Results for "Malcolm Fridlund"

total 648took 0.10s
My Favorite Object L1551 IRS 5Mar 22 2016The L1551-IRS 5 source and its associated atomic jet and molecular outflow has been studied for over 40 years. In this overview of the source this fascinating object and its properties are reviewed and its importance today is re-evaluated.
The way forwardMar 27 2016For the last few decades the study of disks around stars young and old and of different types have progressed significantly. During the same time a completely new discipline, the study of exoplanets, planets orbiting stars other than our Sun, have emerged. ... More
The Spatial Structure of the beta Pictoris Gas DiskOct 06 2003We have used VLT/UVES to spatially resolve the gas disk of beta Pictoris. 88 extended emission lines are observed, with the brightest coming from Fe I, Na I and Ca II. The extent of the gas disk is much larger than previously anticipated; we trace Na ... More
Carbon Burning in Supernovae and Evolving Physical ConstantsOct 18 1999The C(12)+C(12) => Ne(20)+He(4) fusion reaction rate is shown to be extremely sensitive to variations in the strong coupling constant. Connection with the strong coupling constant is established by using the one boson exchange potential for the nuclear ... More
Constraining the Equation of State of Dark Energy with Gamma RaysApr 17 2012Starlight in the Universe impedes the passage of high energy (e.g. TeV) gamma rays due to positron-electron pair production. The history of this stellar radiation field depends upon observations of star formation rate which themselves can only be interpreted ... More
Continuous self-similar evaporation of a rotating cosmic string loopDec 13 2008A solution of the linearized Einstein and Nambu-Goto equations is constructed which describes the evaporation of a certain type of rotating cosmic string - the Allen-Casper-Ottewill loop - under the action of its own self-gravity. The solution evaporates ... More
Cosmic acceleration in models with density dependent moduliMar 12 2004Oct 14 2004The effective equation of state of normal matter is changed in theories where the size of the compact space depends upon the local energy density. In particular we show how the dilution of a fluid due to the expansion of the universe can be compensated ... More
Software Licensing in the Cloud AgeJan 21 2014Cloud computing represents a major shift in information systems architecture, combining both new deployment models and new business models. Rapid provisioning, elastic scaling, and metered usage are essential characteristics of cloud services, and they ... More
Characteristics of proposed 3 and 4 telescope configurations for Darwin and TPF-IJun 29 2006The Darwin and TPF-I missions are Infrared free flying interferometer missions based on nulling interferometry. Their main objective is to detect and characterize other Earth-like planets, analyze the composition of their atmospheres and their capability ... More
Topological Objects in 5D Maxwell Einstein SupergravityOct 17 2000Dec 05 2000In this letter is shown that it is possible to obtain scalar hypersurfaces in 5D N=2 SUGRA where the allowed regions with positive definite scalar metric have a non-trivial topology. This situation may aid in the construction of domain wall solutions ... More
Gravitational waveforms from the evaporating ACO cosmic string loopMar 28 2009The linearly polarized gravitational waveforms from a certain type of rotating, evaporating cosmic string - the Allen-Casper-Ottewill loop - are constructed and plotted over the lifetime of the loop. The formulas for the waveforms are simple and exact, ... More
Decay of Excited String States at Colliders and Cosmic Ray DetectorsSep 19 2005It is argued that in the context of TeV gravity with large extra dimensions, excited string states produced in colliders and in the interaction of cosmic rays with the atmosphere may decay preferentially into invisible bulk modes, rather than visible ... More
Low-High SNR Transition in Multiuser MIMOSep 15 2014Multiuser MIMO (MU-MIMO) plays a key role in the widely adopted 3GPP LTE standard for wireless cellular networks. While exact and asymptotic sum-rate results are well known, the problem of obtaining intuitive analytical results for medium signal-to-noise ... More
CSL-1: Lensing by a Cosmic String or a Dark Matter Filament?Nov 02 2005Nov 03 2005The lens candidate CSL-1 has been interpreted as evidence for a cosmic string. Here we test the hypothesis that the lensing comes from a tidally disrupted dark matter halo. We calculate the mass-density relationship that one would expect from structure ... More
Time varying gauge couplings and di-nucleon statesMay 08 2002In this talk we discuss the effect upon the di-proton, di-neutron and deuteron of a time variation of the QCD gauge coupling. We describe how a time evolution of the size of extra dimensions can give rise to such a variation and show how this is related ... More
Cosmological Constraints on Large Extra DimensionsJan 12 2001Mar 15 2001We calculate the production of massive Kaluza-Klein(KK) modes via nucleon-nucleon gravi-bremsstrahlung in the early universe. Overproduction of these states would result in early matter domination and therefore a low age for the universe so it is possible ... More
KIC 1571511B: A Benchmark Low-Mass Star In An Eclipsing Binary System In The Kepler FieldNov 10 2011KIC 1571511 is a 14d eclipsing binary (EB) in the Kepler dataset. The secondary of this EB is a very low mass star with a mass of 0.14136 +/- 0.00036 M_sun and a radius of 0.17831 +0.00051/-0.00062 R_sun (statistical errors only). The overall system parameters ... More
The 1.2 Millimeter Image of the beta Pictoris DiskFeb 24 2003We present millimeter imaging observations in the 1200 micron continuum of the disk around beta Pictoris. With the 25 arcsec beam, the beta Pic disk is unresolved perpendicularly to the disk plane (< 10 arcsec), but slightly resolved in the northeast-southwest ... More
Comparative Planetology and the Search for Life Beyond the Solar SystemJan 20 2006The study of planets beyond the solar system and the search for other habitable planets and life is just beginning. Ground-based (radial velocity and transits) and space-based surveys (transits and astrometry) will identify planets spanning a wide range ... More
Towards a Molecular Inventory of Protostellar DiscsNov 27 2003The chemical environment in circumstellar discs is a unique diagnostic of the thermal, physical and chemical environment. In this paper we examine the structure of star formation regions giving rise to low mass stars, and the chemical environment inside ... More
Shear Melting at the Crystal-Liquid Interface: Erosion and the Asymmetric Suppression of Interface FluctuationsFeb 17 2016Jul 01 2016The influence of an applied shear on the planar crystal-melt interface is modelled by a nonlinear stochastic partial differential equation of the interface fluctuations. A feature of this theory is the asymmetric destruction of interface fluctuations ... More
Spacetime invariants and their usesApr 26 2015There are various types of global and local spacetime invariant in general relativity. Here I focus on the local invariants obtainable from the curvature tensor and its derivatives. The number of such invariants at each order of differentiation that are ... More
Mixed perturbations from an Inflaton and Two Curvatons - towards understanding non-gaussianity in more complicated curvaton scenariosAug 02 2012We analyse the situation where the primordial curvature perturbations are produced by the joint effects of an inflaton field and two curvaton fields. We present general equations which allow the reader to obtain f_NL for several different scenarios which ... More
Photon Mixing in Domain Walls and the Cosmic Coincidence ProblemJul 02 2005A model is presented where there exists another U(1) gauge group which is extremely weakly coupled to that of QED except inside the core of domain walls. It is possible to choose parameters such that standard model photons crossing such a wall are mixed ... More
K2-264: A transiting multi-planet system in the Praesepe open clusterSep 06 2018Feb 14 2019Planet host stars with well-constrained ages provide a rare window to the time domain of planet formation and evolution. The NASA K2 mission has enabled the discovery of the vast majority of known planets transiting stars in clusters, providing a valuable ... More
Complementarity of Dark Matter Searches at ResonanceJun 12 2014Jan 15 2015We consider models of dark matter where the couplings between the standard model and the dark sector fall at resonance due to kinematics and direct detection experiments become insensitive. To be specific, we consider a simple model of 100 GeV - TeV scale ... More
Time-varying coupling strengths, nuclear forces and unificationDec 20 2001Jan 24 2003We investigate the dependence of the nucleon-nucleon force in the deuteron system on the values of coupling strengths at high energy, which will in general depend on the geometry of extra dimensions. The stability of deuterium at all times after nucleosynthesis ... More
Singlet Fermionic Dark Matter and the Electroweak Phase TransitionMay 15 2013Sep 17 2013We consider a model with a gauge singlet Dirac fermion as a cold dark matter candidate. The dark matter particle communicates with the Standard Model via a gauge singlet scalar mediator that couples to the Higgs. The scalar mediator also serves to create ... More
Binomial and Multinomial Proportions: Accurate Estimation and Reliable Assessment of AccuracyJan 31 2016Misestimates of $\sigma_{P_o}$, the \emph{uncertainty} in $P_o$ from a 2-state Bayes equation used for binary classification, apparently arose from $\hat{\sigma}_{p_i}$, the uncertainty in underlying pdfs estimated from experimental $b$-bin histograms. ... More
Optimal Monte Carlo Estimation of Belief Network InferenceFeb 13 2013We present two Monte Carlo sampling algorithms for probabilistic inference that guarantee polynomial-time convergence for a larger class of network than current sampling algorithms provide. These new methods are variants of the known likelihood weighting ... More
A "Muon Mass Tree" with alpha-quantized Lepton, Quark and Hadron MassesJul 20 2006A "muon mass tree" is displayed that contains the excitation systematics for accurately reproducing the masses of the six Standard Model quarks (u,d,s,c,b,t); the heavy leptons; the proton; the phi, J/Psi and Upsilon vector meson thrshold states; the ... More
The top quark to electron mass ratio m(t) = 18*m(e)/alpha^2 where alpha = e^2/hslash*cMar 24 2006Threshold-state elementary particle lifetimes exhibit a scaling in powers of alpha = e^2/hslash*c, and a reciprocal electron-based 1/alpha scaling in particle masses that extends over two powers of 1/alpha. The m(e)/alpha coupling generates accurate q ... More
Path Intergals and Perturbative Expansions for Non-Compact Symmetric SpacesFeb 05 1992We show how to construct path integrals for quantum mechanical systems where the space of configurations is a general non-compact symmetric space. Associated with this path integral is a perturbation theory which respects the global structure of the system. ... More
Solitonic Black Holes in Gauged N=2 SupergravityDec 29 1995A sequence of zero-temperature black-hole spacetimes with angular momentum and electric and magnetic charges is shown to exist in gauged $N=2$ supergravity. Stability of a subset of these spacetimes is demonstrated by saturation of the Bogomol'nyi bound ... More
Supernova limits on brane world cosmologyNov 01 2005Jan 22 2006By combining the first year data from the Supernova Legacy Survey (SN LS) and the recent detection of the baryon acoustic peak in the Sloan Digital Sky Survey data, we are able to place strong constraints on models where the cosmic acceleration is due ... More
Note on the dark matter explanation of the ARCADE excess and AMS dataJul 17 2014Dec 18 2014In this paper we show that positron data from AMS seems to rule out the explanation of the ARCADE isotropic radio background excess in terms of self-annihilating dark matter. In earlier works it was found that leptonic annihilation channels of light dark ... More
Electroweak Vacuum Stability in light of BICEP2Mar 26 2014Apr 30 2014We consider the effect of a period of inflation with a high energy density upon the stability of the Higgs potential in the early universe. The recent measurement of a large tensor-to-scalar ratio, $r_T \sim 0.16$, by the BICEP-2 experiment possibly implies ... More
Electron generation of leptons and hadrons with reciprocal alpha-quantized lifetimes and massesJun 03 2005Hadron elementary particle measurements have long revealed an alpha-dependence in the long-lived threshold-state lifetimes, together with an alpha-related mass structure, where alpha ~ 1/137 is the fine structure constant. A detailed lifetime analysis ... More
Topological and Hopf charges of a twisted Skyrmion stringAug 03 2015We study topological and Hopf charges of a twisted Skyrmion string. Topological and Hopf charges are defined with the same definition, only differ in vortex solution component.
Star-Planet InteractionsSep 25 2008Much effort has been invested in recent years, both observationally and theoretically, to understand the interacting processes taking place in planetary systems consisting of a hot Jupiter orbiting its star within 10 stellar radii. Several independent ... More
Three Small Planets Transiting a Hyades StarOct 19 2017Feb 15 2018We present the discovery of three small planets transiting K2-136 (LP 358 348, EPIC 247589423), a late K dwarf in the Hyades. The planets have orbital periods of $7.9757 \pm 0.0011$, $17.30681^{+0.00034}_{-0.00036}$, and $25.5715^{+0.0038}_{-0.0040}$ ... More
Capture of Inelastic Dark Matter in White DwarvesJan 15 2010May 26 2010We consider the capture of inelastic dark matter in white dwarves by inelastic spin-independent scattering on nuclei. We show that if the dark matter annihilates to standard-model particles then, under the assumption of primordial globular cluster formation, ... More
Expansion history and f(R) modified gravityJan 31 2007Nov 29 2007We attempt to fit cosmological data using $f(R)$ modified Lagrangians containing inverse powers of the Ricci scalar varied with respect to the metric. While we can fit the supernova data well, we confirm the $a\propto t^{1/2}$ behaviour at medium to high ... More
The experimental lifetime alpha-quantization of the 36 metastable elementary particle lifetimesJun 06 2008The fine structure constant alpha ~ 1/137 appears as a lifetime scaling factor for the 36 metastable (t > 10^-21 sec) elementary particles -- 34 hadrons and the mu and tau leptons. The hadrons divide into 24 long-lived unpaired-quark (UQ) and 3 short-lived ... More
Baryogenesis and Dark Matter with Vector-like FermionsJul 30 2013Nov 05 2013We show that vector-like fermions can act as the dark matter candidate in the universe whilst also playing a crucial role in electroweak baryogenesis through contributing to the barrier in the one-loop thermal scalar potential. In order for the new fermions ... More
Ferroelectrics Manipulate Magnetic Bloch Skyrmions in a Composite BilayerApr 29 2016Aug 26 2016Theoretical investigation demonstrates that the composite bilayer (i.e., chiral-magnetic/ferroelectric bilayer) offers the possibility of electric-induced magnetic Skyrmions [Phys. Rev. B \textbf{94}, 014311 (2016)]. In this Article, we propose a micromagnetic ... More
Tachyon Hair for Two-Dimensional Black HolesNov 01 1993Using a combination of analytical and numerical methods, we obtain a two-dimensional spacetime describing a black hole with tachyon hair. The physical ADM mass of the black hole is finite. The presence of tachyon hair increases the Hawking temperature. ... More
Relative weak mixing of W*-dynamical systems via joiningsAug 22 2017A characterization of relative weak mixing in W*-dynamical systems in terms of a relatively independent joining is proven.
Spin-independent elastic WIMP scattering and the DAMA annual modulation signalAug 05 2008Dec 19 2008We discuss the interpretation of the annual modulation signal seen in the DAMA experiment in terms of spin-independent elastic WIMP scattering. Taking into account channeling in the crystal as well as the spectral signature of the modulation signal we ... More
Reducing the Solar Neutrino Background Using Polarised Helium-3May 27 2016Sep 04 2016Future dark matter detectors plan to have sensitivities such that solar neutrinos will start to become a problematic background. In this work we show that a polarised helium-3 detector would in principle be able to eliminate 98% of these events when the ... More
Two component dark matterOct 23 2008Apr 21 2009We explain the PAMELA positron excess and the PPB-BETS/ATIC e+ + e- data using a simple two component dark matter model (2DM). The two particle species in the dark matter sector are assumed to be in thermal equilibrium in the early universe. While one ... More
Compact Stars as Dark Matter ProbesSep 10 2007Nov 15 2007We discuss the consequences of the accretion of dark matter (DM) particles on compact stars such as white dwarfs and neutron stars. We show that in large regions of the DM parameter space, these objects are sensitive probes of the presence of DM and can ... More
Neutrino emission via the plasma process in a magnetized plasmaJan 13 1999Neutrino emission via the plasma process using the vertex formalism for QED in a strongly magnetized plasma is considered. A new vertex function is introduced to include the axial vector part of the weak interaction. Our results are compared with previous ... More
Exploiting Subgraph Structure in Multi-Robot Path PlanningOct 31 2011Multi-robot path planning is difficult due to the combinatorial explosion of the search space with every new robot added. Complete search of the combined state-space soon becomes intractable. In this paper we present a novel form of abstraction that allows ... More
The involution width of finite simple groupsNov 21 2016For a finite group generated by involutions, the involution width is defined to be the minimal $k\in\mathbb{N}$ such that any group element can be written as a product of at most $k$ involutions. We show that the involution width of every non-abelian ... More
The Potential of the Dwarf Galaxy Triangulum II for Dark Matter Indirect DetectionApr 04 2016Sep 11 2016The recently discovered object Triangulum II appears to be an ultra faint dwarf spheroidal galaxy which may be one of the most dark matter dominated objects yet known. In this work we try to estimate the potential of this object for studies of the indirect ... More
Photon-Axion mixing in an inhomogeneous universeJul 24 2002May 28 2003We consider the dimming of photons from high redshift type 1a supernovae by mixing with a pseudoscalar axion field in the intergalactic medium. We model the electron density using a lognormal probability distribution and assume frozen in magnetic fields. ... More
Brane Splitting via Quantum TunnelingJun 01 2001Apr 26 2002We study the two-centred AdS_7 x S^4 solution of eleven-dimensional supergravity using the Euclidean path-integral approach, and find that it can be interpreted as an instanton, signalling the splitting of the throat of the M5 brane. The instanton is ... More
Interferometric Space Missions for the Search for Terrestrial Exoplanets: Requirements on the Rejection RatioJun 30 2006The requirements on space missions designed to study Terrestrial exoplanets are discussed. We then investigate whether the design of such a mission, specifically the Darwin nulling interferometer, can be carried out in a simplified scenario. The key element ... More
Effects of voids on the reconstruction of the equation of state of Dark EnergyJun 08 2011Oct 12 2011We quantify the effects of the voids known to exist in the Universe upon the reconstruction of the dark energy equation of state $w$. We show that the effect can start to be comparable with some of the other errors taken into account when analysing supernova ... More
Reversible Region of Non-Interest (RONI) Watermarking for Authentication of DICOM ImagesJan 08 2011This paper introduces current watermarking techniques available from the literatures. Requirements for medical watermarking will be discussed. We then propose a watermarking scheme that can recover the original image from the watermarked one. The purpose ... More
The population of massive X-ray binaries I. The Large Magellanic CloudJan 28 2002We present high resolution blue spectroscopy of an almost complete sample of optical counterparts to massive X-ray binaries in the Large Magellanic Cloud (LMC) and derive their spectral classification. We find an spectral type B0II for the optical counterpart ... More
Bayes linear kinematics in a dynamic Bayesian survival modelNov 10 2014Nov 15 2016Bayes linear kinematics and Bayes linear Bayes graphical models provide an extension of Bayes linear methods so that full conditional updates may be combined with Bayes linear belief adjustment. In this paper we investigate the application of this approach ... More
Hysteresis and the dynamic phase transition in thin ferromagnetic filmsDec 11 2000Apr 03 2001Hysteresis and the non-equilibrium dynamic phase transition in thin magnetic films subject to an oscillatory external field have been studied by Monte Carlo simulation. The model under investigation is a classical Heisenberg spin system with a bilinear ... More
AtomtronicsNov 23 2015The progress achieved in micro-fabricating potential for cold atoms has defined a new field in quantum technology - Atomtronics - where a variety of 'atom circuits' of very different spatial shapes and depth have been devised for atom manipulation, with ... More
Luminous Lyman Break Galaxies at z>5 and the Source of ReionizationDec 19 2002Apr 24 2003We have discovered six galaxies with spectroscopically confirmed redshifts of 4.8<z<5.8 in a single 44 square arcminute field imaged deeply in R, I and z-bands. All the spectra show an emission-line in the region around 7000-8400 angstroms with a spectroscopically-detected ... More
Pseudo-Spin Based Dynamical Model for Polarisation Switching in FerroelectricsJun 29 2015Dec 07 2015A microscopic view of the response of the electric dipoles to a dynamic external field in a ferroelectric (FE) chain has been studied by two spin dynamics methods. One is the prominent micromagnetic approach, and the other is the micromagnetic approach ... More
Spin Dynamics in Driven Composite MultiferroicsAug 07 2015Sep 29 2015A spin dynamics approach has been used to study the behavior of the magnetic spins and the electric pseudo-spins in a 1-D composite multiferroic chain with a linear magneto-electric coupling at the interface. The response is investigated with either external ... More
A "nu" look at gravitational waves: The black hole birth rate from neutrinos combined with the merger rate from LIGOApr 17 2017Jul 21 2017We make projections for measuring the black hole birth rate from the diffuse supernova neutrino background (DSNB) by future neutrino experiments, and constrain the black hole merger fraction $\epsilon$, when combined with information on the black hole ... More
Topological Conformal Gravity in Four DimensionsNov 14 1992In this paper, we present a new formulation of topological conformal gravity in four dimensions. Such a theory was first considered by Witten as a possible gravitational counterpart of topological Yang-Mills theory, but several problems left it incomplete. ... More
Large extra dimensions, the galaxy power spectrum and the end of inflationNov 29 2001Feb 19 2002We consider the production of gravitational KK modes via cosmological photon-photon and electron-positron annihilation in models with large factorisable extra dimensions. We place constraints on this production using recent results from a joint analysis ... More
Spitzer Infrared Observations and Independent Validation of the Transiting Super-Earth CoRoT-7bOct 24 2011The detection and characterization of the first transiting super-Earth, CoRoT-7 b, has required an unprecedented effort in terms of telescope time and analysis. Although the star does display a radial velocity signal at the period of the planet, this ... More
Voids as Alternatives to Dark Energy and the Propagation of Gamma Rays through the UniverseNov 19 2011We test the opacity of a void Universe to TeV energy gamma rays having obtained the extra-galactic background light in that Universe using a simple model and the observed constraints on the star formation rate history. We find that the void Universe has ... More
Proton-Proton Fusion in Effective Field Theory to Fifth OrderJan 08 2001The proton-proton fusion process p p->d e^+ nu_e is calculated at threshold to fifth order in pionless effective field theory. There are two unknown two-body currents contributing at the second and fourth orders. Combined with the previous results for ... More
Local sheet conductivity and sheet current density mapping using a single scanning voltage probeSep 18 2013We demonstrate how a single scanning voltage probe can be used to map the local conductivity and current density in a thin film with no a priori knowledge of the geometry of the electrical contacts. With state-of-the-art scanning voltage probes, under ... More
Randall-Sundrum black holes and strange starsJun 25 2002Apr 18 2003It has recently been suggested that the existence of bare strange stars is incompatible with low scale gravity scenarios. It has been claimed that in such models, high energy neutrinos incident on the surface of a bare strange star would lead to catastrophic ... More
Local integrals of motion in the two-site Anderson-Hubbard modelNov 23 2016It has been proposed that the states of fully many-body localized systems can be described in terms of conserved local pseudospins. Due to the multitude of ways to define these, the explicit identification of the optimally local pseudospins in specific ... More
Dynamic Response in a Finite Size Composite Multiferroic Thin FilmNov 06 2015Mar 31 2016Composite multiferroics, heterostructures of ferromagnetic (FM) and ferroelectric (FE) materials, are characterized by a remarkable magnetoelectric effect at the interface. Previous work has supported the ferromagnetic structure with magnetic spins and ... More
Driving Skyrmions in a Composite BilayerJun 15 2016Aug 05 2016Magnetic skyrmions and multiferroics are the most interesting objects in nanostructure science that have great potential in future spin-electronic technology. The study of multiferroic skyrmions has attracted much interest in recent years. This article ... More
Driving Skyrmions on a Composite Multiferroic LatticeJan 07 2016Magnetic skyrmions and multiferroics are the most interesting objects in nanostructure science that have great potential in future spin-electronic technology. The study of the multiferroic skyrmions has attracted much interest in recent years. This paper ... More
Non-Singularity of the Exact Two-Dimensional String Black HoleFeb 09 1993Feb 10 1993We study the global structure of the exact two-dimensional space-time which emerges from string theory. Previous work has shown that in the semi-classical limit, this is a black hole similar to the Schwarzschild solution. However, we find that in the ... More
Doppler tomography of transiting exoplanets: A prograde, low-inclined orbit for the hot Jupiter CoRoT-11bJun 18 2012Jun 19 2012We report the detection of the Doppler shadow of the transiting hot Jupiter CoRoT-11b. Our analysis is based on line-profile tomography of time-series, Keck/HIRES high-resolution spectra acquired during the transit of the planet. We measured a sky-projected, ... More
The transiting multi-planet system HD3167: a 5.7 MEarth Super-Earth and a 8.3 MEarth mini-NeptuneJun 08 2017HD3167 is a bright (V=8.9 mag) K0V star observed by the NASA's K2 space mission during its Campaign 8. It has been recently found to host two small transiting planets, namely, HD3167b, an ultra short period (0.96 d) super-Earth, and HD3167c, a mini-Neptune ... More
Elastic and Inelastic Neutrino-Deuteron Scattering in Effective Field TheoryMay 27 1999Jun 01 1999The differential cross-sections for elastic and inelastic neutrino-deuteron scattering are calculated analytically using nucleon-nucleon effective field theory. For elastic scattering, the deuteron axial form factor and the deuteron strange magnetic moment ... More
Machine Learning, Clustering, and PolymorphyMar 27 2013This paper describes a machine induction program (WITT) that attempts to model human categorization. Properties of categories to which human subjects are sensitive includes best or prototypical members, relative contrasts between putative categories, ... More
Real fermionic symmetry in type II supergravityAug 18 2010Jan 13 2011It is known that the transformations of fermionic T-duality, derived from the worldsheet theory, generically transform real supergravity backgrounds to complex supergravity backgrounds. We consider the low-energy target space theory and show that the ... More
BRS and Anti-BRS Symmetry in Topological Yang--Mills TheorySep 21 1992We incorporate both BRS symmetry and anti-BRS symmetry into the quantisation of topological Yang--Mills theory. This refines previous treatments which consider only the BRS symmetry. Our formalism brings out very clearly the geometrical meaning of topological ... More
Interacting Chiral Gauge Fields in Six Dimensions and Born-Infeld TheoryNov 09 1996Dimensional reduction of a self-dual tensor gauge field in 6d gives an Abelian vector gauge field in 5d. We derive the conditions under which an interacting 5d theory of an Abelian vector gauge field is the dimensional reduction of a 6d Lorentz invariant ... More
Detectability of dirty dust grains in brown dwarf atmospheresMar 14 2006Dust clouds influence the atmospheric structure of brown dwarfs, and they affect the heat transfer and change the gas-phase chemistry. However, the physics of their formation and evolution is not well understood. In this letter, we predict dust signatures ... More
Quantum interference and weak localisation effects in the interlayer magnetoresistance of layered metalsApr 09 2008Studies of angle-dependent magnetoresistance oscillations (AMRO) in the interlayer conductivity of layered metals have generally considered semi-classical electron transport. We consider a quantum correction to the semi-classical conductivity that arises ... More
Varying alpha and black hole entropyDec 10 2002Feb 04 2003Recently it has been suggested that an increase in the fine structure constant alpha with time would decrease the entropy of a Reissner-Nordstrom black hole, thereby violating the second law of thermodynamics. In this note we point out that, at least ... More
Electromagnetic Polarisability of the Nucleon in Chiral Perturbation TheorySep 01 1992We compute the polarisability of the nucleon to leading order in chiral perturbation theory. The contributions from kaons and baryon resonances as intermediate states are included in addition to the contribution from pions and nucleons that had been previously ... More
Frequency-dependent polarizability, plasmons, and screening in the 2D pseudospin-1 dice latticeJan 25 2016Mar 11 2016We calculate the dynamic polarizability under the random phase approximation for the dice lattice. This two-dimensional system gives rise to massless Dirac fermions with pseudospin-1 in the low-energy quantum excitation spectrum, providing a Dirac-cone ... More
The Problem with False Vacuum Higgs InflationMar 28 2014We investigate the possibility of using the only known fundamental scalar, the Higgs, as an inflaton with minimal coupling to gravity. The peculiar appearance of a plateau or a false vacuum in the renormalised effective scalar potential suggests that ... More
Mathematical modeling of the gravitational field of a twisted Skyrmion stringMay 22 2015In this paper we study the gravitational field of a straight string generated from a class of nonlinear sigma models, specifically the Skyrme model without a twist and the Skyrme model with a twist (the twisted Skyrmion string). The twist term, $mkz$, ... More
Baryonic Pinching of Galactic Dark Matter HalosAug 29 2006Jan 03 2007High resolution cosmological N-body simulations of four galaxy-scale dark matter halos are compared to corresponding N-body/hydrodynamical simulations containing dark matter, stars and gas. The simulations without baryons share features with others described ... More
The Gravitational Field Equations of a Twisted Skyrmion String: Numerical SolutionNov 09 2016We study nonlinear sigma model, especially Skyrme model with twist: twisted Skyrmion string where twist term, $mkz$, is indicated in vortex solution. To add gravity, we replace $\eta^{\mu\nu}$ in Lagrangian system with a space-time metric tensor, $g^{\mu\nu}$, ... More
Levelized Cost of Energy for PV and Grid Scale Energy Storage SystemsSep 20 2016With the increasing penetration of renewable energy sources and energy storage devices in the power system, it is important to evaluate the cost of the system by using Levelized Cost of Energy (LCOE). In this paper a new metric, Levelized Cost of Delivery ... More
Morphological evolution of cluster red sequence galaxies in the past 9 GyrJun 23 2016Galaxies arrive on the red sequences of clusters at high redshift ($z>1$) once their star formation is quenched and evolve passively thereafter. However, we have previously found that cluster red sequence galaxies (CRSGs) undergo significant morphological ... More
Distribution of Formation and migration energies of point defects in concentrated solid-solution alloys: Ni_{0.5}Co_{0.5}, Ni_{0.5}Fe_{0.5}, Ni_{0.8}Fe_{0.2} and Ni_{0.8}Cr_{0.2}Jul 15 2016Aug 03 2016Using ab initio calculations and special quasirandom structures, we have characterized the distribution of defect formation energy and migration barrier in Ni-based solid-solution alloys: Ni_{0.5}Co_{0.5}, Ni_{0.5}Fe_{0.5}, Ni_{0.8}Fe_{0.2} and Ni_{0.8}Cr_{0.2}. ... More