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(25143) Itokawa: The Power of Radiometric Techniques for the Interpretation of Remote Thermal Observations in the Light of the Hayabusa Rendezvous ResultsApr 23 2014The near-Earth asteroid (25143) Itokawa was characterised in great detail by the Japanese Hayabusa mission. We revisited the available thermal observations in the light of the true asteroid properties with the goal to evaluate the possibilities and limitations ... More

The spin-$\frac{1}{2}$ Heisenberg ferromagnet on the pyrochlore lattice: A Green's function studySep 26 2018We consider the pyrochlore-lattice quantum Heisenberg ferromagnet and discuss the properties of this spin model at arbitrary temperatures. To this end, we use the Green's function technique within the random-phase (or Tyablikov) approximation as well ... More

Learning representations of molecules and materials with atomistic neural networksDec 11 2018Deep Learning has been shown to learn efficient representations for structured data such as image, text or audio. In this chapter, we present neural network architectures that are able to learn efficient representations of molecules and materials. In ... More

Electron-magnon scattering in elementary ferromagnets from first principles: lifetime broadening and kinksSep 07 2018We study the electron-magnon scattering in bulk Fe, Co, and Ni within the framework of many-body perturbation theory implemented in the full-potential linearized augmented-plane-wave method. To this end, a k-dependent self-energy describing the scattering ... More

Tomonaga-Luttinger liquid in the edge channels of a quantum spin Hall insulatorJan 18 2019Topological quantum matter is characterized by non-trivial global invariants of the bulk which induce gapless electronic states at its boundaries. A case in point are two-dimensional topological insulators (2D-TI) which host one-dimensional (1D) conducting ... More

Comet C/2013 A1 (Siding Spring) as seen with the Herschel Space ObservatoryOct 08 2014Dec 25 2014The thermal emission of comet C/2013 A1 (Siding Spring) was observed on March 31, 2013, at a heliocentric distance of 6.48 au using the PACS photometer camera of the Herschel Space Observatory. The comet was clearly active, showing a coma that could be ... More

PACS photometer calibration block analysisOct 10 2013The absolute stability of the PACS bolometer response over the entire mission lifetime without applying any corrections is about 0.5% (standard deviation) or about 8% peak-to-peak. This fantastic stability allows us to calibrate all scientific measurements ... More

Ultrafast Local Magnetization and Demagnetization in Heusler AlloysMar 17 2016With the goal of pushing Spintronic devices towards faster and faster timescales, we demonstrate, using ab-intio time-dependent density functional theory simulations of bulk Heusler compounds subject to ultrashort intense laser pulses, that the local ... More

Negative curves on algebraic surfacesSep 09 2011Apr 04 2012We study curves of negative self-intersection on algebraic surfaces. We obtain results for smooth complex projective surfaces X on the number of reduced, irreducible curves C of negative self-intersection C^2. The only known examples of surfaces for which ... More

Evidence for structural and electronic instabilities at intermediate temperatures in $κ$-(BEDT-TTF)$_{2}$X for X=Cu[N(CN)$_{2}$]Cl, Cu[N(CN)$_{2}$]Br and Cu(NCS)$_{2}$: Implications for the phase diagram of these quasi-2D organic superconductorsJul 23 2001We present high-resolution measurements of the coefficient of thermal expansion $\alpha (T)=\partial \ln l(T)/\partial T$ of the quasi-twodimensional (quasi-2D) salts $\kappa$-(BEDT-TTF)$_2$X with X = Cu(NCS)$_2$, Cu[N(CN)$_2$]Br and Cu[N(CN)$_2$]Cl. ... More

Coupled Kohn-Sham equations for electrons and phononsMar 20 2018This work establishes the algebraic structure of the Kohn-Sham equations to be solved in a density formulation of electron and phonon dynamics, including the superconducting order parameter. A Bogoliubov transform is required to diagonalize both the fermionic ... More

Dipole force free optical control and cooling of nanofiber trapped atomsAug 11 2017The evanescent field surrounding nano-scale optical waveguides offers an efficient interface between light and mesoscopic ensembles of neutral atoms. However, the thermal motion of trapped atoms, combined with the strong radial gradients of the guided ... More

First-principles modeling of temperature and concentration dependent solubility in the phase separating Fe$_x$Cu$_{1-x}$ alloy systemApr 16 2012We present a novel cluster-expansion (CE) approach for the first-principles modeling of temperature and concentration dependent alloy properties. While the standard CE method includes temperature effects only via the configurational entropy in Monte Carlo ... More

$C^0$-characterization of symplectic and contact embeddings and Lagrangian rigidityJul 11 2016May 11 2017We present a novel $C^0$-characterization of symplectic embeddings and diffeomorphisms in terms of Lagrangian embeddings. Our approach is based on the shape invariant, which was discovered by J.-C. Sikorav and Y. Eliashberg, intersection theory and the ... More

An Obstacle Problem for Elastic Curves: Existence ResultsDec 07 2018We consider an obstacle problem for elastic curves with fixed ends. We attempt to extend the graph approach provided in [8]. More precisely, we investigate nonexistence of graph solutions for special obstacles and extend the class of admissible curves ... More

The Flavours of the Quark-Gluon PlasmaDec 26 2008Quarks of other flavours than up and down, i.e. $s$, $c$, and $b$ quarks, have been long recognized as effective probes of the structure of hot QCD matter. In this talk, I review some of the motivations for their investigation and discuss the salient ... More

Phenomenology of Jet Quenching in Heavy Ion CollisionsAug 20 2002Mar 23 2003We derive an analytical expression for the quenching factor in the strong quenching limit where the $p_T$ spectrum of hard partons is dominated by surface emission. We explore the phenomenological consequences of different scaling laws for the energy ... More

Quark Matter 2005 -- Theoretical SummaryAug 29 2005Nov 14 2005This is a review of the latest developments in the theory of superdense nuclear matter, formed in relativistic heavy ion collisions or in the core of collapsed stars, as they were reported and discussed at the Quark Matter 2005 conference in Budapest ... More

Erdmessung mit Quanten und RelativitätAug 30 2016Recent developments in fundamental physics (in theory as well as in technology) provide novel capabilities for geodetic applications such as refined observations of the Earth`s gravity field. We will focus on two new concepts: one applies atomic interferometry ... More

Epsilon-non-squeezing and $C^0$-rigidity of epsilon-symplectic embeddingsMay 03 2018An embedding $\varphi \colon (M_1, \omega_1) \to (M_2, \omega_2)$ (of symplectic manifolds of the same dimension) is called $\epsilon$-symplectic if the difference $\varphi^* \omega_2 - \omega_1$ is $\epsilon$-small with respect to a fixed Riemannian ... More

A note on the volume flux of smooth and continuous strictly contact isotopiesJul 25 2011This note on the flux homomorphism for strictly contact isotopies complements the recent paper [MS11a] by P. Spaeth and the author. We determine the volume flux restricted to symplectic and volume-preserving contact isotopies and their C^0-limits for ... More

On low-degree representations of the symmetric groupNov 22 2015Jul 07 2016The aim of the present paper is to obtain a classification of all the irreducible modular representations of the symmetric group on $n$ letters of dimension at most $n^3$, including dimension formulae. This is achieved by improving an idea, originally ... More

MPPhys - A many-particle simulation package for computational physics educationMar 07 2014In a first course to classical mechanics elementary physical processes like elastic two-body collisions, the mass-spring model, or the gravitational two-body problem are discussed in detail. The continuation to many-body systems, however, is defered to ... More

Heavy Ions -- Prospects at the LHCOct 07 2004Oct 13 2004This is a review of the physics prospects for relativistic heavy ion collisions in the CERN Large Hadron Collider. The motivation for the study of superdense matter created in relativistic heavy ion collision is the prospect of observing a novel state ... More

Quark Matter '99 --- Theoretical Summary: What Next?Jun 09 1999Jul 15 1999I review the three broad areas where major progress has been reported: The phase structure of strongly interacting matter, the properties of matter at the instant when it freezes out into individual hadrons in the final stage of the expansion of the hot ... More

Parton Energy Loss in Strongly Coupled AdS/CFTOct 20 2010Nov 30 2010This is a brief review of the theory and phenomenology of parton energy loss in strongly coupled field theories with a gravity dual and its comparison with parton energy loss in QCD at weak coupling.

Central limit theorem analogues for multicolour urn modelsApr 11 2016Mar 12 2019The asymptotic behaviour of a generalised P\'olya--Eggenberger urn is well--known to depend on the spectrum of its replacement matrix: If its dominant eigenvalue $r$ is simple and no other eigenvalue is `large' in the sense that its real part is greater ... More

A note on invariant temporal functionsFeb 09 2015Jul 18 2016The purpose of this article is to present a result on the existence of Cauchy temporal functions invariant by the action of a compact group of conformal transformations in arbitrary globally hyperbolic manifolds. Moreover, the previous results about the ... More

$J$-holomorphic disks with pre-Lagrangian boundary conditionsApr 09 2017Apr 28 2017The purpose of this paper is to carry out a classical construction of a non-constant holomorphic disk with boundary on (the suspension of) a Lagrangian submanifold in $\mathbb{R}^{2 n}$ in the case the Lagrangian is the lift of a coisotropic (a.k.a. pre-Lagrangian) ... More

Neutrino Emission as Diagnostics of Core-Collapse SupernovaeApr 24 2019With myriads of detection events from a prospective Galactic core-collapse supernova, current and future neutrino detectors will be able to sample detailed, time-dependent neutrino fluxes and spectra. This offers enormous possibilities for inferring supernova ... More

Branch dependence in the "consistent histories" approach to quantum mechanicsJun 07 2005Nov 12 2006In the consistent histories formalism one specifies a family of histories as an exhaustive set of pairwise exclusive descriptions of the dynamics of a quantum system. We define branching families of histories, which strike a middle ground between the ... More

Numerical Chladni figuresAug 26 2013Chladni patterns of vibrating membranes or thin plates faszinated the people already in the eighteenth century. As a simple way to visualize acoustic phenomena it is a valuable experiment for beginners' courses. In this paper I present NumChladni, an ... More

Investigation of Hot QCD Matter: Theoretical AspectsSep 29 2013Oct 12 2013This lecture presents an overview of the status of the investigation of the properties of the quark-gluon plasma using relativistic heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). It focuses on the ... More

Statistical Fluctuations as Probes of Dense MatterNov 04 2001The use of statistical fluctuations as probes of the microscopic dynamics of hot and dense hadronic matter is reviewed. Critical fluctuations near the critical point of QCD matter are predicted to enhance fluctuations in pionic observables. Chemical fluctuations, ... More

Invariants of 3-manifolds from representations of the framed-tangle categoryMar 03 2002A new class of 3-manifold invariants is constructed from representations of the category of framed tangles.

Metrizability of spaces of homomorphisms between metric vector spacesMay 22 2009Nov 29 2014This note tries to give an answer to the following question: Is there a sufficiently rich class of metric vector spaces such that sufficiently large spaces of continuous linear maps between them are metrizable?

Uniform approximation of homeomorphisms by diffeomorphismsJan 08 2009May 22 2014We prove that a compactly supported homeomorphism of a smooth manifold of dimension greater or equal to 5 can be approximated uniformly by compactly supported diffeomorphisms if and only if it is isotopic to a diffeomorphism. If the given homeomorphism ... More

On the Tree Structure of Orderings and Valuations on arbitrary unital RingsJul 30 2018Dec 20 2018In the present paper, we first introduce the notion of quasi-ordered rings, which axiomatically subsumes the classes of all ordered and valued rings. Then we uniformly define a finer relation $\leq$ on the set of all quasi-orders on a ring $R$, generalizing ... More

Periodic-Orbit Approach to Universality in Quantum ChaosDec 20 2005We show that in the semiclassical limit, classically chaotic systems have universal spectral statistics. Concentrating on short-time statistics, we identify the pairs of classical periodic orbits determining the small-$\tau$ behavior of the spectral form ... More

Decompositions of rational functions over real and complex numbers and a question about invariant curvesFeb 25 2015We consider the connection of functional decompositions of rational functions over the real and complex numbers, and a question about curves on a Riemann sphere which are invariant under a rational function.

Minimax principles, Hardy-Dirac inequalities and operator cores for two and three dimensional Coulomb-Dirac operatorsMar 04 2016For $n\in\{2,3\}$ we prove minimax characterisations of eigenvalues in the gap of the $n$ dimensional Dirac operator with an potential, which may have a Coulomb singularity with a coupling constant up to the critical value $1/(4-n)$. This result implies ... More

The Group of Hamiltonian Homeomorphisms in the L^\infty-normMay 08 2007The group Hameo (M,\omega) of Hamiltonian homeomorphisms of a connected symplectic manifold (M,\omega) was defined and studied in [7] and further in [6]. In these papers, the authors consistently used the L^{(1,\infty)}-Hofer norm (and not the L^\infty-Hofer ... More

Cheeger-Gromov compactness for manifolds with boundaryAug 20 2018We prove Cheeger-Gromov convergence for a subsequence of a given sequence of manifolds (with boundary) of bounded geometry.

Asymptotic flexibility of globally hyperbolic manifoldsOct 05 2011In this short note, a question of patching together globally hyperbolic manifolds is adressed which appeared in the context of the construction of Hadamard states.

Which spacetimes admit conformal compactifications?Sep 29 2014Nov 21 2014We consider the future causal boundary as a tool to find obstructions to conformal extensions, the latter being a slight generalization to conformal compactifications.

Analysis of invariant PDO's on the Heisenberg groupAug 12 2014In these lecture notes, the representation theory of the Heisenberg group as well as Howe's construction of the metaplectic group by means of twisted convolution operators with generalized, complex Gaussians are reviewed, and it is shown how these tools ... More

A criterion for transience of multidimensional branching random walk in random environmentMay 14 2007We develop a criterion for transience for a general model of branching Markov chains. In the case of multi-dimensional branching random walk in random environment (BRWRE) this criterion becomes explicit. In particular, we show that \emph{Condition 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

Simulations of the Glasma in 3+1DApr 08 2019May 20 2019The Glasma is a gluonic state of matter which can be created in collisions of relativistic heavy ions and is a precursor to the quark-gluon plasma. The existence of this state is a prediction of the color glass condensate (CGC) effective theory. In many ... More

Problems of Harmonic Analysis related to finite type hypersurfaces in R^3, and Newton polyhedraAug 31 2012This article, which grew out of my lecture at the conference "Analysis and Applications: A Conference in Honor of Elias M. Stein" in May 2011, is intended to give an overview on a collection of results which have been obtained jointly with I.I. Ikromov, ... More

Magneto-oscillations of the mobility edge in Coulomb frustrated bosons and fermionsJun 24 2016Jul 30 2016We study the crossover from strong to weak localization of hard-core bosons on a two dimensional honeycomb lattice in a magnetic field, as motivated by recent experiments on structured films. Taking into account long range Coulomb interactions among the ... More

Ultrafast demagnetization in bulk vs thin films: an ab-initio studyDec 16 2016Mar 08 2017We report on {\it ab-initio} simulations of the quantum dynamics of electronic charge and spin when subjected to intense laser pulses. By performing separate calculations for a Ni thin film and bulk Ni, we conclude that surface effects have a dramatic ... More

Tunable few electron quantum dots in InAs nanowiresSep 19 2006Quantum dots realized in InAs are versatile systems to study the effect of spin-orbit interaction on the spin coherence, as well as the possibility to manipulate single spins using an electric field. We present transport measurements on quantum dots realized ... More

Learning how to explain neural networks: PatternNet and PatternAttributionMay 16 2017Oct 24 2017DeConvNet, Guided BackProp, LRP, were invented to better understand deep neural networks. We show that these methods do not produce the theoretically correct explanation for a linear model. Yet they are used on multi-layer networks with millions of parameters. ... More

The complex chemistry of hot cores in Sagittarius B2(N): Influence of cosmic-ray ionization and thermal historyJun 11 2019As the number of complex organic molecules (COMs) detected in the interstellar medium increases, it becomes important to place meaningful constraints on the formation pathways of these species. The molecular cloud SgrB2(N) is host to several hot molecular ... More

Prominent role of multi-electron processes in K-shell double and triple photodetachment of oxygen anionsSep 17 2016The photon-ion merged-beams technique was used at a synchrotron light source for measuring absolute cross sections of double and triple photodetachment of O$^{-}$ ions. The experimental photon energy range of 524-543 eV comprised the threshold for K-shell ... More

Competing spin transfer and dissipation at Co/Cu(001) interfaces on femtosecond timescalesMar 08 2018Nov 29 2018By combining interface-sensitive non-linear magneto-optical experiments with femtosecond time resolution and ab-initio time-dependent density functional theory, we show that optically excited spin dynamics at Co/Cu(001) interfaces proceeds via spin-dependent ... More

Quantum dots investigated with charge detection techniquesMay 20 2009The detection of the quantum dot charge state using a quantum point contact charge detector has opened a new exciting route for the investigation of quantum dot devices in recent years. In particular, time-resolved charge detection allowed the precise ... More

All optical quantum control of a spin-quantum state and ultrafast transduction into an electric currentDec 12 2012The ability to control and exploit quantum coherence and entanglement drives research across many fields ranging from ultra-cold quantum gases to spin systems in condensed matter. Transcending different physical systems, optical approaches have proven ... More

Re-exploring Molecular Complexity with ALMA (ReMoCA): Interstellar detection of ureaJun 11 2019Urea, NH2C(O)NH2, is a molecule of great importance in organic chemistry and biology. Two searches for urea in the interstellar medium were reported in the past, but neither were conclusive. We want to take advantage of the increased sensitivity and angular ... More

Momentum isotropisation in random potentialsSep 07 2012Apr 10 2013When particles are multiply scattered by a random potential, their momentum distribution becomes isotropic on average. We study this quantum dynamics numerically and with a master equation. We show how to measure the elastic scattering time as well as ... More

Growth conditions and inverse producing extensionsDec 14 2005We study the invertibility of Banach algebras elements in their extensions, and invertible extensions of Banach and Hilbert space operators with prescribed growth conditions for the norm of inverses. As applications, the solutions of two open problems ... More

Cheeger-Gromov convergence in a conformal settingDec 23 2015Apr 01 2016For a sequence $\{(M_i, g_i, x_i)\}$ of pointed Riemannian manifolds with boundary, the sequence $\{(M_i,\tilde g_i,x_i)\}$ is its conformal satellite if the metric $\tilde g_i$ is conformal to $g_i$, that is, $\tilde g_i=u^{\frac{4}{n-2}}_ig_i$. Assuming ... More

Gromov's alternative, contact shape, and C^0-rigidity of contact diffeomorphismsOct 02 2013We prove that the group of contact diffeomorphisms is closed in the group of all diffeomorphisms in the C^0-topology. By Gromov's alternative, it suffices to exhibit a diffeomorphism that can not be approximated uniformly by contact diffeomorphisms. Our ... More

On a differential inclusion related to the Born-Infeld equationsJan 20 2012Aug 10 2013We study a partial differential relation that arises in the context of the Born-Infeld equations (an extension of the Maxwell's equations) by using Gromov's method of convex integration in the setting of divergence free fields.

Computing canonical heights using arithmetic intersection theoryMay 09 2011Jan 27 2012For several applications in the arithmetic of abelian varieties it is important to compute canonical heights. Following Faltings and Hriljac, we show how the canonical height on the Jacobian of a smooth projective curve can be computed using arithmetic ... More

Counting perfect matchings and the switch chainMay 16 2017Feb 26 2018We examine the problem of exactly or approximately counting all perfect matchings in hereditary classes of nonbipartite graphs. In particular, we consider the switch Markov chain of Diaconis, Graham and Holmes. We determine the largest hereditary class ... More

Compact Lorentzian holonomyFeb 18 2015Mar 22 2016We consider (compact or noncompact) Lorentzian manifolds whose holonomy group has compact closure. Among other results, we obtain that this property is equivalent to admitting a parallel timelike vector field. We also derive some properties of the space ... More

Counting Independent Sets in Cocomparability GraphsAug 29 2018We show that the number of independent sets in cocomparability graphs can be counted in linear time, as can counting cliques in comparability graphs. By contrast, counting cliques in cocomparabilty graphs and counting independent sets in comparability ... More

Smooth tail index estimationDec 06 2006Jul 31 2007Both parametric distribution functions appearing in extreme value theory - the generalized extreme value distribution and the generalized Pareto distribution - have log-concave densities if the extreme value index gamma is in [-1,0]. Replacing the order ... More

Explicit Kummer surface theory for arbitrary characteristicOct 14 2009We explicitly find an equation and a projective embedding of the Kummer surface associated to the Jacobian of a curve of genus 2 given by an equation of the form y^2 + h(x)y = f(x) over an arbitrary ground field as well as several maps that can be used ... More

Charge Fluctuations from the Chiral Magnetic Effect in Nuclear CollisionsSep 06 2010Sep 21 2010We derive a nonlocal effective Lagrangian for the chiral magnetic effect. An electric field is generated by winding number fluctuations of the nonabelian gauge field in the presence of a strong magnetic field. We estimate the magnitude of charge asymmetry ... More

Broué's abelian defect group conjecture holds for the Harada-Norton sporadic simple group $HN$Jun 28 2009In representation theory of finite groups, there is a well-known and important conjecture due to M. Brou\'e. He conjectures that, for any prime $p$, if a $p$-block $A$ of a finite group $G$ has an abelian defect group $P$, then $A$ and its Brauer corresponding ... More

Every conformal class contains a metric of bounded geometryMar 24 2013Oct 12 2015We show that on every manifold, every conformal class of semi-Riemannian metrics contains a metric $g$ such that each $k$-th-order covariant derivative of the Riemann tensor of $g$ has bounded absolute value $a_k$. This result is new also in the Riemannian ... More

Quasimonotone graphsJan 19 2018Feb 26 2018For any class $\mathcal{C}$ of bipartite graphs, we define quasi-$\cal C$ to be the class of all graphs $G$ such that every bipartition of $G$ belongs to $\cal C$. This definition is motivated by a generalisation of the switch Markov chain on perfect ... More

Compatibility of quasi-orderings and valuations; A Baer-Krull Theorem for quasi-ordered RingsJul 26 2017Sep 19 2018In his work of 1969, Merle E. Manis introduced valuations on commutative rings. Recently, the class of totally quasi-ordered rings was developped by the second author. In the present paper, we establish the notion of compatibility between valuations and ... More

Finite non-cyclic $p$-groups whose number of subgroups is minimalMay 24 2019Recent results of Qu and Tuarnauceanu describe explicitly the finite p-groups which are not elementary abelian and have the property that the number of their subgroups is maximal among p-groups of a given order. We complement these results from the bottom ... More

Percolation HamiltoniansFeb 26 2010Jan 09 2011There has been quite some activity and progress concerning spectral asymptotics of random operators that are defined on percolation subgraphs of different types of graphs. In this short survey we record some of these results and explain the necessary ... More

Path large deviations for interacting diffusions with local mean-field interactions in random environmentDec 16 2015Feb 04 2016We consider a system of $N^{d}$ spins in random environment with a random local mean field type interaction. Each spin has a fixed spatial position on the torus $\mathbb{T}^{d}$, an attached random environment and a spin value in $\mathbb{R}$ that evolves ... More

Explicit Kummer varieties of hyperelliptic Jacobian threefoldsNov 29 2012May 04 2014We explicitly construct the Kummer variety associated to the Jacobian of a hyperelliptic curve of genus 3 that is defined over a field of characteristic not equal to 2 and has a Weierstra{\ss} point defined over the same field. We also construct homogeneous ... More

Estimates for the Green's function of the discrete bilaplacian in dimensions 2 and 3Dec 07 2017We prove estimates for the Green's function of the discrete bilaplacian in squares and cubes in two and three dimensions which are optimal except possibly near the corners of the square and the edges and corners of the cube. The main idea is to transfer ... More

Selection of Sparse Vine Copulas in High Dimensions with the LassoMay 16 2017We propose a novel structure selection method for high dimensional (d > 100) sparse vine copulas. Current sequential greedy approaches for structure selection require calculating spanning trees in hundreds of dimensions and fitting the pair copulas and ... More

Invariant bilinear forms on $W$-graph representations and linear algebra over integral domainsJan 09 2017May 06 2017Lie-theoretic structures of type $E_8$ (e.g., Lie groups and algebras, Hecke algebras and Kazhdan-Lusztig cells, ...) are considered to serve as a `gold standard' when it comes to judging the effectiveness of a general algorithm for solving a computational ... More

Topological contact dynamics III: uniqueness of the topological Hamiltonian and C^0-rigidity of the geodesic flowMay 29 2013We prove that a topological contact isotopy uniquely defines a topological contact Hamiltonian. Combined with previous results from [MS11], this generalizes the classical one-to-one correspondence between smooth contact isotopies and their generating ... More

Anisotropic particles near surfaces: Self-propulsion and frictionOct 28 2015Nov 04 2015We theoretically study the phenomenon of self-propulsion through Casimir forces in thermal non-equilibrium. Using fluctuational electrodynamics, we derive a formula for the self-propulsion force for an arbitrary small object in two scenarios, i) for the ... More

Quarkonium inside Quark-gluon Plasma: Diffusion, Dissociation, Recombination and Energy LossNov 23 2018We consider the quarkonium diffusion, dissociation and recombination inside a quark-gluon plasma. We compute scattering amplitudes in potential nonrelativistic QCD for relevant processes. These processes include the gluon absorption/emission at the order ... More

Doubly charmed baryon production in heavy ion collisionsJan 08 2018Apr 04 2018We give an estimate of $\Xi_{cc}^{++}$ production rate and transverse momentum spectra in relativistic heavy ion collisions. We use Boltzmann transport equations to describe the dynamical evolution of charm quarks and diquarks inside quark-gluon plasma. ... More

On the Convergence of the Elastic Flow in the Hyperbolic PlaneJan 10 2019We examine the L^2-gradient flow of Euler's elastic energy for closed curves in hyperbolic space and prove convergence to the global minimizer for initial curves with elastic energy bounded by 16. We show the sharpness of this bound by constructing a ... More

Spectral multiplier theorems of Euclidean type on new classes of 2-step stratified groupsJun 03 2013Apr 22 2014From a theorem of Christ and Mauceri and Meda it follows that, for a homogeneous sublaplacian $L$ on a $2$-step stratified group $G$ with Lie algebra $\mathfrak{g}$, an operator of the form $F(L)$ is of weak type $(1,1)$ and bounded on $L^p(G)$ for $1 ... More

The parameterized space complexity of embedding along a pathFeb 29 2016Jan 06 2017The embedding problem is to decide, given an ordered pair of structures, whether or not there is an injective homomorphism from the first structure to the second. We study this problem using an established perspective in parameterized complexity theory: ... More

Automating Resolution is NP-HardApr 05 2019We show that the problem of finding a Resolution refutation that is at most polynomially longer than a shortest one is NP-hard. In the parlance of proof complexity, Resolution is not automatizable unless P = NP. Indeed, we show it is NP-hard to distinguish ... More

Max Dehn, Axel Thue, and the UndecidableMar 28 2017Apr 23 2018This is a short essay on the roles of Max Dehn and Axel Thue in the formulation of the word problem for (semi-)groups, and the story of the proofs showing that the word problem is undecidable.

Hyperelliptic Curves with Many AutomorphismsNov 17 2017We determine all complex hyperelliptic curves with many automorphisms and decide which of their jacobians have complex multiplication.

Uniqueness of solutions to Schrödinger equations on 2-step nilpotent Lie groupsJul 19 2012Let g=g_1+g_2, [g,g] =g_2, be a nilpotent Lie algebra of step 2, V_1,..., V_m a basis of g_1 and L=\sum_{j,k} a_{jk} V_j V_k be a left-invariant differential operator on G=exp (g), where the coefficients a_{jk} form a real, symmetric mxm-matrix. It is ... More

Parallel Transport of Higher Flat Gerbes as an Extended Homotopy Quantum Field TheoryFeb 28 2018We prove that the parallel transport of a flat (higher) gerbe on any given target space gives rise to an extended homotopy quantum field theory. In case the target space is the classifying space of a finite group, we provide explicit formulae for this ... More

The Little Bundles OperadJan 15 2019Feb 10 2019Hurwitz spaces are homotopy quotients of the braid group action on the moduli space of principal bundles over a punctured plane. By considering a certain model for this homotopy quotient we build an aspherical topological operad that we call the little ... More

Global solvability of massless Dirac-Maxwell systemsJul 04 2014Mar 01 2016We consider the Cauchy problem of massless Dirac-Maxwell equations on an asymptotically flat background and give a global existence and uniqueness theorem for initial values small in an appropriate weighted Sobolev space. The result can be extended via ... More

The effect of delay on contact tracingOct 22 2016We consider a model for an infectious disease in the onset of an outbreak. We introduce contact tracing incorporating a tracing delay. The effect of randomness in the delay and the effect of the length of this delay in comparison to the infectious period ... More

A Bayesian semi-parametric model for small area estimationMay 21 2008In public health management there is a need to produce subnational estimates of health outcomes. Often, however, funds are not available to collect samples large enough to produce traditional survey sample estimates for each subnational area. Although ... More

Topological contact dynamics II: topological automorphisms, contact homeomorphisms, and non-smooth contact dynamical systemsMar 21 2012This sequel to our previous paper [MS11b] continues the study of topological contact dynamics and applications to contact dynamics and topological dynamics. We provide further evidence that the topological automorphism groups of a contact structure and ... More