating from the innermost parts of some debris disks. The origin of this dust, however, is still a matter of debate. We test whether hot exozodiacal dust can ... More
Phase diagram of dipolar-coupled XY moments on disordered square latticesApr 20 2018Aug 23 2018The effects of dilution disorder and random-displacement disorder are analyzed for dipolar-coupled magnetic moments confined in a plane, which were originally placed on the square lattice. In order to distinguish the different phases, new order parameters ... More
Multiwavelength optical properties of compact dust aggregates in protoplanetary disksOct 19 2015In protoplanetary disks micron-size dust grains coagulate to form larger structures with complex shapes and compositions. The coagulation process changes the absorption and scattering properties of particles in the disk in significant ways. To properly ... More
Continuous ground-state degeneracy of classical dipoles on regular latticesMar 04 2019Dipolar interactions are crucial in the modeling of many complex magnetic systems, such as the pyrochlores and artificial spin systems. Remarkably, many classical dipolar coupled spin systems exhibit a continuous ground-state degeneracy, which is unexpected ... More
Truthful Aggregation of Budget ProposalsMay 01 2019We consider a participatory budgeting problem in which each voter submits a proposal for how to divide a single divisible resource (such as money or time) among several possible alternatives (such as public projects or activities) and these proposals ... More
Connecting the shadows: probing inner disk geometries using shadows in transitional disksApr 06 2017Sep 01 2017Shadows in transitional disks are generally interpreted as signs of a misaligned inner disk. This disk is usually beyond the reach of current day high contrast imaging facilities. However, the location and morphology of the shadow features allow us to ... More
Spectroscopic diagnostic for the mineralogy of large dust grainsOct 30 2003We examine the thermal infrared spectra of large dust grains of different chemical composition and mineralogy. Strong resonances in the optical properties result in detectable spectral structure even when the grain is much larger than the wavelength at ... More
Imaging diagnostics for transitional discsSep 03 2013Transitional discs are a special type of protoplanetary discs where planet formation is thought to be taking place. These objects feature characteristic inner cavities and/or gaps of a few tens of AUs in the sub-millimitre images of the disc. This signature ... More
Dynamical MultiferroicityDec 19 2016Apr 10 2017An appealing mechanism for inducing multiferroicity in materials is the generation of electric polarization by a spatially varying magnetization that is coupled to the lattice through the spin-orbit interaction. Here we describe the reciprocal effect, ... More
Security for the Industrial IoT: The Case for Information-Centric NetworkingOct 10 2018Mar 05 2019Industrial production plants traditionally include sensors for monitoring or documenting processes, and actuators for enabling corrective actions in cases of misconfigurations, failures, or dangerous events. With the advent of the IoT, embedded controllers ... More
A fundamental class for intersection spaces of depth one Witt spacesApr 07 2019By a theorem of Banagl-Chriestenson, intersection spaces of depth one pseudomanifolds exhibit generalized Poincar\'{e} duality of Betti numbers, provided that certain characteristic classes of the link bundles vanish. In this paper, we show that the middle-perversity ... More
Single-Peakedness and Total Unimodularity: Efficiently Solve Voting Problems Without Even TryingSep 12 2016Many NP-hard winner determination problems admit polynomial-time algorithms when restricting inputs to be single-peaked. Commonly, such algorithms employ dynamic programming along the underlying axis. We introduce a new technique: carefully chosen integer ... More
The Zak transform on strongly proper $G$-spaces and its applicationsMay 17 2016Oct 21 2016The Zak transform on $\mathbb{R}^d$ is an important tool in condensed matter physics, signal processing, time-frequency analysis, and harmonic analysis in general. This article introduces a generalization of the Zak transform to a class of locally compact ... More
Infinite finitely generated automata semigroups have infinite orbitsJan 30 2018We prove that the semigroup generated by a finite state Mealy automaton $\mathcal{A}=(Q,A,\tau)$ is infinite if and only if there exists some right-infinite word in the alphabet $A$ with infinite orbit.
Automorphism Supergroups Of SupermanifoldsApr 10 2015A classical theorem states that the group of automorphisms of a manifold $M$ preserving a $G$-structure of finite type is a Lie group. We generalize this statement to the category of $cs$ manifolds and give some examples, some of which being generalizations ... More
Groups with graphical C(6) and C(7) small cancellation presentationsSep 30 2012Jul 24 2014We extend fundamental results of small cancellation theory to groups whose presentations satisfy the generalizations of the classical C(6) and C(7) conditions in graphical small cancellation theory. Using these graphical small cancellation conditions, ... More
Non-Autonomous Maximal Regularity for Forms of Bounded VariationJun 11 2014Jun 12 2014We consider a non-autonomous evolutionary problem \[ u' (t)+\mathcal A (t)u(t)=f(t), \quad u(0)=u_0, \] where $V, H$ are Hilbert spaces such that $V$ is continuously and densely embedded in $H$ and the operator $\mathcal A (t)\colon V\to V^\prime$ is ... More
Infinitely presented C(6)-groups are SQ-universalNov 26 2014We prove that infinitely presented classical $C(6)$ small cancellation groups are SQ-universal. We extend the result to graphical $Gr_*(6)$-groups over free products. For every $p\in\mathbb{N}$, we construct uncountably many pairwise non-quasi-isometric ... More
Topological entropy and distributional chaos in hereditary shifts with applications to spacing shifts and beta shiftsNov 01 2011Jan 08 2012Positive topological entropy and distributional chaos are characterized for hereditary shifts. A hereditary shift has positive topological entropy if and only if it is DC2-chaotic (or equivalently, DC3-chaotic) if and only if it is not uniquely ergodic. ... More
The 10 micron amorphous silicate feature of fractal aggregates and compact particles with complex shapesSep 14 2005We model the 10 micron absorption spectra of nonspherical particles composed of amorphous silicate. We consider two classes of particles, compact ones and fractal aggregates composed of homogeneous spheres. For the compact particles we consider Gaussian ... More
The lunar phases of dust grains orbiting FomalhautJan 04 2010Optical images of the nearby star Fomalhaut show a ring of dust orbiting the central star. This dust is in many respects expected to be similar to the zodiacal dust in the solar system. The ring displays a clear brightness asymmetry, attributed to asymmetric ... More
Dust-grain processing in circumbinary discs around evolved binaries. The RV Tauri spectral twins RU Cen and AC HerSep 20 2007Context: We study the structure and evolution of circumstellar discs around evolved binaries and their impact on the evolution of the central system. Aims: To study in detail the binary nature of RUCen and ACHer, as well as the structure and mineralogy ... More
Absorption and scattering properties of arbitrarily shaped particles in the Rayleigh domain: A rapid computational method and a theoretical foundation for the statistical approachApr 04 2005We provide a theoretical foundation for the statistical approach for computing the absorption properties of particles in the Rayleigh domain. We present a general method based on the Discrete Dipole Approximation (DDA) to compute the absorption and scattering ... More
Coagulation and Fragmentation in molecular clouds. II. The opacity of the dust aggregate size distributionJun 16 2011The dust size distribution in molecular clouds can be strongly affected by ice-mantle formation and (subsequent) grain coagulation. Following previous work where the dust size distribution has been calculated from a state-of-the art collision model for ... More
The Zak transform on strongly proper $G$-spaces and its applicationsMay 17 2016The Zak transform on $\mathbb{R}^d$ is an important tool in condensed matter physics, signal processing, time-frequency analysis, and harmonic analysis in general. This article introduces a generalization of the Zak transform to a class of locally compact ... More
Cusp cobordism group of Morse functionsMay 14 2019By a Morse function on a compact manifold with boundary we mean a real-valued function without critical points near the boundary such that its critical points as well as the critical points of its restriction to the boundary are all non-degenerate. For ... More
Mixing times for the simple exclusion process in ballistic random environmentJun 11 2018Mar 04 2019We consider the exclusion process on segments of the integers in a site-dependent random environment. We assume to be in the ballistic regime in which a single particle has positive linear speed. Our goal is to study the mixing time of the exclusion process ... More
Hodge Numbers of Generalised Borcea-Voisin ThreefoldsFeb 16 2017We shall reproof formulas for the Hodge numbers of Calabi-Yau threefolds of Borcea-Voisin type constructed by A. Cattaneo and A. Garbagnati, using the orbifold cohomology formula and the orbifold Euler characteristic.
Abelian varieties with quaternion and complex multiplicationAug 28 2012In this paper we study abelian varieties which correspond to CM points in the coarse moduli space of principally polarized abelian varieties with multiplication by a maximal order in a quaternion algebra over a totally real number field. These are abelian ... More
Polarized scattered light from self-luminous exoplanets. Three-dimensional scattering radiative transfer with ARTESJun 28 2017Nov 08 2018Direct imaging has paved the way for atmospheric characterization of young and self-luminous gas giants. Scattering in a horizontally-inhomogeneous atmosphere causes the disk-integrated polarization of the thermal radiation to be linearly polarized, possibly ... More
A panoptic model for planetesimal formation and pebble deliveryNov 24 2015The journey from dust particle to planetesimal involves physical processes acting on scales ranging from micrometers (the sticking and restructuring of aggregates) to hundreds of astronomical units (the size of the turbulent protoplanetary nebula). Considering ... More
Analysis of the infrared spectra of the peculiar post-AGB stars EPLyr and HD52961Jun 25 2009Aim: We aim to study in detail the peculiar mineralogy and structure of the circumstellar environment of two binary post-AGB stars, EPLyr and HD52961. Both stars were selected from a larger sample of evolved disc sources observed with Spitzer and show ... More
On Strong NP-Completeness of Rational ProblemsFeb 26 2018The computational complexity of the partition, 0-1 subset sum, unbounded subset sum, 0-1 knapsack and unbounded knapsack problems and their multiple variants were studied in numerous papers in the past where all the weights and profits were assumed to ... More
The non-existence of sharply $2$-transitive sets of permutations in $\mathrm{Sp}(2d,2)$ of degree $2^{2d-1} \pm 2^{d-1}$Feb 16 2016We use M\"uller and Nagy's method of contradicting subsets to give a new proof for the non-existence of sharply $2$-transitive subsets of the symplectic groups $\mathrm{Sp}(2d,2)$ in their doubly-transitive actions of degrees $2^{2d-1}\pm 2^{d-1}$. The ... More
Optimal Construction of Compressed Indexes for Highly Repetitive TextsDec 13 2017May 20 2019We propose algorithms that, given the input string of length $n$ over integer alphabet of size $\sigma$, construct the Burrows-Wheeler transform (BWT), the permuted longest-common-prefix (PLCP) array, and the LZ77 parsing in $O(n/\log_{\sigma}n+r\,{\rm ... More
Bordism of constrained Morse functionsMar 29 2018We call a Morse function $f$ on a closed manifold $k$-constrained if neither $f$ nor $-f$ has critical points of indefinite Morse index $< k$. In this paper we study bordism groups of $k$-constrained Morse functions, and thus interpolate between the case ... More
Magnetic fields in star forming systems (I): Idealized synthetic signatures of dust polarization and Zeeman splitting in filamentsMay 07 2018May 09 2018We use the POLARIS radiative transport code to generate predictions of the two main observables directly sensitive to the magnetic field morphology and strength in filaments: dust polarization and gas Zeeman line splitting. We simulate generic gas filaments ... More
Magnetic fields in the Large-Scale Structure of the UniverseSep 19 2011Magnetic fields appear to be ubiquitous in astrophysical environments. Their existence in the intracluster medium is established through observations of synchrotron emission and Faraday rotation. On the other hand, the nature of magnetic fields outside ... More
A spectroscopic event of eta Car viewed from different directions: The data and first resultsJan 28 2005We present spectroscopic observations with high spectral resolution of eta Car as seen by the SE lobe of the Homunculus nebula over the 2003.5 "spectroscopic event". The observed spectra represent the stellar spectrum emitted near the pole of the star ... More
VLT-UVES observations of the Balmer line variations of eta Carinae during the 2003 spectroscopic eventDec 17 2004We present high spectral resolution echelle observations of the Balmer line variations during the 2003.5 ``spectroscopic event'' of eta Carinae. Spectra have been recorded of both eta Carinae and the Homunculus at the FOS4 position in its SE lobe. This ... More
Radiative transfer in very optically thick circumstellar disksFeb 18 2009In this paper we present two efficient implementations of the diffusion approximation to be employed in Monte Carlo computations of radiative transfer in dusty media of massive circumstellar disks. The aim is to improve the accuracy of the computed temperature ... More
Ambipolar quantum dots in undoped silicon fin field-effect transistorsJul 11 2018We integrate ambipolar quantum dots in silicon fin field-effect transistors using exclusively standard complementary metal-oxide-semiconductor fabrication techniques. We realize ambipolarity by replacing conventional highly-doped source and drain electrodes ... More
Animating an Autonomous 3D Talking AvatarMar 13 2019One of the main challenges with embodying a conversational agent is annotating how and when motions can be played and composed together in real-time, without any visual artifact. The inherent problem is to do so---for a large amount of motions---without ... More
Charge Localization Dynamics induced by Oxygen Vacancies on the Titania TiO$_2$(110) SurfaceAug 27 2010The dynamics of an F--center created by an oxygen vacancy on the $\mathrm{TiO_{2}(110)}$ rutile surface has been investigated using {\it ab initio} molecular dynamics. These simulations uncover a truly complex, time-dependent behavior of fluctuating electron ... More
Cosmological parameter estimation and the inflationary cosmologyFeb 05 2002Apr 25 2003We consider approaches to cosmological parameter estimation in the inflationary cosmology, focussing on the required accuracy of the initial power spectra. Parametrizing the spectra, for example by power-laws, is well suited to testing the inflationary ... More
From ab initio quantum chemistry to molecular dynamics: The delicate case of hydrogen bonding in ammoniaJun 20 2003The ammonia dimer (NH3)2 has been investigated using high--level ab initio quantum chemistry methods and density functional theory (DFT). The structure and energetics of important isomers is obtained to unprecedented accuracy without resorting to experiment. ... More
How to relax the cosmological neutrino mass boundJan 14 2019May 29 2019We study the impact of non-standard momentum distributions of cosmic neutrinos on the anisotropy spectrum of the cosmic microwave background and the matter power spectrum of the large scale structure. We show that the neutrino distribution has almost ... More
An Exchange-Coupled Donor Molecule in SiliconDec 16 2013Donors in silicon, conceptually described as hydrogen atom analogues in a semiconductor environment, have become a key ingredient of many "More-than-Moore" proposals such as quantum information processing [1-5] and single-dopant electronics [6, 7]. The ... More
Hyperfine-phonon spin relaxation in a single-electron GaAs quantum dotNov 04 2017Understanding and control of the spin relaxation time $T_1$ is among the key challenges for spin based qubits. A larger $T_1$ is generally favored, setting the fundamental upper limit to the qubit coherence and spin readout fidelity. In GaAs quantum dots ... More
Statistics of turbulence in the energy-containing range of Taylor-Couette compared to canonical wall-bounded flowsAug 29 2017Considering structure functions of the streamwise velocity component in a framework akin to the extended self-similarity hypothesis (ESS), de Silva \textit{et al.} (\textit{J. Fluid Mech.}, vol. 823,2017, pp. 498-510) observed that remarkably the \textit{large-scale} ... More
Molecular Water Lilies: Orienting Single Molecules in a Polymer Film by Solvent Vapor AnnealingNov 07 2016The microscopic orientation and position of photoactive molecules is crucial to the operation of optoelectronic devices such as OLEDs and solar cells. Here, we introduce a shape-persistent macrocyclic molecule as an excellent fluorescent probe to simply ... More
Spectral Analysis and Long-Time Behaviour of a Fokker-Planck Equation with a Non-Local PerturbationJul 24 2012Sep 09 2015In this article we consider a Fokker-Planck equation with a non-local, mass preserving perturbation. We show that the perturbed Fokker-Planck operator generates a $C_0$-semigroup on an exponentially weighted $L^2$-space. Surprisingly, the spectrum of ... More
Maximal subgroups of groups of intermediate growthNov 03 2016Oct 24 2018Finding the number of maximal subgroups of infinite index of a finitely generated group is a natural problem that has been solved for several classes of `geometric' groups (linear groups, hyperbolic groups, mapping class groups, etc). Here we provide ... More
On the condition number of Vandermonde matrices with pairs of nearly-colliding nodesDec 20 2018We prove upper and lower bounds for the spectral condition number of rectangular Vandermonde matrices with nodes on the complex unit circle. The nodes are "off the grid", pairs of nodes nearly collide, and the studied condition number grows linearly with ... More
Topological entropy of compact subsystems of transitive real line mapsAug 20 2012For a continuous map $f$ from the real line (half-open interval $[0,1)$) into itself let ent(f) denote the supremum of topological entropies of $f|_K$, where $K$ runs over all compact $f$-invariant subsets of $\mathbb{R}$ ($[0,1)$, respectively). It is ... More
On Elkies' method for bounding the transitivity degree of Galois groupsMay 14 2019In 2013 Elkies described a method for bounding the transitivity degree of Galois groups. Our goal is to give additional applications of this technique, in particular verifying that the Galois group of the degree 276 polynomial over a degree 12 number ... More
Dynamical Ejections of Stars due to an Accelerating Gas FilamentApr 03 2017Jul 17 2017Observations of the Orion-A integral shaped filament (ISF) have shown indications of an oscillatory motion of the gas filament. This evidence is based on both the wave-like morphology of the filament as well as the kinematics of the gas and stars, where ... More
Optical waveguide devices modulated by surface acoustic wavesNov 07 2018This paper reviews the application of coherent acoustic phonons in the form of piezoelectrically-generated surface acoustic waves to control the response of integrated photonic acousto-optic waveguide structures. We first address the fundamental properties ... More
The mineralogy, geometry and mass-loss history of IRAS 16342-3814Feb 09 2003We present the 2-200 um Infrared Space Observatory (ISO) spectrum and 3.8-20 um ISAAC and TIMMI2 images of the extreme OH/IR star IRAS 16342-3814. Amorphous silicate absorption features are seen, together with crystalline silicate absorption features ... More
Dusty tails of evaporating exoplanets. II. Physical modelling of the KIC 12557548b light curveSep 01 2016Evaporating rocky exoplanets, such as KIC 12557548b, eject large amounts of dust grains, which can trail the planet in a comet-like tail. When such objects occult their host star, the resulting transit signal contains information about the dust in the ... More
On the convex geometry of blind deconvolution and matrix completionFeb 28 2019Mar 12 2019Low-rank matrix recovery from structured measurements has been a topic of intense study in the last decade and many important problems like matrix completion and blind deconvolution have been formulated in this framework. An important benchmark method ... More
Simple Causes of Complexity in Hedonic GamesJul 13 2015Hedonic games provide a natural model of coalition formation among self-interested agents. The associated problem of finding stable outcomes in such games has been extensively studied. In this paper, we identify simple conditions on expressivity of hedonic ... More
Visualizing a Million Time Series with the Density Line ChartAug 17 2018Sep 06 2018Data analysts often need to work with multiple series of data---conventionally shown as line charts---at once. Few visual representations allow analysts to view many lines simultaneously without becoming overwhelming or cluttered. In this paper, we introduce ... More
A Scalable Multiphysics Algorithm for Massively Parallel Direct Numerical Simulations of ElectrophoresisAug 29 2017May 25 2018In this article we introduce a novel coupled algorithm for massively parallel direct numerical simulations of electrophoresis in microfluidic flows. This multiphysics algorithm employs an Eulerian description of fluid and ions, combined with a Lagrangian ... More
The Influence of Frequency, Recency and Semantic Context on the Reuse of Tags in Social Tagging SystemsApr 04 2016In this paper, we study factors that influence tag reuse behavior in social tagging systems. Our work is guided by the activation equation of the cognitive model ACT-R, which states that the usefulness of information in human memory depends on the three ... More
Complex phase retrieval from subgaussian measurementsJun 19 2019Phase retrieval refers to the problem of reconstructing an unknown vector $x_0 \in \mathbb{C}^n$ or $x_0 \in \mathbb{R}^n $ from $m$ measurements of the form $y_i = \big\vert \langle \xi^{\left(i\right)}, x_0 \rangle \big\vert^2 $, where $ \left\{ \xi^{\left(i\right)} ... More
Surface Spline Approximation on SO(3)Nov 10 2009Nov 23 2010The purpose of this article is to introduce a new class of kernels on SO(3) for approximation and interpolation, and to estimate the approximation power of the associated spaces. The kernels we consider arise as linear combinations of Green's functions ... More
Parity Polytopes and BinarizationMar 28 2018Apr 18 2018We consider generalizations of parity polytopes whose variables, in addition to a parity constraint, satisfy certain ordering constraints. More precisely, the variable domain is partitioned into $k$ contiguous groups, and within each group, we require ... More
On homeomorphisms with the two-sided limit shadowing propertyFeb 04 2014We prove that the two-sided limit shadowing property is among the strongest known notions of pseudo-orbit tracing. It implies shadowing, average shadowing, asymptotic average shadowing and specification properties. We also introduce a weaker notion that ... More
Selection Criterion for Log-Linear Models Using Statistical Learning TheoryFeb 07 2003Log-linear models are a well-established method for describing statistical dependencies among a set of n random variables. The observed frequencies of the n-tuples are explained by a joint probability such that its logarithm is a sum of functions, where ... More
Infinitely presented graphical small cancellation groups are acylindrically hyperbolicAug 19 2014Feb 09 2016We prove that infinitely presented graphical $Gr(7)$ small cancellation groups are acylindrically hyperbolic. In particular, infinitely presented classical $C(7)$-groups and, hence, classical $C'(\frac{1}{6})$-groups are acylindrically hyperbolic. We ... More
Optimal Error Estimates for Fully Discrete Galerkin Approximations of Semilinear Parabolic EquationsJul 25 2017We consider a semilinear parabolic equation with a large class of nonlinearities without any growth conditions. We discretize the problem with a discontinuous Galerkin scheme dG(0) in time (which is a variant of the implicit Euler scheme) and with conforming ... More
Fluctuations of Rectangular Young Diagrams of Interlacing Wigner EigenvaluesAug 18 2016Jul 10 2018We prove a new CLT for the difference of linear eigenvalue statistics of a Wigner random matrix $H$ and its minor $\hat H$ and find that the fluctuation is much smaller than the fluctuations of the individual linear statistics, as a consequence of the ... More
The chromatic Brauer category and its linear representationsFeb 14 2019The Brauer category is a symmetric strict monoidal category that arises as a categorification of the Brauer algebras in the context of Banagl's framework of positive topological field theories (TFTs). We introduce the chromatic Brauer category as an enrichment ... More
Revealing stellar brightness profiles by means of microlensing fold causticsFeb 24 2004Jun 23 2004With a handful of measurements of limb-darkening coefficients, galactic microlensing has already proven to be a powerful technique for studying atmospheres of distant stars. Survey campaigns such as OGLE-III are capable of providing ~ 10 suitable target ... More
Determining the abundance of extragalactic planetsSep 23 2003Oct 23 2003Gravitational microlensing provides a unique technique to reveal information about extragalactic planets. A network of at least four 2m-class telescopes distributed around the northern hemisphere could probe 15-35 jupiters and 4-10 saturns around M31 ... More
The binary gravitational lens and its extreme casesMar 01 1999Sep 10 1999The transition of the binary gravitational lens from the equal mass case to small (planetary) mass ratios q is studied. It is shown how the limit of a (pure shear) Chang-Refsdal lens is approached, under what conditions the Chang-Refsdal approximation ... More
Spectroscopy of Quantum-Dot Orbitals with In-Plane Magnetic FieldsMar 31 2018We show that in-plane-magnetic-field assisted spectroscopy allows extraction of the in-plane orientation and full 3D shape of the quantum mechanical orbitals of a single electron GaAs lateral quantum dot with sub-nm precision. The method is based on measuring ... More
Parameter degeneracies and (un)predictability of gravitational microlensing eventsNov 25 2008(abridged) Some difficulties in determining the physical properties that lead to observed anomalies in microlensing light curves, such as the mass and separation of extra-solar planets orbiting the lens star, or the relative source-lens parallax, are ... More
Theory and practice of microlensing lightcurves around fold singularitiesSep 22 2003Jun 23 2004Among all galactic microlensing events, those involving a passage of the observed source star over the caustic created by a binary lens are particularly useful in providing information about stellar atmospheres, the dynamics of stellar populations in ... More
A robust and efficient method for calculating the magnification of extended sources caused by gravitational lensesApr 06 1998To determine the magnification of an extended source caused by gravitational lensing one has to perform a two-dimensional integral over point-source magnifications in general. Since the point-source magnification jumps to an infinite value on caustics, ... More
Galactic microlensing with rotating binariesFeb 04 1997Sep 09 1997The influence of rotating binary systems on the light curves of galactic microlensing events is studied. Three different rotating binary systems are discussed: a rotating binary lens, a rotating binary source, and the motion of the earth around the sun ... More
Planetary mass function and planetary systemsSep 23 2010With planets orbiting stars, a planetary mass function should not be seen as a low-mass extension of the stellar mass function, but a proper formalism needs to take care of the fact that the statistical properties of planet populations are linked to the ... More
Stochastical distributions of lens and source properties for observed galactic microlensing eventsJul 22 2005Dec 27 2005A comprehensive new approach is presented for deriving probability densities of physical properties characterizing lens or source that constitute an observed galactic microlensing event. While previously encountered problems are overcome, constraints ... More
Adaptive Contouring -- an efficient way to calculate microlensing light curves of extended sourcesMar 13 2007The availability of a robust and efficient routine for calculating light curves of a finite source magnified due to bending its light by the gravitational field of an intervening binary lens is essential for determining the characteristics of planets ... More
Lens binarity vs limb darkening in close-impact galactic microlensing eventsOct 18 2004Although point caustics harbour a larger potential for measuring the brightness profile of stars during the course of a microlensing event than (line-shaped) fold caustics, the effect of lens binarity significantly limits the achievable accuracy. Therefore, ... More
Uncovering stellar atmospheres with gravitational microlensing telescopesDec 08 2003A strong differential magnification over the face of the source star passing the caustic created by a binary lens star allows to measure its radial intensity profile with an angular resolution of 20-60 nas from broad-band photometric observations for ... More
A PromiseBQP-complete String Rewriting ProblemMay 08 2007Jan 17 2008We are given three strings s, t, and t' of length L over some fixed finite alphabet and an integer m that is polylogarithmic in L. We have a symmetric relation on substrings of constant length that specifies which substrings are allowed to be replaced ... More
Feldman-Katok pseudometric and the GIKN construction of nonhyperbolic ergodic measuresFeb 07 2017The GIKN construction was introduced by Gorodetski, Ilyashenko, Kleptsyn, and Nalsky in [Functional Analysis and its Applications, 39 (2005), 21--30]. It gives a nonhyperbolic ergodic measure which is a weak$^*$ limit of a special sequence of measures ... More