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A Scenario for Strong Gravity without Extra DimensionsFeb 19 2006A different reason for the apparent weakness of the gravitational interaction is advanced, and its consequences for Hawking evaporation of a Schwarzschild black hole are investigated. A simple analytical formulation predicts that evaporating black holes ... More

Singular chains on topological stacksFeb 17 2015Aug 29 2016We extend the functor Sing of singular chains to the category of topological stacks and establish its main properties. We prove that Sing respects weak equivalences and takes a morphism of topological stacks that is both a Serre and a Reedy fibration ... More

Doing More for Less -- Cache-Aware Parallel Contraction Hierarchies PreprocessingAug 13 2012Contraction Hierarchies is a successful speedup-technique to Dijkstra's seminal shortest path algorithm that has a convenient trade-off between preprocessing and query times. We investigate a shared-memory parallel implementation that uses $O(n+m)$ space ... 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

DBI analog of a decaying vacuum cosmologyJul 03 2013Jul 04 2013In this work I discuss the dynamical and thermodynamical equivalence between a general k-essence scalar field cosmology and an arbitrary cosmological model with a decaying vacuum, thus generalizing the approach proposed by Maia and Lima [Phys. Rev. D ... More

A conjectural extension of the Kazhdan-Lusztig equivalenceOct 22 2018Nov 12 2018A theorem of Kazhdan and Lusztig establishes an equivalence between the category of G(CO)-integrable representations of the Kac-Moody algebra \hat{g}_{-\kappa} at a negative level -\kappa and the category \Rep_q(G) of (algebraic) representations of the ... More

Quantum Mechanics and PerspectivalismJan 28 2018Jan 06 2019Experimental evidene of the last decades has made the status of "collapses of the wave function" even more shaky than it already was on conceptual grounds: interference effects turn out to be detectable even when collapses are typically expected to occur. ... More

Lazy ABCMay 30 2014Dec 04 2014Approximate Bayesian computation (ABC) performs statistical inference for otherwise intractable probability models by accepting parameter proposals when corresponding simulated datasets are sufficiently close to the observations. Producing the large quantity ... More

How Bandwidth Affects the $CONGEST$ ModelApr 20 2017The $CONGEST$ model for distributed network computing is well suited for analyzing the impact of limiting the throughput of a network on its capacity to solve tasks efficiently. For many "global" problems there exists a lower bound of $\Omega(D + \sqrt{n/B})$, ... More

On the Chow Ring of the Classifying Space of some Chevalley GroupsNov 23 2016Let $p$ be a prime and $q$ be a power of $p$. We compute the Chow ring of the classifying space of some Chevalley groups $G(\mathbb{F}_q)$, when considered as a finite algebraic group over a field of characteristic $p$ containing $\mathbb{F}_q$. Using ... 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

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

Binomial Andrews-Gordon-Bressoud identitiesAug 03 2016Binomial versions of the Andrews-Gordon-Bressoud identities are given.

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

Cosmic Explorer: The U.S. Contribution to Gravitational-Wave Astronomy beyond LIGOJul 10 2019This white paper describes the research and development needed over the next decade to realize "Cosmic Explorer," the U.S. node of a future third-generation detector network that will be capable of observing and characterizing compact gravitational-wave ... 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

A Central Limit Theorem for Lipschitz-Killing Curvatures of Gaussian ExcursionsJul 22 2016Nov 21 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

Sheaves of categories and the notion of 1-affinenessJun 18 2013Aug 10 2014We define the notion of 1-affineness for a prestack, and prove an array of results that establish 1-affineness of certain types of prestacks.

Spin-Directed Momentum Transfers in SIDIS Baryon ProductionDec 08 2015The measurement of transverse single-spin asymmetries for baryon production in the target fragmentation region of semi-inclusive deep-inelastic scattering (SIDIS), can produce important insight into those nonperturbative aspects of QCD directly associated ... More

gk: An R Package for the g-and-k and generalised g-and-h DistributionsJun 21 2017The g-and-k and (generalised) g-and-h distributions are flexible univariate distributions which can model highly skewed or heavy tailed data through only four parameters: location and scale, and two shape parameters influencing the skewness and kurtosis. ... More

A Constant-Factor Bi-Criteria Approximation Guarantee for $k$-means++May 16 2016This paper studies the $k$-means++ algorithm for clustering as well as the class of $D^\ell$ sampling algorithms to which $k$-means++ belongs. It is shown that for any constant factor $\beta > 1$, selecting $\beta k$ cluster centers by $D^\ell$ sampling ... More

Lattice HydrodynamicsOct 31 2018Using the combinatorics of two interpenetrating face centered cubic lattices together with the part of calculus naturally encoded in combinatorial topology, we construct from first principles a lattice model of 3D incompressible hydrodynamics on triply ... More

Automatic structure estimation of predictive models for symptom developmentSep 12 2018Online mental health treatment has the premise to meet the increasing demand for mental health treatment at a lower cost than traditional treatment. However, online treatment suffers from high drop-out rates, which might negate their cost effectiveness. ... More

Parameterization of factorizable line bundles by K-theory and motivic cohomologyApr 07 2018Nov 12 2018This note corrects a certain construction in (the old version of) the paper [GL]. The construction in question starts from a Brylinski-Deligne datum, which is an extension of a group G by K_2, and produces a factorization line bundle on the affine Grassmannian ... More

Arithmetically nef line bundlesJun 21 2018Let $L$ be a line bundle on a scheme $X$, proper over a field. The property of $L$ being nef can sometimes be "thickened", allowing reductions to positive characteristic. We call such line bundles arithmetically nef. It is known that a line bundle $L$ ... More

A Central Limit Theorem for Lipschitz-Killing Curvatures of Gaussian ExcursionsJul 22 2016Feb 20 2017This 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

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.

A Free Boundary Problem Related to Thermal Insulation: Flat Implies SmoothNov 18 2015We show that for a new free boundary problem studied by Caffarelli and the author, the interface is locally the union of the graphs of two $C^{1,\alpha}$ functions at most points. Specifically, this happens at all points where the interface is trapped ... More

$C^{1,α}$ Interior Regularity for Nonlinear Nonlocal Elliptic Equations With Rough KernelsApr 28 2013We prove a $C^{1,\alpha}$ interior regularity theorem for fully nonlinear uniformly elliptic integro-differential equations without assuming any regularity of the kernel. We then give some applications to linear theory and higher regularity of a special ... More

The Atiyah-Bott formula for the cohomology of the moduli space of bundles on a curveMay 10 2015This paper is a companion of the paper "Weil's conjecture for function fields" by J. Lurie and the author. We present a different exposition of essentially the same algebro-geometric proof of the Atiyah-Bott for the cohomology of Bun(G), which subsequently ... More

Eisenstein series and quantum groupsMay 10 2015May 23 2016We sketch a proof of a conjecture of [FFKM] that relates the geometric Eisenstein series sheaf with semi-infinite cohomology of the small quantum group with coefficients in the tilting module for the big quantum group.

The Logic of Identity: Distinguishability and Indistinguishability in Classical and Quantum PhysicsMay 13 2014The suggestion that particles of the same kind may be indistinguishable in a fundamental sense, even so that challenges to traditional notions of individuality and identity may arise, has first come up in the context of classical statistical mechanics. ... More

Prolate over oblate dominance in deformed nuclei as a consequence of the SU(3) symmetry and the Pauli principleJul 12 2017We show that the dominance of prolate over oblate shapes in even-even deformed nuclei can be derived from the SU(3) symmetry and the Pauli principle.

On the Chow Ring of the Stack of truncated Barsotti-Tate GroupsNov 27 2016We determine the Chow ring of the stack of truncated displays and more generally the Chow ring of the stack of G-zips. We also investigate the pull-back morphism of the truncated display functor. From this we can determine the Chow ring of the stack of ... More

The semi-infinite intersection cohomology sheaf-II: the Ran space versionAug 23 2017Nov 12 2018This paper is a sequel to [Ga1]. We study the semi-infinite category on the Ran version of the affine Grassmannian, and study a particular object in it that we call the semi-infinite intersection cohomology sheaf. Unlike the situation of [Ga1], this version ... More

From geometric to function-theoretic Langlands (or how to invent shtukas)Jun 30 2016This is an informal note that explains that the classical Langlands theory over function fields can be obtained from the geometric one by taking the trace of Frobenius. The operation of taking the trace of Frobenius takes place at the categorical level, ... More

Quantum Langlands CorrespondenceJan 20 2016These are informal notes written in 2007 that outline the local and global quantum Langlands program. (I decided to make them public in view of the revived interest in the subject.)

Lazier ABCJan 21 2015ABC algorithms involve a large number of simulations from the model of interest, which can be very computationally costly. This paper summarises the lazy ABC algorithm of Prangle (2015), which reduces the computational demand by abandoning many unpromising ... More

Field-Strength Descriptions for a System of Classical SU(2) Charges with Spherical Symmetry and Confining Boundary ConditionsFeb 01 2019The existence of a mechanism within the non-Abelian dynamics of QCD that confines quarks and gluons to the interior of hadrons has long been accepted empirically. To explore what this mechanism might look like, this paper examines field-strength descriptions ... 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 $4s$.

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

Quantum optimal control via gradient ascent in function space and the time-bandwidth quantum speed limitNov 01 2016Apr 03 2018A gradient ascent method for optimal quantum control synthesis is presented that employs a gradient derived with respect to the coefficients of a functional basis expansion of the control. Restricting the space of allowable controls to weighted sums of ... 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

Complete families of immersed curvesNov 01 2017Jan 31 2019We extend results of Chang and Ran regarding large dimensional families of immersed curves of positive genus in projective space in two directions. In one direction, we prove a sharp bound for the dimension of a complete family of smooth rational curves ... More

What is the higher dimensional infinitesimal groupoid of a manifold?Oct 29 2009The construction (by Kapranov) of the space of infinitesimal paths on a manifold is extended to include higher dimensional infinitesimal objects, encoding contractions of infinitesimal loops. This full infinitesimal groupoid is shown to have the algebra ... More

Space, Time and Coordinates in a Rotating WorldJan 31 2010The peculiarities of rotating frames of reference played an important role in the genesis of general relativity. Considering them, Einstein became convinced that coordinates have a different status in the general theory of relativity than in the special ... More

Higher dimensional operadsSep 14 2009Dec 15 2010The theory of operads (May, cyclic, modular, PROPs, etc) is extended to include higher dimensional phenomena, i.e. operations between operations, mimicking the algebraic structure on varieties of arbitrary dimensions, having marked subvarieties of arbitrary ... 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

Hilbert space compression for free products and HNN-extensionsFeb 22 2010Jul 06 2010Given the Hilbert space compression of two groups, we find bounds on the Hilbert space compression of their free product. We also investigate the Hilbert space compression of an HNN-extension of a group relative to a finite normal subgroup or a finite ... 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

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

Quantum Reality, Perspectivalism and CovarianceMay 13 2019Paul Busch has emphasized on various occasions the importance for physics of going beyond a merely instrumentalist view of quantum mechanics. Even if we cannot be sure that any particular realist interpretation describes the world as it actually is, the ... 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

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

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

Recent progress in geometric Langlands theoryJun 30 2016Sep 10 2016The is the English version of the text of the talk at S\'eminaire Bourbaki on February 16, 2016

Detection of Exoplanets Using the Transit MethodMar 15 2018Apr 20 2018I conducted differential photometry on a star GSC 3281-0800, a known host to exoplanet HAT-P-32b, using analysis software AstroImageJ. I plotted the measurements from a series of images taken during the transit, via ADU count given from an earth-based ... More

Some Comments on the Stochastic Eulerian Tour ProblemMar 13 2015The Stochastic Eulerian Tour Problem was introduced in 2008 as a stochastic variant of the well-known Eulerian Tour Problem. In a follow-up paper the same authors investigated some heuristics for solving the Stochastic Eulerian Tour Problem. After a thorough ... 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

Control aspects of holonomic quantum computationFeb 10 2002Mar 27 2018A unifying framework for the control of quantum systems with non-Abelian holonomy is presented. It is shown that, from a control theoretic point of view, holonomic quantum computation can be treated as a control system evolving on a principal fiber bundle. ... More

Chow's theorem and universal holonomic quantum computationNov 14 2001Feb 11 2002A theorem from control theory relating the Lie algebra generated by vector fields on a manifold to the controllability of the dynamical system is shown to apply to Holonomic Quantum Computation. Conditions for deriving the holonomy algebra are presented ... 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