Results for "Ole Peters"

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Optimal leverage from non-ergodicityFeb 17 2009Aug 09 2010In modern portfolio theory, the balancing of expected returns on investments against uncertainties in those returns is aided by the use of utility functions. The Kelly criterion offers another approach, rooted in information theory, that always implies ... More
Menger 1934 revisitedOct 07 2011Karl Menger's 1934 paper on the St. Petersburg paradox contains mathematical errors that invalidate his conclusion that unbounded utility functions, specifically Bernoulli's logarithmic utility, fail to resolve modified versions of the St. Petersburg ... More
The sum of log-normal variates in geometric Brownian motionFeb 08 2018Geometric Brownian motion (GBM) is a key model for representing self-reproducing entities. Self-reproduction may be considered the definition of life [5], and the dynamics it induces are of interest to those concerned with living systems from biology ... More
Ergodicity breaking in geometric Brownian motionSep 20 2012Mar 14 2013Geometric Brownian motion (GBM) is a model for systems as varied as financial instruments and populations. The statistical properties of GBM are complicated by non-ergodicity, which can lead to ensemble averages exhibiting exponential growth while any ... More
Stochastic Market EfficiencyJan 24 2011It is argued that the simple trading strategy of leveraging or deleveraging an investment in the market portfolio cannot outperform the market. Such stochastic market efficiency places strong constraints on the possible stochastic properties of the market. ... More
Escape angles in bulk chi(2) soliton interactionsOct 16 2000Nov 06 2001We develop a theory for non-planar interaction between two identical type I spatial solitons propagating at opposite, but arbitrary transverse angles in quadratic nonlinear (or so-called chi(2)) bulk media. We predict quantitatively the outwards escape ... More
The time resolution of the St. Petersburg paradoxNov 19 2010Mar 23 2011A resolution of the St. Petersburg paradox is presented. In contrast to the standard resolution, utility is not required. Instead, the time-average performance of the lottery is computed. The final result can be phrased mathematically identically to Daniel ... More
Quasiperiodic Envelope SolitonsJul 26 1999We analyse nonlinear wave propagation and cascaded self-focusing due to second-harmonic generation in Fibbonacci optical superlattices and introduce a novel concept of nonlinear physics, the quasiperiodic soliton, which describes spatially localized self-trapping ... More
Tuning- and order parameter in the SOC ensembleDec 11 2009The one-dimensional Oslo model is studied under self-organized criticality (SOC) conditions and under absorbing state (AS) conditions. While the activity signals the phase transition under AS conditions by a sudden increase, this is not the case under ... More
The evolutionary advantage of cooperationJun 10 2015The present study asks how cooperation and consequently structure can emerge in many different evolutionary contexts. Cooperation, here, is a persistent behavioural pattern of individual entities pooling and sharing resources. Examples are: individual ... More
Self-organized Criticality and Absorbing States: Lessons from the Ising ModelNov 29 2004We investigate a suggested path to self-organized criticality. Originally, this path was devised to "generate criticality" in systems displaying an absorbing-state phase transition, but closer examination of the mechanism reveals that it can be used for ... More
Reply to "Comment on `Self-organized Criticality and Absorbing States: Lessons from the Ising Model'"Apr 04 2008In [Braz. J. Phys. 30, 27 (2000)] Dickman et al. suggested that self-organized criticality can be produced by coupling the activity of an absorbing state model to a dissipation mechanism and adding an external drive. We analyzed the proposed mechanism ... More
Rational insurance with linear utility and perfect informationJul 16 2015We present a mathematical solution to the insurance puzzle. Our solution only uses time-average growth rates and makes no reference to risk preferences. The insurance puzzle is this: according to the expectation value of wealth, buying insurance is only ... More
Nonlinearity and disorder: Classification and stability of nonlinear impurity modesSep 03 2000We study the effects produced by competition of two physical mechanisms of energy localization in inhomogeneous nonlinear systems. As an example, we analyze spatially localized modes supported by a nonlinear impurity in the generalized nonlinear Schr\"odinger ... More
Galaxy cluster strong lensing: image deflections from density fluctuations along the line of sightOct 24 2011Dec 08 2011A standard method to study the mass distribution in galaxy clusters is through strong lensing of background galaxies in which the positions of multiple images of the same source constrain the surface mass distribution of the cluster. However, current ... More
Defect states and spin-orbital physics in doped vanadates Y1-xCaxVO3Jan 17 2013We present a model for typical charged defects in weakly doped Y1-xCaxVO3 perovskites and study how they influence the magnetic and orbital order. Starting from a multiband Hubbard model, we show that the charge carriers introduced by doping are bound ... More
Frames containing a Riesz basis and preservation of this property under perturbationSep 22 1995Aldroubi has shown how one can construct any frame $\gtu$ starting with one frame $\ftu $,using a bounded operator $U$ on $l^2(N)$. We study the overcompleteness of the frames in terms of properties of $U$. We also discuss perturbation of frames in the ... More
Classifying Tight Weyl-Heisenberg FramesDec 30 1998A Weyl-Heisenberg frame for L^2(R) is a frame consisting of translates and modulates of a fixed function. In this paper we give necessary and sufficient conditions for this family to form a tight WH-frame. This allows us to write down explicitly all functions ... More
Weyl-Heisenberg frames for subspaces of L^2(R)Nov 24 1998We give sufficient conditions for translates and modulates of a function g in L^2(R) to be a frame for its closed linear span. Even in the case where this family spans all of L^2(R), wou conditions are significantly weaker than the previous known conditions. ... More
Hilbert space frames containing a Riesz basis and Banach spaces which have no subspace isomorphic to $c_0$Sep 22 1995We prove that a Hilbert space frame $\fti$ contains a Riesz basis if every subfamily $\ftj , J \subseteq I ,$ is a frame for its closed span. Secondly we give a new characterization of Banach spaces which do not have any subspace isomorphic to $c_0$. ... More
Evaluating gambles using dynamicsMay 03 2014Jun 05 2015Gambles are random variables that model possible changes in monetary wealth. Classic decision theory transforms money into utility through a utility function and defines the value of a gamble as the expectation value of utility changes. Utility functions ... More
Predictive Active Set Selection Methods for Gaussian ProcessesFeb 22 2011Jun 23 2011We propose an active set selection framework for Gaussian process classification for cases when the dataset is large enough to render its inference prohibitive. Our scheme consists of a two step alternating procedure of active set update rules and hyperparameter ... More
Highly sensitive refractometer with photonic crystal fiber long-period gratingNov 19 2007We present highly sensitive refractometers based on a long-period grating in a large mode area PCF. The maximum sensitivity is 1500 nm/RIU at a refractive index of 1.33, the highest reported for any fiber grating. The minimal detectable index change is ... More
Remarks on the paper "Skew Pieri rules for Hall-Littlewood functions" by Konvalinka and LauveAug 20 2012In a recent paper Konvalinka and Lauve proved several skew Pieri rules for Hall-Littlewood polynomials. In this note we show that q-analogues of these rules are encoded in a q-binomial theorem for Macdonald polynomials due to Lascoux and the author.
Spin-orbital entanglement near quantum phase transitionsJun 17 2007Spin-orbital entanglement in the ground state of a one-dimensional SU(2)$\otimes$SU(2) spin-orbital model is analyzed using exact diagonalization of finite chains. For $S=1/2$ spins and $T=1/2$ pseudospins one finds that the quantum entanglement is similar ... More
Theory of optical spectral weights in Mott insulators with orbital degrees of freedomMar 18 2004Jun 09 2004Introducing partial sum rules for the optical multiplet transitions, we outline a unified approach to magnetic and optical properties of strongly correlated transition metal oxides. On the example of LaVO$_3$ we demonstrate how the temperature and polarization ... More
Compass-Heisenberg Model on the Square Lattice : Spin Order and ExcitationsMay 10 2010Sep 13 2010We explore the physics of the anisotropic compass model under the influence of perturbing Heisenberg interactions and present the phase diagram with multiple quantum phase transitions. The macroscopic ground state degeneracy of the compass model is lifted ... More
Orbitally induced string formation in the spin-orbital polaronsMay 14 2009We study the spectral function of a single hole doped into the (a,b) plane of the Mott insulator LaVO$_3$, with antiferromagnetic (AF) spin order of S=1 spins accompanied by alternating orbital (AO) order of active $\{d_{yz},d_{zx}\}$ orbitals. Starting ... More
The importance of the Selberg integralOct 22 2007It has been remarked that a fair measure of the impact of Atle Selberg's work is the number of mathematical terms which bear his name. One of these is the Selberg integral, an n-dimensional generalization of the Euler beta integral. We trace its sudden ... More
Dimerization versus Orbital Moment Ordering in the Mott insulator YVO$_3$Jun 25 2003We use exact diagonalization combined with mean-field theory to investigate the phase diagram of the spin-orbital model for cubic vanadates. The spin-orbit coupling competes with Hund's exchange and triggers a novel phase, with the ordering of $t_{2g}$ ... More
Photoexcitations in a 1D manganite model: From quasiclassical light absorption to quasiparticle relaxationsOct 23 2016We investigate the behavior of 1D correlated systems following a photo-excitation by combining ab-initio methods, time-dependent matrix product state (MPS) approaches, analytical insights from quantum Boltzmann equations, and molecular dynamics (MD) simulations ... More
Fractional and Complex Pseudo-Splines and the Construction of Parseval FramesFeb 27 2016Apr 16 2016Pseudo-splines of integer order $(m,\ell)$ were introduced by Daubechies, Han, Ron, and Shen as a family which allows interpolation between the classical B-splines and the Daubechies' scaling functions. The purpose of this paper is to generalize the pseudo-splines ... More
Directional time frequency analysis via continuous frameFeb 15 2014Grafakos and Sansing \cite{GS} have shown how to obtain directionally sensitive time-frequency decompositions in $L^2(\mr^n)$ based on Gabor systems in $\ltr;$ the key tool is the "ridge idea," which lifts a function of one variable to a function of several ... More
Far from equilibrium: Wealth reallocation in the United StatesMay 18 2016Studies of wealth inequality often assume that an observed wealth distribution reflects a system in equilibrium. This constraint is rarely tested empirically. We introduce a simple model that allows equilibrium but does not assume it. To geometric Brownian ... More
One-dimensional orbital fluctuations and the exotic magnetic properties of YVO$_3$Jun 17 2007Starting from the Mott insulator picture for cubic vanadates, we derive and investigate the model of superexchange interactions between V$^{3+}$ ions, with nearly degenerate $t_{2g}$ orbitals occupied by two electrons each. The superexchange interactions ... More
Multi-component optical solitary wavesJan 21 2000Apr 12 2000We discuss several novel types of multi-component (temporal and spatial) envelope solitary waves that appear in fiber and waveguide nonlinear optics. In particular, we describe multi-channel solitary waves in bit-parallel-wavelength fiber transmission ... More
Deviations of the exciton level spectrum in cuprous oxide from the hydrogen seriesNov 17 2015Feb 22 2016Recent high-resolution absorption spectroscopy on excited excitons in cuprous oxide [Nature (London) 514, 343 (2014)] has revealed significant deviations of their spectrum from that of the ideal hydrogen-like series. Here we show that the complex band ... More
Solitons in coupled atomic-molecular Bose-Einstein condensates in a trapMay 16 2006Mar 26 2008We consider coupled atomic-molecular Bose-Einstein condensate system in a quasi-one-dimensional trap. In the vicinity of a Feshbach resonance the system can reveal soliton-like behavior. We analyze bright soliton solutions for the system in the trap and ... More
Low-bandwidth and non-compute intensive remote identification of microbes from raw sequencing readsJun 06 2013Jun 21 2013Cheap high-throughput DNA sequencing may soon become routine not only for human genomes but also for practically anything requiring the identification of living organisms from their DNA: tracking of infectious agents, control of food products, bioreactors, ... More
Origin of the Orbital Ordering in LaMnO$_3$Mar 12 2003We use the temperature of the structural phase transition to determine the Jahn-Teller (JT) coupling constant in the model derived for LaMnO$_3$ which includes both the superexchange between S=2 spins and the JT effect. We also investigate the dependence ... More
CPDY: Extending the Dolev-Yao Attacker with Physical-Layer InteractionsJul 09 2016Jul 20 2016We propose extensions to the Dolev-Yao attacker model to make it suitable for arguments about security of Cyber-Physical Systems. The Dolev-Yao attacker model uses a set of rules to define potential actions by an attacker with respect to messages (i.e. ... More
Conjugate Bailey pairsJun 14 1999In this paper it is shown that the one-dimensional configuration sums of the solvable lattice models of Andrews, Baxter and Forrester and the string functions associated with admissible representations of the affine Lie algebra A$_1^{(1)}$ as introduced ... More
Protein Secondary Structure Prediction with Long Short Term Memory NetworksDec 25 2014Jan 04 2015Prediction of protein secondary structure from the amino acid sequence is a classical bioinformatics problem. Common methods use feed forward neural networks or SVMs combined with a sliding window, as these models does not naturally handle sequential ... More
Jahn-Teller Effect and Superexchange in Half-Doped ManganitesMar 12 2003We investigate the stability of the charge exchange (CE) phase within a microscopic model which describes a single plane as in La$_{0.5}$Sr$_{1.5}$MnO$_4$. The model includes Coulomb interactions (on-site and intersite), the Jahn-Teller term and the superexchange ... More
Inverse scattering in multimode structuresJul 22 2007We consider the inverse scattering problem associated with any number of interacting modes in one-dimensional structures. The coupling between the modes is contradirectional in addition to codirectional, and may be distributed continuously or in discrete ... More
Dedekind's eta-function and Rogers-Ramanujan identitiesJan 11 2010Jan 22 2010We prove a q-series identity that generalises Macdonald's A_{2n}^{(2)} eta-function identity and the Rogers-Ramanujan identities. We conjecture our result to generalise even further to also include the Andrews-Gordon identities.
Photoemission spectra of LaMnO3 controlled by orbital excitationsApr 25 2001We investigate the spectral function of a hole moving in the orbital-ordered ferromagnetic planes of LaMnO$_3$, and show that it depends critically on the type of orbital ordering. While the hole does not couple to the spin excitations, it interacts strongly ... More
Evolution of Spin-Orbital-Lattice Coupling in the $R$VO$_3$ PerovskitesMay 11 2008We introduce a microscopic model which unravels the physical mechanisms responsible for the observed phase diagram of the $R$VO$_3$ perovskites. It reveals a nontrivial interplay between superexchange, the orbital-lattice coupling due to the GdFeO$_3$-like ... More
Weyl-Heisenberg Frames, Translation Invariant Systems and the Walnut RepresentationOct 29 1999We present a comprehensive analysis of the convergence properties of the frame operators of Weyl-Heisenberg systems and shift-invariant systems, and relate these to the convergence of the Walnut representation. We give a deep analysis of necessary conditions ... More
Reiter's polaron wavefunction applied to a $t_{2g}$ orbital t-J modelNov 24 2008Using the self-consistent Born approximation we calculate Reiter's wavefunction for a single hole introduced into the undoped and orbitally ordered ground state of the t-J model with $t_{2g}$ orbital degrees of freedom. While the number of excitations ... More
Spectral properties of orbital polarons in Mott insulatorsNov 23 2008We address the spectral properties of Mott insulators with orbital degrees of freedom, and investigate cases where the orbital symmetry leads to Ising-like superexchange in the orbital sector. The paradigm of a hole propagating by its coupling to quantum ... More
Avalanche Behavior in an Absorbing State Oslo ModelMay 19 2004Jul 15 2004Self-organized criticality can be translated into the language of absorbing state phase transitions. Most models for which this analogy is established have been investigated for their absorbing state characteristics. In this article, we transform the ... More
Frames of translatesNov 24 1998We give necessary and sufficient conditions for a subfamily of regularly spaced translates of a function to form a frame (resp. a Riesz basis) for its span. One consequence is that ifthetranslates are taken only from a subset of the natural numbers, then ... More
Perturbations of Weyl-Heisenberg framesAug 22 2000We develop a usable perturbation theory for Weyl-Heisenberg frames. In particular, we prove that if $(E_{mb}T_{na}g)_{m,n\inmathbb Z}$ is a WH-frame and $h$ is a function which is close to $g$ in the Wiener Amalgam space norm, then $(E_{mb}T_{na}h)_{m,n\in ... More
Fingerprints of spin-orbital physics in cubic Mott insulators: Magnetic exchange interactions and optical spectral weightsJan 17 2006The temperature dependence and anisotropy of optical spectral weights associated with different multiplet transitions is determined by the spin and orbital correlations. To provide a systematic basis to exploit this close relationship between magnetism ... More
Spin-Orbital Entanglement and Violation of the Goodenough-Kanamori RulesApr 18 2006We point out that large composite spin-orbital fluctuations in Mott insulators with $t_{2g}$ orbital degeneracy are a manifestation of quantum entanglement of spin and orbital variables. This results in a dynamical nature of the spin superexchange interactions, ... More
Spin-wave theory for dimerized ferromagnetic chainsJun 09 2009We describe a Peierls dimerization which occurs in ferromagnetic spin chains at finite temperature, within the modified spin-wave theory. Usual spin-wave theory is modified by introducing a Lagrange multiplier which enforces a nonmagnetic state at finite ... More
Hidden Quasiparticles and Incoherent Photoemission Spectra in Na2IrO3Feb 01 2013Aug 02 2013We study two Heisenberg-Kitaev t-J-like models on a honeycomb lattice, focusing on the zigzag magnetic phase of Na$_2$IrO$_3$, and investigate hole motion by exact diagonalization and variational methods. The spectral functions are quite distinct from ... More
Hole propagation in the Kitaev-Heisenberg model: From quasiparticles in quantum Neel states to non-Fermi liquid in the Kitaev phaseAug 15 2013Jul 11 2014We explore with exact diagonalization the propagation of a single hole in four magnetic phases of the t-J-like Kitaev-Heisenberg model on a honeycomb lattice: the Neel antiferromagnetic, stripe, zigzag and Kitaev spin-liquid phase. We find coherent propagation ... More
An Adaptive Resample-Move Algorithm for Estimating Normalizing ConstantsApr 07 2016Aug 15 2016The estimation of normalizing constants is a fundamental step in probabilistic model comparison. Sequential Monte Carlo methods may be used for this task and have the advantage of being inherently parallelizable. However, the standard choice of using ... More
Interplay of orbitally polarized and magnetically ordered phases in doped transition metal oxidesFeb 06 2005We investigate the magnetic instabilities of the two-dimensional model of interacting e_g electrons for hole doping away from two electrons per site in the mean-field approximation. In particular, we address the occurrence of orbitally polarized states ... More
A new offspring of PALPJun 22 2011We describe the C program mori.x. It is part of PALP, a package for analyzing lattice polytopes. Its main purpose is the construction and analysis of three--dimensional smooth Calabi--Yau hypersurfaces in toric varieties. The ambient toric varieties are ... More
Wigner's representation of quantum mechanics in integral form and its applicationsNov 21 2016We consider quantum phase space dynamics using the Wigner representation of quantum mechanics. We stress the usefulness of the integral form for the description of Wigner's phase space current~$\bm J$ as an alternative to the popular Moyal bracket. The ... More
Relative and center-of-mass motion in the attractive Bose-Hubbard modelFeb 16 2012Mar 22 2012We present first-principle numerical calculations for few particle solutions of the attractive Bose-Hubbard model with periodic boundary conditions. We show that the low-energy many-body states found by numerical diagonalization can be written as translational ... More
Bubble generation in a twisted and bent DNA-like modelAug 31 2004The DNA molecule is modeled by a parabola embedded chain with long-range interactions between twisted base pair dipoles. A mechanism for bubble generation is presented and investigated in two different configurations. Using random normally distributed ... More
Experimental observation of plasmons in a graphene monolayer resting on a two-dimensional subwavelength silicon gratingJan 15 2013Mar 22 2013We experimentally demonstrate graphene-plasmon polariton excitation in a continuous graphene monolayer resting on a two-dimensional subwavelength silicon grating. The subwavelength silicon grating is fabricated by a nanosphere lithography technique with ... More
The MUSE Data Reduction Pipeline: Status after Preliminary Acceptance EuropeJun 30 2015MUSE, a giant integral field spectrograph, is about to become the newest facility instrument at the VLT. It will see first light in February 2014. Here, we summarize the properties of the instrument as built and outline functionality of the data reduction ... More
Wind and Wave Extremes over the World Oceans from Very Large EnsemblesJul 21 2014Global return values of marine wind speed and significant wave height are estimated from very large aggregates of archived ensemble forecasts at +240-h lead time. Long lead time ensures that the forecasts represent independent draws from the model climate. ... More
Orbital dynamics in ferromagnetic transition metal oxidesDec 08 1998We consider a model of strongly correlated $e_g$ electrons interacting by superexchange orbital interactions in the ferromagnetic phase of LaMnO$_3$. It is found that the classical orbital order with alternating occupied $e_g$ orbitals has a full rotational ... More
On Gabor frames generated by sign-changing windows and B-splinesMar 07 2015For a class of compactly supported windows we characterize the frame property for a Gabor system $\mts,$ for translation parameters $a$ belonging to a certain range depending on the support size. We show that the obstructions to the frame property are ... More
On extensions of wavelet systems to dual pairs of framesJan 05 2014It is an open problem whether any pair of Bessel sequences with wavelet structure can be extended to a pair of dual frames by adding a pair of singly generated wavelet systems. We consider the particular case where the given wavelet systems are generated ... More
Free Field Representations of Extended Superconformal AlgebrasJul 03 1992We study the classical and quantum $G$ extended superconformal algebras from the hamiltonian reduction of affine Lie superalgebras, with even subalgebras $G\oplus sl(2)$. At the classical level we obtain generic formulas for the Poisson bracket structure ... More
Generic features of modulational instability in nonlocal Kerr mediaMay 22 2001The modulational instability (MI) of plane waves in nonlocal Kerr media is studied for a general, localized, response function. It is shown that there always exists a finite number of well-separated MI gain bands, with each of them characterised by a ... More
End-to-End Information Extraction without Token-Level SupervisionJul 16 2017Most state-of-the-art information extraction approaches rely on token-level labels to find the areas of interest in text. Unfortunately, these labels are time-consuming and costly to create, and consequently, not available for many real-life IE tasks. ... More
Six problems in frame theoryAug 23 2013We discuss various problems in frame theory that have been open for some years. A short discussion of frame theory is also provided, but it only contains the information that is necessary in order to understand the open problems and their role.
Convolutional LSTM Networks for Subcellular Localization of ProteinsMar 06 2015Machine learning is widely used to analyze biological sequence data. Non-sequential models such as SVMs or feed-forward neural networks are often used although they have no natural way of handling sequences of varying length. Recurrent neural networks ... More
Four-modulus "Swiss Cheese" chiral modelsNov 28 2008Jun 24 2009We study the 'Large Volume Scenario' on explicit, new, compact, four-modulus Calabi-Yau manifolds. We pay special attention to the chirality problem pointed out by Blumenhagen, Moster and Plauschinn. Namely, we thoroughly analyze the possibility of generating ... More
A Disentangled Recognition and Nonlinear Dynamics Model for Unsupervised LearningOct 16 2017Oct 30 2017This paper takes a step towards temporal reasoning in a dynamically changing video, not in the pixel space that constitutes its frames, but in a latent space that describes the non-linear dynamics of the objects in its world. We introduce the Kalman variational ... More
Debian Astro: An open computing platform for astronomyNov 22 2016Debian Astro is a Debian Pure Blend that aims to distribute the available astronomy software within the Debian operating system. Using Debian as the foundation has unique advantages for end-users and developers such as an easy installation and upgrading ... More
Spherical collapse of dark energy with an arbitrary sound speedAug 31 2010Apr 27 2012We consider a generic type of dark energy fluid, characterised by a constant equation of state parameter w and sound speed c_s, and investigate the impact of dark energy clustering on cosmic structure formation using the spherical collapse model. Along ... More
Ensemble Toolkit: Scalable and Flexible Execution of Ensembles of TasksFeb 01 2016Jun 27 2016There are many science applications that require scalable task-level parallelism and support for flexible execution and coupling of ensembles of simulations. Most high-performance system software and middleware, however, are designed to support the execution ... More
Linear space properties of $H^p$ spaces of Dirichlet seriesJan 19 2018We study $H^p$ spaces of Dirichlet series, called $\mathcal{H}^p$, for the range $0<p< \infty$. We begin by showing that two natural ways to define $\mathcal{H}^p$ coincide. We then proceed to study some linear space properties of $\mathcal{H}^p$. More ... More
Gamification of Quantum Mechanics TeachingJun 26 2015In this small scale study we demonstrate how a gamified teaching setup can be used effectively to support student learning in a quantum mechanics course. The quantum mechanics games were research games, which were played during lectures and the learning ... More
Photon Position Operator and Localization of Photons inside a WaveguideNov 30 2005In this article, we show that in the level of quantum mechanics, a photon position operator with commuting components can be obtained in a more natural way; in the level of quantum field theory, the photon position operator corresponds to the center of ... More
Determining all gas properties in galaxy clusters from the dark matter distribution aloneJun 02 2009We demonstrate that all properties of the hot X-ray emitting gas in galaxy clusters are completely determined by the underlying dark matter (DM) structure. Apart from the standard conditions of spherical symmetry and hydrostatic equilibrium for the gas, ... More
Collapse arrest and soliton stabilization in nonlocal nonlinear mediaJan 19 2002We investigate the properties of localized waves in systems governed by nonlocal nonlinear Schrodinger type equations. We prove rigorously by bounding the Hamiltonian that nonlocality of the nonlinearity prevents collapse in, e.g., Bose-Einstein condensates ... More
Measurement of the dark matter velocity anisotropy profile in galaxy clustersOct 20 2008Dark matter particles form halos that contribute the major part of the mass of galaxy clusters. The formation of these cosmological structures have been investigated both observationally and in numerical simulations, which have confirmed the existence ... More
On stochastic integration for volatility modulated Brownian-driven Volterra processes via white noise analysisMar 19 2013This paper generalizes the integration theory for volatility modulated Brownian-driven Volterra processes onto the space G* of Potthoff-Timpel distributions. Sufficient conditions for integrability of generalized processes are given, regularity results ... More
Sequential Neural Models with Stochastic LayersMay 24 2016Nov 13 2016How can we efficiently propagate uncertainty in a latent state representation with recurrent neural networks? This paper introduces stochastic recurrent neural networks which glue a deterministic recurrent neural network and a state space model together ... More
Toric Construction of Global F-Theory GUTsJan 25 2011Feb 28 2011We systematically construct a large number of compact Calabi-Yau fourfolds which are suitable for F-theory model building. These elliptically fibered Calabi-Yaus are complete intersections of two hypersurfaces in a six dimensional ambient space. We first ... More
Logarithmic and complex constant term identitiesDec 14 2011Mar 04 2012In recent work on the representation theory of vertex algebras related to the Virasoro minimal models M(2,p), Adamovic and Milas discovered logarithmic analogues of (special cases of) the famous Dyson and Morris constant term identities. In this paper ... More
Machine learning methods for nanolaser characterizationNov 10 2016Nanocavity lasers, which are an integral part of an on-chip integrated photonic network, are setting stringent requirements on the sensitivity of the techniques used to characterize the laser performance. Current characterization tools cannot provide ... More
Thermoelectric properties of lead chalcogenide core-shell nanostructuresJun 03 2012We present the full thermoelectric characterization of nanostructured bulk PbTe and PbTe-PbSe samples fabricated from colloidal core-shell nanoparticles followed by spark plasma sintering. An unusually large thermopower is found in both materials, and ... More
Comment on 'Comparative study of beta-decay data for eight nuclides measured at the Physikalisch-Technische Bundesanstalt' [Astropart. Phys., 50, 47-58]Aug 22 2014We would like to comment on a recent paper by Sturrock et al. [1] in which the authors analyze decay data acquired by an ionization chamber in our institute. They interpret the variations in the data as solar-driven changes in the decay rates of the radionuclides ... More
An embedding constant for the Hardy space of Dirichlet seriesJun 09 2016A new and simple proof of the embedding of the Hardy--Hilbert space of Dirichlet series into a conformally invariant Hardy space of the half-plane is presented, and the optimal constant of the embedding is computed.
Lensing by Groups of GalaxiesSep 17 1999Sep 18 1999A large fraction of known galaxy-lens systems require a component of external shear to explain the observed image geometries. In most cases, this shear can be attributed to a nearby group of galaxies. We discuss how the dark-matter mass distribution of ... More
Solvable lattice models labelled by Dynkin diagramsJan 08 1993An equivalence between generalised restricted solid-on-solid (RSOS) models, associated with sets of graphs, and multi-colour loop models is established. As an application we consider solvable loop models and in this way obtain new solvable families of ... More
The sl_3 Selberg integralJan 27 2009Jun 17 2010Using an extension of the well-known evaluation symmetry, a new Cauchy-type identity for Macdonald polynomials is proved. After taking the classical limit this yields a new sl_3 generalisation of the famous Selberg integral. Closely related results obtained ... More
Hall--Littlewood functions and the A_2 Rogers--Ramanujan identitiesOct 28 2004Jun 17 2005We prove an identity for Hall--Littlewood symmetric functions labelled by the Lie algebra A_2. Through specialization this yields a simple proof of the A_2 Rogers--Ramanujan identities of Andrews, Schilling and the author.