Results for "Dennis Stello"

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Detecting Solar-like Oscillations in Red Giants with Deep LearningApr 20 2018Time-resolved photometry of tens of thousands of red giant stars from space missions like Kepler and K2 has created the need for automated asteroseismic analysis methods. The first and most fundamental step in such analysis, is to identify which stars ... More
Confirmation of the ${\rm \it Gaia}$ DR2 parallax zero-point offset using asteroseismology and spectroscopy in the ${\rm \it Kepler}$ fieldMay 07 2018May 09 2019We present an independent confirmation of the zero-point offset of ${\rm \it Gaia}$ Data Release 2 (DR2) parallaxes using asteroseismic data of evolved stars in the ${\rm \it Kepler}$ field. Using well-characterized red giant branch (RGB) stars from the ... More
A Search for Red Giant Solar-like Oscillations in All Kepler DataMar 01 2019Mar 04 2019The recently published Kepler mission Data Release 25 (DR25) reported on ~197,000 targets observed during the mission. Despite this, no wide search for red giants showing solar-like oscillations have been made across all stars observed in Kepler's long-cadence ... More
Asteroseismology Can Reveal Strong Internal Magnetic Fields in Red Giant StarsOct 23 2015Internal stellar magnetic fields are inaccessible to direct observations and little is known about their amplitude, geometry and evolution. We demonstrate that strong magnetic fields in the cores of red giant stars can be identified with asteroseismology. ... More
The problem of the Pleiades distance. Constraints from Stromgren photometry of nearby field starsMay 14 2001The discrepancy between the Pleiades cluster distance based on Hipparcos parallaxes and main sequence fitting is investigated on the basis of Stromgren photometry of F-type stars. Field stars with the same metallicity as the Pleiades have been selected ... More
Gaussian Process Modelling of Asteroseismic DataFeb 23 2009The measured properties of stellar oscillations can provide powerful constraints on the internal structure and composition of stars. To begin this process, oscillation frequencies must be extracted from the observational data, typically time series of ... More
Asteroseismology of red giant starsJan 25 2018If appropriately excited, a star will oscillate like a giant spherical instrument. In most stars, including the Sun, surface convection provides the excitation mechanism (Goldreich and Keeley, 1977). With turbulent velocities reaching speeds comparable ... More
Deep Learning Classification in Asteroseismology Using an Improved Neural Network: Results on 15000 Kepler Red Giants and Applications to K2 and TESS DataFeb 20 2018Deep learning in the form of 1D convolutional neural networks have previously been shown to be capable of efficiently classifying the evolutionary state of oscillating red giants into red giant branch stars and helium-core burning stars by recognizing ... More
Deep Learning Classification in AsteroseismologyMay 18 2017Jun 17 2017In the power spectra of oscillating red giants, there are visually distinct features defining stars ascending the red giant branch from those that have commenced helium core burning. We train a one-dimensional convolutional neural network by supervised ... More
Solar-like oscillations and activity in Procyon: A comparison of the 2007 MOST and ground-based radial velocity campaignsFeb 14 2011Mar 09 2011We compare the simultaneous 2007 space-based MOST photometry and ground-based radial velocity observations of the F5 star Procyon. We identify slow variations in the MOST data that are similar to those reported in the radial velocity (RV) time series, ... More
Confirmation of the zero-point offset in Gaia Data Release 2 parallaxes using asteroseismology and APOGEE spectroscopy in the Kepler fieldMay 07 2018We present an independent confirmation of the zero-point offset of Gaia Data Release 2 (DR2) parallaxes using asteroseismic data of evolved stars in the Kepler field. Using well-characterized red giant branch (RGB) stars from the APOKASC-2 catalogue we ... More
The K2 M67 Study: An Evolved Blue Straggler in M67 from K2 Mission AsteroseismologyNov 03 2016Yellow straggler stars (YSSs) fall above the subgiant branch in optical color-magnitude diagrams, between the blue stragglers and the red giants. YSSs may represent a population of evolved blue stragglers, but none have the direct and precise mass and ... More
Bayesian Inference from Observations of Solar-Like OscillationsAug 26 2006Stellar oscillations can provide a wealth of information about a star, which can be extracted from observed time series of the star's brightness or radial velocity. In this paper we address the question of how to extract as much information as possible ... More
Evidence for spatially-correlated ${\it Gaia}$ parallax errors in the ${\it Kepler}$ fieldJun 28 2017We present evidence for a spatially-dependent systematic error in the first data release of ${\it Gaia}$ parallaxes based on comparisons to asteroseismic parallaxes in the ${\it Kepler}$ field, and present a parametrized model of the angular dependence ... More
Predicting radial-velocity jitter induced by stellar oscillations based on Kepler dataJun 30 2018Radial-velocity (RV) jitter due to intrinsic stellar variability introduces challenges when characterizing exoplanet systems, particularly when studying small (sub-Neptune-sized) planets orbiting solar-type stars. In this Letter we predicted for dwarfs ... More
Modeling Kepler Observations of Solar-like Oscillations in the Red-giant Star HD 186355Sep 05 2011Nov 28 2011We have analysed oscillations of the red giant star HD 186355 observed by the NASA Kepler satellite. The data consist of the first five quarters of science operations of Kepler, which cover about 13 months. The high-precision time-series data allow us ... More
Asteroseismology of main-sequence F stars with \textit{Kepler}: overcoming short mode lifetimesFeb 14 2019Asteroseismology is a powerful way of determining stellar parameters and properties of stars like the Sun. However, main-sequence F-type stars exhibit short mode lifetimes relative to their oscillation frequency, resulting in overlapping radial and quadrupole ... More
Solar-like oscillations in a metal-poor globular cluster with the HSTMay 22 2009We present analyses of variability in the red giant stars in the metal-poor globular cluster NGC6397, based on data obtained with the Hubble Space Telescope. We use an non-standard data reduction approach to turn a 23-day observing run originally aimed ... More
Calculating asteroseismic diagrams for solar-like oscillationsSep 15 2011With the success of the Kepler and CoRoT missions, the number of stars with detected solar-like oscillations has increased by several orders of magnitude, for the first time we are able to perform large-scale ensemble asteroseismology of these stars. ... More
Asteroseismology of 16000 Kepler red giants: Global oscillation parameters, Masses, and radiiFeb 13 2018The Kepler mission has provided exquisite data to perform an ensemble asteroseismic analysis on evolved stars. In this work we systematically characterize solar-like oscillations and granulation for 16,094 oscillating red giants, using end-of-mission ... More
The treatment of mixing in core helium burning models - I. Implications for asteroseismologyJun 03 2015Jul 03 2015The detection of mixed oscillation modes offers a unique insight into the internal structure of core helium burning (CHeB) stars. The stellar structure during CHeB is very uncertain because the growth of the convective core, and/or the development of ... More
Solar-like oscillating stars as standard clocks and rulers for Galactic studiesSep 08 2014The CoRoT and Kepler space missions have detected oscillations in hundreds of Sun-like stars and thousands of field red-giant stars. This has opened the door to a new era of stellar population studies in the Milky Way. We report on the current status ... More
Asteroseismology of 16000 Kepler Red Giants: Global Oscillation Parameters, Masses, and RadiiFeb 13 2018Apr 03 2018The Kepler mission has provided exquisite data to perform an ensemble asteroseismic analysis on evolved stars. In this work we systematically characterize solar-like oscillations and granulation for 16,094 oscillating red giants, using end-of-mission ... More
Binary star detectability in $Kepler$ data from phase modulation of different types of oscillationsMay 11 2016Detecting binary stars in photometric time series is traditionally done by measuring eclipses. This requires the orbital plane to be aligned with the observer. A new method without that requirement uses stellar oscillations to measure delays in the light ... More
Dust and Stellar Populations in the Large Magellanic CloudAug 31 1999We present an analysis of line-of-sight extinction measurements obtained using data from the Magellanic Clouds Photometric Survey, which provides 4-filter photometry for millions of stars in the Large Magellanic Cloud. We find that visual extinctions ... More
The Mass and Extent of the Galactic HaloOct 05 1998We review the various techniques used to constrain the Galactic halo mass profile for radii > 20 kpc with particular emphasis on identifying a self-consistent halo model and resolving the apparent discrepancies present in the literature on this subject. ... More
Evidence For Recent Accretion in Nearby GalaxiesMay 11 1995I discuss observations of magnitude residuals from the B-band Tully-Fisher relationship, B-V color, chemical abundance gradients, and asymmetries in the H I and stellar disks of nearby spiral galaxies within the context of a model in which small satellites ... More
The Case of the Off-Center, Levitating Bar in the Large Magellanic CloudAug 28 2004I explore the hypothesis that many of the unusual aspects of the apparent stellar bar of the Large Magellanic Cloud are the result of viewing a triaxial stellar bulge that is embedded in a highly obscuring thin disk. Specifically, this hypothesis explains ... More
Topological characterization of various types of rings of smooth functionsAug 30 2011Oct 02 2011Topologies on algebraic and equational theories are used to define germ determined, near-point determined, and point determined rings of smooth functions, without requiring them to be finitely generated. It is proved, that any commutative algebra morphism ... More
Is There a Unique Physical Entropy? Micro versus MacroSep 05 2012Entropy in thermodynamics is an extensive quantity, whereas standard methods in statistical mechanics give rise to a non-extensive expression for the entropy. This discrepancy is often seen as a sign that basic formulas of statistical mechanics should ... More
On the dynamic nature of charge quantizationDec 29 2011It is commonly observed that objects in a gravitational field experience a rate of acceleration that is independent of their mass and that, as a result, all massive objects with the same initial conditions follow the same trajectory. It is not generally ... More
Conformal geometry of surfaces in the Lagrangian--Grassmannian and second order PDESep 07 2010Of all real Lagrangian--Grassmannians $LG(n,2n)$, only $LG(2,4)$ admits a distinguished (Lorentzian) conformal structure and hence is identified with the indefinite M\"obius space $S^{1,2}$. Using Cartan's method of moving frames, we study hyperbolic ... More
Comment on "Harold Jeffreys's Theory of Probability Revisited"Jan 18 2010Comment on "Harold Jeffreys's Theory of Probability Revisited" [arXiv:0804.3173]
A Deligne-Riemann-Roch isomorphism I: Preliminaries on virtual categoriesApr 26 2009This is the first article in an upcoming series of papers. They have arisen through an attempt to answer open questions of Deligne proposed in "Le determinant de la cohomologie", Contemp. Mathematics 67 (1987). It amounts to functorial and metrized versions ... More
Outline of the proof of the geometric Langlands conjecture for GL(2)Feb 11 2013Nov 12 2014We outline a proof of the categorical geometric Langlands conjecture for GL(2), as formulated in reference [AG], modulo a number of more tractable statements that we call Quasi-Theorems.
On de Jong's conjectureFeb 11 2004Apr 01 2006Let $X$ be a smooth projective curve over a finite field $F_q$. Let $\rho$ be a continuous representation $\pi(X)\to GL_n(F)$, where $F=F_l((t))$ with $F_l$ being another finite field of order prime to $q$. Assume that $\rho|_{\pi(\bar{X})}$ is irreducible. ... More
Hilbert space compression under direct limits and certain group extensionsSep 10 2010Sep 14 2010We find bounds on the Hilbert space compression of the limit of a directed metric system of groups. We also give estimates on the Hilbert space compression of group extensions of a group $H$ by a a word-hyperbolic group or a group of polynomial growth. ... More
Generalized Nonaveraging Integer SequencesJul 09 2011Let the sequence S_m of nonnegative integers be generated by the following conditions: Set the first term a_0 = 0, and for all k \geq 0, let a_k+1 be the least integer greater than a_k such that no element of {a_0,...,a_k+1} is the average of m - 1 distinct ... More
Coresets for $(k,l)$-Clustering under the Fréchet DistanceJan 07 2019Feb 19 2019Clustering is the task of partitioning a given set of geometric objects. This is thoroughly studied when the objects are points in the euclidean space. There are also several approaches for points in general metric spaces. In this thesis we consider clustering ... More
Centrality and transverse momentum dependence of $J/ψ$ production in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV at mid-rapidity with ALICEOct 16 2017We present new results for the nuclear modification factor \RAA of \jpsi mesons as a function of centrality and transverse momentum at mid-rapidity. The measurement is carried out with the ALICE central barrel detectors in the acceptance range $|y|$ < ... More
General Relativity as a Hybrid theory: The Genesis of Einstein's work on the problem of motionMar 27 2018In this paper I describe the genesis of Einstein's early work on the problem of motion in general relativity (GR): the question of whether the motion of matter subject to gravity can be derived directly from the Einstein field equations. In addressing ... More
Collections of hypersurfaces containing a curveFeb 21 2017Jun 28 2018We consider the closed locus of $r$-tuples of hypersurfaces in $\mathbb{P}^r$ with positive dimensional intersection, and show in a large range of degrees that its largest component is the locus of $r$-tuples of hypersurfaces whose intersection contains ... More
String Topology: Background and Present StateOct 22 2007The data of a "2D field theory with a closed string compactification" is an equivariant chain level action of a cell decomposition of the union of all moduli spaces of punctured Riemann surfaces with each component compactified as a pseudomanifold with ... More
A Free Boundary Problem Related to Thermal Insulation: Flat Implies SmoothNov 18 2015Sep 05 2017We study the regularity of the interface for a new free boundary problem introduced by Caffarelli and Kriventsov. We show that for minimizers of the functional \[ F_1(A,u) = \int_A |\nabla u|^2 d\mathcal{L}^n + \int_{\partial A} u^2 + \bar{C} \mathcal{L}^n(A) ... More
Stellar population synthesis based modelling of the Milky Way using asteroseismology of dwarfs and subgiants from KeplerJan 10 2017Early attempts to apply asteroseismology to study the Galaxy have already shown unexpected discrepancies for the mass distribution of stars between the Galactic models and the data; a result that is still unexplained. Here, we revisit the analysis of ... More
Photometry Using Kepler "Superstamps" of Open Clusters NGC 6791 & NGC 6819Sep 24 2013The Kepler space telescope has proven to be a gold mine for the study of variable stars. Unfortunately, Kepler only returns a handful of pixels surrounding each star on the target list, which omits a large number of stars in the Kepler field. For the ... More
Asteroseismic modelling of the subgiant μ Herculis using SONG data: lifting the degeneracy between age and model input parametersOct 30 2018We model the oscillations of the SONG target $\mu$ Herculis to estimate the parameters of the star. The $\ell$ = 1 mixed modes of $\mu$ Her provide strong constraints on stellar properties. The mass and age given by our asteroseismic modelling are 1.10$^{+0.11}_{-0.06}$ ... More
The Fractured Boer-Mulders Effect in the Production of Polarized BaryonsOct 28 2009The fractured Boer-Mulders functions describe an inriguing class of polarization effects for the production of baryons in the target fragmentation region of deep-inelastic processes. These functions characterize transverse momentum asymmetries related ... More
Single-Spin Observables and Orbital Structures in Hadronic DistributionsSep 07 2006Within the light-quark sector of the standard model, P-odd observables are generated from point-like electroweak processes while A_t- odd observables (neglecting quark mass parameters) come from dynamic spin-orbit correlations within hadrons or within ... More
Shape/Phase Transitions and Critical Point Symmetries in Atomic NucleiJul 28 2008Shape/phase transitions in atomic nuclei have first been discovered in the framework of the Interacting Boson Approximation (IBA) model. Critical point symmetries appropriate for nuclei at the transition points have been introduced as special solutions ... More
Discriminants and Artin conductorsJun 15 2011We study questions of multiplicities of discriminants for degenerations coming from projective duality over discrete valuation rings. The main result is a type of discriminant-different formula in the sense of classical algebraic number theory, and we ... More
Implications and Applications of Kinematic Galaxy Scaling RelationsSep 19 2012Galaxy scaling relations, which describe a connection between ostensibly unrelated physical characteristics of galaxies, testify to an underlying order in galaxy formation that requires understanding. I review the development of a scaling relation that ... More
Twisted Whittaker model and factorizable sheavesMay 31 2007Mar 27 2008Let G be a reductive group. The geometric Satake equivalence realized the category of representations of the Langlands dual group ^LG in terms of spherical perverse sheaves (or D-modules) on the affine Grassmannian Gr_G=G((t))/G[[t]] of the original group ... More
Grothendieck topologies and deformation theory IIAug 08 1995This paper is a continuation of ``Operads, Grothendieck topologies and deformation theory'' (alg-geom/9502010). We show how to develop a cohomology theory that would control deformations of a sheaf of associative algebras over a scheme by means of introducing ... More
A finite time blowup result for quadratic ODE'sNov 01 2010This short paper is dedicated to Mauricio Peixoto who abstracted the practical theory of ODE's and to David Rand who applied the subsequent powerful abstract theory to practical problems.
Derived manifolds and Kuranishi modelsDec 05 2012Jan 12 2014A model structure is defined on the category of derived differentiable schemes, and it is used to analyse the truncation 2-functor from derived manifolds to d-manifolds. It is proved that the induced 1-functor between the homotopy categories is full and ... More
Symmetric noncommutative birational transformationsJul 28 2016In a previous paper (arXiv:1410.5207) certain birational transformations were constructed between the noncommutative schemes associated to quadratic and cubic three dimensional Sklyanin algebras. In the current paper we consider the inverse birational ... More
Measures on polyhedral cones: characterizations and kinematic formulasDec 04 2014Jul 29 2015This paper is about conic intrinsic volumes and their associated integral geometry. We pay special attention to the biconic localizations of the conic intrinsic volumes, the so-called support measures. An analysis of these quantities has so far been confined ... More
The AJ-conjecture and cabled knots over the figure eight knotMay 15 2014Apr 15 2015We show that most cabled knots over the figure eight knot in $S^3$ satisfy the AJ-conjecture, in particular, any $(r,s)$-cabled knot over the figure eight knot satisfies the $AJ$-conjecture if $r$ is not a number between $-4s$ and $4s$.
A comparison of Bayesian and Fourier methods for frequency determination in asteroseismologyJun 21 2010Bayesian methods are becoming more widely used in asteroseismic analysis. In particular, they are being used to determine oscillation frequencies, which are also commonly found by Fourier analysis. It is important to establish whether the Bayesian methods ... More
Stellar population synthesis based modelling of the Milky Way using asteroseismology of 13000 Kepler red giantsMar 17 2016With current space-based missions it is now possible to obtain age-sensitive asteroseismic information for tens of thousands of red giants. This provides a promising opportunity to study the Galactic structure and evolution. We use asteroseismic data ... More
Gap interpolation by inpainting methods : Application to Ground and Space-based Asteroseismic dataOct 22 2014In asteroseismology, the observed time series often suffers from incomplete time coverage due to gaps. The presence of periodic gaps may generate spurious peaks in the power spectrum that limit the analysis of the data. Various methods have been developed ... More
Asteroseismology and Gaia: Testing Scaling Relations Using 2200 Kepler Stars with TGAS ParallaxesMay 12 2017We present a comparison of parallaxes and radii from asteroseismology and Gaia DR1 (TGAS) for 2200 Kepler stars spanning from the main sequence to the red giant branch. We show that previously identified offsets between TGAS parallaxes and distances derived ... More
Functors given by kernels, adjunctions and dualityMar 12 2013Nov 24 2015Let X_1 and X_2 be schemes of finite type over a field of characteristic 0. Let Q be an object in the category D-mod(X_1\times X_2) and consider the functor F:D-mod(X_1)->Dmod(X_2) defined by Q. Assume that F admits a right adjoint also defined by an ... More
The notion of category over an algebraic stackJul 09 2005The goal of this note is to spell out the (apparently well-known and intuitively clear) notion of abelian category over an algebraic stack. In the future we will discuss the (much less evident) notion, when instead of an abelian category one considers ... More
A Central Limit Theorem for Lipschitz-Killing Curvatures of Gaussian ExcursionsJul 22 2016This paper studies the excursion set of a real stationary isotropic Gaussian random field above a fixed level. We show that the standardized Lipschitz-Killing curvatures of the intersection of the excursion set with a window converges in distribution ... More
Quantum Number Density Asymmetries Within QCD Jets Correlated With Lambda PolarizationJun 20 2011Jul 27 2011The observation of jets in a variety of hard-scattering processes has allowed the quantitative study of perturbative quantum chromodynamics (PQCD) by comparing detailed theoretical predictions with a wide range of experimental data. This paper examines ... More
Coherent Spin Manipulations of a Polarized Beam With a Localized RF Magnetic FieldOct 12 2007The coherent manipulation of spin observables in storage rings provides opportunities to test the application of some fundamental dynamical principles. In this context, it is possible to confirm, using gauge invariance and Lorentz invariance, a conjecture ... More
Perturbed and Permuted: Signal Integration in Network-Structured Dynamic SystemsJun 23 2011Biological systems (among others) may respond to a large variety of distinct external stimuli, or signals. These perturbations will generally be presented to the system not singly, but in various combinations, so that a proper understanding of the system ... More
On hypercomplexifying real forms of arbitrary rankSep 28 2002For certain problems involving vector fields, it is possible to find an associated imaginary field that, in conjunction with the first, forms a complex field for which the equation can be solved. This result is generalized to arbitrary Clifford algebras, ... More
Invariant Yang-Mills connections over Non-Reductive Pseudo-Riemannian Homogeneous SpacesOct 09 2007Apr 17 2008We study invariant gauge fields over the 4-dimensional non-reductive pseudo-Riemannian homogeneous spaces G/K recently classified by Fels & Renner (2006). Given H compact semi-simple, classification results are obtained for principal H-bundles over G/K ... More
Adapting the ABC distance functionJul 03 2015Dec 15 2015Approximate Bayesian computation performs approximate inference for models where likelihood computations are expensive or impossible. Instead simulations from the model are performed for various parameter values and accepted if they are close enough to ... More
Ideas in transverse spin physicsSep 08 2014Three simple ideas about transverse spin observables are presented for the purpose of stimulating discussion. The manuscript is based on a presentation at the "Transversity 2014" workshop in Torre Chia, Sardinia, Italy on June 9-13, 2014 where approximately ... More
Kane-Pumplin-Repko Factorization: its application to precision measurements of transverse spin asymmetries and to the study of TMD evolutionJul 22 2013This article presents a summary of overlapping presentations by the author to the QCD Evolution 2013 Workshop and to the Opportunities for Polarized Physics at Fermilab Workshop. It contains an introduction to the concept of Kane-Pumplin-Repko (KPR) factorization ... More
Variational Bayesian hierarchical regression for data analysisNov 08 2018Collected data, which is used for analysis or prediction tasks, often have a hierarchical structure, for example, data from various people performing the same task. Modeling the data's structure can improve the reliability of the derived results and prediction ... More
Von Neumann's Impossibility Proof: Mathematics in the Service of RhetoricsJan 28 2018According to what has become a standard history of quantum mechanics, in 1932 von Neumann persuaded the physics community that hidden variables are impossible as a matter of principle, after which leading proponents of the Copenhagen interpretation put ... More
Time Coordinates and Clocks: Einstein's StruggleJan 28 2018In his Autobiographical Notes, Einstein mentioned that on his road to the final theory of general relativity it was a major difficulty to accustom himself to the idea that coordinates need not possess an immediate physical meaning in terms of lengths ... More
Exceptionally simple PDEMar 27 2016Sep 29 2016We give local descriptions of parabolic contact structures and show how their flat models yield explicit PDE having symmetry algebras isomorphic to all complex simple Lie algebras except $\mathfrak{sl}_2$. This yields a remarkably uniform generalization ... More
Ind-coherent sheavesMay 24 2011Sep 22 2012We develop the theory of ind-coherent sheaves on schemes and stacks. The category of ind-coherent sheaves is closely related, but inequivalent, to the category of quasi-coherent sheaves, and the difference becomes crucial for the formulation of the categorical ... More
On two relaxations of quadratically-constrained cardinality minimizationOct 18 2012This paper considers a quadratically-constrained cardinality minimization problem with applications to digital filter design, subset selection for linear regression, and portfolio selection. Two relaxations are investigated: the continuous relaxation ... More
Clues to the nature of ultra diffuse galaxies from estimated galaxy velocity dispersionsSep 26 2016We describe how to estimate the velocity dispersions of ultra diffuse galaxies, UDGs, using a previously defined galaxy scaling relationship. The method is accurate for the two UDGs with spectroscopically measured dispersions, as well as for ultra compact ... More
The excess formula in functorial formMay 01 2012This article is motivated by the need for better understanding of refined Riemann-Roch theorems and the behavior of the determinant of the cohomology. This poses a certain problem of functoriality and can be understood as that of giving refined constructions ... More
The club of simplicial setsJan 13 2010Dec 15 2010A club structure is defined on the category of simplicial sets. This club generalizes the operad of associative rings by adding "amalgamated" products.
Degenerating Riemann surfaces and the Quillen metricJun 15 2011The degeneration of the Quillen metric for a one-parameter family of Riemann surfaces has been studied by Bismut-Bost and Yoshikawa. In this article we propose a more geometric point of view using Deligne's Riemann-Roch theorem. We obtain an interpretation ... More
The Michelson-Morley experiment in an accelerated reference frameDec 15 2010We analyze the Michelson-Morley experiment in a reference frame moving with constant proper acceleration. Interestingly, we find an expected fringe shift which depends not only on the interferometer's rate of acceleration, but also on its speed relative ... More
Non-Markovian Beables vs. Massive ParallelismMar 16 2010A simple dynamical model over a discrete classical state space is presented. In a certain limit, it reduces to one in a class of models subsuming Bell's field-theoretic version of Bohmian mechanics. But it exhibits the massive parallelism native to quantum ... More
Construction of central elements in the affine Hecke algebra via nearby cyclesDec 09 1999Oct 27 2000Let $G$ be a reductive group, let $Gr=G((t))/G[[t]]$ be the corresponding affine Grassmannian and let $Fl=G((t))/I$ be the affine flag variety. We construct, following an idea of Belinson, a 1-parametric deformation of the product $Gr\times G/B$ to $Fl$. ... More
Notes on 2D Conformal Field Theory and String TheoryNov 09 1998May 27 1999We explain the basics of conformal theory using the language of chiral algebras of Beilinson and Drinfeld.
Contractibility of the space of rational mapsAug 08 2011Feb 23 2012We define an algebro-geometric model for the space of rational maps from a smooth curve X to an algebraic group G, and show that this space is homologically contractible. As a consequence, we deduce that the moduli space Bun(G) of G-bundles on X is uniformized ... More
Chiral Dynamics of the Polarizing Fracture Functions for Baryon ProductionNov 14 2008The concept of spin-directed momentum provides a useful and restrictive framework for describing dynamical mechanisms that can lead to single-spin observables. The value of this framework can be demonstrated by consideration of the polarizing fracture ... More
Algebra, Topology and Algebraic Topology of 3D Ideal FluidsOct 13 2010There is a remarkable and canonical problem in 3D geometry and topology: To understand existing models of 3D fluid motion or to create new ones that may be useful. We discuss from an algebraic viewpoint the PDE called Euler's equation for incompressible ... More
Open and Closed String field theory interpreted in classical Algebraic TopologyFeb 26 2003There is an interpretation of open string field theory in algebraic topology. An interpretation of closed string field theory can be deduced from this open string theory to obtain as well the interpretation of open and closed string field theory combined. ... More
The Gibbs Paradox RevisitedFeb 28 2010The Gibbs paradox has frequently been interpreted as a sign that particles of the same kind are fundamentally indistinguishable; and that quantum mechanics, with its identical fermions and bosons, is indispensable for making sense of this. In this article ... More
Probability in modal interpretations of quantum mechanicsMar 02 2007Modal interpretations have the ambition to construe quantum mechanics as an objective, man-independent description of physical reality. Their second leading idea is probabilism: quantum mechanics does not completely fix physical reality but yields probabilities. ... More
The Adventure and the PrizeSep 12 2011This article presnts a condensed summary of separate, overlapping, presentations to the Workshop on Polarized Drell-Yan Physics (Santa Fe, NM, Oct. 31-Nov.1, 2010),the GHP 2011 Worshop (Anaheim, CA, Apr.21-27, 2011) and the Transversity 2011 Workshop ... More
Chiral Dynamics and Single-Spin AsymmetriesNov 20 2007Parity-conserving single-spin asymmetries provide a specific measure of coherent spin-orbit dynamics in quantum chromodynamics. The origin of these effects can be traced to the interplay of chiral dynamics and confinement in the theory. The most elegant ... More
Chiral Mechanisms Leading to Orbital Quantum Structures in the NucleonApr 13 2007Color confinement and chiral symmetry specify some important territory for the study of hadronic physics. Any hadron can be defined as a color-singlet composite system of qurks and gluons, the fundamental fields of qcd, while the landscape of the hadronic ... More
Extending Immersions into the SphereDec 22 2010We study the problem to extend an immersed circle f in the 2-dimensional sphere to an immersion of the disc. We analyze existence and uniqueness for this problems in terms of the combinatorial structure of a word assigned to f. Our techniques are based ... More
Non-Gaussian signatures of Tachyacoustic CosmologyJun 02 2012Sep 22 2012I investigate non-Gaussian signatures in the context of tachyacoustic cosmology, that is, a noninflationary model with superluminal speed of sound. I calculate the full non-Gaussian amplitude $\mathcal{A}$, its size $f_{\rm NL}$, and corresponding shapes ... More
On the Evolution Equation for Magnetic GeodesicsNov 05 2007Apr 29 2009In this paper we prove the existence of long time solutions for the parabolic equation for closed magnetic geodesics.