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Results for "Ray J. Dolan"

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Ergodicity-breaking reveals time optimal economic behavior in humansJun 11 2019Jun 19 2019Ergodicity describes an equivalence between the expectation value and the time average of observables. Applied to human behaviour, ergodic theory reveals how individuals should tolerate risk in different environments. To optimise wealth over time, agents ... More
Directly detecting sub-GeV dark matter with electrons from nuclear scatteringNov 27 2017Aug 22 2018Dark matter (DM) particles with mass in the sub-GeV range are an attractive alternative to heavier weakly-interacting massive particles, but direct detection of such light particles is challenging. If however DM-nucleus scattering leads to ionisation ... More
Determining the Quantum Numbers of Simplified Models in $t\bar{t}X$ production at the LHCMay 31 2016Jun 09 2016Simplified models provide an avenue for characterising and exploring New Physics for large classes of UV theories. In this article we study the ability of the LHC to probe the spin and parity quantum numbers of a new light resonance $X$ which couples ... More
Low-scale Leptogenesis with Minimal Lepton Flavour ViolationDec 31 2018May 21 2019We analyse the feasibility of low-scale leptogenesis where the inverse seesaw (ISS) and linear seesaw (LSS) terms are not simultaneously present. In order to generate the necessary mass splittings, we adopt a Minimal Lepton Flavour Violation (MLFV) hypothesis ... More
Dark Matter Targets for Axion-like Particle SearchesMay 16 2019Many existing and proposed experiments targeting QCD axion dark matter (DM) can also search for a broad class of axion-like particles (ALPs). We analyze the experimental sensitivities to electromagnetically-coupled ALP DM in different cosmological scenarios ... More
A Bethe Ansatz Study of Free Energy and Excitation Spectrum for Even Spin Fateev Zamolodchikov ModelSep 06 2005A Bethe Ansatz study of a self dual Z_N spin model is undertaken for even spin system. One has to solve a coupled system of Bethe Ansatz Equations (BAE) involving zeroes of two families of transfer matrices. A numerical study on finite size lattices is ... More
Transplanckian Censorship and Global Cosmic StringsJan 19 2017May 21 2017Large field excursions are required in a number of axion models of inflation. These models also possess global cosmic strings, around which the axion follows a path mirroring the inflationary trajectory. Cosmic strings are thus an interesting theoretical ... More
A characterization of all equilateral triangles in \Bbb Z^3Oct 03 2007This paper is a continuation of previous work of the authors. We extend one of the theorems that gave a way to construct equilateral triangles whose vertices have integer coordinates to the general situation. An approximate extrapolation formula for the ... More
Central Limit Theorems for Gaps of Generalized Zeckendorf DecompositionsJun 27 2016Jul 27 2016Zeckendorf proved that every integer can be written uniquely as a sum of non-adjacent Fibonacci numbers $\{1,2,3,5,\dots\}$. This has been extended to many other recurrence relations $\{G_n\}$ (with their own notion of a legal decomposition) and to proving ... More
Performance Characteristics of TreePM codesDec 05 2002We present a detailed analysis of the error budget for the TreePM method for doing cosmological N-Body simulations. It is shown that the choice of filter for splitting the inverse square force into short and long range components suggested in Bagla (2002) ... More
Gravitational Clustering in Redshift Space: Non-Gaussian Tail of the Cosmological Density Distribution FunctionApr 28 2006Apr 29 2006We study the non-Gaussian tail of the probability distribution function of density in cosmological N-Body simulations for a variety of initial conditions. We compare the behaviour of the non-Gaussian tail in the real space with that in the redshift space. ... More
Revised constraints and Belle II sensitivity for visible and invisible axion-like particlesAug 31 2017Jan 04 2018Light pseudoscalars interacting pre-dominantly with Standard Model gauge bosons (so-called axion-like particles or ALPs) occur frequently in extensions of the Standard Model. In this work we review and update existing constraints on ALPs in the keV to ... More
The Bochner measure and holomorphic extension of elementary spherical functionsFeb 26 2009In this paper we determine the Bochner measure for spherical functions on a semi-simple Lie group of rank one.
Spiral instabilities: Mechanism for recurrenceJun 10 2019We argue that self-excited instabilities are the cause of spiral patterns in simulations of unperturbed stellar discs. In previous papers, we have found that spiral patterns were caused by a few concurrent waves, which we claimed were modes. The superposition ... More
Continuous Time Random Walk with time-dependent jump probability : A Direct Probabilistic ApproachDec 13 2011We investigate the dynamics of a particle executing a general Continuous Time Random Walk (CTRW) in three dimensions under the influence of arbitrary time-varying external fields. Contrary to the general approach in recent works, our method invokes neither ... More
Surface morphology of a modified ballistic deposition modelNov 09 2013The surface and bulk properties of a modified ballistic deposition model are investigated. The deposition rule interpolates between nearest and next-nearest neighbor ballistic deposition and the random deposition models. The stickiness of the depositing ... More
Gauge momentum operators for the Calogero-Sutherland model with anti-periodic boundary conditionJul 17 2006Jan 15 2007The integrability of a classical Calogero systems with anti-periodic boundary condition is studied. This system is equivalent to the periodic model in the presence of a magnetic field. Gauge momentum operators for the anti-periodic Calogero system are ... More
Gravitational Collapse in an Expanding Universe: Scaling Relations for Two-Dimensional Collapse RevisitedOct 03 2004Apr 06 2005We investigate non-linear scaling relations for two-dimensional gravitational collapse in an expanding background using a 2D TreePM code and study the strongly non-linear regime ($\bar\xi \leq 200$) for power law models. Evolution of these models is found ... More
A dynamical systems approach to a thin accretion disc and its time-dependent behaviour on large length scalesNov 01 2005Modelling the flow in a thin accretion disc like a dynamical system, we analyse the nature of the critical points of the steady solutions of the flow. For the simple inviscid disc there are two critical points, with the outer one being a saddle point ... More
A First Principles Electronic Structure Study of Quantum Size Effects in (111) Films of delta-PlutoniumJan 16 2004Jul 01 2004First principles linear combinations of Gaussian type orbitals-fitting function (LCGTO-FF) electronic structure calculations are used to study thickness dependencies in the surface energies and work functions of ultra-thin (111) films of fcc delta-Pu, ... More
A Dynamical Systems Approach to an Inviscid and Thin Accretion DiscJul 25 2003Oct 07 2005The inviscid and thin accretion disc is a simple and well understood model system in accretion studies. In this work, modelling such a disc like a dynamical system, we analyse the nature of the fixed points of the stationary solutions of the flow. We ... More
Realizability of stationary spherically symmetric transonic accretionDec 28 2002Sep 20 2004The spherically symmetric stationary transonic (Bondi) flow is considered a classic example of an accretion flow. This flow, however, is along a separatrix, which is usually not physically realizable. We demonstrate, using a pedagogical example, that ... More
Correlation regimes in fluctuations of fatigue crack growthApr 20 2005This paper investigates correlation properties of fluctuations in fatigue crack growth of polycrystalline materials, such as ductile alloys, that are commonly encountered in structures and machinery components of complex electromechanical systems. The ... More
The massive Dirac field on a rotating black hole spacetime: Angular solutionsMay 18 2009Aug 31 2009The massive Dirac equation on a Kerr-Newman background may be solved by the method of separation of variables. The radial and angular equations are coupled via an angular eigenvalue, which is determined from the Chandrasekhar-Page (CP) equation. Obtaining ... More
Vertex Operators for AdS3 Background With Ramond Ramond FluxOct 26 1999In order to study vertex operators for the Type IIB superstring on AdS space, we derive supersymmetric constraint equations for the vertex operators in AdS3xS3 backgrounds with Ramond-Ramond flux, using Berkovits-Vafa-Witten variables. These constraints ... More
Evolutionary tracks for BetelgeuseJun 12 2014Jan 07 2016We have constructed a series of non-rotating quasi-hydrostatic evolutionary models for the M2 Iab supergiant Betelgeuse ($\alpha~Orionis$). Our models are constrained by multiple observed values for the temperature, luminosity, surface composition and ... More
Electromagnetic fields on Kerr spacetime, Hertz potentials and Lorentz gaugeJun 11 2019We review two procedures for constructing the vector potential of the electromagnetic field on Kerr spacetime, namely, the classic method of Cohen & Kegeles, yielding $A^\mu$ in a radiation gauge, and the newer method of Frolov et al., yielding $A^\mu$ ... More
First-Class SubtypesMay 16 2019First class type equalities, in the form of generalized algebraic data types (GADTs), are commonly found in functional programs. However, first-class representations of other relations between types, such as subtyping, are not yet directly supported in ... More
Entropy & equation of state (EOS) for hot bare strange starsMar 31 2000Aug 30 2002Compactness of some stars is explained if they are strange stars (SS) as shown by Dey et al. (1998) (D98) and Li et al. (1999a). One of these compact star candidates is the SAX J1808.4-3658 (SAX in short) believed to be an important link in the genesis ... More
A semiclassical theory of quantum noise in open chaotic systemsNov 13 1998We consider the quantum evolution of classically chaotic systems in contact with surroundings. Based on $\hbar$-scaling of an equation for time evolution of the Wigner's quasi-probability distribution function in presence of dissipation and thermal diffusion ... More
Evolutionary Information Diffusion over Social NetworksSep 11 2013Social networks have become ubiquitous in our daily life, as such it has attracted great research interests recently. A key challenge is that it is of extremely large-scale with tremendous information flow, creating the phenomenon of "Big Data". Under ... More
Self-force via $m$-mode regularization and 2+1D evolution: III. Gravitational field on Schwarzschild spacetimeNov 19 2012This is the third in a series of papers aimed at developing a practical time-domain method for self-force calculations in Kerr spacetime. The key elements of the method are (i) removal of a singular part of the perturbation field with a suitable analytic ... More
Waves and null congruences in a draining bathtubFeb 25 2016We study wave propagation in a draining bathtub: a fluid-mechanical black hole analogue in which perturbations are governed by a Klein-Gordon equation on an effective Lorentzian geometry. Like the Kerr spacetime, the draining bathtub geometry possesses ... More
On Short and Semi-Short Representations for Four Dimensional Superconformal SymmetrySep 06 2002Sep 07 2002Possible short and semi-short representations for $\N=2$ and $\N=4$ superconformal symmetry in four dimensions are discussed. For $\N=4$ the well known short supermultiplets whose lowest dimension conformal primary operators correspond to $\half$-BPS ... More
Dark Energy Cosmological Models with General forms of Scale FactorMay 22 2017Sep 09 2017In this paper, we have constructed dark energy models in an anisotropic Bianchi-V space-time and studied the role of anisotropy in the evolution of dark energy. We have considered anisotropic dark energy fluid with different pressure gradients along different ... More
Luminosity and stellar mass functions of disks and spheroids in the SDSS and the supermassive black hole mass functionDec 23 2006Apr 12 2007Using the Galactica code of Benson et al., we obtain quantitative measurements of spheroid-to-disk ratios for a sample of 8839 galaxies observed in the Sloan Digital Sky Survey. We carry out extensive tests of this code and of Gim2D, finding that they ... More
Indian Buffet Game with Negative Network Externality and Non-Bayesian Social LearningSep 11 2013How users in a dynamic system perform learning and make decision become more and more important in numerous research fields. Although there are some works in the social learning literatures regarding how to construct belief on an uncertain system state, ... More
Renewal-Theoretical Dynamic Spectrum Access in Cognitive Radio Networks with Unknown Primary BehaviorNov 21 2011Dynamic spectrum access in cognitive radio networks can greatly improve the spectrum utilization efficiency. Nevertheless, interference may be introduced to the Primary User (PU) when the Secondary Users (SUs) dynamically utilize the PU's licensed channels. ... More
Challenging the utility of third-order azimuth harmonics in the description of ultra-relativistic heavy-ion collisionsAug 20 2013In recent years it has become conventional practice to include higher-order cylindrical harmonics in the phenomenological description of two-particle angular correlations from ultra-relativistic heavy-ion collisions. These model elements, whose dependence ... More
On the presence of nonjet "higher harmonic" components in 2D angular correlations from high energy heavy ion collisionsJun 23 2012It is conjectured that several higher harmonic flows $v_m$ may result from initial-state geometry fluctuations in \aa collisions coupled to a radially-expanding medium. But as with "elliptic flow" $v_2$ measurements, non-hydrodynamic mechanisms such as ... More
Quick-MESS: A fast statistical tool for Exoplanet Imaging SurveysJun 04 2013Several tools have been developed in the past few years for the statistical analysis of the exoplanet search surveys, mostly using a combination of Monte-Carlo simulations or a Bayesian approach.Here we present the Quick-MESS, a grid-based, non-Monte ... More
Isospin Lattice-Gas Model and Liquid-Gas Phase Transition in Asymmetric Nuclear MatterAug 13 1996An isospin lattice-gas model, which is a spin-1 Ising model, is employed to investigate the liquid-gas phase transition in asymmetric nuclear matter. We consider nuclear matter as a lattice where each lattice site can be either empty or occupied by a ... More
Pulsar optical observation with the Very Large TelescopeApr 10 2000Optical data in the V-band gathered with the 8.2m ESO Very Large Telescope (VLT) at the radio interferometric position of PSR 1706-44 are presented. The pulsar is close to a bright star in projection and was not detected. The pulsar magnitude limit must ... More
Tunable cavity coupling of the zero phonon line of a nitrogen-vacancy defect in diamondJun 16 2015Jun 18 2015We demonstrate the tunable enhancement of the zero phonon line of a single nitrogen-vacancy color center in diamond at cryogenic temperature. An open cavity fabricated using focused ion beam milling provides mode volumes as small as 1.24 $\mu$m$^3$. In-situ ... More
Optimal regularity and nondegeneracy of a free boundary problem related to the fractional LaplacianJan 13 2011Feb 07 2013We discuss the optimal regularity and nondegeneracy of a free boundary problem related to the fractional Laplacian. This work is related to, but addresses a different problem from, recent work of Caffarelli, Roquejoffre, and Sire. A variant of the boundary ... More
Satellite operators with distinct iterates in smooth concordanceMar 16 2014Let P be a knot in an unknotted solid torus (i.e. a satellite operator or pattern), K a knot in S^3 and P(K) the satellite of K with pattern P. For any satellite operator P, this correspondence gives a function P : C -> C on the set of smooth concordance ... More
Non-Rigidity of Cyclic Automorphic Orbits in Free GroupsAug 05 2011We say a subset $\Sigma \subseteq F_N$ of the free group of rank $N$ is \emph{spectrally rigid} if whenever $T_1, T_2 \in \cv_N$ are $\mathbb{R}$-trees in (unprojectivized) outer space for which $|\sigma|_{T_1} = |\sigma|_{T_2}$ for every $\sigma \in ... More
Wave Propagation and Quasinormal Mode Excitation on Schwarzschild SpacetimeJun 21 2011To seek a deeper understanding of wave propagation on the Schwarzschild spacetime, we investigate the relationship between (i) the lightcone of an event and its caustics (self-intersections), (ii) the large-$l$ asymptotics of quasinormal (QN) modes, and ... More
BadNets: Identifying Vulnerabilities in the Machine Learning Model Supply ChainAug 22 2017Mar 11 2019Deep learning-based techniques have achieved state-of-the-art performance on a wide variety of recognition and classification tasks. However, these networks are typically computationally expensive to train, requiring weeks of computation on many GPUs; ... More
Stability of gravitating charged-scalar solitons in a cavityApr 05 2016Jul 12 2016We present new regular solutions of Einstein-charged scalar field theory in a cavity. The system is enclosed inside a reflecting mirror-like boundary, on which the scalar field vanishes. The mirror is placed at the zero of the scalar field closest to ... More
Implementation of the SuSAv2-MEC 1p1h and 2p2h models in GENIE and analysis of nuclear effects in T2K measurementsMay 21 2019May 22 2019We first present the implementation and validation of the SuSAv2-MEC 1p1h and 2p2h models in the GENIE neutrino-nucleus interaction event generator and a comparison of the subsequent predictions to measurements of lepton and hadron kinematics from the ... More
Very Low Frequency QPO in 4U1700-37Jul 07 2011Very low frequency ({\nu} ~ 1.9 mHz) quasi-periodic oscillations (QPO) have been detected in 2 - 60 keV X-rays from 4U1700-37 using auto-correlation function analysis of RXTE archival data. No pulsar signal was detected in the data. Less than 0.5% of ... More
On higher order extensions for the fractional LaplacianFeb 18 2013The technique of Caffarelli and Silvestre, characterizing the fractional Laplacian as the Dirichlet-to-Neumann map for a function U satisfying an elliptic equation in the upper half space with one extra spatial dimension, is shown to hold for general ... More
Presentation of the Iwasawa algebra of the first congruence kernel of a semi-simple, simply connected Chevalley group over $\mathbb{Z}_p$Sep 11 2016It is a general principle that objects coming from semi-simple, simply connected (split) groups have explicit presentations like Serre's presentation of semi-simple algebras and Steinberg's presentation of Chevalley groups. In this paper we give an explicit ... More
Closure operations, Continuous valuations on monoids and Spectral spacesJun 27 2018Nov 05 2018We present several naturally occurring classes of spectral spaces using commutative algebra on pointed monoids. For this purpose, our main tools are finite type closure operations and continuous valuations on monoids which we introduce in this work. In ... More
Massive vector fields on the Schwarzschild spacetime: quasinormal modes and bound statesOct 20 2011Feb 14 2012We study the propagation of a massive vector or Proca field on the Schwarzschild spacetime. The field equations are reduced to a one-dimensional wave equation for the odd-parity part of the field and two coupled equations for the even-parity part of the ... More
Measurement of Throughput Variation Across A Large Format Volume-Phase Holographic GratingSep 30 2005In this paper, we report measurements of diffraction efficiency and angular dispersion for a large format (~ 25 cm diameter) Volume-Phase Holographic (VPH) grating optimized for near-infrared wavelengths (0.9 -- 1.8 micron). The aim of this experiment ... More
Spin-orbit precession for eccentric black hole binaries at first order in the mass ratioAug 16 2016We consider spin-orbit ("geodetic") precession for a compact binary in strong-field gravity. Specifically, we compute $\psi$, the ratio of the accumulated spin-precession and orbital angles over one radial period, for a spinning compact body orbiting ... More
Einstein-charged scalar field theory: black hole solutions and their stabilityNov 17 2015A complex scalar field on a charged black hole in a cavity is known to experience a superradiant instability. We investigate possible final states of this instability. We find hairy black hole solutions of a fully coupled system of Einstein gravity and ... More
Black hole solutions in Einstein-charged scalar field theoryJul 09 2015We investigate possible end-points of the superradiant instability for a charged black hole with a reflecting mirror. By considering a fully coupled system of gravity and a charged scalar field, hairy black hole solutions are obtained. The linear stability ... More
Millisecond X-Ray Pulses from Cygnus X-1Mar 20 2012X-ray pulses with millisecond-long FWHM have been detected in RXTE (Rossi X-Ray Timing Explorer) observations of Cyg X-1. Their identity as short-timescale variations in the X-ray luminosity of the source, and not stochastic variability in the X-ray flux, ... More
The collision between two hydrogen atomsNov 13 2013The electron-electron correlation term in two-atomic collision is the most important, most difficult term to obtain the effective interatomic potential. Generally the H and H collision is a four center problem. It is extremely difficult to compute the ... More
The atom and atom scattering model to control ultracold collisionsJun 24 2012Oct 07 2012A modified static exchange model is introduced, it could be useful to control the elastic s-wave scattering length in studying cold-atomic interaction. The theory includes the long-range van der Waals interaction in addition to short-range exchange force. ... More
Implications of Confirmation of the LSND anti-nu_mu -> anti-nu_e Oscillation SignalNov 03 2004Jan 06 2005Neutrino oscillations have been observed in solar and atmospheric neutrinos, and in the LSND accelerator experiment. The Standard Model cannot accommodate all three positive results. The solar and atmospheric results have been confirmed. An oscillation ... More
Homogenization of a Boundary Obstacle ProblemMay 06 2010We prove the existence of a homogenization limit for solutions of appropriately formulated sequences of boundary obstacle problems for the Laplacian on $C^{1,\alpha}$ domains. Specifically, we prove that the energy minimizers $u_\epsilon$ of $\int |\nabla ... More
Spin-Orbit Misalignment and Precession in the Kepler-13Ab Planetary SystemNov 07 2017Gravity darkening induced by rapid stellar rotation provides us with a unique opportunity to characterize the spin-orbit misalignment of a planetary system through analysis of its photometric transit. We use the gravity-darkened transit modeling code ... More
Plasmonic Optical Modulator based on Adiabatic Coupled WaveguidesOct 04 2017In atomic multi-level systems, adiabatic elimination is a method used to minimize complicity of the system by eliminating irrelevant and strongly coupled levels by detuning them from one-another. Such a three-level system, for instance, can be mapped ... More
Two-Step and Three-Step Nilpotent Lie Algebras Constructed from Schreier GraphsJan 07 2015Jan 16 2015We associate a two-step nilpotent Lie algebra to an arbitrary Schreier graph. We then use properties of the Schreier graph to determine necessary and sufficient conditions for this Lie algebra to extend to a three-step nilpotent Lie algebra. As an application, ... More
Bulk and Edge excitations in a $ν=1$ quantum Hall ferromagnetJan 31 2001In this article, we shall focus on the collective dynamics of the fermions in a $\nu = 1$ quantum Hall droplet. Specifically, we propose to look at the quantum Hall ferromagnet. In this system, the electron spins are ordered in the ground state due to ... More
Quantum Hall Ferromagnets: Induced Topological term and electromagnetic interactionsAug 07 1998The $\nu = 1$ quantum Hall ground state in materials like GaAs is well known to be ferromagnetic in nature. The exchange part of the Coulomb interaction provides the necessary attractive force to align the electron spins spontaneously. The gapless Goldstone ... More
Spectral Rigidity and Subgroups of Free GroupsJan 08 2014A subset $\Sigma \subset F_N$ of the free group of rank $N$ is called \emph{spectrally rigid} if whenever trees $T, T'$ in Culler-Vogtmann Outer Space are such that $\| g \|_T = \| g \|_{T'}$ for every $g \in \Sigma$, it follows that $T = T'$. Results ... More
Globally analytic principal series representation and Langlands base changeJun 10 2018S. Orlik and M. Strauch have studied locally analytic principal series representation for general $p$-adic reductive groups generalizing an earlier work of P. Schneider for $GL(2)$ and related the condition of irreducibility of such locally analytic representation ... More
Presentation of the Iwasawa algebra of the pro-$p$ Iwahori subgroup of $GL_n(\mathbb{Z}_p)$Jul 21 2017Jun 08 2018Iwasawa algebras of compact $p$-adic Lie groups are completed group algebras with applications in number theory in studying class numbers of towers of number fields and representation theory of $p$-adic Lie groups. In our earlier work, we determined an ... More
Use of Effective Audio in E-learning CoursewareMar 16 2015E-Learning uses electronic media, information & communication technologies to provide education to the masses. E-learning deliver hypertext, text, audio, images, animation and videos using desktop standalone computer, local area network based intranet ... More
TreePM Method for Two-Dimensional Cosmological SimulationsJun 01 2004We describe the two-dimensional TreePM method in this paper. The 2d TreePM code is an accurate and efficient technique to carry out large two-dimensional N-body simulations in cosmology. This hybrid code combines the 2d Barnes and Hut Tree method and ... More
Slice knots which bound punctured Klein bottlesJul 03 2012Aug 05 2013We investigate the properties of knots in S^3 which bound Klein bottles, such that a pushoff of the knot has zero linking number with the knot, i.e. has zero framing. This is motivated by the many results in the literature regarding slice knots of genus ... More
Massive stars as thermonuclear reactors and their explosions following core collapseJul 30 2009Nuclear reactions transform atomic nuclei inside stars. This is the process of stellar nucleosynthesis. The basic concepts of determining nuclear reaction rates inside stars are reviewed. How stars manage to burn their fuel so slowly most of the time ... More
LAMP: The Long-term Accretion Monitoring Program of T Tauri stars in Chamaeleon-ISep 03 2012We present the results of a variability study of accreting young stellar objects in the Chameleon I star-forming region which is based on ~300 high resolution optical spectra from the multi-object fibre spectrograph FLAMES/GIRAFFE at the ESO/VLT. Twenty ... More
Supersymmetric Dark Matter after LHC Run 1Aug 05 2015Different mechanisms operate in various regions of the MSSM parameter space to bring the relic density of the lightest neutralino, neutralino_1, assumed here to be the LSP and thus the Dark Matter (DM) particle, into the range allowed by astrophysics ... More
Scattering by a draining bathtub vortexNov 15 2012Jul 01 2013We present an analysis of scattering by a fluid-mechanical `black hole analogue', known as the draining bathtub vortex: a two-dimensional flow which possesses both a sonic horizon and an ergoregion. We consider the scattering of a plane wave of fixed ... More
Fine-Pruning: Defending Against Backdooring Attacks on Deep Neural NetworksMay 30 2018Deep neural networks (DNNs) provide excellent performance across a wide range of classification tasks, but their training requires high computational resources and is often outsourced to third parties. Recent work has shown that outsourced training introduces ... More
Stability of black holes in Einstein-charged scalar field theory in a cavityJul 08 2015Feb 23 2016Can a black hole that suffers a superradiant instability evolve towards a 'hairy' configuration which is stable? We address this question in the context of Einstein-charged scalar field theory. First, we describe a family of static black hole solutions ... More
Chromospheric Inversions of a Micro-flaring RegionJun 30 2017We use spectropolarimetric observations of the Ca II 8542~\AA\ line, taken from the Swedish 1-m Solar Telescope (SST), in an attempt to recover dynamic activity in a micro-flaring region near a sunspot via inversions. These inversions show localized mean ... More
Magnetic Flux Cancellation in Ellerman BombsMar 23 2016Ellerman Bombs (EBs) are often found co-spatial with bipolar photospheric magnetic fields. We use H$\alpha$ imaging spectroscopy along with Fe I 6302.5 \AA\ spectro-polarimetry from the Swedish 1-m Solar Telescope (SST), combined with data from the Solar ... More
Exploring the high pressure phase diagram of La$_{1-x}$Ca$_{x}$MnO$_{3}$Apr 17 2003The structure of La$_{1-x}$Ca$_{x}$MnO$_{3}$ solid solutions (x=0, 0.25, 0.50, 0.67, 1) under high pressure (up to 40-45 GPa) has been investigated by synchrotron X-ray powder diffraction (XRD) in order to characterize their volume \emph{vs.} pressure ... More
Comparing the Dynamics of Skyrmions and Superconducting VorticesDec 18 2013Vortices in type-II superconductors have attracted enormous attention as ideal systems in which to study nonequilibrium collective phenomena, since the self-ordering of the vortices competes with quenched disorder and thermal effects. Dynamic effects ... More
Proper Motions and Variability of the H$_2$ Emission in the HH~46/47systemDec 22 1997We report here on the first proper motion measurements of molecular hydrogen emission features in the Herbig-Haro 46/47 outflow. Assuming a distance of 350 pc to this flow, the inferred tangential velocities range from a few tens to almost 500 km/s . ... More
WiBall: A Time-Reversal Focusing Ball Method for Indoor TrackingDec 18 2017With the development of the Internet of Things technology, indoor tracking has become a popular application nowadays, but most existing solutions can only work in line-of-sight scenarios, or require regular re-calibration. In this paper, we propose WiBall, ... More
A Deep Spitzer Survey of Circumstellar Disks in the Young Double Cluster, h and chi PerseiAug 07 2014We analyze very deep IRAC and MIPS photometry of $\sim$ 12,500 members of the 14 Myr old Double Cluster, h and $\chi$ Persei, building upon on our earlier, shallower Spitzer studies (Currie et al. 2007a, 2008a). Numerous likely members show infrared (IR) ... More
High--cadence observations of spicular-type events on the SunJan 29 2016Feb 01 2016Chromospheric observations taken at high cadence and high spatial resolution show a range of spicule like features, including Type I, Type II (as well as RBEs and RREs) and those which seem to appear within a few seconds, which if interpreted as flows ... More
Ergodicity-breaking reveals time optimal economic behavior in humansJun 11 2019Jun 12 2019Ergodicity describes an equivalence between the expectation value and the time average of observables. Applied to human behaviour, ergodic theory reveals how individuals should tolerate risk in different environments. To optimise wealth over time, agents ... More
High-Resolution Transit Spectroscopy of Warm SaturnsDec 06 2018We present high-resolution optical transmission spectroscopy of two sub-Saturn mass transiting exoplanets, HAT-P-12b and WASP-69b. With relatively low densities and high atmospheric scale heights, these planets are particularly well-suited to characterization ... More
Probing temperature-driven flow lines in a gated two-dimensional electron gas with tunable spin-splittingSep 05 2012We study the temperature flow of conductivities in a gated GaAs two-dimensional electron gas (2DEG) containing self-assembled InAs dots and compare the results with recent theoretical predictions. By changing the gate voltage, we are able to tune the ... More
Bulk emission of scalars by a rotating black holeJan 31 2008Jul 17 2008We study in detail the scalar-field Hawking radiation emitted into the bulk by a higher-dimensional, rotating black hole. We numerically compute the angular eigenvalues, and solve the radial equation of motion in order to find transmission factors. The ... More
Results and prospects of the latest $ν_μ$CC0$π$ analyses from the T2K near detectorsMar 11 2017In order to make precision measurements of GeV-scale neutrino oscillations a detailed understanding of both GeV-scale neutrino-nucleon scattering cross sections and nuclear effects are essential. To achieve this, many of the latest analyses at the T2K ... More
Ergodicity-breaking reveals time optimal economic behavior in humansJun 11 2019Ergodicity describes an equivalence between the expectation value and the time average of observables. Applied to human behaviour, ergodic theory reveals how individuals should tolerate risk in different environments. To optimise wealth over time, agents ... More
Isolated critical point from Lovelock gravityJul 17 2014For any K(=2k+1)th-order Lovelock gravity with fine-tuned Lovelock couplings, we demonstrate the existence of a special isolated critical point characterized by non-standard critical exponents in the phase diagram of hyperbolic vacuum black holes. In ... More
Indole moiety induced biological potency in pseudo- peptides derived from 2-amino-2-(1H-indole-2-yl) based acetamides: synthesis, structure and computational investigationsFeb 12 2018We report the synthesis and theoretical investigations of three novel pseudo-peptide molecules derived from 2-amino-2-(1H-indole-2-yl) acetamides. The compounds were subjected to spectroscopic characterization ($^1$H, $^{13}$C-NMR and MS) and their chemical, ... More
A universal Dirac operator and noncommutative spin bundles over fuzzy complex projective spacesNov 08 2007Sep 15 2008We present a universal Dirac operator for noncommutative spin and spin^c bundles over fuzzy complex projective spaces. We give an explicit construction of these bundles, which are described in terms of finite dimensional matrices, calculate the spectrum ... More
Coding against deletions in oblivious and online modelsDec 19 2016Jul 26 2017We consider binary error correcting codes when errors are deletions. A basic challenge concerning deletion codes is determining $p_0^{(adv)}$, the zero-rate threshold of adversarial deletions, defined to be the supremum of all $p$ for which there exists ... More