Results for "Ole Peters"

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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
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
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
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
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
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
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
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
A recipe for irreproducible resultsJun 23 2017Recent studies have shown that many results published in peer-reviewed scientific journals are not reproducible. This raises the following question: why is it so easy to fool myself into believing that a result is reliable when in fact it is not? Using ... 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
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
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
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
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
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
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
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
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
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
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
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
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
Testing for simultaneous jumps in case of asynchronous observationsJun 23 2016This paper proposes a novel test for simultaneous jumps in a bivariate It\^o semimartingale when observation times are asynchronous and irregular. Inference is built on a realized correlation coefficient for the jumps of the two processes which is estimated ... 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
Laws of large numbers for Hayashi-Yoshida-type functionalsMar 15 2018In high-frequency statistics and econometrics sums of functionals of increments of stochastic processes are commonly used and statistical inference is based on the asymptotic behaviour of these sums as the mesh of the observation times tends to zero. ... More
Modular Nekrasov-Okounkov formulasFeb 09 2019Using Littlewood's map, which decomposes a partition into its $r$-core and $r$-quotient, Han and Ji have shown that many well-known hook-length formulas admit modular analogues. In this paper we present a variant of the Han-Ji `multiplication theorem' ... 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
On R-duals and the duality principle in Gabor analysisApr 11 2014The concept of R-duals of a frame was introduced by Casazza, Kutyniok and Lammers in 2004, with the motivation to obtain a general version of the duality principle in Gabor analysis. For tight Gabor frames and Gabor Riesz bases the three authors were ... More
Approximately dual frame pairs in Hilbert spaces and applications to Gabor framesNov 21 2008We discuss the concepts of pseudo-dual frames and approximately dual frames, and illuminate their relationship to classical frames. Approximately dual frames are easier to construct than the classical dual frames, and might be tailored to yield almost ... More
On various R-duals and the duality principleSep 21 2015The duality principle states that a Gabor system is a frame if and only if the corresponding adjoint Gabor system is a Riesz sequence. In general Hilbert spaces and without the assumption of any particular structure, Casazza, Kutyniok and Lammers have ... More
Compact composition operators with non-linear symbols on the $H^2$ space of Dirichlet seriesMay 12 2015We investigate the compactness of composition operators on the Hardy space of Dirichlet series induced by a map $\varphi(s)=c_0s+\varphi_0(s)$, where $\varphi_0$ is a Dirichlet polynomial. Our results depend heavily on the characteristic $c_0$ of $\varphi$ ... More
Hall-Littlewood polynomials and characters of affine Lie algebrasApr 05 2013Sep 05 2015The Weyl-Kac character formula gives a beautiful closed-form expression for the characters of integrable highest-weight modules of Kac-Moody algebras. It is not, however, a formula that is combinatorial in nature, obscuring positivity. In this paper we ... More
Branching rules for symmetric Macdonald polynomials and sl_n basic hypergeometric seriesMar 24 2009A one-parameter generalisation R_{\lambda}(X;b) of the symmetric Macdonald polynomials and interpolations Macdonald polynomials is studied from the point of view of branching rules. We establish a Pieri formula, evaluation symmetry, principal specialisation ... 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
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
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
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
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
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
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
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
Preheating in an Asymptotically Safe Quantum Field TheoryMar 08 2016We consider reheating in a class of asymptotically safe quantum field theories recently studied in \cite{Litim:2014uca, Litim:2015iea}. These theories allow for an inflationary phase in the very early universe. Inflation ends with a period of reheating. ... More
Deep Belief Nets for Topic ModelingJan 18 2015Applying traditional collaborative filtering to digital publishing is challenging because user data is very sparse due to the high volume of documents relative to the number of users. Content based approaches, on the other hand, is attractive because ... More
Calculation of the Anisotropic Coefficients of Thermal Expansion: A First-Principles ApproachMar 07 2019Predictions of the anisotropic coefficients of thermal expansion are needed to not only compare to experimental measurement, but also as input for macroscopic modeling of devices which operate over a large temperature range. While most current methods ... More
Explicit constructions and properties of generalized shift-invariant systems in $L^2(\mathbb{R})$Oct 13 2016Generalized shift-invariant (GSI) systems, originally introduced by Hern\'andez, Labate & Weiss and Ron & Shen, provide a common frame work for analysis of Gabor systems, wavelet systems, wave packet systems, and other types of structured function systems. ... More
Optimization and projection of coated structures with orthotropic infill materialAug 14 2018The purpose of this work is two-fold. First, we introduce an efficient homogenization-based approach to perform topology optimization of coated structures with orthotropic infill material. By making use of the relaxed design space, we can obtain designs ... More
A Nekrasov-Okounkov formula for Macdonald polynomialsJun 15 2016Feb 19 2018We prove a Macdonald polynomial analogue of the celebrated Nekrasov-Okounkov hook-length formula from the theory of random partitions. As an application we obtain a proof of one of the main conjectures of Hausel and Rodriguez-Villegas from their work ... 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
Amplitude noise and coherence degradation of femtosecond supercontinuum generation in all-normal-dispersion fibersFeb 04 2019Supercontinuum (SC) generation via femtosecond (fs) pumping in all-normal-dispersion (ANDi) fiber is predicted to offer completely coherent broadening mechanisms, potentially allowing for substantially reduced noise levels in comparison to those obtained ... 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
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
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
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
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
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
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
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.
Bayesian inference for spatio-temporal spike-and-slab priorsSep 15 2015Dec 01 2017In this work, we address the problem of solving a series of underdetermined linear inverse problems subject to a sparsity constraint. We generalize the spike-and-slab prior distribution to encode a priori correlation of the support of the solution in ... More
Selfdecomposable FieldsFeb 05 2015In the present paper we study selfdecomposability of random fields, as defined directly rather than in terms of finite-dimensional distributions. The main tools in our analysis are the master L\'evy measure and the associated L\'evy-It\^o representation. ... More
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
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
On entire functions restricted to intervals, partition of unities, and dual Gabor framesAug 26 2013Partition of unities appear in many places in analysis. Typically they are generated by compactly supported functions with a certain regularity. In this paper we consider partition of unities obtained as integer-translates of entire functions restricted ... More
Infill Optimization for Additive Manufacturing -- Approaching Bone-like Porous StructuresAug 15 2016Nov 19 2016Porous structures such as trabecular bone are widely seen in nature. These structures exhibit superior mechanical properties whilst being lightweight. In this paper, we present a method to generate bone-like porous structures as lightweight infill for ... More
Auxiliary Deep Generative ModelsFeb 17 2016Jun 16 2016Deep generative models parameterized by neural networks have recently achieved state-of-the-art performance in unsupervised and semi-supervised learning. We extend deep generative models with auxiliary variables which improves the variational approximation. ... More
BIVA: A Very Deep Hierarchy of Latent Variables for Generative ModelingFeb 06 2019With the introduction of the variational autoencoder (VAE), probabilistic latent variable models have received renewed attention as powerful generative models. However, their performance in terms of test likelihood and quality of generated samples has ... More
Interactions between Rydberg excitons in Cu$_2$OJul 16 2018Highly-excited states of excitons in cuprous oxide have recently been observed at a record quantum number of up to $n=25$. Here, we evaluate the long-range interactions between pairs of Rydberg excitons in Cu$_2$O, which are due to direct Coulomb forces ... More
Domain walls that do not get stuck on impuritiesFeb 19 2019We present a field theoretical model which allows for domain walls that do not get stuck on impurities. For this purpose, we consider a generalized chiral magnet domain wall action with an impurity which couples both to a potential term as well as to ... More
FieldSAFE: Dataset for Obstacle Detection in AgricultureSep 11 2017In this paper, we present a novel multi-modal dataset for obstacle detection in agriculture. The dataset comprises approximately 2 hours of raw sensor data from a tractor-mounted sensor system in a grass mowing scenario in Denmark, October 2016. Sensing ... 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
A highly magnified candidate for a young galaxy seen when the Universe was 500 Myrs oldApr 10 2012The early Universe at redshift z\sim6-11 marks the reionization of the intergalactic medium, following the formation of the first generation of stars. However, those young galaxies at a cosmic age of \lesssim 500 million years (Myr, at z \gtrsim 10) remain ... More
Beam tests of silicon pixel 3D-sensors developed at SINTEFJun 21 2018Aug 05 2018For the purpose of withstanding very high radiation doses, silicon pixel sensors with a 3D electrode geometry are being developed. Detectors of this kind are highly interesting for harch radiation environments such as expected in the High Luminosity LHC, ... More
Dark energy properties from large future galaxy surveysApr 08 2013Apr 29 2014We perform a detailed forecast on how well a {\sc Euclid}-like survey will be able to constrain dark energy and neutrino parameters from a combination of its cosmic shear power spectrum, galaxy power spectrum, and cluster mass function measurements. We ... More
Confronting the sound speed of dark energy with future cluster surveysMay 02 2012Future cluster surveys will observe galaxy clusters numbering in the hundred thousands. We consider this work how these surveys can be used to constrain dark energy parameters: in particular, the equation of state parameter w and the non-adiabatic sound ... More
Gutzwiller theory of band magnetism in LaOFeAsSep 05 2011We use the Gutzwiller variational theory to calculate the ground-state phase diagram and quasi-particle bands of LaOFeAs. The Fe3d--As4p Wannier-orbital basis obtained from density-functional theory defines the band part of our eight-band Hubbard model. ... More
Sensitivity of photonic crystal fiber grating sensors: biosensing, refractive index, strain, and temperature sensingAug 31 2007We study the sensitivity of fiber grating sensors in the applications of strain, temperature, internal label-free biosensing, and internal refractive index sensing. It is shown that optical dispersion plays a central role in determining the sensitivity, ... More
N-conserving Bogoliubov vacuum of a two component Bose-Einstein condensate: Density fluctuations close to a phase separation conditionJan 10 2007Mar 26 2008Two-component Bose-Einstein condensates are considered within a number conserving version of the Bogoliubov theory. We show that the Bogoliubov vacuum state can be obtained in the particle representation in a simple form. We predict considerable density ... More
Ramanujan's {_1ψ_1} summationJun 12 2012Nov 05 2012This paper gives a short but reasonably comprehensive review of Ramanujan's {_1\psi_1} summation and its generalisations. It covers the history of Ramanujan's summation, simple applications to sums of squares and orthogonal polynomials, non-commutative ... More
Proof of the Flohr-Grabow-Koehn conjectures for characters of logarithmic conformal field theoryApr 24 2007In a recent paper Flohr, Grabow and Koehn conjectured that the characters of the logarithmic conformal field theory c_{k,1}, of central charge c=1-6(k-1)^2/k, admit fermionic representations labelled by the Lie algebra D_k. In this note we provide a simple ... More
Rogers-Szego polynomials and Hall-Littlewood symmetric functionsAug 22 2007We use Rogers-Szego polynomials to unify some well-known identities for Hall-Littlewood symmetric functions due to Macdonald and Kawanaka.
A Selberg integral for the Lie algebra A_nAug 08 2007A new q-binomial theorem for Macdonald polynomials is employed to prove an A_n analogue of the celebrated Selberg integral. This confirms the g=A_n case of a conjecture by Mukhin and Varchenko concerning the existence of a Selberg integral for every simple ... More
Tractable approximations for probabilistic models: The adaptive TAP mean field approachFeb 15 2001We develop an advanced mean field method for approximating averages in probabilistic data models that is based on the TAP approach of disorder physics. In contrast to conventional TAP, where the knowledge of the distribution of couplings between the random ... More
Disproof of solar influence on the decay rates of 90Sr/90YJul 09 2014A custom-built liquid scintillation counter was used for long-term measurements of 90Sr/90Y sources. The detector system is equipped with an automated sample changer and three photomultiplier tubes, which makes the application of the triple-to-double ... More
A Higgs mass at 125 GeV calculated from neutron to proton decay in a u(3) Lie group Hamiltonian frameworkFeb 07 2013May 01 2014We investigate the neutron to proton decay via a Higgs mechanism in the framework of a reinterpreted Kogut-Susskind Hamiltonian on the Lie group u(3). We calculate expressions for a scalar Higgs mass, an electroweak energy scale, and vector gauge boson ... More