Results for "Tom Van Doorsselaere"

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Line-of-sight geometrical and instrumental resolution effects on intensity perturbations by sausage modesMar 25 2013Diagnostics of MHD waves in the solar atmosphere is a topic which often encounters problems of interpretation, due partly to the high complexity of the solar atmospheric medium. Forward modeling can significantly guide interpretation, bridging the gap ... More
Forward Modelling of Standing Kink Modes in Coronal Loops II. ApplicationsFeb 24 2016Magnetohydrodynamic waves are believed to play a significant role in coronal heating, and could be used for remote diagnostics of solar plasma. Both the heating and diagnostic applications rely on a correct inversion (or backward modelling) of the observables ... More
Forward Modelling of Standing Kink Modes in Coronal Loops I. Synthetic ViewsMar 04 2016Kink magnetohydrodynamic (MHD) waves are frequently observed in various magnetic structures of the solar atmosphere. They may contribute significantly to coronal heating and could be used as a tool to diagnose the solar plasma. In this study, we synthesise ... More
Stellar flares observed in long cadence data from the Kepler missionNov 07 2017We aim to perform a statistical study of stellar flares observed by Kepler. We want to study the flare amplitude, duration, energy and occurrence rates, and how they are related to the spectral type and rotation period. To that end, we have developed ... More
Coronal loop transverse oscillations excited by different driver frequenciesMay 14 2019We analyse transverse oscillations of a coronal loop excited by continuous monoperiodic motions of the loop footpoint at different frequencies in the presence of gravity. Using the MPI-AMRVAC code, we perform three-dimensional numerical magnetohydrodynamic ... More
Generalized phase mixing: Turbulence-like behaviour from unidirectionally propagating MHD wavesFeb 08 2017Nov 02 2017We present the results of three-dimensional (3D) ideal magnetohydrodynamics (MHD) simulations on the dynamics of a perpendicularly inhomogeneous plasma disturbed by propagating Alfv\'enic waves. Simpler versions of this scenario have been extensively ... More
Broadening of the DEM by multi-shelled and turbulent loopsOct 15 2018Broad differential emission measure (DEM) distributions in the corona are a sign of multi-thermal plasma along the line-of-sight. Traditionally, this is interpreted as evidence of multi-stranded loops. Recently, however, it has been shown that multi-stranded ... More
Simulations of Gyrosynchrotron Microwave Emission from an Oscillating 3D Magnetic LoopFeb 24 2015Radio observations of solar flares often reveal various periodic or quasi-periodic oscillations. Most likely, these oscillations are caused by magnetohydrodynamic (MHD) oscillations of flaring loops which modulate the emission. Interpretation of the observations ... More
High-frequency dynamics of active region moss as observed by IRISMay 02 2019The high temporal, spatial and spectral resolution of Interface Region Imaging Spectrograph (IRIS) has provided new insights into the understanding of different small-scale processes occurring at the chromospheric and transition region (TR) heights. We ... More
An Analytical Model of the Kelvin-Helmholtz Instability of Transverse Coronal Loop OscillationsJan 18 2019Recent numerical simulations have demonstrated that transverse coronal loop oscillations are susceptible to the Kelvin-Helmholtz (KH) instability due to the counter-streaming motions at the loop boundary. We present the first analytical model of this ... More
Observational signatures of transverse MHD waves and associated dynamic instabilitiesFeb 02 2017MHD waves permeate the solar atmosphere and constitute potential coronal heating agents. Yet, the waves detected so far may be but a small subset of the true existing wave power. Detection is limited by instrumental constraints, but also by wave processes ... More
Wave heating in simulated multi-stranded coronal loopsJul 18 2019It has been found that the Kelvin-Helmholtz instability (KHI) induced by both transverse and torsional oscillations in coronal loops can reinforce the effects of wave heating. In this study, we model a coronal loop as a system of individual strands, and ... More
Quasi-periodic pulsations in solar and stellar flares: an overview of recent resultsSep 09 2016Quasi-periodic pulsations (or QPPs) are periodic intensity variations in the flare emission, across all wavelength bands. In this paper, we review the observational and modelling achievements since the previous review on this topic by Nakariakov & Melnikov ... More
Observational Signatures of Waves and Flows in the Solar CoronaOct 05 2015Propagating perturbations have been observed in extended coronal loop structures for a number of years, but the interpretation in terms of slow (propagating) magneto-acoustic waves and/or as quasi-periodic upflows remains unresolved. We used forward-modelling ... More
Modelling observed decay-less oscillations as resonantly enhanced Kelvin-Helmholtz vortices from transverse MHD waves and their seismological applicationSep 30 2016In the highly structured solar corona, resonant absorption is an unavoidable mechanism of energy transfer from global transverse MHD waves to local azimuthal Alfv\'en waves. Due to its localised nature, a direct detection of this mechanism is extremely ... More
Wave modes excited by photospheric p-modes and mode conversion in a multi-loop systemMay 06 2019Context. Waves are ubiquitous in the solar corona and there are indications that they are excited by photospheric p-modes. However, it is unclear how p-modes in coronal loops are converted to sausage modes and transverse (kink) modes, which are observed ... More
Resonant absorption of surface sausage and surface kink modes under photospheric conditionsOct 09 2017Nov 17 2017We study the effect of resonant absorption of surface sausage and surface kink modes under photospheric conditions where the slow surface sausage modes undergo resonant damping in the slow continuum and the surface kink modes in the slow and Alfv\'{e}n ... More
Observational Tests of Damping by Resonant Absorption in Coronal Loop OscillationsSep 17 2003One of the proposed damping mechanisms of coronal (transverse) loop oscillations in the kink-mode is resonant absorption as a result of the Alfven speed variation at the outer boundary of coronal loops. Analytical expressions for the period and damping ... More
Forward Modeling of SDO/AIA and X-Ray Emission from a Simulated Flux Rope EjectionApr 22 2019We conduct forward-modeling analysis based on our 2.5 dimensional magnetohydrodynamics (MHD) simulation of magnetic flux rope (MFR) formation and eruption driven by photospheric converging motion. The current sheet (CS) evolution during the MFR formation ... More
Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. II- Numerical aspectsJun 30 2015Transverse magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere and may be responsible for generating the Sun's million-degree outer atmosphere. However, direct evidence of the dissipation process and heating from these waves remains ... More
Non-equilibrium Ionization Effects on Extreme-Ultraviolet Emissions Modulated by Standing Sausage Modes in Coronal LoopsNov 21 2018Forward-modeling the emission properties in various passbands is important for confidently identifying magnetohydrodynamic waves in the structured solar corona. We examine how Non-equilibrium Ionization (NEI) affects the Extreme Ultraviolet (EUV) emissions ... More
Forward Modelling of Propagating Slow Waves in Coronal Loops and Their Frequency-Dependent DampingFeb 02 2016Propagating slow waves in coronal loops exhibit a damping which depends upon the frequency of the waves. In this study we aim to investigate the relationship of the damping length (L$_d$) with the frequency of the propagating wave. We present a 3-D coronal ... More
Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. I- Observational aspectsJun 30 2015Transverse magnetohydrodynamic (MHD) waves have been shown to be ubiquitous in the solar atmosphere and can in principle carry sufficient energy to generate and maintain the Sun's million-degree outer atmosphere or corona. However, direct evidence of ... More
Resonant Absorption of Axisymmetric Modes in Twisted Magnetic Flux TubesJun 29 2017It has been shown recently that magnetic twist and axisymmetric MHD modes are ubiquitous in the solar atmosphere and therefore, the study of resonant absorption for these modes have become a pressing issue as it can have important consequences for heating ... More
Reflection Of Propagating Slow Magneto-acoustic Waves In Hot Coronal Loops : Multi-instrument Observations and Numerical ModellingApr 27 2016May 20 2016Slow MHD waves are important tools for understanding the coronal structures and dynamics. In this paper, we report a number of observations, from X-Ray Telescope (XRT) on board HINODE and SDO/AIA of reflecting longitudinal waves in hot coronal loops. ... More
Heating effects from driven transverse and Alfvén waves in coronal loopsNov 19 2018Recent numerical studies revealed that transverse motions of coronal loops can induce the Kelvin-Helmholtz Instability (KHI). This process could be important in coronal heating because it leads to dissipation of energy at small spatial-scale plasma interactions. ... More
Quasi-periodic pulsations in a solar flare with an unusual phase shiftDec 24 2018Two kinds of processes could occur during the flare decay phase: processes of energy release or processes of energy relaxation. Quasi-periodic pulsations (QPPs) of the broadband emission are a good tool for the verification of mechanisms. We aim to study ... More
Galileons from Lovelock actionsFeb 02 2011Feb 10 2011We demonstrate how, for an arbitrary number of dimensions, the Galileon actions and their covariant generalizations can be obtained through a standard Kaluza-Klein compactification of higher-dimensional Lovelock gravity. In this setup, the dilaton takes ... More
Captain Einstein: a VR experience of relativityJun 28 2018Captain Einstein is a virtual reality (VR) movie that takes you on a boat trip in a world with a slow speed of light. This allows for a direct experience of the theory of special relativity, much in the same spirit as in the Mr. Tompkins adventure by ... More
Heating by transverse waves in simulated coronal loopsJun 08 2017Jun 13 2017Recent numerical studies of oscillating flux tubes have established the significance of resonant absorption in the damping of propagating transverse oscillations in coronal loops. The nonlinear nature of the mechanism has been examined alongside the Kelvin-Helmholtz ... More
Fine strand-like structure in the solar corona from MHD transverse oscillationsMay 01 2014Current analytical and numerical modelling suggest the existence of ubiquitous thin current sheets in the corona that could explain the observed heating requirements. On the other hand, new high resolution observations of the corona indicate that its ... More
Wave heating in gravitationally stratified coronal loops in the presence of resistivity and viscosityJan 09 2019Jan 15 2019In recent years, coronal loops have been the focus of studies related to the damping of different magnetohydrodynamic (MHD) surface waves and their connection with coronal seismology and wave heating. For a better understanding of wave heating, we need ... More
Inverse Magnetic Catalysis in the three-flavor NJL model with axial-vector interactionNov 27 2014Dec 12 2014In this paper we explore the chiral phase transition in QCD within the three-flavor Nambu-Jona-Lasinio (NJL) model with a negative coupling constant in the isoscalar axial-vector channel, which is associated with a polarized instanton--anti-instanton ... More
An Inside Look at Sunspot Oscillations with Higher Azimuthal WavenumbersMay 17 2017Solar chromospheric observations of sunspot umbrae offer an exceptional view of magneto-hydrodynamic wave phenomena. In recent years, a wealth of wave signatures related to propagating magneto-acoustic modes have been presented, which demonstrate complex ... More
Coronal rain in magnetic arcades: Rebound shocks, Limit cycles, and Shear flowsJul 03 2015We extend our earlier multidimensional, magnetohydrodynamic simulations of coronal rain occurring in magnetic arcades with higher resolution, grid-adaptive computations covering a much longer ($>6$ hour) timespan. We quantify how in-situ forming blob-like ... More
Frequency-dependent damping in propagating slow magneto-acoustic wavesJun 13 2014Propagating slow magneto-acoustic waves are often observed in polar plumes and active region fan loops. The observed periodicities of these waves range from a few minutes to few tens of minutes and their amplitudes were found to decay rapidly as they ... More
Phonon spectrum of QCD vacuum in magnetic-field-induced superconducting phaseJan 01 2014Jun 16 2014In the background of a sufficiently strong magnetic field the vacuum was suggested to become an ideal electric conductor (highly anisotropic superconductor) due to an interplay between the strong and electromagnetic forces. The superconducting ground ... More
On chromoelectric (super)conductivity of the Yang-Mills vacuumDec 13 2012Jan 28 2014We argue that in the Copenhagen (``spaghetti'') picture of the QCD vacuum the chromomagnetic flux tubes exhibit chromoelectric superconductivity. We show that the superconducting chromoelectric currents in the tubes may be induced by the topological charge ... More
Spontaneous electromagnetic superconductivity and superfluidity of QCDxQED vacuum in strong magnetic fieldJun 13 2012It was recently shown that the vacuum in the background of a strong enough magnetic field may become an electromagnetic superconductor due to interplay between strong and electromagnetic forces. The superconducting ground state of the QCDxQED sector of ... More
Magnetic-field-induced superconductivity and superfluidity of W and Z bosons: in tandem transport and kaleidoscopic vortex statesMar 27 2012Sep 09 2013We show that in a background of a sufficiently strong magnetic field the electroweak sector of the quantum vacuum exhibits superconducting and, unexpectedly, superfluid properties due to the magnetic-field-induced condensation of, respectively, W and ... More
Forward Modelling of Standing Slow Modes in Flaring Coronal LoopsApr 28 2015Standing slow mode waves in hot flaring loops are exclusively observed in spectrometers and are used to diagnose the magnetic field strength and temperature of the loop structure. Due to the lack of spatial information, the longitudinal mode cannot be ... More
Omnipresent long-period intensity oscillations in open coronal structuresSep 12 2012Quasi-periodic propagating disturbances in coronal structures have been interpreted as slow magneto-acoustic waves and/or periodic upflows. Here we aim to understand their nature from the observed properties using a three-hour imaging sequence from AIA/SDO ... More
Fermion zero modes in a chromomagnetic vortex latticeJan 23 2014Mar 21 2014We prove the existence of zero modes of massless quarks in a background of spaghetti vacuum of chromomagnetic vortices in QCD. We find a general solution for the zero modes and show that the modes can be localized at pairs of vortices.
Photospheric plasma and magnetic field dynamics during the formation of solar AR 11190Jan 08 2019The Sun features on its surface typical flow patterns called the granulation, mesogranulation, and supergranulation. These patterns arise due to convective flows transporting energy from the interior of the Sun to its surface. In this paper we will shed ... More
Mapping the internal structure of hadrons through color and spin effectsDec 18 2018Originally it was thought that the proton is not divisible into smaller particles. However, from collision experiments it follows that it consists of a 'soup' of countless 'colored' elementary particles such as quarks and gluons that are kept together ... More
Amplitudes and energy fluxes of simulated decayless kink oscillationsJun 05 2019Recent observations with the Atmospheric Imaging Assembly (AIA) instrument on the SDO spacecraft have revealed the existence of decayless coronal kink oscillations. These transverse oscillations are not connected to any external phenomena like flares ... More
The polytropic index of solar coronal plasma in sunspot fan loops and its temperature dependenceOct 19 2018Observations of slow magneto-acoustic waves have been demonstrated to possess a number of applications in coronal seismology. Determination of the polytropic index ($\gamma$) is one such important application. Analysing the amplitudes of oscillations ... More
The variance of the Euler totient functionJun 13 2017In this paper we study the variance of the Euler totient function (normalized to $\varphi(n)/n$) in the integers $\mathbb{Z}$ and in the polynomial ring $\mathbb{F}_q[T]$ over a finite field $\mathbb{F}_q$. It turns out that in $\mathbb{Z}$, under some ... More
A Parity Game Tale of Two CountersJul 26 2018Aug 02 2018Parity games have important practical applications in formal verification and synthesis, especially for problems related to linear temporal logic and to the modal mu-calculus. The problem is believed to admit a solution in polynomial time, motivating ... More
Modelling of Reflective Propagating Slow-mode Wave in a Flaring LoopSep 15 2015Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in EUV images over a decade, and are widely accepted to be slow magnetosonic waves. However, spectroscopic observations from Hinode/EIS revealed their association ... More
A Bayesian Approach for Inferring Local Causal Structure in Gene Regulatory NetworksSep 18 2018Gene regulatory networks play a crucial role in controlling an organism's biological processes, which is why there is significant interest in developing computational methods that are able to extract their structure from high-throughput genetic data. ... More
Necessary conditions for Schur-maximalityNov 27 2017May 08 2018McNamara and Pylyavskyy conjectured precisely which connected skew shapes are maximal in the Schur-positivity order, which says that $B\leq _s A$ if $s_A-s_B$ is Schur-positive. Towards this, McNamara and van Willigenburg proved that it suffices to study ... More
A large HI cloud near the centre of the Virgo clusterMay 19 2005We report the discovery of a large HI cloud in the central regions of the Virgo cluster. It is 110 x 25 kpc in size and contains 3.4 x 10^8 Msol of HI. The morphology and kinematics of this cloud strongly suggest that it consists of HI removed from the ... More
Investigating `dark' energy in the solar corona using forward modeling of MHD wavesJun 26 2019It is now well established that the Alfv\'enic waves are ubiquitous in the solar corona. However, the Alfv\'enic wave energy estimated from the Doppler velocity measurements in the corona was found to be four orders of magnitude less than that estimated ... More
Modules over axial algebrasApr 20 2017Jan 25 2018We introduce axial representations and modules over axial algebras as new tools to study axial algebras. All known interesting examples of axial algebras fall into this setting, in particular the Griess algebra whose automorphism group is the Monster ... More
The Sierpinski Object in the Scott Realizability ToposApr 30 2019May 21 2019We study the Sierpinski Object in the Scott Realizability Topos.
Import2vec - Learning Embeddings for Software LibrariesMar 27 2019We consider the problem of developing suitable learning representations (embeddings) for library packages that capture semantic similarity among libraries. Such representations are known to improve the performance of downstream learning tasks (e.g. classification) ... More
Local Gromov-Witten Invariants are Log InvariantsDec 14 2017Apr 28 2019We prove a simple equivalence between the virtual count of rational curves in the total space of an anti-nef line bundle and the virtual count of rational curves maximally tangent to a smooth section of the dual line bundle. We conjecture a generalization ... More
The Role of Normware in Trustworthy and Explainable AIDec 06 2018For being potentially destructive, in practice incomprehensible and for the most unintelligible, contemporary technology is setting high challenges on our society. New conception methods are urgently required. Reorganizing ideas and discussions presented ... More
Revisiting Decision Diagrams for SATMay 09 2018Symbolic variants of clause distribution using decision diagrams to eliminate variables in SAT were shown to perform well on hard combinatorial instances. In this paper we revisit both existing ZDD and BDD variants of this approach. We further investigate ... More
Ranking soccer teams on basis of their current strength: a comparison of maximum likelihood approachesMay 26 2017Nov 13 2018We present ten different strength-based statistical models that we use to model soccer match outcomes with the aim of producing a new ranking. The models are of four main types: Thurstone-Mosteller, Bradley-Terry, Independent Poisson and Bivariate Poisson, ... More
Cold accretion flows and the nature of high column density HI absorption at redshift 3Sep 26 2011Jan 04 2012Simulations predict that galaxies grow primarily through the accretion of gas that has not gone through an accretion shock near the virial radius and that this cold gas flows towards the central galaxy along dense filaments and streams. There is, however, ... More
The Angular Momentum of Gas in Proto-Galaxies: II -- The Impact of PreheatingAug 07 2003We examine the effect of preheating of the intergalactic medium on galaxy formation using cosmological hydrodynamical simulations. By performing simulations both with and without a simple model for preheating, we analyse and compare the angular momentum ... More
Plasmon confinement in fractal quantum systemsJan 19 2018Recent progress in the fabrication of materials has made it possible to create arbitrary non-periodic two-dimensional structures in the quantum plasmon regime. This paves the way for exploring the plasmonic properties of electron gases in complex geometries ... More
Directed flow from C-odd gluon correlations at small $x$May 14 2018Jul 25 2018It is shown that odd harmonic azimuthal correlations, including the directed flow $v_1$, in forward two-particle production in peripheral proton-nucleus ($pA$) collisions can arise simply from the radial nuclear profile of a large nucleus. This requires ... More
A new, kinematically anomalous HI component in the spiral galaxy NGC 2403Oct 16 2001We discuss new, high sensitivity HI observations of the spiral galaxy NGC2403 which show extended emission at anomalous velocities with respect to the `cold' disk. This `anomalous' gas component (~1/10 of the total HI mass) is probably located in the ... More
Bisimilarity of Open Terms in Stream GSOSNov 08 2018Feb 12 2019Stream GSOS is a specification format for operations and calculi on infinite sequences. The notion of bisimilarity provides a canonical proof technique for equivalence of closed terms in such specifications. In this paper, we focus on open terms, which ... More
Cold gas & mergers: fundamental difference in HI properties of different types of radio galaxies?Jan 30 2008We present results of a study of large-scale neutral hydrogen (HI) gas in nearby radio galaxies. We find that the early-type host galaxies of different types of radio sources (compact, FR-I and FR-II) appear to contain fundamentally different large-scale ... More
Actions Speak Louder Than Goals: Valuing Player Actions in SoccerFeb 18 2018Assessing the impact of the individual actions performed by soccer players during games is a crucial aspect of the player recruitment process. Unfortunately, most traditional metrics fall short in addressing this task as they either focus on rare events ... More
How do neural networks see depth in single images?May 16 2019Deep neural networks have lead to a breakthrough in depth estimation from single images. Recent work often focuses on the accuracy of the depth map, where an evaluation on a publicly available test set such as the KITTI vision benchmark is often the main ... More
The vertical structure and kinematics of HI in spiral galaxiesOct 20 2000We discuss the distribution and kinematics of neutral hydrogen in the halos of spiral galaxies. We focus in particular on new results obtained for the nearby Sc galaxy NGC 2403 which have revealed the presence of extended HI emission (here referred to ... More
Deep H I Survey of the Spiral Galaxy NGC 2403Mar 22 2002High sensitivity H I observations of the nearby spiral galaxy NGC 2403 obtained with the VLA are presented and discussed. The properties of the extended, differentially rotating H I layer with its H I holes, spiral structure and outer warp are described. ... More
The HI halos of spiral galaxiesSep 07 2000The results of observational studies on the vertical HI density distribution and kinematics of the disks of spiral galaxies are reported and discussed. Attention is drawn to the presence of HI emission, unknown before and here referred to as the `beard', ... More
Switch chain mixing times through triangle countsNov 16 2017Sampling uniform simple graphs with power-law degree distributions with degree exponent $\tau\in(2,3)$ is a non-trivial problem. We propose a method to sample uniform simple graphs that uses a constrained version of the configuration model together with ... More
Computing Treewidth on the GPUSep 28 2017We present a parallel algorithm for computing the treewidth of a graph on a GPU. We implement this algorithm in OpenCL, and experimentally evaluate its performance. Our algorithm is based on an $O^*(2^{n})$-time algorithm that explores the elimination ... More
Renormalization group invariants in supersymmetric theories: one- and two-loop resultsJul 13 2015Sep 10 2015We stress the potential usefulness of renormalization group invariants. Especially particular combinations thereof could for instance be used as probes into patterns of supersymmetry breaking in the MSSM at inaccessibly high energies. We search for these ... More
Drag and lift forces on a counter-rotating cylinder in rotating flowNov 24 2009Apr 06 2010Results are reported of an experimental investigation into the motion of a heavy cylinder free to move inside a water-filled drum rotating around a horizontal axis. The cylinder is observed to either co- or, counter intuitively, counter-rotate with respect ... More
On Exploring Temporal Graphs of Small PathwidthJul 31 2018We show that the Temporal Graph Exploration Problem is NP-complete, even when the underlying graph has pathwidth 2 and at each time step, the current graph is connected.
Analysis of a Gibbs sampler method for model based clustering of gene expression dataJan 14 2008Over the last decade, a large variety of clustering algorithms have been developed to detect coregulatory relationships among genes from microarray gene expression data. Model based clustering approaches have emerged as statistically well grounded methods, ... More
The Capabilities of the EISCAT Svalbard Radar for Inter-hemispheric Coordinated StudiesApr 21 2004In this article we want to present the EISCAT Svalbard Radar (ESR) in some detail, as well as some of the instruments of interest for ionospheric and magnetospheric research that are located in the vicinity of it. We particularly describe how this instrument ... More
The HI halo of NGC 2403Sep 07 2000Deep VLA HI observations of the nearby spiral galaxy NGC 2403 reveal the presence of an extended HI halo that shows slower rotation and a general inflow (about 15-25 km\s) towards the center of the galaxy.
Efficient sampling of Gaussian graphical models using conditional Bayes factorsSep 09 2014Bayesian estimation of Gaussian graphical models has proven to be challenging because the conjugate prior distribution on the Gaussian precision matrix, the G-Wishart distribution, has a doubly intractable partition function. Recent developments provide ... More
Enrichment and aggregation of topological motifs are independent organizational principles of integrated interaction networksSep 09 2011Topological network motifs represent functional relationships within and between regulatory and protein-protein interaction networks. Enriched motifs often aggregate into self-contained units forming functional modules. Theoretical models for network ... More
Positivity bounds on gluon TMDs for hadrons of spin $\le$ 1Sep 22 2017We consider the transverse momentum dependent gluon distribution functions (called gluon TMDs) by studying the light-front gluon-gluon correlator, extending the results for unpolarized and vector polarized targets to also include tensor polarized targets ... More
Damping of nonlinear standing kink oscillations: a numerical studySep 22 2016We aim to study the standing fundamental kink mode of coronal loops in the nonlinear regime, investigating the changes in energy evolution in the cross-section and oscillation amplitude of the loop which are related to nonlinear effects, in particular ... More
The instability and non-existence of multi-stranded loops, when driven by transverse wavesApr 14 2016In recent years, omni-present transverse waves have been observed in all layers of the solar atmosphere. Coronal loops are often modeled as a collection of individual strands, in order to explain their thermal behaviour and appearance. We perform 3D ideal ... More
Circuit-Model Analysis for Spintronic Devices with Chiral Molecules as Spin InjectorsApr 05 2019Jun 07 2019Recent research discovered that charge transfer processes in chiral molecules can be spin selective and named the effect chiral-induced spin selectivity (CISS). Follow-up work studied hybrid spintronic devices with conventional electronic materials and ... More
Simulations of fully deformed oscillating flux tubesJan 23 2018In recent years, a number of numerical studies have been focusing on the significance of the Kelvin-Helmholtz instability (KHI) in the dynamics of oscillating coronal loops. This process enhances the transfer of energy into smaller scales, and has been ... More
Circuit-Model Analysis for Spintronic Devices with Chiral Molecules as Spin InjectorsApr 05 2019Recent research discovered that charge transfer processes in chiral molecules can be spin selective and named the effect Chiral-Induced Spin Selectivity (CISS). Follow-up work studied hybrid spintronic devices with conventional electronic materials and ... More
$A$-dependence of quasielastic charged-current neutrino-nucleus cross sectionsApr 25 2017Mar 26 2018Background: 12C has been and is still widely used in neutrino-nucleus scattering and oscillation experiments. More recently, 40Ar has emerged as an important nuclear target for current and future experiments. Liquid argon time projection chambers (LArTPCs) ... More
Dictionary-free MR Fingerprinting reconstruction of balanced-GRE sequencesNov 24 2017Magnetic resonance fingerprinting (MRF) can successfully recover quantitative multi-parametric maps of human tissue in a very short acquisition time. Due to their pseudo-random nature, the large spatial undersampling artifacts can be filtered out by an ... More
Stable divisorial gonality is in NPAug 21 2018Divisorial gonality and stable divisorial gonality are graph parameters, which have an origin in algebraic geometry. Divisorial gonality of a connected graph $G$ can be defined with help of a chip firing game on $G$. The stable divisorial gonality of ... More
The nature of Elsässer variables in compressible MHDFeb 05 2019The Els\"{a}sser variables are often used in studies of plasma turbulence, in helping differentiate between MHD waves propagating parallel or anti-parallel to the main magnetic field. While for pure Alfv\'en waves in a homogeneous plasma the method is ... More
Extra-planar HI in the starburst galaxy NGC 253Oct 03 2004Observations of the nearby starburst galaxy NGC 253 in the 21-cm line reveal the presence of neutral hydrogen in the halo, up to 12 kpc from the galactic plane. This extra-planar HI is found only in one half of the galaxy and is concentrated in a half-ring ... More
High velocity HI in NGC 6946 and extra-planar gas in NGC 253Oct 01 2004Multi-wavelength observations of nearby spiral galaxies have shown that neutral and ionized gas are present up to a few kpc from the disk and that star formation and supernovae probably play an important role in bringing gas into the halo. We have obtained ... More
Improving Strong-Scaling of CNN Training by Exploiting Finer-Grained ParallelismMar 15 2019Scaling CNN training is necessary to keep up with growing datasets and reduce training time. We also see an emerging need to handle datasets with very large samples, where memory requirements for training are large. Existing training frameworks use a ... More
Probabilistic Fault-Tolerant Universal Quantum Computation and Sampling Problems in Continuous VariablesJun 18 2018Nov 07 2018Continuous-Variable (CV) devices are a promising platform for demonstrating large-scale quantum information protocols. In this framework, we define a general quantum computational model based on a CV hardware. It consists of vacuum input states, a finite ... More
Neural Networks for Information RetrievalJan 07 2018Machine learning plays a role in many aspects of modern IR systems, and deep learning is applied in all of them. The fast pace of modern-day research has given rise to many approaches to many IR problems. The amount of information available can be overwhelming ... More
Gluon transverse momentum dependent correlators in polarized high energy processesSep 09 2016We investigate the gluon transverse momentum dependent correlators as Fourier transform of matrix elements of nonlocal operator combinations. At the operator level these correlators include both field strength operators and gauge links bridging the nonlocality. ... More
Numerical simulations of transverse oscillations in radiatively cooling coronal loopsOct 29 2015We aim to study the influence of radiative cooling on the standing kink oscillations of a coronal loop. Using the FLASH code, we solved the 3D ideal magnetohydrodynamic equations. Our model consists of a straight, density enhanced and gravitationally ... More