Results for "Hannes Pichler"

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Measurement Protocol for the Entanglement Spectrum of Cold AtomsMay 27 2016Nov 22 2016Entanglement, and, in particular the entanglement spectrum, plays a major role in characterizing many-body quantum systems. While there has been a surge of theoretical works on the subject, no experimental measurement has been performed to date because ... More
Chiral quantum optics with V-level atoms and coherent quantum feedbackJun 23 2016Sep 20 2016We study the dissipative dynamics of an atom in a V-level configuration driven by lasers and coupled to a semi-infinite waveguide. The coupling to the waveguide is chiral, in that each transition interacts only with the modes propagating in a given direction, ... More
A Measurement Protocol for the Entanglement Spectrum of Cold AtomsMay 27 2016Entanglement plays a major role in characterizing many-body quantum systems. In particular, the entanglement spectrum holds a great promise to characterize essential physics of quantum many-body systems. While there has been a surge of theoretical works ... More
Quantum Optimization for Maximum Independent Set Using Rydberg Atom ArraysAug 31 2018We describe and analyze an architecture for quantum optimization to solve maximum independent set (MIS) problems using neutral atom arrays trapped in optical tweezers. Optimizing independent sets is one of the paradigmatic, NP-hard problems in computer ... More
Chiral Quantum OpticsAug 01 2016At the most fundamental level, the interaction between light and matter is manifested by the emission and absorption of single photons by single quantum emitters. Controlling light--matter interaction is the basis for diverse applications ranging from ... More
Computational complexity of the Rydberg blockade in two dimensionsSep 13 2018We discuss the computational complexity of finding the ground state of the two-dimensional array of quantum bits that interact via strong van der Waals interactions. Specifically, we focus on systems where the interaction strength between two spins depends ... More
Photonic Quantum Circuits with Time DelaysOct 15 2015We study the dynamics of photonic quantum circuits consisting of nodes coupled by quantum channels. We are interested in the regime where time delay in communication between the nodes is significant. This includes the problem of quantum feedback, where ... More
Quantum Approximate Optimization Algorithm: Performance, Mechanism, and Implementation on Near-Term DevicesDec 03 2018The Quantum Approximate Optimization Algorithm (QAOA) is a hybrid quantum-classical variational algorithm designed to tackle combinatorial optimization problems. Despite its promise for near-term quantum applications, not much is currently understood ... More
Thermal vs. Entanglement Entropy: A Measurement Protocol for Fermionic Atoms with a Quantum Gas MicroscopeFeb 05 2013Jun 07 2013We show how to measure the order-two Renyi entropy of many-body states of spinful fermionic atoms in an optical lattice in equilibrium and non-equilibrium situations. The proposed scheme relies on the possibility to produce and couple two copies of the ... More
An entropy perspective on the thermal crossover in a fermionic Hubbard chainApr 19 2013We study the Renyi entropy in the finite temperature crossover regime of a Hubbard chain using quantum Monte Carlo. The ground state entropy has characteristic features such as a logarithmic divergence with block size and $2\kF$ oscillations that are ... More
Quantum Kibble-Zurek mechanism and critical dynamics on a programmable Rydberg simulatorSep 14 2018Apr 01 2019Quantum phase transitions (QPTs) involve transformations between different states of matter that are driven by quantum fluctuations. These fluctuations play a dominant role in the quantum critical region surrounding the transition point, where the dynamics ... More
Strategies To Evaluate The Riemann Zeta FunctionJan 31 2012This paper continues a series of investigations on converging representations for the Riemann Zeta function. We generalize some identities which involve Riemann's zeta function, and moreover we give new series and integrals for the zeta function. The ... More
Spectral Risk Measures, With Adaptions For Stochastic OptimizationSep 17 2012Stochastic optimization problems often involve the expectation in its objective. When risk is incorporated in the problem description as well, then risk measures have to be involved in addition to quantify the acceptable risk, often in the objective. ... More
Delayed Coherent Quantum Feedback from a Scattering Theory and a Matrix Product State PerspectiveJun 23 2017Sep 14 2017We study the scattering of photons propagating in a semi-infinite waveguide terminated by a mirror and interacting with a quantum emitter. This paradigm constitutes an example of coherent quantum feedback, where light emitted towards the mirror gets redirected ... More
Quantum State Transfer via Noisy Photonic and Phononic WaveguidesNov 30 2016Mar 28 2017We describe a quantum state transfer protocol, where a quantum state of photons stored in a first cavity can be faithfully transferred to a second distant cavity via an infinite 1D waveguide, while being immune to arbitrary noise (e.g. thermal noise) ... More
Quantum Spin Dimers from Chiral Dissipation in Cold-Atom ChainsAug 19 2014Dec 08 2014We consider the non-equilibrium dynamics of a driven dissipative spin chain with chiral coupling to a 1D bosonic bath, and its atomic implementation with a two-species mixture of cold quantum gases. The reservoir is represented by a spin-orbit coupled ... More
Periodic orbits, entanglement and quantum many-body scars in constrained models: matrix product state approachJul 04 2018Jan 30 2019We analyze quantum dynamics of strongly interacting, kinetically constrained many-body systems. Motivated by recent experiments demonstrating surprising long-lived, periodic revivals after quantum quenches in Rydberg atom arrays, we introduce a manifold ... More
Exploring Code Clones in Programmable Logic Controller SoftwareJun 13 2017The reuse of code fragments by copying and pasting is widely practiced in software development and results in code clones. Cloning is considered an anti-pattern as it negatively affects program correctness and increases maintenance efforts. Programmable ... More
Heating dynamics of bosonic atoms in a noisy optical latticeJan 13 2013Feb 28 2013We analyze the heating of interacting bosonic atoms in an optical lattice due to intensity fluctuations of the lasers forming the lattice. We focus in particular on fluctuations at low frequencies below the band gap frequency, such that the dynamics is ... More
Quantum Optics of Chiral Spin NetworksNov 11 2014Apr 15 2015We study the driven-dissipative dynamics of a network of spin-1/2 systems coupled to one or more chiral 1D bosonic waveguides within the framework of a Markovian master equation. We determine how the interplay between a coherent drive and collective decay ... More
Quantum State Transfer via Noisy Photonic and Phononic WaveguidesNov 30 2016We describe a quantum state transfer protocol, where a quantum state of photons stored in a first cavity can be faithfully transferred to a second distant cavity via an infinite 1D waveguide, while being immune to arbitrary noise (e.g. thermal noise) ... More
Photonic tensor networks produced by a single quantum emitterFeb 07 2017We propose and analyze a protocol to generate two dimensional tensor network states using a single quantum system that sequentially interacts with a 1D string of qubits. This is accomplished by using parts of the string itself as a quantum queue memory. ... More
Non-Markovian Dynamics in Chiral Quantum Networks with Spins and PhotonsFeb 02 2016Jun 23 2016We study the dynamics of chiral quantum networks consisting of nodes coupled by unidirectional or asymmetric bidirectional quantum channels. In contrast to familiar photonic networks where driven two-level atoms exchange photons via 1D photonic nanostructures, ... More
Generation and manipulation of Schrödinger cat states in Rydberg atom arraysMay 14 2019May 15 2019Quantum entanglement involving coherent superpositions of macroscopically distinct states is among the most striking features of quantum theory, but its realization is challenging, since such states are extremely fragile. Using a programmable quantum ... More
Entropy Based Risk MeasuresJan 22 2018Entropy is a measure of self-information which is used to quantify losses. Entropy was developed in thermodynamics, but is also used to compare probabilities based on their deviating information content. Corresponding model uncertainty is of particular ... More
Preduals for spaces of operators involving Hilbert spaces and trace-class operatorsMar 03 2017Mar 27 2018Continuing the study of preduals of spaces $\mathcal{L}(H,Y)$ of bounded, linear maps, we consider the situation that $H$ is a Hilbert space. We establish a natural correspondence between isometric preduals of $\mathcal{L}(H,Y)$ and isometric preduals ... More
Inductive limits of semiprojective C*-algebrasApr 13 2018Feb 18 2019We prove closure properties for the class of C*-algebras that are inductive limits of semiprojective C*-algebras. Most importantly, we show that this class is closed under shape domination, and so in particular under shape and homotopy equivalence. It ... More
The topological dimension of type I C*-algebrasOct 16 2012Feb 05 2013While there is only one natural dimension concept for separable, metric spaces, the theory of dimension in noncommutative topology ramifies into different important concepts. To accommodate this, we introduce the abstract notion of a noncommutative dimension ... More
Inductive limits of projective C*-algebrasMay 10 2011Dec 14 2017We show that a separable C*-algebra is an inductive limits of projective C*-algebras if and only if it has trivial shape, that is, if it is shape equivalent to the zero C*-algebra. In particular, every contractible C*-algebra is an inductive limit of ... More
The generator rank for C*-algebrasOct 24 2012The invariant that assigns to a C*-algebra its minimal number of generators lacks natural permanence properties. In particular, it may increase when passing to ideals or inductive limits. It is therefore hard to compute this invariant directly. To obtain ... More
New bulk scalar field solutions in brane worldsOct 04 2004We use nonlinear perturbation theory to obtain new solutions for brane world models that incorporate a massive bulk scalar field. We then consider tensor perturbations and show that Newtonian gravity is recovered on the brane for both a light scalar field ... More
Hopf bifurcation and time periodic orbits in reaction-diffusion systems with pde2path - algorithms and applicationsApr 06 2016Aug 28 2017We describe the algorithms used in the Matlab continuation and bifurcation package pde2path for Hopf bifurcation and continuation of branches of periodic orbits in systems of PDEs in 1, 2, and 3 spatial dimensions, including the computation of Floquet ... More
The variation of the maximal function of a radial functionFeb 02 2017We study the problem concerning the variation of the Hardy-Littlewood maximal function in higher dimensions. As the main result, we prove that the variation of the non-centered Hardy-Littlewood maximal function of a radial function is comparable to the ... More
kt - factorization and CCFM - the solution for describing the hadronic final states - everywhere ?Nov 20 2003Nov 25 2003The basic ideas of kt-factorization and CCFM parton evolution is discussed. The unintegrated gluon densities, obtained from CCFM fits to the proton structure function data at HERA are used to predict hadronic final state cross sections like jet production ... More
A numerical study of the dispersion and dissipation properties of virtual element methods for the Helmholtz problemJun 24 2019We study numerically the dispersion and dissipation properties of the plane wave virtual element method and the nonconforming Trefftz virtual element method for the Helmholtz problem. Whereas the former method is based on a conforming virtual partition ... More
Hopf bifurcation and time periodic orbits in reaction-diffusion systems with pde2path -- a tutorial via reaction-diffusion systems and distributed optimal controlApr 06 2016Jun 06 2016We describe how to use the Matlab continuation and bifurcation package pde2path for Hopf bifurcations and the continuation of branches of periodic orbits, including the computation of Floquet multipliers, in systems of PDEs in 1, 2, and 3 spatial dimensions. ... More
The pde2path add-on toolbox p2pOC for solving infinite time-horizon spatially distributed optimal control problems - Quickstart Guide -Mar 18 2015May 22 2015p2pOC is an add-on toolbox to the Matlab package pde2path. It is aimed at the numerical solution of optimal control (OC) problems with an infinite time horizon for parabolic systems of PDE over 1D or 2D spatial domains. The basic idea is to treat the ... More
Computational Complexity of the Minimum Cost Homomorphism Problem on Three-Element DomainsAug 06 2013Sep 29 2013In this paper we study the computational complexity of the (extended) minimum cost homomorphism problem (Min-Cost-Hom) as a function of a constraint language, i.e. a set of constraint relations and cost functions that are allowed to appear in instances. ... More
On the conditional distributions of low-dimensional projections from high-dimensional dataApr 22 2013We study the conditional distribution of low-dimensional projections from high-dimensional data, where the conditioning is on other low-dimensional projections. To fix ideas, consider a random d-vector Z that has a Lebesgue density and that is standardized ... More
Un-integrated PDFs in CCFMNov 22 2004The un-integrated parton distribution functions (uPDFs) obtained from a CCFM evolution are studied in terms of the intrinsic transverse momentum distribution at low scales. The uPDFs are studied for variations of the renormalization and factorization ... More
Inductive limits of projective C*-algebrasMay 10 2011We show that a C*-algebra is an inductive limits of projective C*-algebras if and only if it has trivial shape, i.e., is shape equivalent to the zero C*-algebra. In particular, every contractible C*-algebra is an inductive limit of projectives, and one ... More
Three-Element Min-Sol and Conservative Min-Cost-HomDec 31 2012Sep 29 2013Thapper and Zivny [STOC'13] recently classified the complexity of VCSP for all finite-valued constraint languages. However, the complexity of VCSPs for constraint languages that are not finite-valued remains poorly understood. In this paper we study the ... More
Electromagnetic radiative corrections to pionic beta decay π^+ to π^0 e^+ ν_eSep 25 2002Pionic beta decay \pi^+ to \pi^0 e^+ \nu_e is analyzed in chiral perturbation theory with virtual photons and leptons. All electromagnetic corrections up to order e^2 p^2 are taken into account. Theoretical results are confronted with preliminary data ... More
Evaluation and selection of models for out-of-sample prediction when the sample size is small relative to the complexity of the data-generating processFeb 22 2008Oct 24 2008In regression with random design, we study the problem of selecting a model that performs well for out-of-sample prediction. We do not assume that any of the candidate models under consideration are correct. Our analysis is based on explicit finite-sample ... More
Semiprojectivity and semiinjectivity in different categoriesFeb 14 2018Projectivity and injectivity are fundamental notions in category theory. We consider natural weakenings termed semiprojectivity and semiinjectivity, and study these concepts in different categories. For example, in the category of metric spaces, (semi)injective ... More
Recent results from CCFM evolutionDec 04 2003Recent developments of the small $x$ CCFM evolution are described, including improvements of the splitting function. The resulting unintegrated gluon densities are used for predictions of hadronic final state measurements like jet production at HERA and ... More
Vector meson cross sections at HERAJan 13 2008Inelastic and elastic (exclusive) cross section measurements of vector meson production at HERA are discussed.
The distribution of a linear predictor after model selection: Unconditional finite-sample distributions and asymptotic approximationsNov 07 2006We analyze the (unconditional) distribution of a linear predictor that is constructed after a data-driven model selection step in a linear regression model. First, we derive the exact finite-sample cumulative distribution function (cdf) of the linear ... More
On the Relative Expressiveness of Argumentation Frameworks, Normal Logic Programs and Abstract Dialectical FrameworksMay 05 2014We analyse the expressiveness of the two-valued semantics of abstract argumentation frameworks, normal logic programs and abstract dialectical frameworks. By expressiveness we mean the ability to encode a desired set of two-valued interpretations over ... More
Optimal harvesting and spatial patterns in a semi arid vegetation systemMay 22 2015Jan 11 2016We consider an infinite time horizon spatially distributed optimal harvesting problem for a vegetation and soil water reaction diffusion system, with rainfall as the main external parameter. By Pontryagin's maximum principle we derive the associated four ... More
On the differentiability of directionally differentiable functions and applicationsAug 20 2012May 10 2013In the first part of this paper we establish, in terms of so called k-tangential sets, a kind of optimal estimate for the size and structure of the set of non-differentiability of Lipshitz functions with one-sided directional derivatives. These results ... More
Semicircularity, Gaussianity and Monotonicity of EntropyDec 21 2005Mar 10 2006S. Artstein, K. Ball, F. Barthe, and A. Naor have shown that if (X_j) are i.i.d. random variables, then the entropy of n^{-1/2}(X_1+....+X_n) increases as n increases. The free analogue was recently proven by D. Shlyakhtenko. That is, if (x_j) are freely ... More
Dressed, noise- or disorder- resilient optical latticesMay 28 2012External noise is inherent in any quantum system, and can have especially strong effects for systems exhibiting sensitive many-body phenomena. We show how a dressed lattice scheme can provide control over certain types of noise for atomic quantum gases ... More
Quantum MetasurfacesApr 15 2019Metasurfaces mold the flow of classical light waves by engineering sub-wavelength patterns from dielectric or metallic thin films. We describe and analyze a method in which quantum operator-valued reflectivity can be used to control both spatio-temporal ... More
One-way quantum repeater based on near-deterministic photon-emitter interfacesJul 11 2019We propose a novel one-way quantum repeater architecture based on photonic tree-cluster states. Encoding a qubit in a photonic tree-cluster protects the information from transmission loss and enables long-range quantum communication through a chain of ... More
Numerical study of the chiral $\mathbb{Z}_3$ quantum phase transition in one spatial dimensionJun 05 2018Jul 16 2018Recent experiments on a one-dimensional chain of trapped alkali atoms [arXiv:1707.04344] have observed a quantum transition associated with the onset of period-3 ordering of pumped Rydberg states. This spontaneous $\mathbb{Z}_3$ symmetry breaking is described ... More
On the motion of a compact elastic bodyAug 07 2005Feb 02 2007We study the problem of motion of a relativistic, ideal elastic solid with free surface boundary by casting the equations in material form ("Lagrangian coordinates"). By applying a basic theorem due to Koch, we prove short-time existence and uniqueness ... More
Brown measure and iterates of the Aluthge transform for some operators arising from measurable actionsDec 09 2005Feb 05 2008We consider the Aluthge transform $|T|^{1/2}U|T|^{1/2}$ of a Hilbert space operator $T$, where $T=U|T|$ is the polar decomposition of $T$. We prove that the map that sends $T$ to its Aluthge transform is continuous with respect to the norm topology and ... More
Well-posedness of some initial-boundary-value problems for dynamo-generated poloidal magnetic fieldsDec 13 2012Given a bounded domain $G \subset \R^d$, $d\geq 3$, we study smooth solutions of a linear parabolic equation with non-constant coefficients in $G$, which at the boundary have to $C^1$-match with some harmonic function in $\R^d \setminus \ov{G}$ vanishing ... More
Banach algebras generated by an invertible isometry of an $L^p$-spaceMay 22 2014Dec 18 2014We provide a complete description of those Banach algebras that are generated by an invertible isometry of an $L^p$-space together with its inverse. Examples include the algebra $PF_p(\mathbb{Z})$ of $p$-pseudofunctions on $\mathbb{Z}$, the commutative ... More
Optimal management and spatial patterns in a distributed shallow lake modelMar 18 2015Jun 10 2015We present a numerical framework to treat infinite time horizon spatially distributed optimal control problems via the associated canonical system derived by Pontryagin's Maximum Principle. The basic idea is to consider the canonical system in two steps. ... More
Saturation effects in final states due to CCFM with absorptive boundaryDec 22 2008Jan 26 2009We apply the absorptive boundary prescription to include saturation effects in CCFM evolution equation. We are in particular interested in saturation effects in exclusive processes which can be studied using Monte Carlo event generator CASCADE. We calculate ... More
On underwater sound reflection from layered ice sheetsApr 08 2016Reflection of sound from ice sheets floating on water is simulated using Thomson and Haskell's method of matrix propagation. The reflection coefficient is computed as a function of incidence angle and frequency for selected ice parameters of a uniform ... More
Preduals and complementation of spaces of bounded linear operatorsSep 17 2016Mar 21 2018For Banach spaces X and Y, we establish a natural bijection between preduals of Y and preduals of L(X,Y) that respect the right L(X)-module structure. If X is reflexive, it follows that there is a unique predual making L(X) into a dual Banach algebra. ... More
Reversible Work Transiton State Theory: Application to Dissociative Adsorption of HydrogenNov 16 1994Nov 18 1994A practical method for finding free energy barriers for transitions in high-dimensional classical and quantum systems is presented and used to calculate the dissociative sticking probability of H2 on a metal surface within transition state theory (TST). ... More
Extending representations of Banach algebras to their bidualsMar 02 2017Mar 23 2018We show that a representation of a Banach algebra $A$ on a Banach space $X$ can be extended to a canonical representation of $A^{**}$ on $X$ if and only if certain orbit maps $A\to X$ are weakly compact. When this is the case, we show that the essential ... More
A Morse type uniqueness theorem for non-parametric minimizing hypersurfacesJul 02 2007A classical result about minimal geodesics on R^2 with Z^2 periodic metric that goes back to H.M. Morse asserts that a minimal geodesic that is asymptotic to a periodic minimal geodesic cannot intersect any periodic minimal geodesic of the same period. ... More
Determination of transverse momentum dependent gluon density from HERA structure function measurementsJun 08 2012The transverse momentum dependent gluon density obtained with CCFM evolution is determined from a fit to the latest combined HERA structure function measurements.
Incorporating statistical model error into the calculation of acceptability prices of contingent claimsMar 16 2017Jan 30 2019The determination of acceptability prices of contingent claims requires the choice of a stochastic model for the underlying asset price dynamics. Given this model, optimal bid and ask prices can be found by stochastic optimization. However, the model ... More
Quantum Hall Physics with Cold Atoms in Cylindrical Optical LatticesJun 30 2015Oct 15 2015We propose and study various realizations of a Hofstadter-Hubbard model on a cylinder geometry with fermionic cold atoms in optical lattices. The cylindrical optical lattice is created by copropagating Laguerre-Gauss beams, i.e.~light beams carrying orbital ... More
Searching for three-nucleon resonancesOct 09 1995We search for three-neutron resonances which were predicted from pion double charge exchange experiments on He-3. All partial waves up to J=5/2 are nonresonant except the J=3/2^+ one, where we find a state at E=14 MeV energy with 13 MeV width. The parameters ... More
Dictator Functions Maximize Mutual InformationApr 07 2016Aug 11 2016Let $(X^n, Y^n)$ denote $n$ independent, identically distributed copies of two arbitrarily correlated Rademacher random variables $(X, Y)$ on $\{-1,1\}$. We prove that the inequality $I(f(X^n); g(Y^n)) \le I(X; Y)$ holds for any two Boolean functions: ... More
Do Hard SAT-Related Reasoning Tasks Become Easier in the Krom Fragment?Nov 21 2017Oct 29 2018Many reasoning problems are based on the problem of satisfiability (SAT). While SAT itself becomes easy when restricting the structure of the formulas in a certain way, the situation is more opaque for more involved decision problems. We consider here ... More
Probing many-body dynamics on a 51-atom quantum simulatorJul 13 2017Nov 30 2017Controllable, coherent many-body systems can provide insights into the fundamental properties of quantum matter, enable the realization of new quantum phases and could ultimately lead to computational systems that outperform existing computers based on ... More
Photonic Band Structure of Two-dimensional Atomic LatticesAug 11 2017Two-dimensional atomic arrays exhibit a number of intriguing quantum optical phenomena, including subradiance, nearly perfect reflection of radiation and long-lived topological edge states. Studies of emission and scattering of photons in such lattices ... More
Topological Quantum Optics in Two-Dimensional Atomic ArraysMar 15 2017Jul 17 2017We demonstrate that two-dimensional atomic emitter arrays with subwavelength spacing constitute topologically protected quantum optical systems where the photon propagation is robust against large imperfections while losses associated with free space ... More
Dynamics of condensate formation in stochastic transport with pair-factorized steady states: Nucleation and coarsening time scalesFeb 02 2016Jul 26 2016Driven diffusive systems such as the zero-range process (ZRP) and the pair-factorized steady states (PFSS) stochastic transport process are versatile tools that lend themselves to the study of transport phenomena on a generic level. While their mathematical ... More
Emergence of dynamic phases in the presence of different kinds of open boundaries in stochastic transport with short-range interactionsAug 03 2015Jan 15 2016We discuss the effects of open boundary conditions and boundary induced drift on condensation phenomena in the pair-factorized steady states transport process, a versatile model for stochastic transport with tunable nearest-neighbour interactions. Varying ... More
The DIAMOND System for Argumentation: Preliminary ReportDec 20 2013Abstract dialectical frameworks (ADFs) are a powerful generalisation of Dung's abstract argumentation frameworks. In this paper we present an answer set programming based software system, called DIAMOND (DIAlectical MOdels eNcoDing). It translates ADFs ... More
Direct Numerical Simulations of Local and Global Torque in Taylor-Couette Flow up to Re=30.000Jun 06 2012The torque in turbulent Taylor-Couette flows for shear Reynolds numbers Re_S up to 3x10^4 at various mean rotations is studied by means of direct numerical simulations for a radius ratio of \eta=0.71. Convergence of simulations is tested using three criteria ... More
Gauge fixing in lattice QCD with multi-GPUsMay 15 2013Here we present the cuLGT code for gauge fixing in lattice gauge field theories with graphic processing units (GPUs). Implementations for SU(3) Coulomb, Landau and maximally Abelian gauge fixing are available and the overrelaxation, stochastic relaxation ... More
Preduals and complementation of spaces of bounded linear operatorsSep 17 2016For Banach spaces X and Y, we establish a natural bijection between preduals of Y and preduals of L(X,Y) that respect the right L(X)-module structure. If X is reflexive, it follows that there is a unique predual making L(X) into a dual Banach algebra. ... More
On the Ambiguity of Interaction and Nonlinear Main Effects in a Regime of Dependent CovariatesDec 09 2015Frequently the analysis of large experimental datasets reveals significant interactions that are difficult to interpret within the theoretical framework guiding the research. Some of these interactions are actually spurious artifacts arising from the ... More
Density functional theory calculations and thermodynamic analysis of the forsterite $Mg_{2}SiO_{4}$(010) surfaceAug 30 2018Sep 13 2018The stability of possible termination structures for the (010) surface of forsterite, $ Mg_2SiO_4 $, is studied using a density functional theory (DFT) based thermodynamic approach. The DFT calculations are used to estimate the surface Gibbs free energy ... More
Bifurcation of Nonlinear Bloch Waves from the Spectrum in the Gross-Pitaevskii EquationSep 15 2014Dec 14 2015We rigorously analyze the bifurcation of stationary so called nonlinear Bloch waves (NLBs) from the spectrum in the Gross-Pitaevskii (GP) equation with a periodic potential, in arbitrary space dimensions. These are solutions which can be expressed as ... More
Group algebras acting on $L^p$-spacesAug 24 2014Apr 18 2015For $p\in [1,\infty)$ we study representations of a locally compact group $G$ on $L^p$-spaces and $QSL^p$-spaces. The universal completions $F^p(G)$ and $F^p_{\mathrm{QS}}(G)$ of $L^1(G)$ with respect to these classes of representations (which were first ... More
Conditional predictive inference for high-dimensional stable algorithmsSep 05 2018We investigate generically applicable and intuitively appealing prediction intervals based on leave-one-out residuals. The conditional coverage probability of the proposed interval, given the observations in the training sample, is close to the nominal ... More
The generator problem for Z-stable C*-algebrasJan 18 2012The generator problem was posed by Kadison in 1967, and it remains open until today. We provide a solution for the class of C*-algebras absorbing the Jiang-Su algebra Z tensorially. More precisely, we show that every unital, separable, Z-stable C*-algebras ... More
Numerical results for snaking of patterns over patterns in some 2D Selkov-Schnakenberg Reaction-Diffusion systemsApr 05 2013Oct 15 2013For a Selkov--Schnakenberg model as a prototype reaction-diffusion system on two dimensional domains we use the continuation and bifurcation software pde2path to numerically calculate branches of patterns embedded in patterns, for instance hexagons embedded ... More
Bernstein-von Mises theorems and uncertainty quantification for linear inverse problemsNov 09 2018We consider the statistical inverse problem of approximating an unknown function $f$ from a linear measurement corrupted by additive Gaussian white noise. We employ a nonparametric Bayesian approach with standard Gaussian priors, for which the posterior-based ... More
Need for fully unintegrated parton densitiesAug 27 2005Associated with the use of conventional integrated parton densities are kinematic approximations on parton momenta which result in unphysical differential distributions for final-state particles. We argue that it is important to reformulate perturbative ... More
Towards precision determination of uPDFsJul 29 2007The unintegrated Parton Density Function of the gluon is obtained from a fit to dijet production in DIS as measured at HERA. Reasonable descriptions of the measurements are obtained, and a first attempt to constrain the intrinsic transverse momentum distribution ... More
Small-x Physics and Forward Jet Production at THERAMay 14 2001We discuss some aspects of forward jet production as a signature for small $x$ physics at THERA energies.
cuLGT: Lattice Gauge Fixing on GPUsDec 11 2014We adopt CUDA-capable Graphic Processing Units (GPUs) for Landau, Coulomb and maximally Abelian gauge fixing in 3+1 dimensional SU(3) and SU(2) lattice gauge field theories. A combination of simulated annealing and overrelaxation is used to aim for the ... More
Representations of $p$-convolution algebras on $L^q$-spacesSep 27 2016For a nontrivial locally compact group $G$, and $p\in [1,\infty)$, consider the Banach algebras of $p$-pseudofunctions, $p$-pseudomeasures, $p$-convolvers, and the full group $L^p$-operator algebra. We show that these Banach algebras are operator algebras ... More
Eigenvalue placement for regular matrix pencils with rank one perturbationsApr 12 2016A regular matrix pencil sE-A and its rank one perturbations are considered. We determine the sets in the extended complex plane which are the eigenvalues of the perturbed pencil. We show that the largest Jordan chains at each eigenvalue of sE-A may disappear ... More
Gauge fixing using overrelaxation and simulated annealing on GPUsSep 18 2012We adopt CUDA-capable Graphic Processing Units (GPUs) for Coulomb, Landau and maximally Abelian gauge fixing in 3+1 dimensional SU(3) lattice gauge field theories. The local overrelaxation algorithm is perfectly suited for highly parallel architectures. ... More
Role of two-flavor color superconductor pairing in a three-flavor Nambu--Jona-Lasinio model with axial anomalyJul 29 2010Oct 18 2010The phase diagram of strongly interacting matter is studied within a three-flavor Nambu--Jona-Lasinio model, which contains the coupling between chiral and diquark condensates through the axial anomaly. Our results show that it is essential to include ... More
Quantum Critical Dynamics Simulation of Dirty Boson SystemsSep 14 2011Nov 23 2011Recently the scaling result $z=d$ for the dynamic critical exponent at the Bose glass to superfluid quantum phase transition has been questioned both on theoretical and numerical grounds. This motivates a careful evaluation of the critical exponents in ... More
Statistics for surface modes of nanoparticles with shape fluctuationsFeb 23 2010We develop a numerical method for approximating the surface modes of sphere-like nanoparticles in the quasi-static limit, based on an expansion of (the angular part of) the potentials into spherical harmonics. Comparisons of the results obtained in this ... More