Results for "Michael Hanfland"

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High-pressure study of X-ray diffuse scattering in ferroelectric perovskitesJul 27 2007We present a high-pressure x-ray diffuse scattering study of the ABO$_3$ ferroelectric perovskites BaTiO_3 and KNbO_3. The well-known diffuse lines are observed in all the phases studied. In KNbO_3, we show that the lines are present up to 21.8 GPa, with ... More
Crystal structure of solid Oxygen at high pressure and low temperatureNov 21 2001Results of X-ray diffraction experiments on solid oxygen at low temperature and at pressures up to 10 GPa are presented.A careful sample preparation and annealing around 240 K allowed to obtain very good diffraction patterns in the orthorhombic delta-phase. ... More
Jahn-Teller, polarity and insulator-to-metal transition in BiMnO3 at high pressureJun 25 2013Feb 20 2014The interaction of coexisting structural instabilities in multiferroic materials gives rise to intriguing coupling phenomena and extraordinarily rich phase diagrams, both in bulk materials and strained thin films. Here we investigate the multiferroic ... More
Formation of transition metal hydrides at high pressuresJul 13 2009Silane (SiH4) is found to (partially) decompose at pressures above 50 GPa at room temperature into pure Si and H2. The released hydrogen reacts with surrounding metals in the diamond anvil cell to form metal hydrides. A formation of rhenium hydride is ... More
Anisotropic compression in the high pressure regime of pure and Cr-doped vanadium dioxideOct 09 2011May 24 2012We present structural studies of V$_{1-x}$Cr$_x$O$_2$ (pure, 0.7% and 2.5% Cr doped) compounds at room temperature in a diamond anvil cell for pressures up to 20 GPa using synchrotron x-ray powder diffraction. All the samples studied show a persistence ... More
Observation of the Sb2S3-type post-post-GdFeO3-perovskite: A model structure for high density ABX3 and A2X3 phasesOct 10 2014Ten years have passed since the description of the perovskite to post-perovskite transition in MgSiO3 and its' impact on the mineralogy and rheology of the D" region at the base of the Earth's mantle. Much work has explored the mechanisms operating during ... More
High-pressure behavior of methylammonium lead iodide (MAPbI3) hybrid perovskiteMay 11 2016In this paper we provide an accurate high-pressure structural and optical study of MAPbI3 hybrid perovskite. Structural data show the presence of a phase transition towards an orthorhombic structure around 0.3 GPa followed by full amorphization of the ... More
Symmetry preserving lattice collapse in tetragonal SrFe_(2-x)Ru_xAs_2 (x = 0, 0.2) -- a combined experimental and theoretical studyApr 27 2011In a joint experimental and theoretical study, we investigate the isostructural collapse from the ambient pressure tetragonal phase to a collapsed tetragonal phase for non-superconducting metallic SrFe2As2 and SrFe_1.8Ru_0.2As_2. The crystallographic ... More
Pressure induced Hydrogen-Hydrogen interaction in metallic FeH revealed by NMRFeb 08 2019Knowledge of the behavior of hydrogen in metal hydrides is the key for understanding their electronic properties. So far, no experimental methods exist to access these properties beyond 100 GPa, where high-Tc superconductivity emerges. Here, we present ... More
Structural transformations of Li2C2 at high pressuresApr 26 2016Structural changes of Li2C2 under pressure were studied by synchrotron x-ray diffraction in a diamond anvil cell under hydrostatic conditions and by using evolutionary search methodology for crystal structure prediction. We show that the high-pressure ... More
Gibbs energy of ices III, V and VI: wholistic thermodynamics and elasticity of the water phase diagram to 2300 MPaJul 22 2019Gibbs energy representations for ice III, V and VI are reported. These were constructed using new measurements of volumes at high pressure over a range of low temperatures combined with calculated vibrational energies grounded in statistical physics. ... More
Discovery of a superhard iron tetraboride superconductorApr 18 2013Single crystals of novel orthorhombic (space group Pnnm) iron tetraboride FeB4 were synthesised at pressures above 8 GPa and high temperatures. Magnetic susceptibility measurements demonstrated bulk superconductivity below 2.9 K. The putative isotope ... More
FeOOH instability at the lower mantle conditionsAug 06 2019Goethite, {\alpha}-FeOOH, is a major component among oxidized iron species, called rust, which formed as a product of metabolism of anoxygenic prokaryotes (1, 2) inhabiting the Earth from about 3.8 billion years (Gy) ago until the Great Oxidation Event ... More
Deconfinement transition and dimensional crossover in the Bechgaard-Fabre salts: pressure- and temperature-dependent optical investigationsSep 25 2009The infrared response of the organic conductor (TMTSF)$_2$PF$_6$ and the Mott insulator (TMTTF)$_2$PF$_6$ are investigated as a function of temperature and pressure and for the polarization parallel and perpendicular to the molecular stacks. By applying ... More
Superconductivity in Weyl Semimetal Candidate MoTe2Aug 14 2015Mar 02 2016In recent years, layered transition-metal dichalcogenides (TMDs) have attracted considerable attention because of their rich physics; for example, these materials exhibit superconductivity, charge density waves, and the valley Hall effect. As a result, ... More
High-pressure synthesis of ultraincompressible hard rhenium nitride pernitride Re$_{2}$(N$_{2}$)N$_{2}$ stable at ambient conditionsFeb 25 2019Here we report the synthesis of metallic, ultraincompressible (bulk modulus $K_{0}$ = 428(10) GPa) and very hard (nanoindentation hardness 36.7(8) GPa) rhenium (V) nitride pernitride Re$_{2}$(N$_{2}$)N$_{2}$. While the empirical chemical formula of the ... More
Superconducting and normal phases of FeSe single crystals at high pressureApr 11 2009May 12 2009We report on the synthesis of superconducting single crystals of FeSe, and their characterization by X-ray diffraction, magnetization and resistivity. We have performed ac susceptibility measurements under high pressure in a hydrostatic liquid argon medium ... More
Plasmons in Sodium under Pressure: Increasing Departure from Nearly-Free-Electron BehaviorApr 18 2011We have measured plasmon energies in Na under high pressure up to 43 GPa using inelastic x-ray scattering (IXS). The momentum-resolved results show clear deviations, growing with increasing pressure, from the predictions for a nearly-free electron metal. ... More
Structural properties of the sesquicarbide superconductor La2C3 at high pressureMar 24 2005The effect of pressure on the structural properties of lanthanum sesquicarbide La2C3 (T_c = 13 K) has been investigated at room temperature by angle-dispersive powder x-ray diffraction in a diamond anvil cell. The compound remains in the cubic Pu2C3-type ... More
Quantum and Classical Orientational Ordering in Solid HydrogenMay 14 1996Jan 17 1997We present a unified view of orientational ordering in phases I, II, and III of solid hydrogen. Phases II and III are orientationally ordered, while the ordering objects in phase II are angular momenta of rotating molecules, and in phase III the molecules ... More
Pressure-driven orbital reorientation and change in Mott-Hubbard gap in YTiO3Apr 15 2005We investigate the crystal structure of YTiO3 at high pressures up to 30 GPa by synchrotron x-ray powder diffraction (T = 295 K). The variation of the Ti--O bond lengths with pressure evidences a distinct change in the distortion of the TiO_6 octahedra ... More
Crystal structure of LaTiO_3.41 under pressureFeb 27 2004The crystal structure of the layered, perovskite-related LaTiO_3.41 (La_5Ti_5O_{17+\delta}) has been studied by synchrotron powder x-ray diffraction under hydrostatic pressure up to 27 GPa (T = 295 K). The ambient-pressure phase was found to remain stable ... More
Pressure-induced structural phase transition in the Bechgaard-Fabre saltsMay 28 2009The crystal structures of the quasi-one-dimensional organic salts (TMTTF)$_2$PF$_6$ and (TMTSF)$_2$PF$_6$ were studied by pressure-dependent x-ray diffraction up to 10 GPa at room temperature. The unit-cell parameters exhibit a clear anomaly due to a ... More
Structural investigations on $ε$-FeGe at high pressure and low temperatureMar 01 2007The structural parameters of $\epsilon$-FeGe have been determined at ambient conditions using single crystal refinement. Powder diffraction have been carried out to determine structural properties and compressibility for pressures up to 30 GPa and temperatures ... More
A Worst-case Bound for Topology Computation of Algebraic CurvesApr 08 2011Computing the topology of an algebraic plane curve $\mathcal{C}$ means to compute a combinatorial graph that is isotopic to $\mathcal{C}$ and thus represents its topology in $\mathbb{R}^2$. We prove that, for a polynomial of degree $n$ with coefficients ... More
Comparison between step strains and slow steady shear in a bubble raftDec 20 2004We report on a comparison between stress relaxations after an applied step strain and stress relaxations during slow, continuous strain in a bubble raft. A bubble raft serves as a model two-dimensional foam and consists of a single layer of bubbles on ... More
Evaluation of Contactless Smartcard AntennasJul 23 2015This report summarizes the results of our evaluation of antennas of contactless and dual interface smartcards and our ideas for user-switchable NFC antennas. We show how to disassemble smartcards with contactless capabilities in order to obtain the bare ... More
The periodic Floer homology of a Dehn twistOct 04 2004May 02 2005The periodic Floer homology of a surface symplectomorphism, defined by the first author and M. Thaddeus, is the homology of a chain complex which is generated by certain unions of periodic orbits, and whose differential counts certain embedded pseudoholomorphic ... More
A Variant of K-theory: K_{+-}Feb 11 2003We describe a variant of K-theory for spaces with involution, built from vector bundles which are sent to their negative under the involution.
CPT and Other Symmetries in String/M TheorySep 20 2004Feb 05 2005We initiate a search for non-perturbative consistency conditions in M theory. Some non-perturbative conditions are already known in Type I theories; we review these and search for others. We focus principally on possible anomalies in discrete symmetries. ... More
Linear programming methods for exponential dominationJan 19 2018For a graph $G,$ we consider $D \subset V(G)$ to be a porous exponential dominating set if $1 \le \sum_{d \in D}$ $\left( \tfrac{1}{2} \right)^{dist(d,v) -1}$ for every $v \in V(G),$ where $dist(d,v)$ denotes the length of the shortest $dv$ path. The ... More
Scaling of the diffraction measure of $k$-free integers near the originMar 30 2019Asymptotics are derived for the scaling of the total diffraction intensity for the set of $k$-free integers near the origin, which is a measure for the degree of patch fluctuations.
On exponential domination of the consecutive circulant graphDec 14 2017For a graph $G,$ we consider $D \subset V(G)$ to be a porous exponential dominating set if $1\le \sum_{d \in D}$ $\left( \frac{1}{2} \right)^{\text{dist}(d,v) -1}$ for every $v \in V(G),$ where dist$(d,v)$ denotes the length of the smallest $dv$ path. ... More
Hysteresis and phase transitions in a lattice regularization of an ill-posed forward-backward diffusion equationOct 18 2016We consider a lattice regularization for an ill-posed diffusion equation with trilinear constitutive law and study the dynamics of phase interfaces in the parabolic scaling limit. Our main result guarantees for a certain class of single-interface initial ... More
Stopping Active Learning based on Predicted Change of F Measure for Text ClassificationJan 26 2019During active learning, an effective stopping method allows users to limit the number of annotations, which is cost effective. In this paper, a new stopping method called Predicted Change of F Measure will be introduced that attempts to provide the users ... More
The role of blood circulatory system in thermal regulation of animals explained by entropy production analysisAug 16 2013A novel model of thermal regulation of homoeothermic animals has been implemented. The model is based on a non-equilibrium thermodynamic approach which introduces entropy balance and the rate of entropy generation as a formulation of The Second Law. The ... More
Ab-initio wave-length dependent Raman spectra: Placzek approximation and beyondJun 11 2018Jun 13 2019We analyze how to obtain non-resonant and resonant Raman spectra within the Placzek as well as the Albrecht approximation. Both approximations are derived from the matrix element for light scattering by application of the Kramers, Heisenberg and Dirac ... More
A note on Neumann problems on graphsMar 22 2018We discuss Neumann problems for self-adjoint Laplacians on (possibly infinite) graphs. Under the assumption that the heat semigroup is ultracontractive we discuss the unique solvability for non-empty subgraphs with respect to the vertex boundary and provide ... More
Hysteresis and phase transitions in a lattice regularization of an ill-posed forward-backward diffusion equationOct 18 2016Aug 06 2017We consider a lattice regularization for an ill-posed diffusion equation with trilinear constitutive law and study the dynamics of phase interfaces in the parabolic scaling limit. Our main result guarantees for a certain class of single-interface initial ... More
Colored Khovanov-Rozansky homology for infinite braidsSep 19 2017We show that the limiting unicolored $\mathfrak{sl}(N)$ Khovanov-Rozansky chain complex of any infinite positive braid categorifies a highest-weight projector. This result extends an earlier result of Cautis categorifying highest-weight projectors using ... More
Open Mobile API: Accessing the UICC on Android DevicesJan 12 2016This report gives an overview of secure element integration into Android devices. It focuses on the Open Mobile API as an open interface to access secure elements from Android applications. The overall architecture of the Open Mobile API is described ... More
On Covert Acoustical Mesh Networks in AirJun 04 2014Covert channels can be used to circumvent system and network policies by establishing communications that have not been considered in the design of the computing system. We construct a covert channel between different computing systems that utilizes audio ... More
Root Refinement for Real PolynomialsApr 07 2011Jun 12 2013We consider the problem of approximating all real roots of a square-free polynomial $f$. Given isolating intervals, our algorithm refines each of them to a width of $2^{-L}$ or less, that is, each of the roots is approximated to $L$ bits after the binary ... More
A linear programming method for exponential dominationJan 19 2018Mar 01 2018For a graph $G,$ the set $D \subseteq V(G)$ is a porous exponential dominating set if $1 \le \sum_{d \in D} \left( 2 \right)^{1-dist(d,v)}$ for every $v \in V(G),$ where $dist(d,v)$ denotes the length of the shortest $dv$ path. The porous exponential ... More
A natural probability measure derived from Stern's diatomic sequenceJun 01 2017Mar 15 2018Stern's diatomic sequence with its intrinsic repetition and refinement structure between consecutive powers of $2$ gives rise to a rather natural probability measure on the unit interval. We construct this measure and show that it is purely singular continuous, ... More
Logic Programming with Graph Automorphism: Integrating naut with Prolog (Tool Description)Jul 17 2016Aug 01 2016This paper presents the plnauty~library, a Prolog interface to the nauty graph-automorphism tool. Adding the capabilities of nauty to Prolog combines the strength of the "generate and prune" approach that is commonly used in logic programming and constraint ... More
Slow Steady-Shear of Plastic Bead RaftsOct 12 2004Experimental measurements of the response of a two dimensional system of plastic beads subjected to steady shear are reported. The beads float at the surface of a fluid substrate and are subjected to a slow, steady-shear in a Couette geometry. The flow ... More
Asymmetric response of a jammed plastic bead raftMay 18 2006Fluctuation-dissipation relations have received significant attention as a potential method for defining an effective temperature in nonequilibrium systems. The successful development of an effective temperature would be an important step in the application ... More
Examples of nonpolygonal limit shapes in i.i.d. first-passage percolation and infinite coexistence in spatial growth modelsSep 13 2010Mar 13 2013We construct an edge-weight distribution for i.i.d. first-passage percolation on $\mathbb{Z}^2$ whose limit shape is not a polygon and whose extreme points are arbitrarily dense in the boundary. Consequently, the associated Richardson-type growth model ... More
Group analysis of differential equations and generalized functionsDec 28 1999We present an extension of the methods of classical Lie group analysis of differential equations to equations involving generalized functions (in particular: distributions). A suitable framework for such a generalization is provided by Colombeau's theory ... More
Interface dynamics in discrete forward-backward diffusion equationsApr 05 2013We study the motion of phase interfaces in a diffusive lattice equation with bistable nonlinearity and derive a free boundary problem with hysteresis to describe the macroscopic evolution in the parabolic scaling limit. The first part of the paper deals ... More
What the characters of irreducible subrepresentations of Jordan cells can tell us about LCFTJul 22 2013Jan 04 2014In this article, we review some aspects of logarithmic conformal field theories which can be inferred from the characters of irreducible submodules of indecomposable modules. We will mainly consider the W(2,2p-1,2p-1,2p-1) series of triplet algebras and ... More
An algorithm for quantifying dependence in multivariate data setsJul 04 2012Sep 27 2012We describe an algorithm to quantify dependence in a multivariate data set. The algorithm is able to identify any linear and non-linear dependence in the data set by performing a hypothesis test for two variables being independent. As a result we obtain ... More
Vacuum instability and gravitational collapseNov 06 2002Dec 11 2002We argue that $(0,1)$ heterotic string models with 4 non-heterotic spacetime dimensions may provide an instability of the vacuum to gravitational polarization in globally strong gravitational fields. This instability would be triggered during gravitational ... More
SL(n,C)- Representation spaces of Knot GroupsFeb 11 2016The first part of this article is a general introduction to the the theory of representation spaces of discrete groups into SL(n,C). Special attention is paid to knot groups. In Section 2 we discuss the difference between the tangent space at the representation ... More
The Non-Existent Complex 6-SphereOct 25 2016The possible existence of a complex structure on the 6-sphere has been a famous unsolved problem for over 60 years. In that time many ``solutions'' have been put forward, in both directions. Mistakes have always been found. In this paper I present a short ... More
Boundary form factors in the Smirnov--Fateev model with a diagonal boundary $S$ matrixJan 07 2008The boundary conditions with diagonal boundary $S$ matrix and the boundary form factors for the Smirnov--Fateev model on a half line has been considered in the framework of the free field representation. In contrast to the case of the sine-Gordon model, ... More
Acoustic methods for measuring bullet velocityDec 27 2008This article describes two acoustic methods to measure bullet velocity with an accuracy of 1% or better. In one method, a microphone is placed within 0.1 m of the gun muzzle and a bullet is fired at a steel target 45 m away. The bullet's flight time is ... More
Sheaf and cosheaf methods for analyzing multi-model systemsApr 15 2016There is an interplay between models, specified by variables and equations, and their connections to one another. This dichotomy should be reflected in the abstract as well. Without referring to the models directly -- only that a model consists of spaces ... More
Intrinsic flat convergence with bounded Ricci curvatureMay 13 2014Apr 24 2015In this paper we address the relationship between Gromov-Hausdorff limits and intrinsic flat limits of complete Riemannian manifolds. In \cite{SormaniWenger2010, SormaniWenger2011}, Sormani-Wenger show that for a sequence of Riemannian manifolds with ... More
Generalization bound for kernel similarity learningOct 12 2016Similarity learning has received a large amount of interest and is an important tool for many scientific and industrial applications. In this framework, we wish to infer the distance (similarity) between points with respect to an arbitrary distance function ... More
On the autonomous metric on groups of Hamiltonian diffeomorphisms of closed hyperbolic surfacesMay 13 2013May 30 2014Let $\Sigma_g$ be a closed hyperbolic surface of genus $g$ and let $Ham(\Sigma_g)$ be the group of Hamiltonian diffeomorphisms of $\Sigma_g$. The most natural word metric on this group is the autonomous metric. It has many interesting properties, most ... More
Quasi-morphisms and L^p-metrics on groups of volume-preserving diffeomorphismsOct 14 2011Sep 03 2012Let M be a smooth compact connected oriented manifold of dimension at least two endowed with a volume form. We show that every homogeneous quasi-morphism on the identity component $Diff_0(M,vol)$ of the group of volume preserving diffeomorphisms of M, ... More
Isomorphisms of Hilbert C*-Modules and $*$-Isomorphisms of Related Operator C*-AlgebrasMay 09 1995Let $\cal M$ be a Banach C*-module over a C*-algebra $A$ carrying two $A$-valued inner products $< .,. >_1$, $<.,. >_2$ which induce equivalent to the given one norms on $\cal M$. Then the appropriate unital C*-algebras of adjointable bounded $A$-linear ... More
A half-normal distribution scheme for generating functions and the unexpected behavior of Motzkin pathsMay 10 2016We present an extension of a theorem by Michael Drmota and Mich\`ele Soria [Images and Preimages in Random Mappings, 1997] that can be used to identify the limiting distribution for a class of combinatorial schemata. This is achieved by determining analytical ... More
"Did I Say Something Wrong?" A Word-Level Analysis of Wikipedia Articles for Deletion DiscussionsMar 25 2016This thesis focuses on gaining linguistic insights into textual discussions on a word level. It was of special interest to distinguish messages that constructively contribute to a discussion from those that are detrimental to them. Thereby, we wanted ... More
Processing Complex Sentences in the Centering FrameworkMay 14 1996We extend the centering model for the resolution of intra-sentential anaphora and specify how to handle complex sentences. An empirical evaluation indicates that the functional information structure guides the search for an antecedent within the sentence. ... More
Never Look Back: An Alternative to CenteringJun 25 1998I propose a model for determining the hearer's attentional state which depends solely on a list of salient discourse entities (S-list). The ordering among the elements of the S-list covers also the function of the backward-looking center in the centering ... More
Measuring the Size of Large No-Limit Poker GamesFeb 27 2013Mar 07 2013In the field of computational game theory, games are often compared in terms of their size. This can be measured in several ways, including the number of unique game states, the number of decision points, and the total number of legal actions over all ... More
Large-Scale Reasoning with OWLFeb 14 2016With the growth of the Semantic Web in size and importance, more and more knowledge is stored in machine-readable formats such as the Web Ontology Language OWL. This paper outlines common approaches for efficient reasoning on large-scale data consisting ... More
Non-Abelian twisted kinks in chiral Gross-Neveu model with isospinDec 12 2015Apr 05 2016The two-dimensional, massless Gross-Neveu model with Nc colors and SU(2) isospin is studied analytically in the large Nc limit. The chiral SU(2)L X SU(2)R symmetry is broken spontaneously in the vacuum. Twisted kinks connecting two arbitrary points on ... More
Space-Efficient Latent ContractsApr 08 2016Jun 01 2016Standard higher-order contract monitoring breaks tail recursion and leads to space leaks that can change a program's asymptotic complexity. Space efficient semantics restore tail recursion and bound the amount of space used by contacts. Space efficient ... More
A quasi-exactly solvable model: two charges in a magnetic field, subject to a non-Coulomb mutual interactionSep 24 2015We extend the class of QM problems which permit for quasi-exact solutions. Specifically, we consider planar motion of two interacting charges in a constant uniform magnetic field. While Turbiner and Escobar-Ruiz (2013) addressed the case of the Coulomb ... More
Graphics Turing TestMar 31 2006We define a Graphics Turing Test to measure graphics performance in a similar manner to the definition of the traditional Turing Test. To pass the test one needs to reach a computational scale, the Graphics Turing Scale, for which Computer Generated Imagery ... More
The Universal Severi Variety of Rational Curves on K3 SurfacesOct 19 2011We investigate the universal Severi variety of rational curves on K3 surfaces, which parametrises irreducible rational curves in a fixed class on varying K3 surfaces of fixed genus. We investigate the conjecuted irreducibility of this space in the case ... More
Equivariant Cohomology and Representations of the Symmetric GroupDec 21 2000A cohomological study is made of an equivariant map betwen the configuration space of n points in space and the flag manifold of U(n).
Taubes's proof of the Weinstein conjecture in dimension threeJun 13 2009Sep 22 2009This is an introduction to Taubes's proof of the Weinstein conjecture, written for the AMS Current Events Bulletin. It is intended to be accessible to nonspecialists, so much of the article is devoted to background and context.
Non Super-Cell SuperConductivity Of High Tc MaterialsMay 20 2010Recently we have described materials interface transport coupling rigorously utilizing NEGF nonequilibrium Green's functions, and have discussed the Hamiltonian terms that from Green's theorem and boundary conditions can be rewritten as Self Energy. We ... More
Further Exploration of Riemann's Functional EquationSep 10 2016A previous exploration of the Riemann functional equation that focussed on the critical line, is extended over the complex plane. Significant results include a simpler derivation of the fundamental equation developed previously, and its generalization ... More
Warm Gas at High Redshift - Clues to Gravitational Structure Formation from Optical Spectroscopy of Lyman Alpha Absorption SystemsDec 01 1995We discuss the effects of gravitational collapse on the shape of absorption line profiles for low column density (log N(HI) < 14) Lyman Alpha forest clouds and argue by comparison with cosmological simulations that Lyman alpha forest observations show ... More
Large NSep 08 2005Some mysterious features of the strong interactions become easily understood if our usual QCD with N=3 is `close to' SU(oo) and if the latter theory is confining. N=oo theories are theoretically simpler; in particular there has been much progress in constructing ... More
J/ψProduction in Direct and Resolved Photon CollisionsApr 29 2003The production of J/Psi mesons in photon photon collisions allows for a test of factorization in color-octet processes as predicted by NRQCD and observed at the Tevatron. We calculate the cross sections for J/Psi production with direct and resolved photons, ... More
Theory of hard photoproductionJun 19 2002The present theoretical knowledge about photons and hard photoproduction processes, i.e. the production of jets, light and heavy hadrons, quarkonia, and prompt photons in photon-photon and photon-hadron collisions, is reviewed. Virtual and polarized photons ... More
Hofer's length spectrum of symplectic surfacesNov 09 2014Following a question of F. Le Roux, we consider a system of invariants $l_A : H_1(M; \mathbb{Z})\to\mathbb{R}$ of a symplectic surface $M$. These invariants compute the minimal Hofer energy needed to translate a disk of area $A$ along a given homology ... More
Lectures on Nehari's Theorem on the PolydiskJan 12 2006We give a leisurely proof of a result of Ferguson--Lacey (math.CA/0104144) and Lacey--Terwelleger (math.CA/0601192) on a Nehari theorem for "little" Hankel operators on a polydisk. If H_b is a little Hankel operator with symbol b on product Hardy space ... More
Thermodynamics of Time MachinesFeb 08 2013In this note, a brief review of the consistent state approach to systems containing closed timelike curves or similar devices is given, and applied to the well known thermodynamic problem of Maxwell's demon. The 'third party paradox' for acausal systems ... More
Experimental Test of the Final State HypothesisMar 13 2014The black hole final state projection model, also known as the Horowitz-Maldacena model has garnished new interest due to the current debate over black hole firewalls. The nonlinear quantum mechanics of post-selection preserves information and avoids ... More
Conical tip in frozen water dropsApr 17 2014A theory is presented for the formation of a conical tip in water drops that are frozen on a flat surface below freezing temperature. For the known ice to water density ratio r = .917, the angle of aperture of this cone is found to be {\theta} = 33.550, ... More
Critique of "Quantum Enigma:Physic encounters Consciousness"May 14 2007May 15 2007The central claim that understanding quantum mechanics requires a conscious observer, which is made made by B. Rosenblum and F. Kuttner in their book "Quantum Enigma: Physics encounters consciousnes", is shown to be based on various misunderstandings ... More
The evolution of radiation towards thermal equilibrium: A soluble model which illustrates the foundations of Statistical MechanicsMay 10 2003In 1916 Einstein introduced the first rules for a quantum theory of electromagnetic radiation, and he applied them to a model of matter in thermal equilibrium with radiation to derive Planck's black-body formula. Einstein's treatment is extended here ... More
The Reception of Newton's PrincipiaMar 23 2015Newton's Principia, when it appeared in 1687, was received with the greatest admiration, not only by the foremost mathematicians and astronomers in Europe, but also by philosophers like Voltaire and Locke and by members of the educated public. In this ... More
Hooke's memorandum on the development of orbital dynamicsApr 13 2005I discuss a memorandum entitled " A True state of the Case and Controversy between Sir Isaak Newton and Dr. Robert Hooke as the Priority of that Noble Hypothesis of motion of ye Planets about ye Sun as their Centers", where Hooke summarizes his life long ... More
Democratic Superstring Field Theory: Gauge FixingOct 08 2010Mar 22 2011We show that a partial gauge fixing of the NS sector of the democratic-picture superstring field theory leads to the non-polynomial theory. Moreover, by partially gauge fixing the Ramond sector we obtain a non-polynomial fully RNS theory at pictures 0 ... More
Uncertainty in hybrid gravitational waveforms: Optimizing initial orbital frequencies for binary black-hole simulationsMar 25 2011Aug 31 2011A general method is presented for estimating the uncertainty in hybrid models of gravitational waveforms from binary black-hole systems with arbitrary physical parameters, and thence the highest allowable initial orbital frequency for a numerical-relativity ... More
The Future of Nuclear Energy: Facts and Fiction Chapter I: Nuclear Fission Energy TodayAug 05 2009Nuclear fission energy is considered to be somewhere between the holy grail, required to solve all energy worries of the human industrialized civilization, and a fast path directly to hell. Discussions about future energy sources and the possible contribution ... More
The End of Cheap UraniumJun 18 2011Jun 21 2011Historic data from many countries demonstrate that on average no more than 50-70% of the uranium in a deposit could be mined. An analysis of more recent data from Canada and Australia leads to a mining model with an average deposit extraction lifetime ... More
The Future of Nuclear Energy: Facts and Fiction Chapter II: What is known about Secondary Uranium Resources?Aug 21 2009During 2009 nuclear power plants, with a capacity of 370 GWe, will produce roughly 14% of the worldwide electric energy. About 65000 tons of natural uranium equivalent are required to operate these reactors. For 15 years on average only 2/3 of this fuel ... More
On the structure of universal differentiability setsJul 20 2016We prove that universal differentiability sets in Euclidean spaces possess distinctive structural properties. Namely, we show that any universal differentiability set contains a `kernel' in which the points of differentiability of each Lipschitz function ... More
Temporal Modulation of the Control Parameter in Electroconvection in the Nematic Liquid Crystal I52Jul 18 2000I report on the effects of a periodic modulation of the control parameter on electroconvection in the nematic liquid crystal I52. Without modulation, the primary bifurcation from the uniform state is a direct transition to a state of spatiotemporal chaos. ... More
One-dimensional classical adjoint SU(2) Coulomb GasJan 21 1997The equation of state of a one-dimensional classical nonrelativistic Coulomb gas of particles in the adjoint representation of SU(2) is given. The problem is solved both with and without sources in the fundamental representation at either end of the system. ... More