Results for "Enno Giese"

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Light shifts in atomic Bragg diffractionDec 20 2016Bragg diffraction of an atomic wave packet in a retroreflective geometry with two counterpropagating optical lattices exhibits a light shift induced phase. We show that the temporal shape of the light pulse determines the behavior of this phase shift: ... More
Interference of Clocks: A Quantum Twin ParadoxMay 22 2019The phase of matter waves depends on proper time and is therefore susceptible to special-relativistic (kinematic) and gravitational time dilation (redshift). Hence, it is conceivable that atom interferometers measure general-relativistic time-dilation ... More
Uniqueness of Ground States for Pseudo-Relativistic Hartree EquationsJan 25 2008Sep 17 2008We prove uniqueness of ground states $Q$ in $H^{1/2}$ for pseudo-relativistic Hartree equations in three dimensions, provided that $Q$ has sufficiently small $L^2$-mass. This result shows that a uniqueness conjecture by Lieb and Yau in [CMP 112 (1987),147--174] ... More
Higher commutativity and nilpotency in finite groupsMay 21 2010We consider ordered tuples in finite groups generating nilpotent subgroups. Given an integer $q$ we consider the poset of nilpotent subgroups of class less than $q$ and its corresponding coset poset. These posets give rise to a family of finite Dirichlet ... More
Incremental View Maintenance for Deductive Graph Databases Using Generalized Discrimination NetworksDec 06 2016Nowadays, graph databases are employed when relationships between entities are in the scope of database queries to avoid performance-critical join operations of relational databases. Graph queries are used to query and modify graphs stored in graph databases. ... More
Well-Posedness for Semi-Relativistic Hartree Equations of Critical TypeMay 22 2005Aug 29 2005We prove local and global well-posedness for semi-relativistic, nonlinear Schr\"odinger equations $i \partial_t u = \sqrt{-\Delta + m^2} u + F(u)$ with initial data in $H^s(\mathbb{R}^3)$, $s \geq 1/2$. Here $F(u)$ is a critical Hartree nonlinearity that ... More
A Short Primer on the Half-Wave Maps EquationMar 05 2019We review the current state of results about the half-wave maps equation on the domain $\mathbb{R}^d$ with target $\mathbb{S}^2$. In particular, we focus on the energy-critical case $d=1$, where we discuss the classification of traveling solitary waves ... More
Model Checking Probabilistic Real-Time Properties for Service-Oriented Systems with Service Level AgreementsNov 14 2011The assurance of quality of service properties is an important aspect of service-oriented software engineering. Notations for so-called service level agreements (SLAs), such as the Web Service Level Agreement (WSLA) language, provide a formal syntax to ... More
Requirements and Assessment of Languages and Frameworks for Adaptation ModelsMay 17 2018Approaches to self-adaptive software systems use models at runtime to leverage benefits of model-driven engineering (MDE) for providing views on running systems and for engineering feedback loops. Most of these approaches focus on causally connecting ... More
Adaptation and Abstract Runtime ModelsMay 17 2018Runtime adaptability is often a crucial requirement for today's complex software systems. Several approaches use an architectural model as a runtime representation of a managed system for monitoring, reasoning and performing adaptation. To ease the causal ... More
Full-field mode sorter using two optimized phase transformations for high-dimensional quantum cryptographyMay 03 2019High-dimensional encoding schemes have emerged as a novel way to perform quantum information tasks. For high dimensionality, temporal and transverse spatial modes of photons are the two paradigmatic degrees of freedom commonly used in such experiments. ... More
The phase sensitivity of a fully quantum three-mode nonlinear interferometerAug 18 2018We study a nonlinear interferometer consisting of two consecutive parametric amplifiers, where all three optical fields (pump, signal and idler) are treated quantum mechanically, allowing for pump depletion and other quantum phenomena. The interaction ... More
A high-gain Quantum free-electron laser: emergence & exponential gainMay 24 2019We derive an effective Dicke model in momentum space to describe collective effects in the quantum regime of a free-electron laser (FEL). The resulting exponential gain from a single passage of electrons allows the operation of a Quantum FEL in the high-gain ... More
The influence of pump coherence on the generation of position-momentum entanglement in down-conversionDec 22 2018Strong correlations in two conjugate variables are the signature of quantum entanglement and have played a key role in the development of modern physics. Entangled photons have become a standard tool in quantum information and foundations. An impressive ... More
Quantum, Nonlocal Aberration CancellationJun 11 2019Phase distortions, or aberrations, can negatively influence the performance of an optical imaging system. Through the use of position-momentum entangled photons, we nonlocally correct for aberrations in one photon's optical path by intentionally introducing ... More
Measurement of the Photon-Plasmon Coupling PhaseApr 23 2019Scattering processes have played a crucial role in the development of quantum theory. In the field of optics, scattering phase shifts have been utilized to unveil interesting forms of light-matter interactions. Here, we investigate the mode-coupling phase ... More
A Primary Radiation Standard Based on Quantum Nonlinear OpticsAug 15 2018The spectrum of vacuum fluctuations of the electromagnetic field is determined solely from first physical principles and can be seen as a fundamental property that qualifies as a primary radiation standard. We demonstrate that the amplitude of these quantum ... More
The interface of gravity and quantum mechanics illuminated by Wigner phase spaceFeb 05 2014Sep 28 2015We provide an introduction into the formulation of non-relativistic quantum mechanics using the Wigner phase-space distribution function and apply this concept to two physical situations at the interface of quantum theory and general relativity: (i) the ... More
Beyond the perturbative description of the nonlinear optical response of low-index materialsFeb 14 2017Jul 15 2017We show that standard approximations in nonlinear optics are violated for situations involving a small value of the linear refractive index. Consequently, the conventional equation for the intensity-dependent refractive index, $n(I) = n_0 + n_2 I$, becomes ... More
Controlling induced coherence for quantum imagingFeb 24 2017Induced coherence in parametric down-conversion between two coherently pumped nonlinear crystals that share a common idler mode can be used as an imaging technique. Based on the interference between the two signal modes of the crystals, an image can be ... More
Influence of pump coherence on the quantum properties of spontaneous parametric down-conversionJul 12 2018The correlation properties of the pump field in spontaneous parametric down-conversion are crucial in determining the degree of entanglement of generated signal and idler photons. We find theoretically that continuous-variable entanglement of the transverse ... More
Mean-Field Limit of Quantum Bose Gases and Nonlinear Hartree EquationSep 09 2004We discuss the Hartree equation arising in the mean-field limit of large systems of bosons and explain its importance within the class of nonlinear Schroedinger equations. Of special interest to us is the Hartree equation with focusing nonlinearity (attractive ... More
On Singularity formation for the L^2-critical Boson star equationMar 16 2011Nov 29 2011We prove a general, non-perturbative result about finite-time blowup solutions for the $L^2$-critical boson star equation $i\partial_t u = \sqrt{-\Delta+m^2} \, u - (|x|^{-1} \ast |u|^2) u$ in 3 space dimensions. Under the sole assumption that the solution ... More
Accuracy of Diffusion Approximations for High Frequency Markov DataFeb 20 2006We consider triangular arrays of Markov chains that converge weakly to a diffusion process. Edgeworth type expansions of third order for transition densities are proved. This is done for time horizons that converge to 0. For this purpose we represent ... More
Neural Feature Embedding for User Response Prediction in Real-Time Bidding (RTB)Feb 02 2017May 18 2017In the area of ad-targeting, predicting user responses is essential for many applications such as Real-Time Bidding (RTB). Many of the features available in this domain are sparse categorical features. This presents a challenge especially when the user ... More
Affine diffusions with non-canonical state spaceApr 03 2010May 06 2010Multidimensional affine diffusions have been studied in detail for the case of a canonical state space. We present results for general state spaces and provide a complete characterization of all possible affine diffusions with polyhedral and quadratic ... More
Additive isotone regressionSep 06 2007This paper is about optimal estimation of the additive components of a nonparametric, additive isotone regression model. It is shown that asymptotically up to first order, each additive component can be estimated as well as it could be by a least squares ... More
Fundamental Groups of Commuting Elements in Lie GroupsSep 14 2006We compute the fundamental group of the spaces of ordered commuting $n$-tuples of elements in the Lie groups SU(2), U(2) and SO(3). For SO(3) the computation of the mod-2 cohomology of the components of these spaces is also obtained.
The Boson star equation with initial data of low regularityMay 28 2013Nov 07 2013The Cauchy problem for the L^2-critical boson star equation with initial data of low regularity in spatial dimension d=3 is studied. Local well-posedness in H^s for s > 1/4 is proved. Moreover, for radial initial data, local well-posedness is established ... More
Dynamical Ionization Bounds for AtomsJul 30 2012We study the long-time behavior of the 3-dimensional repulsive nonlinear Hartree equation with an external attractive Coulomb potential $-Z/|x|$, which is a nonlinear model for the quantum dynamics of an atom. We show that, after a sufficiently long time, ... More
Lightweight LCP-Array Construction in Linear TimeDec 20 2010The suffix tree is a very important data structure in string processing, but it suffers from a huge space consumption. In large-scale applications, compressed suffix trees (CSTs) are therefore used instead. A CST consists of three (compressed) components: ... More
Light Hadron Masses and Decay ConstantsNov 11 2009Aug 09 2010The extraction of the light hadron spectrum from a first-principle Quantum Chromodynamics approach is a profound application for lattice simulations of Quantum Chromodynamics. This review will cover recent lattice results for the masses and decay constants ... More
Blow-Up for Nonlinear Wave Equations describing Boson StarsNov 01 2005Mar 17 2006We consider the nonlinear wave equation $i \partial_t u= \sqrt{-\Delta + m^2} u - (|x|^{-1} \ast |u|^2) u$ on $\RR^3$ modelling the dynamics of (pseudo-relativistic) boson stars. For spherically symmetric initial data, $u_0(x) \in C^\infty_{\mathrm{c}}(\RR^3)$, ... More
Negative volatility for a 2-dimensional square root SDEJul 08 2008Nov 25 2008In affine term structure models the short rate is modelled as an affine transformation of a multi-dimensional square root process. Sufficient conditions to avoid negative volatility factors are the multivariate Feller conditions. We will prove their necessity ... More
Reductions of modular Galois representations of Slope (2,3)Jan 26 2018We compute the semisimplifications of the mod-$p$ reductions of $2$-dimensional crystalline representations of $\Gal(\Qb_p/\Q_p)$ of slope $(2,3)$ and arbitrary weight, building on work of Bhattacharya-Ghate
On energy-critical half-wave maps into $\mathbb{S}^2$Feb 20 2017Mar 24 2017We consider the energy-critical half-wave maps equation $$\partial_t \mathbf{u} + \mathbf{u} \wedge |\nabla| \mathbf{u} = 0$$ for $\mathbf{u} : [0,T) \times \mathbb{R} \to \mathbb{S}^2$. We give a complete classification of all traveling solitary waves ... More
High Resolution Radio Astronomy Using Very Long Baseline InterferometryMar 20 2008Mar 22 2008Very Long Baseline Interferometry, or VLBI, is the observing technique yielding the highest-resolution images today. Whilst a traditionally large fraction of VLBI observations is concentrating on Active Galactic Nuclei, the number of observations concerned ... More
A representation of a compressed de Bruijn graph for pan-genome analysis that enables searchFeb 10 2016Recently, Marcus et al. (Bioinformatics 2014) proposed to use a compressed de Bruijn graph to describe the relationship between the genomes of many individuals/strains of the same or closely related species. They devised an $O(n \log g)$ time algorithm ... More
The affine transform formula for affine jump-diffusions with a general closed convex state spaceMay 06 2010Oct 12 2010We establish existence of exponential moments and the validity of the affine transform formula for affine jump-diffusions with a general closed convex state space. This extends known results for affine jump-diffusions with a canonical state space. The ... More
Small time Edgeworth-type expansions for weakly convergent nonhomogeneous Markov chainsMay 22 2007We consider triangular arrays of Markov chains that converge weakly to a diffusion process. Second order Edgeworth type expansions for transition densities are proved. The paper differs from recent results in two respects. We allow nonhomogeneous diffusion ... More
Proper time in atom interferometers: Diffractive versus specular mirrorsFeb 04 2019We compare a conventional Mach-Zehnder light-pulse atom interferometer based on diffractive mirrors with one that uses specular reflection. In contrast to diffractive mirrors that generate a symmetric configuration, specular mirrors realized, for example, ... More
Sharp commutator estimates via harmonic extensionsSep 27 2016We give an alternative proof of several sharp commutator estimates involving Riesz transforms, Riesz potentials, and fractional Laplacians. Our methods only involve harmonic extensions to the upper half-space, integration by parts, and trace space characterizations. ... More
Blowup for Biharmonic NLSMar 05 2015Apr 21 2015We consider the Cauchy problem for the biharmonic (i.\,e.~fourth-order) NLS with focusing nonlinearity given by $i \partial_t u = \Delta^2 u - \mu \Delta u -|u|^{2 \sigma} u$ for $(t,x) \in [0,T) \times \mathbb{R}^d$, where $0 < \sigma <\infty$ for $d ... More
Physical results from 2+1 flavor Domain Wall QCDSep 18 2008We review recent results for the chiral behavior of meson masses and decay constants and the determination of the light quark masses by the RBC and UKQCD collaborations. We find that one-loop SU(2) chiral perturbation theory represents the behavior of ... More
Dynamical Collapse of White Dwarfs in Hartree- and Hartree-Fock TheoryAug 07 2006We study finite-time blow-up for pseudo-relativistic Hartree- and Hartree-Fock equations, which are model equations for the dynamical evolution of white dwarfs. In particular, we prove that radially symmetric initial configurations with negative energy ... More
A Lax Pair Structure for the Half-Wave Maps EquationJul 17 2017Nov 14 2017We consider the half-wave maps equation $$ \partial_t \vec{S} = \vec{S} \wedge |\nabla| \vec{S}, $$ where $\vec{S}= \vec{S}(t,x)$ takes values on the two-dimensional unit sphere $\mathbb{S}^2$ and $x \in \mathbb{R}$ (real line case) or $x \in \mathbb{T}$ ... More
Sharp commutator estimates via harmonic extensionsSep 27 2016Dec 07 2016We give an alternative proof of several sharp commutator estimates involving Riesz transforms, Riesz potentials, and fractional Laplacians. Our methods only involve harmonic extensions to the upper half-space, integration by parts, and trace space characterizations. ... More
A sharp rearrangement principle in Fourier space and symmetry results for PDEs with arbitrary orderMay 16 2018Mar 05 2019We prove sharp inequalities for the symmetric-decreasing rearrangement in Fourier space of functions in $\mathbb{R}^d$. Our main result can be applied to a general class of (pseudo-)differential operators in $\mathbb{R}^d$ of arbitrary order with radial ... More
Minimizers for the Hartree-Fock-Bogoliubov Theory of Neutron Stars and White DwarfsSep 15 2008Mar 23 2010We prove the existence of minimizers for Hartree-Fock-Bogoliubov (HFB) energy functionals with attractive two-body interactions given by Newtonian gravity. This class of HFB functionals serves as model problem for self-gravitating relativistic Fermi systems, ... More
The functional of super Riemann surfaces -- a "semi-classical" surveyNov 16 2015This article provides a brief discussion of the functional of super Riemann surfaces from the point of view of classical (i.e. not "super-) differential geometry. The discussion is based on symmetry considerations and aims to clarify the "borderline" ... More
A Testing Scheme for Self-Adaptive Software Systems with Architectural Runtime ModelsMay 17 2018Self-adaptive software systems (SASS) are equipped with feedback loops to adapt autonomously to changes of the software or environment. In established fields, such as embedded software, sophisticated approaches have been developed to systematically study ... More
Cooling dynamics of a dilute gas of inelastic rods: a many particle simulationJun 30 1997Oct 23 1997We present results of simulations for a dilute gas of inelastically colliding particles. Collisions are modelled as a stochastic process, which on average decreases the translational energy (cooling), but allows for fluctuations in the transfer of energy ... More
Uniqueness of ground states for the L^2-critical boson star equationMay 19 2009We establish uniqueness of ground states $u(x) \geq 0$ for the $L^2$-critical boson star equation $\sqrt{-\Delta} u - (|x|^{-1} \ast |u|^2) u = -u$ in $\R^3$. The proof blends variational arguments with the harmonic extension to the halfspace $\R^4_+$. ... More
Uniqueness and Nondegeneracy of Ground States for $(-Δ)^s Q + Q - Q^{α+1} = 0$ in $\mathbb{R}$Sep 21 2010Mar 23 2015We prove uniqueness of ground state solutions $Q = Q(|x|) \geq 0$ for the nonlinear equation $(-\Delta)^s Q + Q - Q^{\alpha+1}= 0$ in $\mathbb{R}$, where $0 < s < 1$ and $0 < \alpha < \frac{4s}{1-2s}$ for $s < 1/2$ and $0 < \alpha < \infty$ for $s \geq ... More
Multi-Step stochastic correction in dynamical fermion updating algorithmsSep 25 2006Oct 20 2006The advantages of using Multi-Step corrections for simulations of lattice gauge theories with dynamical fermions will be discussed. This technique is suited for algorithms based on the Multi-Boson representation of the dynamical fermions as well as for ... More
Rate-optimal estimation for a general class of nonparametric regression models with unknown link functionsMar 20 2008This paper discusses a nonparametric regression model that naturally generalizes neural network models. The model is based on a finite number of one-dimensional transformations and can be estimated with a one-dimensional rate of convergence. The model ... More
Bandwidth selection for smooth backfitting in additive modelsJul 21 2005The smooth backfitting introduced by Mammen, Linton and Nielsen [Ann. Statist. 27 (1999) 1443-1490] is a promising technique to fit additive regression models and is known to achieve the oracle efficiency bound. In this paper, we propose and discuss three ... More
A simple smooth backfitting method for additive modelsFeb 22 2007In this paper a new smooth backfitting estimate is proposed for additive regression models. The estimate has the simple structure of Nadaraya--Watson smooth backfitting but at the same time achieves the oracle property of local linear smooth backfitting. ... More
Motion planning algorithms for Configuration SpacesApr 25 2014Aug 15 2014We provide explicit motion planners for Euiclidean configuration spaces. This allows us to recover some known values of the topological complexity and the Lusternik-Schinirelman category of these spaces.
Comparison of Heparin Red, Azure A and Toluidine Blue assays for direct quantification of heparins in human plasmaDec 09 2017Heparins are are sulfated polysaccharides that have tremendous clinical importance as anticoagulant drugs. Monitoring of heparin blood levels can improve patient safety. In clinical practice, heparins are monitored indirectly by their inhibtory effect ... More
Leptonic decay-constant ratio $f_K/f_π$ from clover-improved $N_f=2+1$ QCDOct 04 2016The leptonic decay-constant ratio $f_K/f_\pi$ is calculated from lattice-QCD simulations using $N_f=2+1$ dynamical fermion flavors in the clover-improved formulation and 2-HEX smearing. The simulations were performed for a range of mass-degenerate light ... More
Nonparametric Estimation of an Additive Model With a Link FunctionAug 30 2005This paper describes an estimator of the additive components of a nonparametric additive model with a known link function. When the additive components are twice continuously differentiable, the estimator is asymptotically normally distributed with a ... More
A Unifying Framework for the Identification of Motor PrimitivesMar 22 2016A long-standing hypothesis in neuroscience is that the central nervous system accomplishes complex motor behaviors through the combination of a small number of motor primitives. Many studies in the last couples of decades have identified motor primitives ... More
Quantification of sulfated polysaccharides in mouse and rat plasma by the Heparin Red mix-and-read fluorescence assayDec 15 2017Sulfated polysaccharides constitute a large and complex group of macromolecules which possess a wide range of important biological properties. Many of them hold promise as new therapeutics, but determination of their blood levels during pharmacokinetic ... More
Should I Bug You? Identifying Domain Experts in Software Projects Using Code Complexity MetricsSep 20 2018In any sufficiently complex software system there are experts, having a deeper understanding of parts of the system than others. However, it is not always clear who these experts are and which particular parts of the system they can provide help with. ... More
Integral representations for Horn's $H_2$ function and Olsson's $F_P$ functionJul 25 2016Sep 29 2016We derive some Euler type double integral representations for hypergeometric functions in two variables. In the first part of this paper we deal with Horn's $H_2$ function, in the second part with Olsson's $F_P$ function. Our double integral representing ... More
Integral representations for Horn's $H_2$ function and Olsson's $F_P$ functionJul 25 2016Apr 26 2018We derive some Euler type double integral representations for hypergeometric functions in two variables. In the first part of this paper we deal with Horn's $H_2$ function, in the second part with Olsson's $F_P$ function. Our double integral representing ... More
Differentiation by integration using orthogonal polynomials, a surveyFeb 25 2011Jan 23 2012This survey paper discusses the history of approximation formulas for n-th order derivatives by integrals involving orthogonal polynomials. There is a large but rather disconnected corpus of literature on such formulas. We give some results in greater ... More
Modal Specifications for Probabilistic Timed SystemsJun 12 2013Modal automata are a classic formal model for component-based systems that comes equipped with a rich specification theory supporting abstraction, refinement and compositional reasoning. In recent years, quantitative variants of modal automata were introduced ... More
On ground states for the L^2-critical boson star equationOct 14 2009Oct 26 2010We consider ground state solutions $u \geq 0$ for the $L^2$-critical boson star equation $$ \sqrt{-\Delta} \, u - \big (|x|^{-1} \ast |u|^2 \big) u = -u \quad {in $\R^3$}. $$ We prove analyticity and radial symmetry of $u$. In a previous version of this ... More
Generalizations of an integral for Legendre polynomials by Persson and StrangMay 13 2010Dec 08 2011Persson and Strang (2003) evaluated the integral over [-1,1] of a squared odd degree Legendre polynomial divided by x^2 as being equal to 2. We consider a similar integral for orthogonal polynomials with respect to a general even orthogonality measure, ... More
Evidence of antiblockade in an ultracold Rydberg gasSep 04 2009We present the experimental observation of the antiblockade in an ultracold Rydberg gas recently proposed by Ates et al. [Phys. Rev. Lett. 98, 023002 (2007)]. Our approach allows the control of the pair distribution in the gas and is based on a strong ... More
Infrared-Faint Radio Sources: A Cosmological View - AGN Number Counts, the Cosmic X-Ray Background and SMBH FormationApr 04 2011Context. Infrared Faint Radio Sources (IFRS) are extragalactic emitters clearly detected at radio wavelengths but barely detected or undetected at optical and infrared wavelengths, with 5 sigma sensitivities as low as 1 uJy. Aims. Recent SED-modelling ... More
On Stability of Pseudo-Conformal Blowup for L^2-critical Hartree NLSAug 18 2008We consider $L^2$-critical focusing nonlinear Schroedinger equations with Hartree type nonlinearity $$i \pr_t u = -\DD u - \big (\Phi \ast |u|^2 \big) u \quad {in $\RR^4$},$$ where $\Phi(x)$ is a perturbation of the convolution kernel $|x|^{-2}$. Despite ... More
Optimal estimation of sparse high-dimensional additive modelsMar 24 2016In this paper we discuss the estimation of a nonparametric component $f_1$ of a nonparametric additive model $Y=f_1(X_1) + ...+ f_q(X_q) + \varepsilon$. We allow the number $q$ of additive components to grow to infinity and we make sparsity assumptions ... More
Expansion for moments of regression quantiles with application to nonparametric testingJun 26 2013Dec 02 2015We discuss nonparametric tests for parametric specifications of regression quantiles. The test is based on the comparison of parametric and nonparametric fits of these quantiles. The nonparametric fit is a Nadaraya-Watson quantile smoothing estimator. ... More
Conflation: a new type of accelerated expansionJul 16 2015Sep 01 2016In the framework of scalar-tensor theories of gravity, we construct a new kind of cosmological model that conflates inflation and ekpyrosis. During a phase of conflation, the universe undergoes accelerated expansion, but with crucial differences compared ... More
Nonparametric inference for continuous-time event counting and link-based dynamic network modelsMay 10 2017Aug 24 2018A flexible approach for modeling both dynamic event counting and dynamic link-based networks based on counting processes is proposed, and estimation in these models is studied. We consider nonparametric likelihood based estimation of parameter functions ... More
Statistical convergence of Markov experiments to diffusion limitsJan 30 2012Mar 14 2014Assume that one observes the $k$th, $2k$th$,\ldots,nk$th value of a Markov chain $X_{1,h},\ldots,X_{nk,h}$. That means we assume that a high frequency Markov chain runs in the background on a very fine time grid but that it is only observed on a coarser ... More
Ekpyrotic Perturbations With Small Non-Gaussian CorrectionsOct 30 2013Nov 06 2013The entropic mechanism for producing nearly scale-invariant density perturbations in a contracting ekpyrotic universe relies on having an unstable scalar potential. Here we develop a variant of this mechanism (recently proposed by Qiu, Gao and Saridakis, ... More
The evolving starburst-AGN connection: Implications for SKA and its pathfindersApr 24 2008How well is the modern-day starburst-AGN connection mirrored in the early Universe? This is starting to be answered by deep wide radio surveys such as ATLAS, which are giving us a new view of high redshift galaxies. For example, we find powerful radio-loud ... More
Uniqueness of radial solutions for the fractional LaplacianFeb 11 2013Mar 23 2015We prove general uniqueness results for radial solutions of linear and nonlinear equations involving the fractional Laplacian $(-\Delta)^s$ with $s \in (0,1)$ for any space dimensions $N \geq 1$. By extending a monotonicity formula found by Cabre and ... More
Nonparametric regression with nonparametrically generated covariatesJul 24 2012We analyze the statistical properties of nonparametric regression estimators using covariates which are not directly observable, but have be estimated from data in a preliminary step. These so-called generated covariates appear in numerous applications, ... More
Semi-parametric regression: Efficiency gains from modeling the nonparametric partApr 22 2011It is widely admitted that structured nonparametric modeling that circumvents the curse of dimensionality is important in nonparametric estimation. In this paper we show that the same holds for semi-parametric estimation. We argue that estimation of the ... More
Expansion for moments of regression quantiles with application to nonparametric testingJun 26 2013Jul 14 2017We discuss nonparametric tests for parametric specifications of regression quantiles. The test is based on the comparison of parametric and nonparametric fits of these quantiles. The nonparametric fit is a Nadaraya-Watson quantile smoothing estimator. ... More
Non-parametric estimation of morphological lopsidednessJun 23 2016Asymmetries in the neutral hydrogen gas distribution and kinematics of galaxies are thought to be indicators for both gas accretion and gas removal processes. These are of fundamental importance for galaxy formation and evolution. Upcoming large blind ... More
Direct quantification of brown algae-derived fucoidans in human plasma by a fluorescent probe assayJul 30 2016Fucoidan is a generic term for a class of fucose rich, structurally diverse sulfated polysaccharides that are found in brown algae and other marine organisms. Depending on the species from which the fucoidan is extracted, a wide variety of biological ... More
On the continuum limit for discrete NLS with long-range lattice interactionsAug 31 2011Jul 24 2012We consider a general class of discrete nonlinear Schroedinger equations (DNLS) on the lattice $h \mathbb{Z}$ with mesh size $h>0$. In the continuum limit when $h \to 0$, we prove that the limiting dynamics are given by a nonlinear Schroedinger equation ... More
Chiral perturbation theory for partially quenched twisted mass lattice QCDFeb 04 2004Oct 08 2004Partially quenched Quantum Chromodynamics with Wilson fermions on a lattice is considered in the framework of chiral perturbation theory. Two degenerate quark flavours are associated with a chirally twisted mass term. The pion masses and decay constants ... More
Multilingual and Unsupervised Subword Modeling for Zero-Resource LanguagesNov 09 2018Unsupervised subword modeling aims to learn low-level representations of speech audio in "zero-resource" settings: that is, without using transcriptions or other resources from the target language (such as text corpora or pronunciation dictionaries). ... More
Multivariate Feller conditions in term structure models: Why do(n't) we care?Apr 07 2008In this paper, the relevance of the Feller conditions in discrete time macro-finance term structure models is investigated. The Feller conditions are usually imposed on a continuous time multivariate square root process to ensure that the roots have nonnegative ... More
On symmetry and uniqueness of ground states for linear and nonlinear elliptic PDEsAug 19 2019We study ground state solutions for linear and nonlinear elliptic PDEs in $\mathbb{R}^n$ with (pseudo-)differential operators of arbitrary order. We prove a general symmetry result in the nonlinear case as well as a uniqueness result for ground states ... More
Blowup for fractional NLSSep 29 2015Oct 12 2015We consider fractional NLS with focusing power-type nonlinearity $$i \partial_t u = (-\Delta)^s u - |u|^{2 \sigma} u, \quad (t,x) \in \mathbb{R} \times \mathbb{R}^N,$$ where $1/2< s < 1$ and $0 < \sigma < \infty$ for $s \geq N/2$ and $0 < \sigma \leq ... More
Commuting elements, simplicial spaces, and filtrations of classifying spacesDec 31 2008Sep 12 2011Using spaces of homomorphisms and the descending central series of the free groups, simplicial spaces are constructed for each integer q>1 and every topological group G, with realizations B(q,G) that filter the classifying space BG. In particular for ... More
Super Riemann surfaces, metrics, and gravitinosDec 16 2014Aug 23 2015The underlying even manifold of a super Riemann surface is a Riemann surface with a spinor valued differential form called gravitino. Consequently infinitesimal deformations of super Riemann surfaces are certain infinitesimal deformations of the Riemann ... More
Nondispersive solutions to the L2-critical half-wave equationMar 12 2012We consider the focusing $L^2$-critical half-wave equation in one space dimension $$ i \partial_t u = D u - |u|^2 u, $$ where $D$ denotes the first-order fractional derivative. Standard arguments show that there is a critical threshold $M_* > 0$ such ... More
Numerical solution of the 2+1 Teukolsky equation on a hyperboloidal and horizon penetrating foliation of Kerr and application to late-time decaysJan 08 2013In this work we present a formulation of the Teukolsky equation for generic spin perturbations on the hyperboloidal and horizon penetrating foliation of Kerr recently proposed by Racz and Toth. An additional, spin-dependent rescaling of the field variable ... More
Smooth backfitting in generalized additive modelsMar 13 2008Generalized additive models have been popular among statisticians and data analysts in multivariate nonparametric regression with non-Gaussian responses including binary and count data. In this paper, a new likelihood approach for fitting generalized ... More
Ill-posed Estimation in High-Dimensional Models with Instrumental VariablesJun 02 2018This paper is concerned with inference about low-dimensional components of a high-dimensional parameter vector beta_0 which is identified through in- strumental variables. We allow for eigenvalues of the expected outer product of included and excluded ... More
High-resolution spectroscopy of triplet states of Rb2 by femtosecond pump-probe photoionization of doped helium nanodropletsJul 16 2009The dynamics of vibrational wave packets in triplet states of rubidium dimers (Rb2) formed on helium nanodroplets are studied using femtosecond pump-probe photoionization spectroscopy. Due to fast desorption of the excited Rb2 molecules off the droplets ... More