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A dynamical magnetic field accompanying the motion of ferroelectric domain wallsApr 12 2019The recently proposed dynamical multiferroic effect describes the generation of magnetization from temporally varying electric polarization. Here, we show that the effect can lead to a magnetic field at moving ferroelectric domain walls, where the rearrangement ... More

Force-detected nuclear magnetic resonance: Recent advances and future challengesJun 18 2010We review recent efforts to detect small numbers of nuclear spins using magnetic resonance force microscopy. Magnetic resonance force microscopy (MRFM) is a scanning probe technique that relies on the mechanical measurement of the weak magnetic force ... More

Radio-frequency magnetometry using a single electron spinOct 04 2012Jan 11 2013We experimentally demonstrate a simple and robust protocol for the detection of weak radio-frequency magnetic fields using a single electron spin in diamond. Our method relies on spin locking, where the Rabi frequency of the spin is adjusted to match ... More

Scanning magnetic field microscope with a diamond single-spin sensorMay 08 2008Sep 23 2008We describe a scanning device where a single spin is used as an ultrasensitive, nanoscale magnetic field sensor. As this "probe spin" we consider a single nitrogen-vacancy defect center in a diamond nanocrystal, attached to the tip of the scanning device. ... More

When redundancy is rational: A Bayesian approach to 'overinformative' referring expressionsMar 19 2019Referring is one of the most basic and prevalent uses of language. How do speakers choose from the wealth of referring expressions at their disposal? Rational theories of language use have come under attack for decades for not being able to account for ... More

High-speed domain wall racetracks in a magnetic insulatorFeb 14 2019Recent reports of current-induced switching of ferrimagnetic oxides coupled to a heavy metal layer have opened realistic prospects for implementing magnetic insulators into electrically addressable spintronic devices. However, key aspects such as the ... More

CBinfer: Change-Based Inference for Convolutional Neural Networks on Video DataApr 14 2017Jun 21 2017Extracting per-frame features using convolutional neural networks for real-time processing of video data is currently mainly performed on powerful GPU-accelerated workstations and compute clusters. However, there are many applications such as smart surveillance ... More

The Pointillist Family of Multitarget Tracking FiltersMay 29 2015Jun 19 2015The family of pointillist multitarget tracking filters is defined to be the class of filters that is characterized by a joint target-measurement finite point process. The probability generating functional (PGFL) of the joint process is derived directly ... More

Quantum sensingNov 08 2016"Quantum sensing" describes the use of a quantum system, quantum properties or quantum phenomena to perform a measurement of a physical quantity. Historical examples of quantum sensors include magnetometers based on superconducting quantum interference ... More

Coherent control of solid state nuclear spin nano-ensemblesFeb 08 2018Detecting and controlling nuclear spin nano-ensembles is crucial for the further development of nuclear magnetic resonance (NMR) spectroscopy and for the emerging solid state quantum technology. Here we present the fabrication of a $\approx$ 1 nanometre ... More

Thermal Quantum Fields without Cut-offs in 1+1 Space-time DimensionsMar 26 2004We construct interacting quantum fields in 1+1 dimensional Minkowski space, representing neutral scalar bosons at positive temperature. Our work is based on prior work by Klein and Landau and Hoegh-Krohn

Relaxed Logarithmic Barrier Function Based Model Predictive Control of Linear SystemsMar 11 2015In this paper, we investigate the use of relaxed logarithmic barrier functions in the context of linear model predictive control. We present results that allow to guarantee asymptotic stability of the corresponding closed-loop system, and discuss further ... More

A stabilizing iteration scheme for model predictive control based on relaxed barrier functionsMar 15 2016Apr 06 2016We propose and analyze a stabilizing iteration scheme for the algorithmic implementation of model predictive control for linear discrete-time systems. Polytopic input and state constraints are considered and handled by means of so-called relaxed logarithmic ... More

On spatial and temporal multilevel dynamics and scaling effects in epileptic seizuresMar 30 2011Jul 29 2011Epileptic seizures are one of the most well-known dysfunctions of the nervous system. During a seizure, a highly synchronized behavior of neural activity is observed that can cause symptoms ranging from mild sensual malfunctions to the complete loss of ... More

Duck Traps: Two-dimensional Critical Manifolds in Planar SystemsAug 30 2018Nov 05 2018In this work we consider two-dimensional critical manifolds in planar fast-slow systems near fold and so-called canard (=`duck') points. These higher-dimension, and lower-codimension, situation is directly motivated by the case of hysteresis operators ... More

Risk Concentration and Diversification: Second-Order PropertiesOct 13 2009Dec 19 2009The quantification of diversification benefits due to risk aggregation plays a prominent role in the (regulatory) capital management of large firms within the financial industry. However, the complexity of today's risk landscape makes a quantifiable reduction ... More

Nanoscale imaging of current density with a single-spin magnetometerSep 30 2016Charge transport in nanostructures and thin films is fundamental to many phenomena and processes in science and technology, ranging from quantum effects and electronic correlations in mesoscopic physics, to integrated charge- or spin-based electronic ... More

Local dynamics of topological magnetic defects in the itinerant helimagnet FeGeMar 23 2015Jul 22 2016Chiral magnetic interactions induce complex spin textures including helical and conical spin waves, as well as particle-like objects such as magnetic skyrmions and merons. These spin textures are the basis for innovative device paradigms and give rise ... More

Feedback cooling of a cantilever's fundamental mode below 5 mKFeb 20 2007We cool the fundamental mechanical mode of an ultrasoft silicon cantilever from a base temperature of 2.2 K to 2.9 +/- 0.3 mK using active optomechanical feedback. The lowest observed mode temperature is consistent with limits determined by the properties ... More

A quantum spectrum analyzer enhanced by a nuclear spin memoryOct 11 2016We realize a two-qubit sensor designed for achieving high spectral resolution in quantum sensing experiments. Our sensor consists of an active "sensing qubit" and a long-lived "memory qubit", implemented by the electronic and the nitrogen-15 nuclear spins ... More

Staggered domain wall fermionsSep 16 2016We construct domain wall fermions with a staggered kernel and investigate their spectral and chiral properties numerically in the Schwinger model. In some relevant cases we see an improvement of chirality by more than an order of magnitude as compared ... More

Differential Characters and Geometric ChainsMar 26 2013Apr 09 2013We study Cheeger-Simons differential characters and provide geometric descriptions of the ring structure and of the fiber integration map. The uniqueness of differential cohomology (up to unique natural transformation) is proved by deriving an explicit ... More

Distances and large deviations in the spatial preferential attachment modelSep 26 2018Sep 27 2018We investigate two asymptotic properties of a spatial preferential-attachment model introduced by E. Jacob and P. M\"orters (2013). First, in a regime of strong linear reinforcement, we show that typical distances are at most of doubly-logarithmic order. ... More

Friction force: from mechanics to thermodynamicsNov 17 2009Jul 01 2010We study some mechanical problems in which a friction force is acting on the system. Using the fundamental concepts of state, time evolution and energy conservation we explain how to extend Newtonian mechanics to thermodynamics. We arrive at the two laws ... More

On the relativistic KMS condition for the P(φ)_2 modelSep 29 2006The relativistic KMS condition introduced by Bros and Buchholz provides a link between quantum statistical mechanics and quantum field theory. We show that for the $P(\phi)_2$ model at positive temperature, the two point function for fields satisfies ... More

Spectral properties and chiral symmetry violations of (staggered) domain wall fermions in the Schwinger modelFeb 26 2016Jul 05 2016We follow up on a suggestion by Adams and construct explicit domain wall fermion operators with staggered kernels. We compare different domain wall formulations, namely the standard construction as well as Borici's modified and Chiu's optimal construction, ... More

Thermal Quantum Fields with Spatially Cut-off Interactions in 1+1 Space-time DimensionsJul 25 2003We construct interacting quantum fields in 1+1 space-time dimensions, representing charged or neutral scalar bosons at positive temperature and zero chemical potential. Our work is based on prior work by Klein and Landau and Hoegh-Krohn. Generalized path ... More

Nuclear Magnetic Resonance Imaging with 90 nm ResolutionFeb 27 2007Magnetic resonance imaging, based on the manipulation and detection of nuclear spins, is a powerful imaging technique that typically operates on the scale of millimeters to microns. Using magnetic resonance force microscopy, we have demonstrated that ... More

The role of spin noise in the detection of nanoscale ensembles of nuclear spinsOct 11 2007Oct 31 2007When probing nuclear spins in materials on the nanometer scale, random fluctuations of the spin polarization will exceed the mean Boltzmann polarization for sample volumes below about (100nm)^3. In this work, we use magnetic resonance force microscopy ... More

On the Vacuum Polarization Density Caused by an External FieldJul 01 2003Feb 11 2004We consider an external potential, $-\lambda \phi$, due to one or more nuclei. Following the Dirac picture such a potential polarizes the vacuum. The polarization density as derived in physics literature, after a well known renormalization procedure, ... More

Quantum field theory meets Hopf algebraNov 14 2006Sep 11 2010This paper provides a primer in quantum field theory (QFT) based on Hopf algebra and describes new Hopf algebraic constructions inspired by QFT concepts. The following QFT concepts are introduced: chronological products, S-matrix, Feynman diagrams, connected ... More

A differential identity for Green functionsFeb 15 2006If P is a differential operator with constant coefficients, an identity is derived to calculate the action of exp(P) on the product of two functions. In many-body theory, P describes the interaction Hamiltonian and the identity yields a hierarchy of Green ... More

Quantum groups and interacting quantum fieldsAug 19 2002If C is a cocommutative coalgebra, a bialgebra structure can be given to the symmetric algebra S(C). The symmetric product is twisted by a Laplace pairing and the twisted product of any number of elements of S(C) is calculated explicitly. This is used ... More

Continuous-Variable Quantum Key Distribution with Entanglement in the MiddleMay 07 2012We analyze the performance of continuous-variable quantum key distribution protocols where the entangled source originates not from one of the trusted parties, Alice or Bob, but from the malicious eavesdropper in the middle. This is in contrast to the ... More

Tight Running Time Lower Bounds for Vertex Deletion ProblemsNov 17 2015May 17 2016For a graph class $\Pi$, the $\Pi$-Vertex Deletion problem has as input an undirected graph $G=(V,E)$ and an integer $k$ and asks whether there is a set of at most $k$ vertices that can be deleted from $G$ such that the resulting graph is a member of ... More

A quantum-information-theoretic complement to a general-relativistic implementation of a beyond-Turing computerMay 21 2014Jun 11 2014There exists a growing literature on the so-called physical Church-Turing thesis in a relativistic spacetime setting. The physical Church-Turing thesis is the conjecture that no computing device that is physically realizable (even in principle) can exceed ... More

Vacuum Polarisation Tensors in Constant Electromagnetic Fields: Part IJan 27 2000Dec 29 2000The string-inspired technique is used for the calculation of vacuum polarisation tensors in constant electromagnetic fields. In the first part of this series, we give a detailed exposition of the method for the case of the QED one-loop N-photon amplitude ... More

Blue Stragglers in Globular Clusters: Observations, Statistics and PhysicsJun 13 2014This chapter explores how we might use the observed {\em statistics} of blue stragglers in globular clusters to shed light on their formation. This means we will touch on topics also discussed elsewhere in this book, such as the discovery and implications ... More

Dualité onde-corpuscule formée par une masselotte oscillante dans un milieu élastique : étude théorique et similitudes quantiquesSep 29 2016We introduce a dual wave-particle macroscopic system, where a bead oscillator oscillates in an elastic media which obeys the Klein-Gordon equation. This theoretical system comes mainly from bouncing drops experiments and also a sliding bead on a vibrating ... More

Equality of multiplicity free skew charactersJun 11 2008Oct 09 2008In this paper we show that two skew diagrams lambda/mu and alpha/beta can represent the same multiplicity free skew character [lambda/mu]=[alpha/beta] only in the the trivial cases when lambda/mu and alpha/beta are the same up to translation or rotation ... More

Nuclearity and split for thermal quantum field theoriesNov 26 1998Jan 05 2000We review the heuristic arguments suggesting that any thermal quantum field theory, which can be interpreted as a quantum statistical mechanics of (interacting) relativistic particles, obeys certain restrictions on its number of local degrees of freedom. ... More

On the geometry of metric measure spaces with variable curvature boundsJun 10 2015Sep 09 2015Motivated by a classical comparison result of J. C. F. Sturm we introduce a curvature-dimension condition CD(k,N) for general metric measure spaces and variable lower curvature bound k. In the case of non-zero constant lower curvature our approach coincides ... More

Auxiliary matrices for the six-vertex model at roots of 1 and a geometric interpretation of its symmetriesFeb 03 2003Apr 24 2003The construction of auxiliary matrices for the six-vertex model at a root of unity is investigated from a quantum group theoretic point of view. Employing the concept of intertwiners associated with the quantum loop algebra $U_q(\tilde{sl}_2)$ at $q^N=1$ ... More

Colours associated to non simply-laced Lie algebras and exact S-matricesOct 31 2000Jan 02 2001A new set of exact scattering matrices in 1+1 dimensions is proposed by solving the bootstrap equations. Extending earlier constructions of colour valued scattering matrices this new set has its colour structure associated to non simply-laced Lie algebras. ... More

PT Symmetry of the non-Hermitian XX Spin-Chain: Non-local Bulk Interaction from Complex Boundary FieldsMar 31 2008The XX spin-chain with non-Hermitian diagonal boundary conditions is shown to be quasi-Hermitian for special values of the boundary parameters. This is proved by explicit construction of a new inner product employing a "quasi-fermion" algebra in momentum ... More

Turning the Quantum Group Invariant XXZ Spin-Chain Hermitian: A Conjecture on the Invariant ProductSep 24 2007This is a continuation of a previous joint work with Robert Weston on the quantum group invariant XXZ spin-chain (math-ph/0703085). The previous results on quasi-Hermiticity of this integrable model are briefly reviewed and then connected with a new construction ... More

Solving Baxter's TQ-equation via representation theoryNov 09 2004Nov 23 2004Baxter's TQ-equation is solved for the six-vertex model using the representation theory of quantum groups at roots of unity. A novel simplified construction of the Q-operator is given depending on a new free parameter. Specializing this general construction ... More

On the logarithm of the characteristic polynomial of the Ginibre ensembleJul 30 2015We prove a slightly sharper version of a result of Rider and Vir\'ag who proved that after centering, the logarithm of the absolute value of the characteristic polynomial of the Ginibre ensemble converges in law to the Gaussian Free Field on the unit ... More

Spin squeezing, entanglement and quantum metrology with Bose-Einstein condensatesMar 23 2012Squeezed states, a special kind of entangled states, are known as a useful resource for quantum metrology. In interferometric sensors they allow to overcome the "classical" projection noise limit stemming from the independent nature of the individual ... More

Cosmology and gravitational waves in the Nordstrom-Vlasov system, a laboratory for Dark EnergyJan 24 2013We discuss a cosmological solution of the system which was originally introduced by Calogero and is today popularly known as "Nordstrom-Vlasov system". Although the model is un-physical, its cosmological solution results interesting for the same reasons ... More

Effective temperature for black holesJul 26 2011Jul 28 2011The physical interpretation of black hole's quasinormal modes is fundamental for realizing unitary quantum gravity theory as black holes are considered theoretical laboratories for testing models of such an ultimate theory and their quasinormal modes ... More

A precise response function for the magnetic component of Gravitational Waves in Scalar-Tensor GravityFeb 03 2011Feb 04 2011The important issue of the magnetic component of gravitational waves (GWs) has been considered in various papers in the literature. From such analyses, it resulted that such a magnetic component becomes particularly important in the high frequency portion ... More

A longitudinal component in massive gravitational waves arising from a bimetric theory of gravityNov 06 2008After a brief review of the work of de Paula, Miranda and Marinho on massive gravitational waves arising from a bimetric theory of gravity, in this paper it is shown that the presence of the mass generates a longi- tudinal component in a particular polarization ... More

Analysis of the transverse effect of Einstein's gravitational wavesJul 13 2007The investigation of the transverse effect of gravitational waves (GWs) could constitute a further tool to discriminate among several relativistic theories of gravity on the ground. After a review of the TT gauge, the transverse effect of GWs arising ... More

Interpretation of Mössbauer experiment in a rotating system: a new proof for general relativityFeb 14 2015A historical experiment by K\"undig on the transverse Doppler shift in a rotating system measured with the M\"ossbauer effect has been recently first re-analyzed and then replied [1,2]. The results have shown that a correct re-processing of K\"undig's ... More

Black hole quantum spectrumOct 26 2012Nov 19 2013Introducing a black hole (BH) effective temperature, which takes into account both the non-strictly thermal character of Hawking radiation and the countable behavior of emissions of subsequent Hawking quanta, we recently re-analysed BH quasi-normal modes ... More

Massive relic gravitational waves from f(R) theories of gravity: production and potential detectionJul 23 2010The production of a stochastic background of relic gravitational waves is well known in various works in the literature, where, by using the so called adiabatically-amplified zero-point fluctuations process, it has been shown how the standard inflationary ... More

A review of the stochastic background of gravitational waves in f(R) gravity with WMAP constrainsJan 09 2009Jan 15 2009This paper is a review of previous works on the stochastic background of gravitational waves (SBGWs) which has been discussed in various peer-reviewed journals and international conferences. The SBGWs is analyzed with the aid of the Wilkinson Microwave ... More

A non-geodesic motion in the R^-1 theory of gravity tuned with observationsJan 01 2008Jan 11 2008In the general picture of high order theories of gravity, recently, the R^-1 theory has been analyzed in two different frameworks. In this letter a third context is added, considering an explicit coupling between the R^-1 function of the Ricci scalar ... More

The production of matter from curvature in a particular linearized high order theory of gravity and the longitudinal response function of interferometersMar 26 2007The strict analogy between scalar-tensor theories of gravity and high order gravity is well known in literature. In this paper it is shown that, from a particular high order gravity theory known in literature, it is possible to produce, in the linearized ... More

When is the underlying space of an orbifold a manifold with boundary?Sep 22 2015We answer the question of when the underlying space of an orbifold is a manifold with boundary in several categories.

Efficient Gluing of Numerical Continuation and a Multiple Solution Method for Elliptic PDEsJun 26 2014Oct 18 2014Numerical continuation calculations for ordinary differential equations (ODEs) are, by now, an established tool for bifurcation analysis in dynamical systems theory as well as across almost all natural and engineering sciences. Although several excellent ... More

Time-Scale and Noise Optimality in Self-Organized Critical Adaptive NetworksOct 25 2011Dec 23 2011Recent studies have shown that adaptive networks driven by simple local rules can organize into "critical" global steady states, providing another framework for self-organized criticality (SOC). We focus on the important convergence to criticality and ... More

A Remark on Geometric Desingularization of a Non-Hyperbolic Point using Hyperbolic SpaceMar 15 2014A steady state (or equilibrium point) of a dynamical system is hyperbolic if the Jacobian at the steady state has no eigenvalues with zero real parts. In this case, the linearized system does qualitatively capture the dynamics in a small neighborhood ... More

On highly regular strongly regular graphsApr 30 2014Oct 19 2016In this paper we unify many existing regularity conditions for graphs, including strong regularity, $k$-isoregularity, and the $t$-vertex condition. We develop an algebraic composition/decomposition theory of regularity conditions. Using our theoretical ... More

Scattering theory for Klein-Gordon equations with non-positive energyJan 11 2011Sep 09 2011We study the scattering theory for charged Klein-Gordon equations: \[\{{array}{l} (\p_{t}- \i v(x))^{2}\phi(t,x) \epsilon^{2}(x, D_{x})\phi(t,x)=0,[2mm] \phi(0, x)= f_{0}, [2mm] \i^{-1} \p_{t}\phi(0, x)= f_{1}, {array}. \] where: \[\epsilon^{2}(x, D_{x})= ... More

Spectral and scattering theory of charged $P(\varphi)_2$ modelsJun 30 2009We consider in this paper space-cutoff charged $P(\varphi)_{2}$ models arising from the quantization of the non-linear charged Klein-Gordon equation: \[ (\p_{t}+\i V(x))^{2}\phi(t, x)+ (-\Delta_{x}+ m^{2})\phi(t,x)+ g(x)\p_{\overline{z}}P(\phi(t,x), \overline{\phi}(t,x))=0, ... More

k-Means Clustering Is Matrix FactorizationDec 23 2015We show that the objective function of conventional k-means clustering can be expressed as the Frobenius norm of the difference of a data matrix and a low rank approximation of that data matrix. In short, we show that k-means clustering is a matrix factorization ... More

A note on Prüfer-like coding and counting forests of uniform hypertreesOct 02 2011This note presents an encoding and a decoding algorithms for a forest of (labelled) rooted uniform hypertrees and hypercycles in linear time, by using as few as $n - 2$ integers in the range $[1,n]$. It is a simple extension of the classical Pr\"{u}fer ... More

Getting Started with Isabelle/jEditAug 07 2012Jan 31 2013We give a beginner-oriented introduction to Isabelle/jEdit, providing motivation for using it as well as pointing at some differences to the traditional Proof General interface and current limitations.

Galilean IsometriesMar 09 2009We introduce three nested Lie algebras of infinitesimal `isometries' of a Galilei space-time structure which play the r\^ole of the algebra of Killing vector fields of a relativistic Lorentz space-time. Non trivial extensions of these Lie algebras arise ... More

Recent progress constraining the nuclear equation of state from astrophysics and heavy ion reactionsJun 01 2007The quest for the nuclear equation of state (EoS) at high densities and/or extreme isospin is one of the longstanding problems of nuclear physics. Ab initio calculations for the nuclear many-body problem make predictions for the density and isospin dependence ... More

More Compact Oracles for Approximate Distances in Planar GraphsSep 12 2011Oct 28 2011Distance oracles are data structures that provide fast (possibly approximate) answers to shortest-path and distance queries in graphs. The tradeoff between the space requirements and the query time of distance oracles is of particular interest and the ... More

Rank k Cholesky Up/Down-dating on the GPU: gpucholmodV0.2Nov 04 2010In this note we briefly describe our Cholesky modification algorithm for streaming multiprocessor architectures. Our implementation is available in C++ with Matlab binding, using CUDA to utilise the graphics processing unit (GPU). Limited speed ups are ... More

The Mössbauer rotor experiment and the general theory of relativityFeb 12 2016Feb 16 2016This paper is a rebuttal to Eur. Phys. Jour. Plus 130, 191 (2015), which claims that the results in arXiv:1502.04911 (Ann. Phys. 355, 360 (2015)) are incorrect. For this reason, some of the results in arXiv:1502.04911 have been reviewed and clarified. ... More

A quantitative theory for the continuity equationFeb 09 2016Mar 24 2016In this work, we provide stability estimates for the continuity equation with Sobolev vector fields. The results are inferred from contraction estimates for certain logarithmic Kantorovich--Rubinstein distances. As a by-product, we obtain a new proof ... More

Newton's Theorem of Revolving Orbits in Curved SpacetimeFeb 01 2016Oct 04 2016Newton's theorem of revolving orbits states that one can multiply the angular speed of a Keplerian orbit by a factor $k$ by applying a radial inverse cubed force proportional to $(1-k^2)$. In this paper we derive an extension of this theorem in general ... More

Cosmological flux noise and measured noise power spectra in SQUIDsSep 16 2014Jun 20 2016The understanding of the origin of $1/f$ magnetic flux noise commonly observed in superconducting devices such as SQUIDS and qubits is still a major unsolved puzzle. Here we discuss the possibility that a significant part of the observed low-frequency ... More

Possible resonance effect of axionic dark matter in Josephson junctionsSep 15 2013Nov 20 2013We provide theoretical arguments that dark matter axions from the galactic halo that pass through the earth may generate a small observable signal in resonant S/N/S Josephson junctions. The corresponding interaction process is based on uniqueness of the ... More

Statistical mechanics of the vacuumDec 07 2011Mar 01 2012The vacuum is full of virtual particles which exist for short moments of time. In this paper we construct a chaotic model of vacuum fluctuations associated with a fundamental entropic field that generates an arrow of time. The dynamics can be physically ... More

Complexity of chaotic fields and standard model parametersFeb 11 2007In order to understand the parameters of the standard model of electroweak and strong interactions (coupling constants, masses, mixing angles) one needs to embed the standard model into some larger theory that accounts for the observed values. This means ... More

Axion mass estimates from resonant Josephson junctionsMar 22 2014Jun 10 2014Recently it has been proposed that dark matter axions from the galactic halo can produce a small Shapiro step-like signal in Josephson junctions whose Josephson frequency resonates with the axion mass [C. Beck, PRL 111, 231801 (2013)]. Here we show that ... More

Generalized statistical mechanics for superstatistical systemsJul 06 2010Mesoscopic systems in a slowly fluctuating environment are often well described by superstatistical models. We develop a generalized statistical mechanics formalism for superstatistical systems, by mapping the superstatistical complex system onto a system ... More

Laboratory tests on dark energyDec 13 2005Mar 07 2006The physical nature of the currently observed dark energy in the universe is completely unclear, and many different theoretical models co-exist. Nevertheless, if dark energy is produced by vacuum fluctuations then there is a chance to probe some of its ... More

Superstatistics: Recent developments and applicationsFeb 12 2005We review some recent developments which make use of the concept of `superstatistics', an effective description for nonequilibrium systems with a varying intensive parameter such as the inverse temperature. We describe how the asymptotic decay of stationary ... More

Generalized statistical mechanics and fully developed turbulenceOct 03 2001The statistical properties of fully developed hydrodynamic turbulence can be successfully described using methods from nonextensive statistical mechanics. The predicted probability densities and scaling exponents precisely coincide with what is measured ... More

Magnetically driven outflows from Jovian circum-planetaryaccretion disksOct 01 2003We discuss the possibility to launch outflows from the close vicinity of a protoplanetary core considering a scenario where the protoplanet surrounded by a circum-planetary accretion disk is located in a circum-stellar disk. For the circum-planetary disk ... More

The remote_build ToolMay 15 2018This is an introduction to the remote_build tool for transparent remote session builds. The intended workflow for a user is to locally issue a build command for some session heap images and then continue working, while the actual build runs on a remote ... More

Moments and Classification for Conjugation-Invariant Rotations and Fake Uniformity in the Stochastic Radon TransformMar 06 2012We consider a generalisation of the stochastic Radon transform, introduced for an inverse problem in tomography by Panaretos. Specifically, we allow the distribution of the three-dimensional rotation in the statistical model of that work to be different ... More

On the arithmetic and geometric means of the prime numbersSep 26 2016In this paper we establish explicit upper and lower bounds for the ratio of the arithmetic and geometric means of the prime numbers, which improve the current best estimates. Further, we prove several conjectures related to this ration stated by Hassani. ... More

The Generalized Subterm Criterion in TTT2Sep 12 2016We present an SMT encoding of a generalized version of the subterm criterion and evaluate its implementation in TTT2.

Contact between Lagrangian manifoldsNov 26 2018Tangential intersections of Lagrangian manifolds up to contact equivalence correspond to smooth function germs (generating functions) up to right equivalence locally around the intersection point. We extend this result of Golubitsky and Guillemin for ... More

Heat and Gravitation. II. StabilityApr 02 2009In this second article of a series we propose to base criteria of stability on the hamiltonian functional that is provided by the variational principle, to replace the reliance that has often been placed on {\it ad hoc} definitions of the "energy". We ... More

Generalization and Exact Deformations of Quantum GroupsJun 25 1996A large family of "standard" coboundary Hopf algebras is investigated. The existence of a universal R-matrix is demonstrated for the case when the parameters are in general position. Algebraic surfaces in parameter space are characterized by the appearance ... More

Universal T-matrix for Twisted Quantum gl(N)May 16 1995The Universal T-matrix is the capstone of the structure that consists of a quantum group and its dual, and the central object from which spring the T-matrices (monodromies) of all the associated integrable models. A closed expression is obtained for the ... More

Advertising, consensus, and ageing in multilayer Sznajd modelDec 13 2003In the Sznajd consensus model on the square lattice, two people who agree in their opinions convince their neighbours of this opinion. We generalize it to many layers representing many age levels, and check if still a consensus among all layers is possible. ... More

The domino effect for marketsOct 22 2001A generalization of the Cont-Bouchaud market model to three markets agrees with the correlations netween New York, Tokyo, and Frankfurt observed by Vandewalle et al.

Sornette-Ide model for markets: Trader expectations as imaginary partJan 12 2002A nonlinear differential equation of Sornette-Ide type with noise, for a complex variable, yields endogenous crashes, preceded by roughly log-periodic oscillations in the real part, and a strong increase in the imaginary part. The latter is interpreted ... More

Leptonic contributions to the effective electromagnetic coupling at four-loop order in QEDMay 02 2013The running of the effective electromagnetic coupling is for many electroweak observables the dominant correction. It plays an important role for deriving constraints on the Standard Model in the context of electroweak precision measurements. We compute ... More

Hamiltonians with Riesz Bases of Generalised Eigenvectors and Riccati EquationsMay 28 2010An algebraic Riccati equation for linear operators is studied, which arises in systems theory. For the case that all involved operators are unbounded, the existence of infinitely many selfadjoint solutions is shown. To this end, invariant graph subspaces ... More