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Heteroatom-doped hydrogenated amorphous carbons, a-C:H:X 'Volatile' silicon, sulphur and nitrogen depletion, blue photoluminescence, diffuse interstellar bands and ferro-magnetic carbon grain connections (Research Note)Nov 21 2014Context. Hydrogenated amorphous carbons, a-C:H, can incorporate a variety of heteroatoms, which can lead to interesting effects. Aims. To investigate the doping of interstellar a-C:H grains with, principally, Si, O, N and S atoms within the astrophysical ... More

Dust evolution, a global view: IV. Tying up a few loose endsApr 27 2018This work is an attempt to tie together some of the, seemingly disparate, loose ends from the preceding papers in this series into the global view of dust evolution in the interstellar medium. In particular, the nature of the hydro-carbonaceous, infrared ... More

Depletion patterns and dust evolution in the ISMJul 06 1999We review the use of elemental depletions in determining the composition of interstellar dust and present a new interpretation of the elemental depletion patterns for the dust forming elements in a range of diffuse cloud types. We discuss this within ... More

The characterisation of irregularly-shaped particles: a re-consideration of finite-sized, porous and fractal grainsNov 05 2015Context. A porous and/or fractal description can generally be applied where particles have undergone coagulation into aggregates. Aims. To characterise finite-sized, porous and fractal particles and to understand the possible limitations of these descriptions. ... More

Variations on a theme - the evolution of hydrocarbon solids: III. Size-dependent properties - the optEC(s)(a) modelNov 05 2015Context. The properties of hydrogenated amorphous carbon (a-C:H) dust evolve in response to the local radiation field in the interstellar medium and the evolution of these properties is particularly dependent upon the particle size. Aims. A model for ... More

Variations on a theme - the evolution of hydrocarbon solids: II. Optical property modelling - the optEC(s) modelNov 05 2015Context. The properties of hydrogenated amorphous carbon (a-C:H) dust are known to evolve in response to the local conditions. Aims. We present an adaptable model for the determination of the optical properties of low-temperature, interstellar a-C:H grains ... More

Variations on a theme - the evolution of hydrocarbon solids: I. Compositional and spectral modelling - the eRCN and DG modelsNov 05 2015Context. The compositional properties of hydrogenated amorphous carbons are known to evolve in response to the local conditions. Aims. To present a model for low-temperature, amorphous hydrocarbon solids, based on the microphysical properties of random ... More

H2 formation via the UV photo-processing of a-C:H nano-particlesJul 30 2015Context. The photolysis of hydrogenated amorphous carbon, a-C(:H), dust by UV photon-irradiation in the laboratory leads to the release of H2 as well as other molecules and radicals. This same process is also likely to be important in the interstellar ... More

Probing the Intracluster star-light with ChandraMar 20 2002Mar 20 2002We propose a method to test for the presence of intracluster star-light using X-ray binaries as a trace population. We discuss a particular application of this method to observations of the Virgo cluster.

The Kelvin-Helmholtz instability in weakly ionised plasmas II: multifluid effects in molecular cloudsNov 02 2011We present a study of the Kelvin-Helmholtz instability in a weakly ionised, multifluid MHD plasma with parameters matching those of a typical molecular cloud. The instability is capable of transforming well-ordered flows into disordered flows. As a result, ... More

Finite size scaling of the correlation length above the upper critical dimensionDec 07 2004We show numerically that correlation length at the critical point in the five-dimensional Ising model varies with system size L as L^{5/4}, rather than proportional to L as in standard finite size scaling (FSS) theory. Our results confirm a hypothesis ... More

The Interstellar dust properties of nearby galaxiesNov 20 2017Dec 06 2017This article gives an overview of the constitution, physical conditions and observables of dust in the interstellar medium of nearby galaxies. We first review the macroscopic, spatial distribution of dust in these objects, and its consequence on our ability ... More

Interstellar nanodiamonds: the carriers of mid-infrared emission bands?Dec 23 1999In this paper we pursue the natural consequences of the structure of nanodiamonds and their surface relaxation and reconstruction to surfaces exhibiting sp2 carbon atoms. We show that in the interstellar radiation field nanodiamonds can be stochastically ... More

Rotational Response of Two-Component Bose-Einstein Condensates in Ring TrapsJan 28 2010Apr 26 2010We consider a two-component Bose-Einstein condensate (BEC) in a ring trap in a rotating frame, and show how to determine the response of such a configuration to being in a rotating frame, via accumulation of a Sagnac phase. This may be accomplished either ... More

Applying the linear delta expansion to `i phi^3'Oct 22 1997The linear $\delta$ expansion (LDE) is applied to the Hamiltonian $H=(p^2 +m^2 x^2)/2 + igx^3$, which arises in the study of Lee-Yang zeros in statistical mechanics. Despite being non-Hermitian, this Hamiltonian appears to possess a real, positive spectrum. ... More

Separation of foregrounds from cosmic microwave background observations with the MAP satelliteOct 15 1998Simulated observations of a $10\dg \times 10\dg$ field by the Microwave Anisotropy Probe (MAP) are analysed in order to separate cosmic microwave background (CMB) emission from foreground contaminants and instrumental noise and thereby determine how accurately ... More

On dust-correlated Galactic emission in the Tenerife dataFeb 15 2000Feb 17 2000Recently correlation analyses between Galactic dust emission templates and a number of CMB data sets have led to differing claims on the origin of the Galactic contamination at low frequencies. de Oliviera-Costa {\em et al} (1999) have presented work ... More

Two-electron excitation of an interacting cold Rydberg gasAug 26 2010We report the creation of an interacting cold Rydberg gas of strontium atoms. We show that the excitation spectrum of the inner valence electron is sensitive to the interactions in the Rydberg gas, even though they are mediated by the outer Rydberg electron. ... More

A new method to probe the thermal electron content of the Galaxy through spectral analysis of background sourcesMay 19 2016We present a new method for probing the thermal electron content of the Galaxy by spectral analysis of background point sources in the absorption-only limit to the radiative transfer equation. In this limit, calculating the spectral index, $\alpha$, of ... More

Multichannel Quantum Defect Theory of Strontium Rydberg SeriesFeb 24 2014Using the reactance matrix approach, we systematically develop new multichannel quantum defect theory models for the singlet and triplet S, P, D and F states of strontium based on improved energy level measurements. The new models reveal additional insights ... More

An introduction to artificial neural networksFeb 13 2001Artificial neural networks are algorithms which have been developed to tackle a range of computational problems. These range from modelling brain function to making predictions of time-dependent phenomena to solving hard (NP-complete) problems. In this ... More

Long-range Rydberg-Rydberg interactions in calcium, strontium and ytterbiumMar 16 2012May 11 2012Long-range dipole-dipole and quadrupole-quadrupole interactions between pairs of Rydberg atoms are calculated perturbatively for calcium, strontium and ytterbium within the Coulomb approximation. Quantum defects, obtained by fitting existing laser spectroscopic ... More

Opening angles, Lorentz factors and confinement of X-ray binary jetsJan 20 2006We present a collation of the available data on the opening angles of jets in X-ray binaries, which in most cases are small (less than 10 degrees). Under the assumption of no confinement, we calculate the Lorentz factors required to produce such small ... More

The AT20G high angular resolution catalogueJun 05 2013We present the high angular resolution catalogue for the Australia Telescope 20 GHz (AT20G) survey, using the high angular resolution 6-km antenna data at the baselines of ~ 4500 m of the Australia Telescope Compact Array (ATCA). We have used the data ... More

Intercombination Effects in Resonant Energy TransferMar 25 2015Oct 15 2015We investigate the effect of intercombination transitions in excitation hopping processes such as those found in F\"orster resonance energy transfer. Taking strontium Rydberg states as our model system, the breakdown of $LS$-coupling leads to weakly allowed ... More

Random Conformal WeldingsSep 07 2009We construct a conformally invariant random family of closed curves in the plane by welding of random homeomorphisms of the unit circle. The homeomorphism is constructed using the exponential of $\beta X$ where $X$ is the restriction of the two dimensional ... More

Silicate emission in OrionFeb 14 2000We present mid-infrared spectro-imagery and high-resolution spectroscopy of the Orion bar and of a region in the Orion nebula. These observations have been obtained in the Guaranteed Time with the Circular Variable Filters of the ISO camera (CAM-CVF) ... More

On the possible reason for non-detection of TeV-protons in SNRsDec 03 2001The theory of shock acceleration predicts the maximum particle energy to be limited only by the acceleration time and the size (geometry) of the shock. This led to optimistic estimates for the galactic cosmic ray energy achievable in the SNR shocks. The ... More

Random Curves by Conformal WeldingDec 17 2009We construct a conformally invariant random family of closed curves in the plane by welding of random homeomorphisms of the unit circle given in terms of the exponential of Gaussian Free Field. We conjecture that our curves are locally related to SLE$(\kappa)$ ... More

Single Molecule Fluorescence Imaging as a Technique for Barium Tagging in Neutrinoless Double Beta DecaySep 13 2016Sep 20 2016Background rejection is key to success for future neutrinoless double beta decay experiments. To achieve sensitivity to effective Majorana lifetimes of $\sim10^{28}$ years, backgrounds must be controlled to better than 0.1 count per ton per year, beyond ... More

Spectroscopy of strontium Rydberg states using electromagnetically induced transparencyOct 05 2007Oct 07 2007We report on the all-optical detection of Rydberg states in a effusive atomic beam of strontium atoms using electromagnetically induced transparency (EIT). Using narrow-linewidth CW lasers we obtain an EIT linewidth of 5 MHz. To illustrate the high spectroscopic ... More

Intrinsic energy cut-off in diffusive shock acceleration: possible reason for non-detection of TeV-protons in SNRsJul 14 2001The linear theory of shock acceleration predicts the maximum particle energy to be limited only by the acceleration time and the size of the shock. We study the combined effect of acceleration nonlinearity (shock modification by accelerated particles, ... More

Rapidly detecting disorder in rhythmic biological signals: A spectral entropy measure to identify cardiac arrhythmiasOct 08 2008Feb 16 2009We consider the use of a running measure of power spectrum disorder to distinguish between the normal sinus rhythm of the heart and two forms of cardiac arrhythmia: atrial fibrillation and atrial flutter. This spectral entropy measure is motivated by ... More

ISM properties in low-metallicity environments I. mid-infrared spectra of dwarf galaxiesOct 04 2005We present new ISOCAM mid-infrared spectra of three starbursting nearby dwarf galaxies, NGC1569, IIZw40, NGC1140 and the 30Dor region of the LMC and explore the properties of the ISM in low-metallicity environments, also using additional sources from ... More

Distribution and characteristics of Infrared Dark Clouds using genetic forward modellingAug 26 2009Infrared Dark Clouds (IRDCs) are dark clouds seen in silhouette in mid-infrared surveys. They are thought to be the birthplace of massive stars, yet remarkably little information exists on the properties of the population as a whole (e.g. mass spectrum, ... More

Exoplanets from the CHEPS: Discovery of the Double Planet System HD191760Nov 18 2008Nov 26 2008The paper was withdrawn due to another possible solution to the dataset that is significantly different in nature. This issue will be addressed shortly and clarified with an additional data point.

An incomplete model of RRATs and of nulls mode-changes and subpulsesFeb 21 2013A model for pulsars with polar-cap magnetic flux density B antiparallel with rotational spin is described. It recognizes the significance of two elementary processes, proton production in electromagnetic showers and photoelectric transitions in ions accelerated ... More

Interaction and ablation of fall-back disks in isolated neutron starsSep 24 2007An analysis of ablation processes is made for a fall-back disk with inner and outer radii external to the neutron-star light cylinder. The calculated ablation rate leads, with certain other assumptions, to a simple expression relating the inner radius ... More

Type II superconductivity and magnetic flux transport in neutrons starsOct 13 2005The transition to a type II proton superconductor which is believed to occur in a cooling neutron star is accompanied by changes in the equation of hydrostatic equilibrium and by the formation of proton vortices with quantized magnetic flux. Analysis ... More

End-point of the rp process and periodic gravitational wave emissionFeb 09 2005Sep 28 2005The general end-point of the rp process in rapidly accreting neutron stars is believed to be a surface distribution of matter whose nuclear composition may depend on position. Its evolution during compression beyond the neutron-drip threshold density ... More

Heterogeneity of solid neutron-star matter: transport coefficients and neutrino emissivityMar 17 2004Calculations of weak-interaction transition rates and of nuclear formation enthalpies show that in isolated neutron stars, the solid phase, above the neutron-drip threshold, is amorphous and heterogeneous in nuclear charge. The neutrino emissivities obtained ... More

Polar caps in the presence of an induction fieldAug 14 2015Following the early paper of Goldreich & Julian (1969), polar-cap models have usually assumed that the closed sector of a pulsar magnetosphere corotates with the neutron star. Recent work by Melrose & Yuen has been a reminder that in an oblique rotator, ... More

Electron-positron bremsstrahlung and pair creation in very high magnetic fieldsAug 04 2010Cross-sections for Rutherford scattering, Coulomb bremsstrahlung and pair creation, have been calculated at very high magnetic fields in order to investigate the photo-production of protons at the polar caps of pulsars whose spin is antiparallel with ... More

Constraints on fall-back disks in radio pulsars and anomalous X-ray pulsarsFeb 04 2008Calculations have been made of fall-back disk heating by the pulsar wind as distinct from the soft X-rays emitted by the neutron-star surface. The relation between these heating rates and measured near-infrared fluxes in the K and Ks bands places severe ... More

Type I and Two-Gap Superconductivity in Neutron Star MagnetismJun 30 2006Aug 18 2006Neutron-star inner cores with several charged baryonic components are likely to be analogues of the two-gap superconductor which is of current interest in condensed-matter physics. Consequently, type I superconductivity is less probable than type II but ... More

Chromospheric Activities and Kinematics for Solar Type Dwarfs and Subgiants: Analysis of the Activity Distribution and the AVRMar 03 2011In this work we present chromospheric activity indices, kinematics, radial-velocities and rotational velocities for more than 850 FGK-type dwarfs and subgiant stars in the southern hemisphere and test how best to calibrate and measure S-indices from echelle ... More

The Calan-Hertfordshire Extrasolar Planet SearchDec 29 2009The detailed study of the exoplanetary systems HD189733 and HD209458 has given rise to a wealth of exciting information on the physics of exoplanetary atmospheres. To further our understanding of the make-up and processes within these atmospheres we require ... More

A Metal-biased Planet SearchOct 01 2008We have begun a metal-rich planet search project using the HARPS instrument in La Silla, Chile to target planets with a high potential to transit their host star and add to the number of bright benchmark transiting planets. The sample currently consists ... More

Disorder resistivity of solid neutron-star matterJul 30 2004Nov 01 2004Lower limits are found for the disorder resistivity of solid neutron-star matter in the neutron-drip region which is amorphous and heterogeneous in nuclear charge. This temperature-independent resistivity, large compared with that produced by phonon scattering, ... More

Nulls subpulse drift and mode-switching in pulsars: the polar-cap surfaceApr 20 2012Little attention has so far been paid to the division of the observed population between pulsars of the two spin directions that are possible. Almost all pulsars with positive corotational charge density at the polar caps are expected to satisfy space-charge ... More

Fermion zero-mode influence on neutron-star magnetic field evolutionFeb 03 2009May 11 2009The quantum phenomenon of spectral flow which has been observed in laboratory superfluids, such as 3He-B, controls the drift velocity of proton type II superconductor vortices in the liquid core of a neutron star and so determines the rate at which magnetic ... More

Automation of 2-loop Amplitude CalculationsAug 12 2016Some of the tools and techniques that have recently been used to compute Higgs boson pair production at NLO in QCD are discussed. The calculation relies on the use of integral reduction, to reduce the number of integrals which must be computed, and expressing ... More

The Status of the MicroBooNE ExperimentOct 07 2011The MicroBooNE experiment is an upcoming liquid argon TPC experiment which will pursue a program of short baseline neutrino physics in the Fermilab Booster Neutrino Beam, starting in early 2014. I give a description of the experiment and review the current ... More

IceCube Sterile Neutrino SearchesFeb 17 2019Anomalies in short baseline experiments have been interpreted as evidence for additional neutrino mass states with large mass splittings from the known, active flavors. This explanation mandates a corresponding signature in the muon neutrino disappearance ... More

A framework for resolving the origin, nature and evolution of the diffuse interstellar band carriers?Nov 21 2014The carriers of the diffuse interstellar bands (DIBs) still remain an unknown commodity. Both dust and molecules have been suggested as carriers but none proposed have yet been able to explain the nature and the diversity of the DIBs. Hence, it is perhaps ... More

Pulsar emission: Langmuir modes in a relativistic multi-component plasmaSep 17 2014Ions, protons and possibly a small flux of electrons and positrons are accelerated outward from the polar cap of a normal or millisecond pulsar whose rotational spin is antiparallel with its magnetic moment. The Langmuir modes of this relativistic plasma ... More

Linear-drifting sub-pulse sources in radio pulsarsNov 20 2013Analysis of plasma acceleration in pulsars with positive corotational charge density has shown that any element of area on the polar cap is bi-stable: it can be in phases either of pure proton emission or of mixed ions and protons (the ion phase). Ion-phase ... More

PSR B1133+16: radio emission height and plasma compositionMay 20 2013Jun 20 2013Recent operation of LOFAR by Hassall et al has produced severe constraints on the size and altitude of the 40 MHZ emission region in this pulsar. It is shown that these limits, given a limited number of unexceptionable assumptions, demonstrate that an ... More

Nuclear physics of reverse electron flow at pulsar polar capsSep 21 2009Protons produced in electromagnetic showers formed by the reverse-electron flux are usually the largest component of the time-averaged polar-cap open magnetic flux-line current in neutron stars with positive corotational charge density. Although the electric-field ... More

Ion-proton pulsarsApr 06 2016Evidence derived with minimal assumptions from existing published observations is presented to show that an ion-proton plasma is the source of radio-frequency emission in millisecond and in normal isolated pulsars. There is no primary involvement of electron-positron ... More

A multi-component Langmuir-mode source for the observed pulsar coherent emissionApr 08 2015Several classes of neutron star are sources of coherent emission at frequencies of 10^2 - 10^3 MHz: others are radio-quiet. The primary emission spectra are broadly universal in form over many orders of magnitude in rotation period and polar-cap magnetic ... More

The mechanism of coherent radio emission in some classes of pulsarSep 02 2014Radio luminosities have been estimated from published data for a well-defined homogeneous set of 29 normal pulsars. The radio-frequency energies per unit charge in the primary accelerated particle beam are given for each pulsar and form a distribution ... More

The effect of photo-electric absorption on space-charge limited flow in pulsarsSep 14 2011Photo-electric absorption of blackbody photons is an important process which limits the acceleration of ions under the space-charge limited flow boundary condition at the polar caps of pulsars with positive corotational charge density. Photo-electric ... More

Circular polarization shows the nature of pulsar magnetosphere compositionNov 10 2015It has been argued in previous papers that an ion-proton plasma is formed at the polar caps of neutron stars with positive polar-cap corotational charge density. The present paper does not offer a theory of the development of turbulence from the unstable ... More

Instabilities nulls and sub-pulse drift in radio pulsarsJan 31 2011This paper continues a previous study of neutron stars with positive polar-cap corotational charge density in which free emission of ions maintains the surface electric-field boundary condition E.B = 0. The composition of the accelerated plasma on any ... More

Dynamical Pion Collapse and the Coherence of Conventional Neutrino BeamsDec 06 2014Feb 05 2015In this paper we consider the coherence properties of neutrinos produced by the decays of pions in conventional neutrino beams. Using a multi-particle density matrix formalism we derive the oscillation probability for neutrinos emitted by a decaying pion ... More

Nature of fault planes in solid neutron star matterOct 09 2002The properties of tectonic earthquake sources are compared with those deduced here for fault planes in solid neutron-star matter. The conclusion that neutron-star matter cannot exhibit brittle fracture at any temperature or magnetic field is significant ... More

Damping of Neutron Star Shear Modes by Superfluid FrictionJan 07 2003The forced motion of superfluid vortices in shear oscillations of rotating solid neutron star matter produces damping of the mode. A simple model of the unpinning and repinning processes is described, with numerical calculations of the consequent energy ... More

A Simulation of the Optical Attenuation of TPB Coated Light-guide DetectorsJul 26 2013Aug 30 2013This note describes simple simulations which were performed in order to understand the attenuation behaviors of acrylic light-guides operated in air and argon, which were characterized in \cite{Baptista:2012bf}. Whilst these simulations are only at the ... More

The Crab pulsar: ion-proton plasma and high-frequency radio spectrumFeb 08 2018Salient features of the remarkable band structure seen in the high-frequency interpulse of the Crab pulsar are summarized. It is argued that its source must lie in a current sheet, probably coincident with the open-closed magnetosphere separatrix, and ... More

The effect of a spatially varying Galactic spectral index on the maximum entropy reconstruction of Planck Surveyor satellite dataOct 15 1998We study the effect of Galactic foregrounds with spatially varying spectral indices on analysis of simulated data from the Planck Satellite. We also briefly mention the effect the extra-galactic point sources have on the data analysis and summarise the ... More

The effects of superconductor-stabilizer interfacial resistance on quench of a pancake coil made out of coated conductorJul 21 2010Jul 28 2010We present the results of numerical analysis of normal zone propagation in a stack of $YBa_2Cu_3O_{7-x}$ coated conductors which imitates a pancake coil. Our main purpose is to determine whether the quench protection quality of such coils can be substantially ... More

A Single-Ion Trap with Minimized Ion-Environment InteractionsOct 21 2015We present a new single-ion endcap trap for high precision spectroscopy that has been designed to minimize ion-environment interactions. We describe the design in detail and then characterize the working trap using a single trapped 171 Yb ion. Excess ... More

SN Ia Enrichment in Virgo Early-Type Galaxies from ROSAT and ASCA ObservationsMar 14 2000We analyzed nine X-ray bright Virgo early-type galaxies observed by both ASCA and ROSAT. Through spatially resolved spectroscopy, we determined the radial temperature profile and abundances of Mg, Si and Fe for six galaxies. The temperature profiles are ... More

Composite pulses in NMR quantum computationJun 25 2009I describe the use of techniques based on composite rotations to combat systematic errors in quantum logic gates. Although developed and described within the context of Nuclear Magnetic Resonance (NMR) quantum computing these sequences should be applicable ... More

NMR implementations of Gauss sumsJul 10 2008I describe the use of NMR experiments which implement Gauss sums as a method for factoring numbers and discuss whether this approach can be computationally useful.

NMR Quantum ComputationSep 01 2000In this article I will describe how NMR techniques may be used to build simple quantum information processing devices, such as small quantum computers, and show how these techniques are related to more conventional NMR experiments.

Automorphism groups of maps, hypermaps and dessinsMay 24 2018A detailed proof is given of a theorem describing the centraliser of a transitive permutation group, with applications to automorphism groups of objects in various categories of maps, hypermaps, dessins, polytopes and covering spaces, where the automorphism ... More

Joining dessins togetherOct 09 2018An operation of joining coset diagrams for a given group, introduced by Higman and developed by Conder in connection with Hurwitz groups, is reinterpreted and generalised as a connected sum operation on dessins d'enfants of a given type. A number of examples ... More

Regular embeddings of complete bipartite graphs: classification and enumerationNov 23 2009The regular embeddings of complete bipartite graphs $K_{n,n}$ in orientable surfaces are classified and enumerated, and their automorphism groups and combinatorial properties are determined. The method depends on earlier classifications in the cases where ... More

Application of novel analysis techniques to Cosmic Microwave Background astronomyMar 11 1999The data from Cosmic Microwave Background (CMB) experiments are becoming more complex with each new experiment. A consistent way of analysing these data sets is required so that direct comparison is possible between the various experimental results. This ... More

NUV signatures of environment driven galaxy quenching in SDSS groupsSep 08 2016We have investigated the effect of group environment on residual star formation in galaxies, using Galex NUV galaxy photometry with the SDSS group catalogue of Yang et al. (2007). We compared the (NUV $- r$) colours of grouped and non-grouped galaxies, ... More

The imaging X-ray detector for Lobster-ISSMay 07 2003Lobster-ISS is a revolutionary astrophysical X-ray all-sky monitor scheduled for deployment as an attached payload on the International Space Station (ISS) in 2009. Using a new wide field-of-view focusing optic, Lobster-ISS provides an order-of-magnitude ... More

A Search for Biomolecules in Sagittarius B2 (LMH) with the ATCAOct 10 2006We have used the Australia Telescope Compact Array to conduct a search for the simplest amino acid, glycine (conformers I and II), and the simple chiral molecule propylene oxide at 3-mm in the Sgr B2 LMH. We searched 15 portions of spectrum between 85 ... More

Initial study on the shape optimisation of the CLIC crab cavityOct 16 2008The compact linear collider (CLIC) requires a crab cavity to align bunches prior to collision. The bunch structure demands tight amplitude and phase tolerances of the RF fields inside the cavity, for the minimal luminosity loss. Beam loading effects require ... More

Environments and Morphologies of Red Sequence Galaxies with Residual Star Formation in Massive ClustersOct 28 2013We present a photometric investigation into recent star formation in galaxy clusters at z ~ 0.1. We use spectral energy distribution templates to quantify recent star formation in large X-ray selected clusters from the LARCS survey using matched GALEX ... More

Number-resolved imaging of excited-state atoms using a scanning autoionization microscopeDec 13 2012We report on a scanning microscopy technique for atom-number-resolved imaging of excited-state atoms. A tightly focused laser beam leads to local autoionization, and the resulting ions are counted electronically. Scanning the beam across the cloud builds ... More

ISM Properties in Low-Metallicity Environments III. The Dust Spectral Energy Distributions of II Zw 40, He 2-10 and NGC 1140Jan 28 2005We present new 450 and 850 micron SCUBA data and 1.3 mm MAMBO data of the dwarf galaxies II Zw 40, He 2-10 and NGC 1140. Additional ISOCAM, IRAS as well as ground based data are used to construct the observed mid-infrared to millimeter spectral energy ... More

Designing short robust NOT gates for quantum computationMar 07 2013May 07 2013Composite pulses, originally developed in Nuclear Magnetic Resonance (NMR), have found widespread use in experimental quantum information processing (QIP) to reduce the effects of systematic errors. Most pulses used so far have simply been adapted from ... More

Quantum Computing with NMRNov 05 2010A review of progress in NMR quantum computing and a brief survey of the literature

Characteristically simple Beauville groups, I: cartesian powers of alternating groupsApr 19 2013A Beauville surface (of unmixed type) is a complex algebraic surface which is the quotient of the product of two curves of genus at least 2 by a finite group G acting freely on the product, where G preserves the two curves and their quotients by G are ... More

Regular dessins with a given automorphism groupSep 20 2013Dessins d'enfants are combinatorial structures on compact Riemann surfaces defined over algebraic number fields, and regular dessins are the most symmetric of them. If G is a finite group, there are only finitely many regular dessins with automorphism ... More

Characteristically simple Beauville groups, II: low rank and sporadic groupsApr 19 2013A Beauville surface is a rigid complex surface of general type, isogenous to a higher product by the free action of a finite group, called a Beauville group. Here we consider which characteristically simple groups can be Beauville groups. We show that ... More

Automorphism groups of edge-transitive mapsMay 31 2016Nov 15 2016For each of the 14 classes of edge-transitive maps described by Graver and Watkins, necessary and sufficient conditions are given for a group to be the automorphism group of a map, or of an orientable map without boundary, in that class. Extending earlier ... More

Conjugacy classes of reflections of mapsDec 03 2014This paper considers how many conjugacy classes of reflections a map can have, under various transitivity conditions. It is shown that for vertex- and for face-transitive maps there is no restriction on their number or size, whereas edge-transitive maps ... More

Combinatorial categories and permutation groupsSep 24 2013The regular objects in various categories, such as maps, hypermaps or covering spaces, can be identified with the normal subgroups N of a given group \Gamma, with quotient group isomorphic to \Gamma/N. It is shown how to enumerate such objects with a ... More

Chiral covers of hypermapsNov 18 2013Generalising a conjecture of Singerman, it is shown that there exist orientably regular chiral hypermaps of every non-spherical type. The proof uses the representation theory of automorphism groups acting on homology and on various spaces of differentials. ... More

Characterisations and Galois conjugacy of generalised Paley mapsJun 02 2010A generalised Paley map is a Cayley map for the additive group of a finite field F, with a subgroup S=-S of the multiplicative group as generating set, cyclically ordered by powers of a generator of S. We characterise these as the orientably regular maps ... More

Realisation of groups as automorphism groups in categoriesJul 02 2018Oct 15 2018It is shown that in various categories, including many consisting of maps or hypermaps, oriented or unoriented, of a given hyperbolic type, every countable group $A$ is isomorphic to the automorphism group of uncountably many non-isomorphic objects, infinitely ... More

Foregrounds and experiments below 33GHzMay 07 1999In this paper I report on the recent results obtained from the Tenerife switched beam (10 GHz to 33 GHz) experiment and Jodrell Bank 5 GHz interferometer and their predictions for foreground levels. The full data analysis and results will be presented ... More