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Results for "Michael D. J. Cole"

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Tenfold reduction of Brownian noise in optical interferometryFeb 26 2013Thermally induced fluctuations impose a fundamental limit on precision measurement. In optical interferometry, the current bounds of stability and sensitivity are dictated by the excess mechanical damping of the high-reflectivity coatings that comprise ... More
The role of spin in the calculation of Hubbard $U$ and Hund's $J$ parameters from first principlesFeb 25 2018Nov 19 2018The density functional theory (DFT)+$U$ method is a pragmatic and effective approach for calculating the ground-state properties of strongly-correlated systems, and linear response calculations are widely used to determine the requisite Hubbard parameters ... More
Relative entropy derivation of the uncertainty principle with quantum side informationMay 24 2011Dec 07 2011We give a simple proof of the uncertainty principle with quantum side information, as in [Berta et al. Nature Physics 6, 659 (2010)], invoking the monotonicity of the relative entropy. Our proof shows that the entropic uncertainty principle can be viewed ... More
A geometric invariant characterising initial data for the Kerr-Newman spacetimeSep 16 2016We describe the construction of a geometric invariant characterising initial data for the Kerr-Newman spacetime. This geometric invariant vanishes if and only if the initial data set corresponds to exact Kerr-Newman initial data, and so characterises ... More
Killing spinors as a characterisation of rotating black hole spacetimesJan 18 2016Apr 26 2016We investigate the implications of the existence of Killing spinors in a spacetime. In particular, we show that in vacuum and electrovacuum a Killing spinor, along with some assumptions on the associated Killing vector in an asymptotic region, guarantees ... More
Quantum Logic of Semantic Space: An Exploratory Investigation of Context Effects in Practical ReasoningDec 21 2006This article is an exploratory account of the the non-monotonic behaviour of conceptual associations in the light of context. Computational approximations of conceptual space are furnished by semantic space models which are emerging from the fields of ... More
Global Alfven Eigenmodes in the H-1 heliacApr 07 2017Recent upgrades in H-1 power supplies have enabled the operation of the H-1 experiment at higher heating powers than previously attainable. A heating power scan in mixed hydrogen/helium plasmas reveals a change in mode activity with increasing heating ... More
The Shapes and Alignments of Dark Matter HalosNov 23 2011Apr 24 2012We present measurements of the triaxial dark matter halo shapes and alignment correlation functions in the Millennium and Millennium-2 dark matter N-body simulations. These two simulations allow us to measure the distributions of halo shapes down to 10% ... More
Fast generation of ensembles of cosmological N-body simulations via mode-resamplingMar 14 2011May 31 2011We present an algorithm for quickly generating multiple realizations of N-body simulations to be used, for example, for cosmological parameter estimation from surveys of large-scale structure. Our algorithm uses a new method to resample the large-scale ... More
Uncertainty relations from simple entropic propertiesDec 02 2011Apr 16 2012Uncertainty relations provide constraints on how well the outcomes of incompatible measurements can be predicted, and, as well as being fundamental to our understanding of quantum theory, they have practical applications such as for cryptography and witnessing ... More
Twistor Theory of the Airy EquationDec 30 2013Apr 02 2014We demonstrate how the complex integral formula for the Airy functions arises from Penrose's twistor contour integral formula. We then use the Lax formulation of the isomonodromy problem with one irregular singularity of order four to show that the Airy ... More
Verification of the global gyrokinetic stellarator code XGC-S for linear ion temperature gradient driven modesMay 14 2019XGC (X-point Gyrokinetic Code) is a whole-volume, total-f gyrokinetic particle-in-cell code developed for modelling tokamaks. In recent work, XGC has been extended to model more general 3D toroidal magnetic configurations, such as stellarators. These ... More
Ligand Discrimination in Myoglobin from Linear-Scaling DFT+UMay 23 2013Myoglobin modulates the binding of diatomic molecules to its heme group via hydrogen-bonding and steric interactions with neighboring residues, and is an important benchmark for computational studies of biomolecules. We have performed calculations on ... More
Cooling-by-measurement and mechanical state tomography via pulsed optomechanicsNov 29 2012May 15 2013Observing a physical quantity without disturbing it is a key capability for the control of individual quantum systems. Such back-action-evading or quantum-non-demolition measurements were first introduced in the 1970s in the context of gravitational wave ... More
Using the Ca II Triplet to Trace Abundance Variations in Individual Red Giant Branch stars in Three Nearby GalaxiesJul 02 2001Spectroscopic abundance determinations for stars spanning a Hubble time in age are necessary in order to unambiguously determine the evolutionary histories of galaxies. Using FORS1 in Multi-Object Spectroscopy mode on ANTU (UT1) at the ESO-VLT on Paranal ... More
Minimization of phonon-tunneling dissipation in mechanical resonatorsJul 28 2010Micro- and nanoscale mechanical resonators have recently emerged as ubiquitous devices for use in advanced technological applications, for example in mobile communications and inertial sensors, and as novel tools for fundamental scientific endeavors. ... More
Collapse of the quantum correlation hierarchy links entropic uncertainty to entanglement creationMar 14 2012Nov 10 2012Quantum correlations have fundamental and technological interest, and hence many measures have been introduced to quantify them. Some hierarchical orderings of these measures have been established, e.g., discord is bigger than entanglement, and we present ... More
Entropic framework for wave-particle duality in multipath interferometersDec 30 2015Jun 09 2016An interferometer - no matter how clever the design - cannot reveal both the wave and particle behavior of a quantum system. This fundamental idea has been captured by inequalities, so-called wave-particle duality relations (WPDRs), that upper bound the ... More
Non-negative discord strengthens the subadditivity of quantum entropy functionsJan 10 2011The definition of quantum discord is generalized to allow for any concave entropy function, and its non-negativity strengthens the subadditivity condition for that entropy function. In a sense, this condition is intermediate in strength between subadditivity ... More
Helicity asymmetry of optically-pumped NMR spectra in GaAsJan 21 2008May 09 2008The origin of helicity asymmetries in the optically-pumped NMR signal and hyperfine shift in GaAs is derived analytically and tested experimentally. The ratio of the optically-pumped to the equilibrium electron polarizations is a key parameter in determining ... More
Unification of different views of decoherence and discordOct 07 2011Mar 23 2012Macroscopic behavior such as the lack of interference patterns has been attributed to "decoherence", a word with several possible definitions such as (1) the loss of off-diagonal density matrix elements, (2) the flow of information to the environment, ... More
Role of complementarity in superdense codingAug 07 2013Nov 26 2013The complementarity of two observables is often captured in uncertainty relations, which quantify an inevitable tradeoff in knowledge. Here we study complementarity in the context of an information processing task: we link the complementarity of two observables ... More
Rational combinations of Betti diagrams of complete intersectionsJul 30 2015Dec 14 2015We investigate decompositions of Betti diagrams over a polynomial ring within the framework of Boij-S\"oderberg theory. That is, given a Betti diagram, we determine if it is possible to decompose it into the Betti diagrams of complete intersections. To ... More
Rational combinations of Betti diagrams of complete intersectionsJul 30 2015Apr 04 2017We investigate decompositions of Betti diagrams over a polynomial ring within the framework of Boij-S\"oderberg theory. That is, given a Betti diagram, we determine if it is possible to decompose it into the Betti diagrams of complete intersections. To ... More
Galaxy and Mass Assembly (GAMA): Projected Galaxy ClusteringSep 07 2015We measure the projected 2-point correlation function of galaxies in the 180 deg$^2$ equatorial regions of the GAMA II survey, for four different redshift slices between z = 0.0 and z=0.5. To do this we further develop the Cole (2011) method of producing ... More
Single atom-scale diamond defect allows large Aharonov-Casher phaseOct 22 2009We propose an experiment that would produce and measure a large Aharonov-Casher (A-C) phase in a solid-state system under macroscopic motion. A diamond crystal is mounted on a spinning disk in the presence of a uniform electric field. Internal magnetic ... More
Electrostatic considerations affecting the calculated HOMO-LUMO gap in protein moleculesFeb 19 2013A detailed study of energy differences between the highest occupied and lowest unoccupied molecular orbitals (HOMO-LUMO gaps) in protein systems and water clusters is presented. Recent work questioning the applicability of Kohn-Sham density-functional ... More
Pulsar timing analysis in the presence of correlated noiseJul 27 2011Pulsar timing observations are usually analysed with least-square-fitting procedures under the assumption that the timing residuals are uncorrelated (statistically "white"). Pulsar observers are well aware that this assumption often breaks down and causes ... More
Demonstration of an ultracold micro-optomechanical oscillator in a cryogenic cavityJan 13 2009Oct 21 2013Preparing and manipulating quantum states of mechanical resonators is a highly interdisciplinary undertaking that now receives enormous interest for its far-reaching potential in fundamental and applied science. Up to now, only nanoscale mechanical devices ... More
Renormalization of myoglobin-ligand binding energetics by quantum many-body effectsApr 22 2014We carry out a first-principles atomistic study of the electronic mechanisms of ligand binding and discrimination in the myoglobin protein. Electronic correlation effects are taken into account using one of the most advanced methods currently available, ... More
Modelling the redshift-space distortion of galaxy clusteringJul 16 1997We use a set of large, high-resolution cosmological N-body simulations to examine the redshift-space distortions of galaxy clustering on scales of order 10-200h^{-1} Mpc. Galaxy redshift surveys currently in progress will, on completion, allow us to measure ... More
Classical and Quantum Mechanical Motion in Magnetic FieldsMar 03 2016We study the motion of a particle in a particular magnetic field configuration both classically and quantum mechanically. For flux-free radially symmetric magnetic fields defined on circular regions, we establish that particle escape speeds depend, classically, ... More
Correlated transport through junction arrays in the small Josephson energy limit: incoherent Cooper-pairs and hot electronsOct 03 2013Aug 26 2014We study correlated transport in a Josephson junction array for small Josephson energies. In this regime transport is dominated by Cooper-pair hopping, although we observe that quasiparticles can not be neglected. We assume that the energy dissipated ... More
A Mid-Infrared Study of the Class 0 Cluster in LDN 1448Dec 21 2005We present ground-based mid-infrared observations of Class 0 protostars in LDN 1448. Of the five known protostars in this cloud, we detected two, L1448N:A and L1448C, at 12.5, 17.9, 20.8, and 24.5 microns, and a third, L1448 IRS 2, at 24.5 microns. We ... More
Wave-mechanics and the adhesion approximationApr 29 2006Nov 22 2006The dynamical equations describing the evolution of a self-gravitating fluid of cold dark matter (CDM) can be written in the form of a Schrodinger equation coupled to a Poisson equation describing Newtonian gravity. It has recently been shown that, in ... More
Amplification of Primordial Magnetic Fields by Anisotropic Gravitational CollapseAug 17 2005If a magnetic field is frozen into a plasma that undergoes spherical compression then the magnetic field B varies with the plasma density \rho according to B \propto \rho^{2/3}. In the gravitational collapse of cosmological density perturbations, however, ... More
Probing the Eclipse of J0737-3039A with ScintillationSep 08 2004Dec 22 2004We have examined the interstellar scintillations of the pulsars in the double pulsar binary system. Near the time of the eclipse of pulsar A by the magnetosphere of B, the scintillations from both pulsars should be highly correlated because the radiation ... More
Calcium II Triplet Spectroscopy of LMC Red Giants. I. Abundances and Velocities for a Sample of Populous ClustersJul 04 2006Abridged Abstract - Utilizing the FORS2 instrument on the VLT, we have obtained near infrared spectra for more than 200 stars in 28 populous LMC clusters. This cluster sample spans a large range of ages (~ 1-13 Gyr) and metallicities (-0.3 > [Fe/H] > ... More
Novel substrates for Helium adsorption: Graphane and Graphene-FluorideApr 13 2012The discovery of fullerenes has stimulated extensive exploration of the resulting behavior of adsorbed films. Our study addresses the planar substrates graphene-fluoride (GF) and graphane (GH) in comparison to graphene. We present initial results concerning ... More
Spontaneous emission from radiative chiral nematic liquid crystals at the photonic band gap edge: an investigation into the role of the density of photon states near resonanceFeb 18 2018In this article, we investigate the spontaneous emission properties of radiating molecules embedded in a chiral nematic liquid crystal, under the assumption that the electronic transition frequency is close to the photonic edge mode of the structure, ... More
Interferometry using Adiabatic Passage in Dilute Gas Bose-Einstein CondensatesJul 26 2012Nov 16 2012We theoretically examine three-well interferometry in Bose-Einstein condensates using adiabatic passage. Specifically, we demonstrate that a fractional coherent transport adiabatic passage protocol enables stable spatial splitting in the presence of nonlinear ... More
Observation of non-Markovian micro-mechanical Brownian motionMay 29 2013Jul 28 2015All physical systems are to some extent open and interacting with their environment. This insight, basic as it may seem, gives rise to the necessity of protecting quantum systems from decoherence in quantum technologies and is at the heart of the emergence ... More
Quantum-Dot Cellular Automata using Buried DopantsJul 26 2004Apr 25 2005The use of buried dopants to construct quantum-dot cellular automata is investigated as an alternative to conventional electronic devices for information transport and elementary computation. This provides a limit in terms of miniaturisation for this ... More
Improved entropic uncertainty relations and information exclusion relationsJul 16 2013Feb 18 2014The uncertainty principle can be expressed in entropic terms, also taking into account the role of entanglement in reducing uncertainty. The information exclusion principle bounds instead the correlations that can exist between the outcomes of incompatible ... More
Estimating beta from redshift-space distortions in the 2dF galaxy surveyMay 14 1999Aug 29 1999Given the failure of existing models for redshift-space distortions to provide a highly accurate measure of the beta-parameter, and the ability of forthcoming surveys to obtain data with very low random errors, it becomes necessary to develop better models ... More
Dynamo action in thermally unstable interstellar flowsNov 21 2010Apr 27 2012Numerous studies have investigated the role of thermal instability in regulating the phase transition between the cold cloudy and warm diffuse medium of the interstellar medium. Considerable interest has also been devoted in investigating the properties ... More
Dynamics of a magnetized Bianchi I universe with vacuum energyDec 07 2006Mar 27 2007We make use of a flat, axisymmetric Bianchi I metric to investigate the effects of a magnetic field upon the dynamics of the universe for the case in which the accompanying fluid is a cosmological constant and derive two exact solutions to the dynamical ... More
Sculpting microscopic magnetic flux landscapes in a BSCCO2212 vortex lensMay 15 2006We demonstrate experimentally that the micromagnetic profile of the out-of-plane component of magnetic induction, B_z, in the crossing lattices regime of layered superconductors can be manipulated by varying the in-plane magnetic field, H_{||}. Moving ... More
Modeling ultrafast shadowgraphy in laser-plasma interaction experimentsSep 29 2015Ultrafast shadowgraphy is a new experimental technique that uses few cycle laser pulses to image density gradients in a rapidly evolving plasma. It enables structures that move at speeds close to the speed of light, such as laser driven wakes, to be visualized. ... More
Gravitational instability via the Schrodinger equationApr 29 2006Nov 22 2006We explore a novel approach to the study of large-scale structure formation in which self-gravitating cold dark matter (CDM) is represented by a complex scalar field whose dynamics are governed by coupled Schrodinger and Poisson equations. We show that, ... More
Complementary sequential measurements generate entanglementMay 15 2013Jan 08 2014We present a new paradigm for capturing the complementarity of two observables. It is based on the entanglement created by the interaction between the system observed and the two measurement devices used to measure the observables sequentially. Our main ... More
State-Dependent Approach to Entropic Measurement-Disturbance RelationsNov 29 2013Nov 21 2014Heisenberg's intuition was that there should be a tradeoff between measuring a particle's position with greater precision and disturbing its momentum. Recent formulations of this idea have focused on the question of how well two complementary observables ... More
Electromagnetic effects in the stabilization of turbulence by sheared flowAug 05 2013We have extended our study of the competition between the drive and stabilization of plasma microinstabilities by sheared flow to include electromagnetic effects at low plasma $\beta$ (the ratio of plasma to magnetic pressure). The extended system of ... More
COLIN: Planning with Continuous Linear Numeric ChangeJan 23 2014In this paper we describe COLIN, a forward-chaining heuristic search planner, capable of reasoning with COntinuous LINear numeric change, in addition to the full temporal semantics of PDDL. Through this work we make two advances to the state-of-the-art ... More
Electronic transport in Si:P delta-doped wiresJul 15 2015Despite the importance of Si:P delta-doped wires for modern nanoelectronics, there are currently no computational models of electron transport in these devices. In this paper we present a nonequilibrium Green's function model for electronic transport ... More
Galaxy Disruption as the Origin of Intracluster Light in the Coma ClusterDec 02 1998Although the existence of a faint background of starlight in the core of the Coma cluster has been well established (1,2), its origin is uncertain. This vast sea of stars could have formed outside the galaxies, using gas left over from the time of the ... More
The Ghosts of Galaxies: Tidal Debris in ClustersOct 16 2003Gravitational interactions in rich clusters can strip material from the outer parts of galaxies or even completely disrupt entire systems, giving rise to large scale, low surface brightness ghostly features stretching across intergalactic space. The nearby ... More
A deep generative model for gene expression profiles from single-cell RNA sequencingSep 07 2017Jan 16 2018We propose a probabilistic model for interpreting gene expression levels that are observed through single-cell RNA sequencing. In the model, each cell has a low-dimensional latent representation. Additional latent variables account for technical effects ... More
A deep generative model for single-cell RNA sequencing with application to detecting differentially expressed genesOct 13 2017Oct 17 2017We propose a probabilistic model for interpreting gene expression levels that are observed through single-cell RNA sequencing. In the model, each cell has a low-dimensional latent representation. Additional latent variables account for technical effects ... More
Laser-driven plasma acceleration in a regime of strong-mismatch between the incident laser envelope and the nonlinear plasma responseApr 10 2017We explore a regime of laser-driven plasma acceleration of electrons where the radial envelope of the laser-pulse incident at the plasma entrance is strongly mismatched to the nonlinear plasma electron response excited by it. This regime has been experimentally ... More
Observations of the neutral gas and dust in the radio galaxy 3C305Oct 10 2002We present MERLIN and Hubble Space Telescope (HST) observations of the central region of the nearby radio galaxy 3C305 and use them to study the gas and dust in this object. The MERLIN observations are of neutral hydrogen (HI) absorption against the strong ... More
Circuit-QED analogue of a single-atom injection maser: Lasing, trapping states and multistabilityDec 16 2010We study a superconducting single-electron transistor (SSET) which is coupled to a LC-oscillator via the phase difference across one of the Josephson junctions. This leads to a strongly anharmonic coupling between the SSET and the oscillator. The coupling ... More
Prosodic entrainment in dialog actsOct 30 2018We examined prosodic entrainment in spoken dialogs separately for several dialog acts in cooperative and competitive games. Entrainment was measured for intonation features derived from a superpositional intonation stylization as well as for rhythm features. ... More
An Upper Limit to the Age of the Galactic BarJun 12 2002Using data from the Two Micron All-Sky Survey (2MASS), we identify a population of infrared carbon (IR C) stars with J-K >= 2 in the Milky Way. These stars are shown to trace the stellar bar previously identified in IR and optical surveys. The properties ... More
C^1 Hypersurfaces of the Heisenberg Group are N-RectifiableJul 13 2004Nov 01 2005We show that C^1 hypersurfaces in the Heisenberg group are countably N-rectifiable. As a corollary, this shows that all C^1_H graphs over the xy-plane are countable N-rectifiable, showing the equivalence of this notion of rectifiability with that of Franchi, ... More
Parkes Pulsar Timing Array constraints on ultralight scalar-field dark matterOct 07 2018Nov 22 2018It is widely accepted that dark matter contributes about a quarter of the critical mass-energy density in our Universe. The nature of dark matter is currently unknown, with the mass of possible constituents spanning nearly one hundred orders of magnitude. ... More
Optically active mechanical modes of tapered optical fibersNov 04 2013Tapered optical fibers with a nanofiber waist are widely used tools for efficient coupling of light to photonic devices or quantum emitters via the nanofiber's evanescent field. In order to ensure well-controlled coupling, the phase and polarization of ... More
Detecting relics of a thermal gravitational wave background in the early UniverseJul 24 2009Sep 30 2009A thermal gravitational wave background can be produced in the early Universe if a radiation dominated epoch precedes the usual inflationary stage. This background provides a unique way to study the initial state of the Universe. We discuss the imprint ... More
Substructure in the stellar halos of the Aquarius simulationsJan 13 2011Oct 31 2011We characterize substructure in the simulated stellar halos of Cooper et al. (2010) which were formed by the disruption of satellite galaxies within the cosmological N-body simulations of galactic halos of the Aquarius Project. These stellar halos exhibit ... More
The Age-Metallicity Relation of the SMCJul 04 2006The Small Magellanic Cloud (SMC) is the only dwarf galaxy in the Local Group known to have formed and preserved populous star clusters continuously over the past 12 Gyr. These clusters provide a unique, closely spaced set of single-age, single-metallicity ... More
Young stars in an old bulge: a natural outcome of internal evolution in the Milky WayJan 02 2014The center of our disk galaxy, the Milky Way, is dominated by a boxy/peanut-shaped bulge. Numerous studies of the bulge based on stellar photometry have concluded that the bulge stars are exclusively old. The perceived lack of young stars in the bulge ... More
Optical vector network analysis of ultra-narrow transitions in $^{166}$Er$^{3+}$:$^7$LiYF$_4$Jan 01 2018We present optical vector network analysis (OVNA) of an isotopically purified $^{166}$Er$^{3+}$:$^7$LiYF$_4$ crystal. The OVNA method is based on generation and detection of modulated optical sideband by using a radio-frequency vector network analyzer. ... More
Spin-selective AC Stark shifts in a charged quantum dotDec 05 2018Dec 18 2018A strong, far-detuned laser can shift the energy levels of an optically active quantum system via the AC Stark effect. We demonstrate that the polarization of the laser results in a spin-selective modification to the energy structure of a charged quantum ... More
Comparing the Ancient Star Formation Histories of the Magellanic CloudsJan 30 2013We present preliminary results from a new HST archival program aimed at tightly constraining the ancient (>4 Gyr ago) star formation histories (SFHs) of the field populations of the SMC and LMC. We demonstrate the quality of the archival data by constructing ... More
Identifying an Experimental Two-State Hamiltonian to Arbitrary AccuracyJan 21 2005Apr 25 2005Precision control of a quantum system requires accurate determination of the effective system Hamiltonian. We develop a method for estimating the Hamiltonian parameters for some unknown two-state system and providing uncertainty bounds on these parameters. ... More
Matterwave Transport Without TransitSep 07 2007Classically it is impossible to have transport without transit, i.e., if the points one, two and three lie sequentially along a path then an object moving from one to three must, at some point in time, be located at two. However, for a quantum particle ... More
The ISLAndS project II: The Lifetime Star Formation Histories of Six Andromeda dSphsJun 03 2016The Initial Star formation and Lifetimes of Andromeda Satellites (ISLAndS) project uses Hubble Space Telescope imaging to study a representative sample of six Andromeda dSph satellite companion galaxies. The main goal of the program is to determine whether ... More
Identifying a Two-State Hamiltonian in the Presence of DecoherenceSep 22 2005Jun 28 2006Mapping the system evolution of a two-state system allows the determination of the effective system Hamiltonian directly. We show how this can be achieved even if the system is decohering appreciably over the observation time. A method to include various ... More
Pulsed quantum optomechanicsNov 03 2010Oct 11 2011Studying mechanical resonators via radiation pressure offers a rich avenue for the exploration of quantum mechanical behavior in a macroscopic regime. However, quantum state preparation and especially quantum state reconstruction of mechanical oscillators ... More
Strong bound between trace distance and Hilbert-Schmidt distance for low-rank statesMar 28 2019The trace distance between two quantum states, $\rho$ and $\sigma$, is an operationally meaningful quantity in quantum information theory. However, in general it is difficult to compute, involving the diagonalization of $\rho - \sigma$. In contrast, the ... More
An equality between entanglement and uncertaintyFeb 24 2013Dec 22 2014Heisenberg's uncertainty principle implies that if one party (Alice) prepares a system and randomly measures one of two incompatible observables, then another party (Bob) cannot perfectly predict the measurement outcomes. This implication assumes that ... More
Reliable numerical key rates for quantum key distributionOct 16 2017Jul 19 2018In this work, we present a reliable, efficient, and tight numerical method for calculating key rates for finite-dimensional quantum key distribution (QKD) protocols. We illustrate our approach by finding higher key rates than those previously reported ... More
Entanglement spectroscopy with a depth-two quantum circuitJun 22 2018Jan 08 2019Noisy intermediate-scale quantum (NISQ) computers have gate errors and decoherence, limiting the depth of circuits that can be implemented on them. A strategy for NISQ algorithms is to reduce the circuit depth at the expense of increasing the qubit count. ... More
Scanning Quantum Decoherence MicroscopyNov 12 2008The use of qubits as sensitive magnetometers has been studied theoretically and recent demonstrated experimentally. In this paper we propose a generalisation of this concept, where a scanning two-state quantum system is used to probe the subtle effects ... More
Lattice charge models and core level shifts in disordered alloysJun 10 2013Sep 20 2013Differences in core level binding energies between atoms belonging to the same chemical species can be related to differences in their intra- and extra-atomic charge distributions, and differences in how their core holes are screened. With this in mind, ... More
Entanglement scaling and spatial correlations of the transverse field Ising model with perturbationsFeb 09 2017May 20 2017We study numerically the entanglement entropy and spatial correlations of the one dimensional transverse field Ising model with three different perturbations. First, we focus on the out of equilibrium, steady state with an energy current passing through ... More
Achieving Convergence in Galaxy Formation Models by Augmenting N-body Merger TreesApr 07 2016Aug 16 2016Accurate modeling of galaxy formation in a hierarchical, cold dark matter universe requires the use of sufficiently high-resolution merger trees to obtain convergence in the predicted properties of galaxies. When semi-analytic galaxy formation models ... More
Radial Velocity and Metallicity of the Globular Cluster IC4499 Obtained with AAOmegaOct 04 2010We present radial velocity and metallicity measurements for the far-southern Galactic globular cluster IC4499. We selected several hundred target red giant stars in and around the cluster from the 2MASS point source catalog, and obtained spectra at the ... More
Equivalence of wave-particle duality to entropic uncertaintyMar 19 2014Sep 16 2014Interferometers capture a basic mystery of quantum mechanics: a single particle can exhibit wave behavior, yet that wave behavior disappears when one tries to determine the particle's path inside the interferometer. This idea has been formulated quantitively ... More
The Millennium Galaxy Catalogue: The photometric accuracy, completeness and contamination of the 2dFGRS and SDSS-EDR & DR1 datasetsDec 11 2003The Millennium Galaxy Catalogue (MGC) is a deep ($\mu_{\rm B,lim}=26$ mag arcsec$^{-2}$), wide field CCD imaging survey, covering 37.5deg$^2$ and is completely contained within the 2dFGRS and SDSS-EDR. We compare the photometry and completeness of the ... More
Marvin: A Heuristic Search Planner with Online Macro-Action LearningOct 12 2011This paper describes Marvin, a planner that competed in the Fourth International Planning Competition (IPC 4). Marvin uses action-sequence-memoisation techniques to generate macro-actions, which are then used during search for a solution plan. We provide ... More
Topological insulators in longitudinally driven waveguides: Lieb and Kagome latticesApr 26 2018Mar 09 2019Topological insulators are studied via tight-binding approximations of longitudinally driven photonic lattices with three lattice sites per unit cell. Two cases are considered in detail: Lieb and Kagome lattices. The lattice is decomposed into three sublattices ... More
Tight-binding methods for general longitudinally driven photonic lattices -- edge states and solitonsAug 03 2017A systematic approach for deriving tight-binding approximations in general longitudinally driven lattices is presented. As prototypes, honeycomb and staggered square lattices are considered. Time-reversal symmetry is broken by varying/rotating the waveguides, ... More
Halo concentrations from extended Press-Schechter merger historiesDec 14 2018We apply the model relating halo concentration to formation history proposed by Ludlow et al. to merger trees generated using an algorithm based on excursion set theory. We find that while the model correctly predicts the median relation between halo ... More
The ISLANDS project I: Andromeda XVI, An Extremely Low Mass Galaxy not Quenched by ReionizationMar 02 2016Based on data aquired in 13 orbits of HST time, we present a detailed evolutionary history of the M31 dSph satellite Andromeda XVI, including its life-time star formation history, the spatial distribution of its stellar populations, and the properties ... More
Comparing M31 and Milky Way Satellites: The Extended Star Formation Histories of Andromeda II and Andromeda XVIMay 19 2014We present the first comparison between the lifetime star formation histories (SFHs) of M31 and Milky Way (MW) satellites. Using the Advanced Camera for Surveys aboard the Hubble Space Telescope, we obtained deep optical imaging of Andromeda II (M$_{V} ... More
The parity effect in Josephson junction arraysMar 06 2015We study the parity effect and transport due to quasiparticles in circuits comprised of many superconducting islands. We develop a general approach and show that it is equivalent to previous methods for describing the parity effect in their more limited ... More
Quasi-one-dimensional electron gas bound to a helium-coated nanotubeDec 29 2015A much-studied system is the quasi-2D electron gas in image-potential bound states at the surface of helium and hydrogen. In this paper, we report on an analogous quasi-1D system: electrons bound by image-like polarization forces to the surface of a helium-coated ... More
The ACS LCID project. X. The Star Formation History of IC 1613: Revisiting the Over-Cooling ProblemMar 18 2014We present an analysis of the star formation history (SFH) of a field near the half light radius in the Local Group dwarf irregular galaxy IC 1613 based on deep Hubble Space Telescope Advanced Camera for Surveys imaging. Our observations reach the oldest ... More
The ISLAnds Project III: Variable Stars in Six Andromeda Dwarf Spheroidal GalaxiesOct 25 2017We present a census of variable stars in six M31 dwarf spheroidal satellites observed with the Hubble Space Telescope. We detect 870 RR Lyrae (RRL) stars in the fields of And I (296), II (251), III (111), XV (117), XVI (8), XXVIII (87). We also detect ... More