Results for "Manuel Meyer"

total 7138took 0.11s
Majorana-Weyl crossings in topological multi-terminal junctionsOct 23 2018We analyze the Andreev spectrum in a four-terminal Josephson junction between one-dimensional topological superconductors in class D. We find that a topologically protected crossing in the space of three superconducting phase differences can occur between ... More
Non-trivial Chern numbers in three-terminal Josephson junctionsMay 06 2017Recently it has been predicted that the Andreev bound state spectrum of 4-terminal Josephson junctions may possess zero-energy Weyl singularities. Using one superconducting phase as a control parameter, these singularities are associated with topological ... More
Magnetic screening properties of superconductor-ferromagnet bilayersMar 12 2009Sep 28 2009We study theoretically the magnetic screening properties of thin, diffusive superconductor/ferromagnet bilayers subject to a perpendicular magnetic field. We find that the effective penetration depth characterizing the magnetic response oscillates with ... More
Quasiclassical theory of disordered Rashba superconductorsFeb 16 2015Jul 30 2015We derive the quasiclassical equations that describe two-dimensional superconductors with a large Rashba spin-orbit coupling and in the presence of impurities. These equations account for the helical phase induced by an in-plane magnetic field, with a ... More
Andreev current induced by ferromagnetic resonanceApr 06 2012We study charge transport through a metallic dot coupled to a superconducting and a ferromagnetic lead with a precessing magnetization due to ferromagnetic resonance. Using the quasiclassical theory, we find that the magnetization precession induces a ... More
Searches for Axionlike Particles Using Gamma-Ray ObservationsNov 23 2016Axionlike particles (ALPs) are a common prediction of theories beyond the Standard Model of particle physics that could explain the entirety of the cold dark matter. These particles could be detected through their mixing with photons in external electromagnetic ... More
Enhancement of the upper critical field in disordered transition metal dichalcogenide monolayersMay 04 2017Jun 16 2017We calculate the effect of impurities on the superconducting phase diagram of transition metal dichalcogenide monolayers in the presence of an in-plane magnetic field. Due to strong intrinsic spin-orbit coupling, the upper critical field greatly surpasses ... More
Magnetic resonance in a singlet-triplet Josephson junctionSep 01 2015We study a singlet-triplet Josephson junction between a conventional s-wave superconductor and an unconventional p$_{\rm x}$-wave superconductor. The Andreev spectrum of the junction yields a spontaneous magnetization in equilibrium. This allows manipulating ... More
Diffuse axion-like particle searchesDec 05 2017We propose a new method to search for axion-like particles (ALPs) based on the gamma-rays produced concomitant with high-energy astrophysical neutrinos. The existence of high-energy neutrinos implies production of gamma-rays in the same sources. Photons ... More
Superharmonic long-range triplet current in a diffusive Josephson junctionMar 05 2013We study the Josephson current through a long ferromagnetic bilayer in the diffusive regime. For non-collinear magnetizations, we find that the current-phase relation is dominated by its second harmonic, which corresponds to the long-range coherent propagation ... More
Weak localization in transition metal dichalcogenide monolayers and their heterostructures with grapheneAug 17 2018We calculate the interference correction to the conductivity of doped transition metal dichalcogenide monolayers (TMDC). Because of the interplay between valley structure and intrinsic spin-orbit coupling (SOC), these materials exhibit a rich weak localization ... More
Class Schema Evolution for Persistent Object-Oriented Software: Model, Empirical Study, and Automated SupportMar 03 2011Jun 21 2012With the wide support for object serialization in object-oriented programming languages, persistent objects have become common place and most large object-oriented software systems rely on extensive amounts of persistent data. Such systems also evolve ... More
Constraints on Axions and Axionlike Particles from Fermi Large Area Telescope Observations of Neutron StarsJan 30 2016We present constraints on the nature of axions and axionlike particles (ALPs) by analyzing gamma--ray data from neutron stars using the Fermi Large Area Telescope. In addition to axions solving the strong CP problem of particle physics, axions and ALPs ... More
Online Top-k-Position Monitoring of Distributed Data StreamsOct 29 2014Consider n nodes connected to a single coordinator. Each node receives an individual online data stream of numbers and, at any point in time, the coordinator has to know the k nodes currently observing the largest values, for a given k between 1 and n. ... More
Signatures of odd-frequency correlations in the Josephson current of superconductor/ferromagnet hybrid junctionsApr 16 2015Contacting a bilayer ferromagnet with a singlet even-frequency superconductor allows for the realization of an effective triplet odd-frequency superconductor. In this work, we investigate the Josephson effect between superconductors with different symmetries ... More
Modelling gamma-ray-axion-like particle oscillations in turbulent magnetic fields: relevance for observations with Cherenkov telescopesDec 08 2014Axion-like particles (ALPs) are a common prediction of certain theories beyond the Standard Model and couple to photons in the presence of external magnetic fields. As a consequence, photon-ALP conversions could lead to an enhancement of the flux of extragalactic ... More
Characterizing the gamma-ray variability of the brightest flat spectrum radio quasars observed with the Fermi LATFeb 06 2019Almost 10 years of $\gamma$-ray observations with the Fermi Large Area Telescope (LAT) have revealed extreme $\gamma$-ray outbursts from flat spectrum radio quasars (FSRQs), temporarily making these objects the brightest $\gamma$-ray emitters in sky. ... More
Density of states in gapped superconductors with pairing-potential impuritiesOct 30 2015We study the density of states in disordered s-wave superconductors with a small gap anisotropy. Disorder comes in the form of common nonmagnetic scatterers and pairing-potential impurities, which interact with electrons via an electric potential and ... More
Probing the peak of the star formation rate density with the extragalactic background lightMar 01 2012Jul 19 2012The extragalactic background light (EBL), i.e., the diffuse meta-galactic photon field in the ultraviolet to infrared, is dominated by the emission from stars in galaxies. It is, therefore, intimately connected with the integrated star formation rate ... More
Impact of oscillations of photons into axion-like particles on the very-high energy gamma-ray spectrum of the blazar PKS1424+240Oct 08 2013Very high energy (VHE) gamma-rays undergo pair production with low energy photons of background radiation fields. This leads to an attenuation of the primary gamma-ray flux of extragalactic sources in the interaction with the extragalactic background ... More
Preliminary Results of the Fermi High-Latitude Extended Source CatalogSep 19 2017We report on preliminary results from the Fermi High-Latitude Extended Sources Catalog (FHES), a comprehensive search for spatially extended gamma-ray sources at high Galactic latitudes ($|b|>5^\circ$) based on data from the Fermi Large Area Telescope ... More
Fragile Complexity of Comparison-Based AlgorithmsJan 09 2019We initiate a study of algorithms with a focus on the computational complexity of individual elements, and introduce the fragile complexity of comparison-based algorithms as the maximal number of comparisons any individual element takes part in. We give ... More
Pair-production opacity at high and very-high gamma-ray energiesSep 16 2013The propagation of high energy (HE, $E_\gamma>100$ MeV) and very high-energy gamma-rays (VHE, $E_\gamma>100$ GeV) in the extra-galactic photon field leads to pair-production and consequently energy- and distance-dependent attenuation of the primary intensity. ... More
Parallel and I/O-efficient Randomisation of Massive Networks using Global Curveball TradesApr 23 2018Aug 17 2018Graph randomisation is a crucial task in the analysis and synthesis of networks. It is typically implemented as an edge switching process (ESMC) repeatedly swapping the nodes of random edge pairs while maintaining the degrees involved. Curveball is a ... More
Indications for a pair-production anomaly from the propagation of VHE gamma-raysJan 23 2012Jan 30 2012In the recent years, the number of detected very high energy (VHE: E > 100 GeV) gamma-ray sources has increased rapidly. The sources have been observed at redshifts up to z = 0.536 without strong indications for the presence of absorption features in ... More
Detecting Photon-Photon Interactions in a Superconducting CircuitMay 20 2015A local interaction between photons can be engineered by coupling a nonlinear system to a transmission line. The required high impedance transmission line can be conveniently formed from a chain of Josephson junctions. The nonlinearity is generated by ... More
Strong effects of weak ac driving in short superconducting junctionsOct 14 2014We study a short superconducting junction subject to a dc and ac phase bias. The ac modulation changes the occupation of the Andreev bound states formed at the constriction by transitions between bound states and the continuum. In a short junction, the ... More
Multi-terminal Josephson junctions as topological materialsMar 23 2015Topological materials and their unusual transport properties are now at the focus of modern experimental and theoretical research. Their topological properties arise from the bandstructure determined by the atomic composition of a material and as such ... More
The Search for the Laws of Automatic Random TestingNov 14 2012Can one estimate the number of remaining faults in a software system? A credible estimation technique would be immensely useful to project managers as well as customers. It would also be of theoretical interest, as a general law of software engineering. ... More
AutoReq: expressing and verifying requirements for control systemsOct 08 2017Feb 04 2019The considerable effort of writing requirements is only worthwhile if the result meets two conditions: the requirements reflect stakeholders' needs, and the implementation satisfies them. In usual approaches, the use of different notations for requirements ... More
A Communication-Efficient Distributed Data Structure for Top-k and k-Select QueriesSep 21 2017We consider the scenario of $n$ sensor nodes observing streams of data. The nodes are connected to a central server whose task it is to compute some function over all data items observed by the nodes. In our case, there exists a total order on the data ... More
Non-Clairvoyant Scheduling to Minimize Max Flow Time on a Machine with Setup TimesSep 18 2017Consider a problem in which $n$ jobs that are classified into $k$ types arrive over time at their release times and are to be scheduled on a single machine so as to minimize the maximum flow time. The machine requires a setup taking $s$ time units whenever ... More
Sensitivity of the Cherenkov Telescope Array to the detection of a dark matter signal in comparison to direct detection and collider experimentsJun 05 2017Sep 21 2017Imaging atmospheric Cherenkov telescopes (IACTs) that are sensitive to potential $\gamma$-ray signals from dark matter (DM) annihilation above $\sim50$ GeV will soon be superseded by the Cherenkov Telescope Array (CTA). CTA will have a point source sensitivity ... More
Episodic excursions of low-mass protostars on the Hertzsprung-Russell diagramDec 28 2018Following our recent work devoted to the effect of accretion on the pre-main-sequence evolution of low-mass stars, we perform a detailed analysis of episodic excursions of low-mass protostars in the Hertzsprung-Russell (H-R) diagram triggered by strong ... More
Probing the EBL evolution at high redshift using GRBs detected with the Fermi-LATOct 06 2017The extragalactic background light (EBL), from ultraviolet to infrared wavelengths, is predominantly due to emission from stars, accreting black holes and reprocessed light due to Galactic dust. The EBL can be studied through the imprint it leaves, via ... More
Looking Under a Better Lamppost: MeV-scale Dark Matter CandidatesMar 14 2019The era of precision cosmology has revealed that about 85% of the matter in the universe is dark matter. Two well-motivated candidates are weakly interacting massive particles (WIMPs) and weakly interacting sub-eV particles (WISPs) (e.g. axions). Both ... More
Communication-free Massively Distributed Graph GenerationOct 20 2017Mar 18 2019Analyzing massive complex networks yields promising insights about our everyday lives. Building scalable algorithms to do so is a challenging task that requires a careful analysis and an extensive evaluation. However, engineering such algorithms is often ... More
First lower limits on the photon-axion-like particle coupling from very high energy gamma-ray observationFeb 05 2013Aug 26 2013The intrinsic flux of very high energy (VHE, Energy > 100 GeV) gamma-rays from extragalactic sources is attenuated due to pair production in the interaction with photons of the extragalactic background light (EBL). Depending on the distance of the source, ... More
Non-equilibrium spin transport in Zeeman-split superconductorsDec 22 2014Mar 08 2015We investigate theoretically the non-local conductance through a superconducting wire in tunnel contact with normal and ferromagnetic leads. In the presence of an in-plane magnetic field, the superconducting density of states is spin-split, and the current ... More
Studying cosmological $γ$-ray propagation with the Cherenkov Telescope ArraySep 13 2017Sep 26 2017The measurement of $\gamma$-rays originating from active galactic nuclei offers the unique opportunity to study the propagation of very-high-energy photons over cosmological distances. Most prominently, $\gamma$-rays interact with the extragalactic background ... More
Topological Josephson $φ_0$-junctionsMar 06 2015Jul 24 2015We study the effect of a magnetic field on the current-phase relation of a topological Josephson junction formed by connecting two superconductors through the helical edge states of a quantum spin-Hall insulator. We predict that the Zeeman effect along ... More
Sensitivity of the Cherenkov Telescope Array to the Detection of Intergalactic Magnetic FieldsMar 10 2016Aug 22 2016Very high energy (VHE; energy $E \gtrsim 100\,$GeV) $\gamma$-rays originating from extragalactic sources undergo pair production with low-energy photons of background radiation fields. These pairs can inverse-Compton-scatter background photons, initiating ... More
On detecting oscillations of gamma rays into axion-like particles in turbulent and coherent magnetic fieldsJun 23 2014Sep 04 2014Background radiation fields pervade the Universe, and above a certain energy any $\gamma$-ray flux emitted by an extragalactic source should be attenuated due to $e^+e^-$ pair production. The opacity could be alleviated if photons oscillated into hypothetical ... More
Revisiting the Indication for a low opacity Universe for very high energy gamma-raysNov 27 2012Jan 10 2013Very high energy (VHE, energy >~ 100 GeV) {\gamma}-rays undergo pair production with photons of the extragalactic background light (EBL). Thus, the intrinsic {\gamma}-ray flux of cosmological sources is attenuated and the Universe should be opaque to ... More
The VHE Gamma-Ray View of the FSRQ PKS~1510-089Mar 20 2019The flat spectrum radio quasar PKS 1510-089 is a monitored target in many wavelength bands due to its high variability. It was detected as a very-high-energy (VHE) $\gamma$-ray emitter with H.E.S.S. in 2009, and has since been a regular target of VHE ... More
Homological algebra for Schwartz algebras of reductive p-adic groupsJan 31 2005Jun 02 2005Let G be a reductive group over a non-Archimedean local field. Then the canonical functor from the derived category of smooth tempered representations of G to the derived category of all smooth representations of G is fully faithful. Here we consider ... More
The cyclic homology and K-theory of certain adelic crossed productsDec 16 2003The multiplicative group of a global field acts on its adele ring by multiplication. We consider the crossed product algebra of the resulting action on the space of Schwartz functions on the adele ring and compute its Hochschild, cyclic and periodic cyclic ... More
Quantizing Two-Dimensional Dilaton Gravity with Fermions: The Vienna WayDec 28 2006I review recent work on nonperturbative path integral quantization of two-dimensional dilaton gravity coupled to Dirac fermions, employing the "Vienna school" approach.
Classical and Quantum Dilaton Gravity in Two Dimensions with FermionsJul 17 2006In this thesis the first order formulation of generalized dilaton gravities in two dimensions coupled to a Dirac fermion is considered. After a Hamiltonian analysis of the gauge symmetries and constraints of the theory and fixing Eddington-Finkelstein ... More
Equivariant Kasparov theory and generalized homomorphismsJan 17 2000Apr 30 2000Let G be a locally compact group. We describe elements of KK^G (A,B) by equivariant homomorphisms, following Cuntz's treatment in the non-equivariant case. This yields another proof for the universal property of KK^G: It is the universal split exact stable ... More
Vibrational band structure of nanoscale phononic crystalsNov 02 2015Nov 24 2017The vibrational properties of two-dimensional phononic crystals are studied with large-scale molecular dynamics simulations and finite element method calculation. The vibrational band structure derived from the molecular dynamics simulations shows the ... More
Excision in Hochschild and cyclic homology without continuous linear sectionsDec 18 2009We prove that continuous Hochschild and cyclic homology satisfy excision for extensions of nuclear H-unital Frechet algebras and use this to compute them for the algebra of Whitney functions on an arbitrary closed subset of a smooth manifold. Using a ... More
Recursive Numerical Evaluation of the Cumulative Bivariate Normal DistributionApr 21 2010We propose an algorithm for evaluation of the cumulative bivariate normal distribution, building upon Marsaglia's ideas for evaluation of the cumulative univariate normal distribution. The algorithm is mathematically transparent, delivers competitive ... More
Atomic Transport in Dense, Multi-Component Metallic LiquidsJun 19 2002Jun 27 2002Pd43Ni10Cu27P0 has been investigated in its equilibrium liquid state with incoherent, inelastic neutron scattering. As compared to simple liquids, liquid PdNiCuP is characterized by a dense packing with a packing fraction above 0.5. The intermediate scattering ... More
Modularity experiments on $S_4$-symmetric double octicsOct 08 2018We will invest quite some computer power to find double octic threefolds that are connected to weight four modular forms.
On a representation of the idele class group related to primes and zeros of L-functionsNov 26 2003Mar 16 2005Let K be a global field. Using natural spaces of functions on the adele ring and the idele class group of K, we construct a virtual representation of the idele class group of K whose character is equal to the Weil distribution that occurs in Andre Weil's ... More
The Bivariate Normal CopulaDec 15 2009We collect well known and less known facts about the bivariate normal distribution and translate them into copula language. In addition, we prove a very general formula for the bivariate normal copula, we compute Gini's gamma, and we provide improved ... More
On Term Rewriting Systems Having a Rational DerivationMay 28 2007Several types of term rewriting systems can be distinguished by the way their rules overlap. In particular, we define the classes of prefix, suffix, bottom-up and top-down systems, which generalize similar classes on words. Our aim is to study the derivation ... More
Extreme lattices and vexillar designsDec 14 2008We define a notion of vexillar design for the flag variety in the spirit of the spherical designs introduced by Delsarte, Goethals and Seidel. For a finite subgroup of the orthogonal group, we explain how conditions on the group have the orbits of any ... More
Representations of *-algebras by unbounded operators: C*-hulls, local-global principle, and inductionJul 15 2016Sep 29 2016We define a C*-hull for a *-algebra, given a notion of integrability for its representations on Hilbert modules. We establish a local-global principle which, in many cases, characterises integrable representations on Hilbert modules through the integrable ... More
Selling train tickets by SMSJul 06 2011Selling train tickets has evolved in the last ten years from queuing in the railway station, to buying tickets on the internet and printing them. Both alternatives are still viable options, though they are time consuming or need printing devices. Nowadays ... More
A Popperian Falsification of Artificial Intelligence - Lighthill DefendedApr 23 2017Apr 18 2018The area of computation called artificial intelligence (AI) is falsified by describing a previous 1972 falsification of AI by British applied mathematician James Lighthill. It is explained how Lighthill's arguments continue to apply to current AI. It ... More
Extinction debt repayment via timely habitat restorationMar 25 2018Habitat destruction threatens the viability of many populations, but its full consequences can take considerable time to unfold. Much of the discourse surrounding extinction debts--the number of species that persist transiently following habitat loss, ... More
Watersheds, waterfalls, on edge or node weighted graphsApr 12 2012We present an algebraic approach to the watershed adapted to edge or node weighted graphs. Starting with the flooding adjunction, we introduce the flooding graphs, for which node and edge weights may be deduced one from the other. Each node weighted or ... More
A spectral interpretation for the zeros of the Riemann zeta functionDec 14 2004Aug 27 2013Based on work of Alain Connes, I have constructed a spectral interpretation for zeros of L-functions. Here we specialise this construction to the Riemann zeta function. We construct an operator on a nuclear Frechet space whose spectrum is the set of non-trivial ... More
Misbehavior in Mobile Application MarketsJul 06 2011Mobile application markets facilitate the distribution of applications and thus help developers advertise their work and customers find useful applications. In addition, the operators of mobile application markets can control the quality and the content ... More
Breaking GSM with rainbow TablesJul 06 2011Since 1998 the GSM security has been academically broken but no real attack has ever been done until in 2008 when two engineers of Pico Computing (FPGA manufacture) revealed that they could break the GSM encryption in 30 seconds with 200'000$ hardware ... More
Bounded turning circles are weak-quasicirclesMar 30 2010Jun 09 2010We show that a metric Jordan curve $\Gamma$ is \emph{bounded turning} if and only if there exists a \emph{weak-quasisymmetric} homeomorphism $\phi\colon \mathsf{S}^1 \to \Gamma$.
Measuring Resonance Parameters of Heavy Higgs Bosons at TESLAAug 13 2003This study investigates the potential of the TESLA Linear Collider for measuring resonance parameters of Higgs bosons beyond the mass range studied so far. The analysis is based on the reconstruction of events from the Higgsstrahlung process e+e- -> HZ. ... More
Smooth and rough modules over self-induced algebrasNov 19 2009A non-unital algebra in a closed monoidal category is called self-induced if the multiplication induces an isomorphism between A\otimes_A A and A. For such an algebra, we define smoothening and roughening functors that retract the category of modules ... More
Non-equilibrium Josephson effect through helical edge statesAug 18 2011We study Josephson junctions between superconductors connected through the helical edge states of a two-dimensional topological insulator in the presence of a magnetic barrier. As the equilibrium Andreev bound states of the junction are 4Pi-periodic in ... More
Online Top-k-Position Monitoring of Distributed Data StreamsOct 29 2014Oct 27 2016Consider n nodes connected to a single coordinator. Each node receives an individual online data stream of numbers and, at any point in time, the coordinator has to know the k nodes currently observing the largest values, for a given k between 1 and n. ... More
I/O-Efficient Generation of Massive Graphs Following the LFR BenchmarkApr 29 2016Jun 14 2017LFR is a popular benchmark graph generator used to evaluate community detection algorithms. We present EM-LFR, the first external memory algorithm able to generate massive complex networks following the LFR benchmark. Its most expensive component is the ... More
How many quasiparticles can be in a superconductor?Mar 14 2016Experimentally and mysteriously, the concentration of quasiparticles in a gapped superconductor at low temperatures always by far exceeds its equilibrium value. We study the dynamics of localized quasiparticles in superconductors with a spatially fluctuating ... More
Nonlocal spin correlations mediated by a superconductorApr 02 2013Nonlocal charge correlations induced in two normal metals contacted separately to a supercon- ductor have been studied intensively in the past few years. Here we investigate nonlocal correlations induced by the transfer of pure spin currents through a ... More
Anomalous Josephson effect in semiconducting nanowires as a signature of the topologically nontrivial phaseDec 09 2015May 07 2016We study Josephson junctions made of semiconducting nanowires with Rashba spin-orbit coupling, where superconducting correlations are induced by the proximity effect. In the presence of a suitably directed magnetic field, the system displays the anomalous ... More
Limits on the extragalactic background light in the Fermi eraFeb 13 2012Very high energy (VHE, energy $E \gtrsim 100$\,GeV) \gamma-rays from cosmological sources are attenuated due to the interaction with photons of the extragalactic background light (EBL) in the ultraviolet to infrared wavelength band. The EBL, thus, leaves ... More
On Competitive Algorithms for Approximations of Top-k-Position Monitoring of Distributed StreamsJan 18 2016Oct 27 2016Consider the continuous distributed monitoring model in which $n$ distributed nodes, receiving individual data streams, are connected to a designated server. The server is asked to continuously monitor a function defined over the values observed across ... More
Monitoring of Domain-Related Problems in Distributed Data StreamsJun 12 2017Consider a network in which $n$ distributed nodes are connected to a single server. Each node continuously observes a data stream consisting of one value per discrete time step. The server has to continuously monitor a given parameter defined over all ... More
I/O-efficient Generation of Massive Graphs Following the LFR BenchmarkApr 29 2016Sep 02 2016LFR is a popular benchmark graph generator used to evaluate community detection algorithms. We present EM-LFR, the first external memory algorithm able to generate massive complex networks following the LFR benchmark. Its most expensive component is the ... More
On Competitive Algorithms for Approximations of Top-k-Position Monitoring of Distributed StreamsJan 18 2016Jan 21 2016Consider the continuous distributed monitoring model in which $n$ distributed nodes, receiving individual data streams, are connected to a designated server. The server is asked to continuously monitor a function defined over the values observed across ... More
Cores of Countably Categorical StructuresDec 13 2006Jan 25 2007A relational structure is a core, if all its endomorphisms are embeddings. This notion is important for computational complexity classification of constraint satisfaction problems. It is a fundamental fact that every finite structure has a core, i.e., ... More
Some Comments on "Split" SupersymmetryJan 13 2005An argument against tolerating finetuning in the Higgs sector is presented, by emphasizing the difference between (well understood) quantum corrections to scalar masses and the (unsolved) problem of the cosmological constant. I also point out that ``split'' ... More
Dark Matter and the SUSY Mass ScaleJan 19 2001Feb 02 2001The connection between the present density of neutralinos that are left over from the Big Bang and the superparticle mass scale is briefly reviewed. Superparticle mass scales in the range from a few GeV to several TeV can lead to an acceptable density ... More
Particle Dark MatterSep 09 1996Sep 13 1996There is plenty of evidence that most matter in the Universe is dark (non-luminous). Particle physics offers several possible explanations. In this talk I focus on cold dark matter; the most promising candidates are then axions and the lightest supersymetric ... More
Bounds for D-finite closure propertiesAug 23 2014We provide bounds on the size of operators obtained by algorithms for executing D-finite closure properties. For operators of small order, we give bounds on the degree and on the height (bit-size). For higher order operators, we give degree bounds that ... More
Some new models for strange quark stars with isotropic pressureJun 28 2014We found new class of solutions to the Einstein-Maxwell system of equations for charged quark matter within the framework of MIT Bag Model considering a gravitational potential Z(x) proposed by Thirukkanesh and Ragel (2013), which depends on an adjustable ... More
Models for Quark Stars with Charged Anisotropic MatterOct 05 2014In this paper, we found new exact solutions to the Einstein- Maxwell system of equations within the framework of MIT Bag Model considering a particular form for the measure of anisotropy and a gravitational potential which depends on an adjustable parameter ... More
The intersection homology D--module in finite characteristicOct 22 2001Let R be a regular, local and F-finite ring defined over a field of finite characteristic. Let I be an ideal of height c with normal quotient $A=R/I$. It is shown that the local cohomology module H^c_I(R) contains a unique simple D_R--submodule L(A,R). ... More
Tubular neighborhoods in the sub-Riemannian Heisenberg groupsMar 05 2017Sep 21 2017We consider the Carnot-Carath\'eodory distance $\delta_E$ to a closed set $E$ in the sub-Riemannian Heisenberg groups $\mathbb{H}^n$, $n\ge 1$. The $\mathbb{H}$-regularity of $\delta_E$ is proved under mild conditions involving a general notion of singular ... More
A Korn-Poincaré-type inequality for special functions of bounded deformationMar 23 2015Dec 14 2015We present a Korn-Poincar\'e-type inequality in a planar setting which is in the spirit of the Poincar\'e inequality in SBV due to De Giorgi, Carriero, Leaci. We show that for each function in SBD$^2$ one can find a modification which differs from the ... More
On quasi-isometric nilpotent Lie groupsOct 12 2017Nov 20 2017In this article we provide evidence for a well-known conjecture which states that quasi-isometric simply-connected nilpotent Lie groups are isomorphic. We do so by constructing new examples which are rigid in the sense that whenever they are quasi-isometric ... More
The Serverless Scheduling Problem and NOAHSep 17 2018The serverless scheduling problem poses a new challenge to Cloud service platform providers because it is rather a job scheduling problem than a traditional resource allocation or request load balancing problem. Traditionally, elastic cloud applications ... More
Conjecture of Wilf: a surveyFeb 09 2019This paper intends to survey the vast literature devoted to a problem posed by Wilf in 1978 which, despite the attention it attracted, remains unsolved. As it frequently happens with combinatorial problems, many researchers who got involved in the search ... More
Primitive rational points on expanding horospheres in Hilbert modular surfacesJan 07 2019In recent work by Einsiedler, Mozes, Shah and Shapira the limiting distributions of primitive rational points on expanding horospheres was examined in arbitrary dimension, and a suspended version of this result was announced. Motivated by this, we prove ... More
Wing Expansion Menu - An approach for faster and more precise navigation with cascading pull-down menusNov 16 2018This paper presents a new design suggestion for cascading pull-down menus to make user interaction with it faster and therefore easier: The Wing Expansion Menu (WEM). The proposal is based on the Steering Law, which implies a wider steering path for menu ... More
Evaluating TQFT invariants from G-crossed braided spherical fusion categories via Kirby diagrams with 3-handlesOct 13 2018A family of TQFTs parametrised by G-crossed braided spherical fusion categories has been defined recently as a state sum model and as a Hamiltonian lattice model. Concrete calculations of the resulting manifold invariants are scarce because of the combinatorial ... More
Dark Matter TheoryNov 15 2018I begin by briefly reviewing the evidence for the existence of Dark Matter (DM), emphasizing that {\em many} observations, at length scales between kpc (the size of the smallest galaxies) and Gpc (the Hubble radius) can be described by the same simple ... More
Deriving sorting algorithms via abductive logic program transformationOct 04 2018Logic program transformation by the unfold/fold method ad- vocates the writing of correct logic programs via the application of some rules to a naive program. This work focuses on how to overcome subgoal- introduction difficulties in synthesizing efficient ... More
Dynamical control of the constraints growth in free evolutions of Einstein's equationsApr 17 2003I present a new, simple method to dynamically control the growth of the discretized constraints during a free evolution of Einstein's equations. During an evolution, any given family of formulations is adjusted off the constraints surface in a way such ... More