Results for "A. Brill"

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Finding consensus in speech recognition: word error minimization and other applications of confusion networksOct 07 2000We describe a new framework for distilling information from word lattices to improve the accuracy of speech recognition and obtain a more perspicuous representation of a set of alternative hypotheses. In the standard MAP decoding approach the recognizer ... More
Global Structure of a Black-Hole Cosmos and its ExtremesApr 06 1993We analyze the global structure of a family of Einstein-Maxwell solutions parametrized by mass, charge and cosmological constant. In a qualitative classification there are: (i) generic black-hole solutions, describing a Wheeler wormhole in a closed cosmos ... More
Closed Timelike Curves in Flat Lorentz SpacetimesJan 21 2002Jul 10 2002We consider the region of closed timelike curves (CTC's) in three-dimensional flat Lorentz spacetimes. The interest in this global geometrical feature goes beyond the purely mathematical. Such spacetimes may be considered lower-dimensional toy models ... More
Urn Models and Fibonacci SeriesJun 24 2018We use probability urn models to discover some known and unknown series identities involving Fibonacci numbers.
Electro-Reflectance Spectra of Blue BronzeJul 03 2003Jul 24 2003We show that the infrared reflectance of the quasi-one dimensional charge-density-wave (CDW) conductor K0.3MoO3 (blue bronze) varies with position when a voltage greater than the CDW depinning threshold is applied. The spatial dependence and spectra associated ... More
The Maximin Support Method: An Extension of the D'Hondt Method to Approval-Based Multiwinner ElectionsSep 17 2016Sep 05 2018We propose the maximin support method, a novel extension of the D'Hondt apportionment method to approval-based multiwinner elections. The maximin support method is based on maximizing the support of the least supported elected candidate. It can be computed ... More
Some Advances in Transformation-Based Part of Speech TaggingJun 02 1994Most recent research in trainable part of speech taggers has explored stochastic tagging. While these taggers obtain high accuracy, linguistic information is captured indirectly, typically in tens of thousands of lexical and contextual probabilities. ... More
Euclidean Maxwell-Einstein TheorySep 24 1992After reviewing the context in which Euclidean propagation is useful we compare and contrast Euclidean and Lorentzian Maxwell-Einstein theory and give some examples of Euclidean solutions.
2+1-dimensional black holes with momentum and angular momentumDec 18 1999Exact solutions of Einstein's equations in 2+1-dimensional anti-de Sitter space containing any number of black holes are described. In addition to the black holes these spacetimes can possess ``internal'' structure. Accordingly the generic spacetime of ... More
Geometry of Black Holes and Multi-Black-Holes in 2+1 dimensionsJul 11 1996Lecture given at ``Raychaudhuri session," ICGC-95 conference, Pune (India), December 1995. Contents: I. Introduction II. (2+1)-Dimensional Initial Values in Stereographic Projection A. The single, non-rotating black hole B. Non-rotating multi-black-holes ... More
Reversibility Checking for Markov ChainsJun 26 2018In this paper, we present reversibility preserving operations on Markov chain transition matrices. Simple row and column operations allow us to create new reversible transition matrices and yield an easy method for checking a Markov chain for reversibility. ... More
Black Holes and Wormholes in 2+1 DimensionsApr 30 1999Jun 12 1999Vacuum Einstein theory in three spacetime dimensions is locally trivial, but admits many solutions that are globally different, particularly if there is a negative cosmological constant. The classical theory of such locally "anti-de Sitter" spaces is ... More
Exploring deep learning as an event classification method for the Cherenkov Telescope ArraySep 18 2017Telescopes based on the imaging atmospheric Cherenkov technique (IACTs) detect images of the atmospheric showers generated by gamma rays and cosmic rays as they are absorbed by the atmosphere. The much more frequent cosmic-ray events form the main background ... More
Epitaxial Ba2IrO4 thin-films grown on SrTiO3 substrates by pulsed laser depositionFeb 26 2014We have synthesized epitaxial Ba2IrO4 (BIO) thin-films on SrTiO3 (001) substrates by pulsed laser deposition and studied their electronic structure by dc-transport and optical spectroscopic experiments. We have observed that BIO thin-films are insulating ... More
Specific Heat of Sr4Ru3O10Jan 26 2004We have measured the specific heat of single crystals of the triple-layer Ruddlesden-Popper material, Sr4Ru3O10, grown both in an image furnace and by flux-growth. The flux grown sample has a sharp mean-field-like anomaly at the onset of magnetic order, ... More
Investigations of metastable Ca2IrO4 epitaxial thin-films: systematic comparison with Sr2IrO4 and Ba2IrO4May 19 2016We have synthesized thermodynamically metastable Ca2IrO4 thin-films on YAlO3 (110) substrates by pulsed laser deposition. The epitaxial Ca2IrO4 thin-films are of K2NiF4-type tetragonal structure. Transport and optical spectroscopy measurements indicate ... More
Compressive strain-induced metal-insulator transition in orthorhombic SrIrO3 thin filmsJun 25 2014We have investigated the electronic properties of epitaxial orthorhombic SrIrO3 thin-films under compressive strain. The metastable, orthorhombic SrIrO3 thin-films are synthesized on various substrates using an epi-stabilization technique. We have observed ... More
The Emission Pattern of High-Energy Pions: A New Probe for the Early Phase of Heavy Ion CollisionsMay 15 2000The emission pattern of charged pions has been measured in Au+Au collisions at 1 GeV/nucleon incident energy. In peripheral collisions and at target rapidities, high-energy pions are emitted preferentially towards the target spectator matter. In contrast, ... More
Multi-Black-Holes in 3D and 4D anti-de Sitter SpacetimesAug 05 1996The (single) black hole solutions of Ba\~nados, Teitelboim and Zanelli (BTZ) in 2+1 dimensional anti-de Sitter space are generalized to an arbitrary number $n$ of such black holes. The resulting multi-black-hole (MBH) spacetime is locally isometric to ... More
Is the gravitational action additive?Mar 09 1994Mar 10 1994The gravitational action is not always additive in the usual sense. We provide a general prescription for the change in action that results when different portions of the boundary of a spacetime are topologically identified. We discuss possible implications ... More
Comments on Initial Value FormulationOct 25 1993This is the reply given at the conference ``Mach's Principle" at T\"ubingen in July 1993 to the paper by Isenberg (1993a). Unfortunately the Isenberg paper itself was not submitted to gr-qc.
Spacetime and Euclidean GeometryJul 06 2004Aug 04 2004Using only the principle of relativity and Euclidean geometry we show in this pedagogical article that the square of proper time or length in a two-dimensional spacetime diagram is proportional to the Euclidean area of the corresponding causal domain. ... More
Black Hole Collisions, Analytic Continuation, and Cosmic CensorshipJan 20 1995Mar 27 1995Exact solutions of the Einstein-Maxwell equations that describe moving black holes in a cosmological setting are discussed with the aim of discovering the global structure and testing cosmic censorship. Continuation beyond the horizons present in these ... More
Characterization of the Torsional Piezoelectric-like Response of Tantalum Trisulfide Associated with Charge-Density-Wave DepinningMay 14 2009Jun 17 2009We have studied the frequency and voltage dependence of voltage-induced torsional strains in orthorhombic TaS3 [V. Ya. Pokrovskii, et al, Phys. Rev. Lett. 98, 206404 (2007)] by measuring the modulation of the resonant frequency of an RF cavity containing ... More
Multi-Black-Hole Geometries in (2+1)-Dimensional GravityNov 06 1995Generalizations of the Black Hole geometry of Ba\~nados, Teitelboim and Zanelli (BTZ) are presented. The theory is three-dimensional vacuum Einstein theory with a negative cosmological constant. The $n$-black-hole solution has $n$ asymptotically anti-de ... More
Aspects of Analyticity (Lectures held at Kazan Summer School)Jul 07 1995CONTENTS: 1 Introduction 2 Analytic Manifolds and Analytic Continuation of Metrics 3 Walker's Spacetimes and their Maximal Extension 4 Global Structure of de Sitter and Reissner-Nordstr\"om-de Sitter Cosmos 4.1 Special Cases 4.2 Collapsing Dust 5 Euclidean ... More
Comments on Dragging EffectsOct 25 1993This is a reply, given at the conference ``Mach's Principle" in T\"ubingen in July 1993, to the paper by Pfister (1993). Unfortunately the Pfister paper itself was not sent to gr-qc.
The Cavendish Experiment in General RelativitySep 24 1997Solutions of Einstein's equations are discussed in which the ``gravitational force" is balanced by an electrical force, and which can serve as models for the Cavendish experiment.
A Rule-Based Approach To Prepositional Phrase Attachment DisambiguationOct 25 1994In this paper, we describe a new corpus-based approach to prepositional phrase attachment disambiguation, and present results comparing performance of this algorithm with other corpus-based approaches to this problem.
Soliton Analysis of the Electro-Optical Response of Blue BronzeJan 26 2004In recent measurements on the charge-density-wave (CDW) conductor blue bronze (K0.3MoO3), the electro-transmittance and electro-reflectance spectra were searched for intragap states that could be associated with solitons created by injection of electrons ... More
Lattice Universes in 2+1-dimensional gravityDec 04 2003Lattice universes are spatially closed space-times of spherical topology in the large, containing masses or black holes arranged in the symmetry of a regular polygon or polytope. Exact solutions for such spacetimes are found in 2+1 dimensions for Einstein ... More
Splitting of an Extremal Reissner-Nordström Throat via Quantum TunnelingFeb 12 1992Mar 12 1992The interior near the horizon of an extremal Reissner-Nordstr\"om black hole is taken as an initial state for quantum mechanical tunneling. An instanton is presented that connects this state with a final state describing the presence of several horizons. ... More
Competing Ground States in Triple-layered Sr4Ru3O10: Verging on Itinerant Ferromagnetism with Critical FluctuationsApr 17 2003Sr4Ru3O10 is characterized by a sharp metamagnetic transition and ferromagnetic behavior occurring within the basal plane and along the c-axis, respectively. Resistivity at magnetic field, B, exhibits low-frequency quantum oscillations when B||c-axis ... More
Anisotropic electronic properties of a-axis-oriented Sr2IrO4 epitaxial thin-filmsAug 20 2013Sep 06 2013We have investigated the transport and optical properties along the c-axis of a-axis-oriented Sr2IrO4 epitaxial thin-films grown on LaSrGaO4 (100) substrates. The c-axis resistivity is approximately one order of magnitude larger than that of the ab-plane. ... More
A Pictorial History of Some Gravitational InstantonsFeb 26 1993Mar 03 1993Four-dimensional Euclidean spaces that solve Einstein's equations are interpreted as WKB approximations to wavefunctionals of quantum geometry. These spaces are represented graphically by suppressing inessential dimensions and drawing the resulting figures ... More
Interlayer Thermal Conductivity of Rubrene Measured by ac-CalorimetryApr 26 2013Jul 08 2013We have measured the interlayer thermal conductivity of crystals of the organic semiconductor rubrene, using ac-calorimetry. Since ac-calorimetry is most commonly used for measurements of the heat capacity, we include a discussion of its extension for ... More
Frequency Domain Simulations of Charge-Density-Wave Strains: Comparison with Electro-Optic MeasurementsDec 10 2007We have studied changes in charge-density-wave strain under application of square-wave currents of variable amplitude and frequency by numerically solving the phase-slip augmented diffusion model introduced by Adelman et al (Phys. Rev. B 53, 1833 (1996)). ... More
Bagging and Boosting a Treebank ParserJun 05 2000Bagging and boosting, two effective machine learning techniques, are applied to natural language parsing. Experiments using these techniques with a trainable statistical parser are described. The best resulting system provides roughly as large of a gain ... More
Exploiting Diversity in Natural Language Processing: Combining ParsersJun 01 2000Three state-of-the-art statistical parsers are combined to produce more accurate parses, as well as new bounds on achievable Treebank parsing accuracy. Two general approaches are presented and two combination techniques are described for each approach. ... More
Light bending and perihelion precession: A unified approachDec 19 1997The standard General Relativity results for precession of particle orbits and for bending of null rays are derived as special cases of perturbation of a quantity that is conserved in Newtonian physics, the Runge-Lenz vector. First this method is applied ... More
Muon-Spin Rotation Measurements of the Magnetic Field Dependence of the Vortex-Core Radius and Magnetic Penetration Depth in NbSe2Aug 15 1997Muon-spin rotation spectroscopy has been used to measure the internal magnetic field distribution in NbSe2 for Hc1 << H < 0.25 Hc2. The deduced profiles of the supercurrent density indicate that the vortex-core radius in the bulk decreases sharply with ... More
Tuning electronic structures via epitaxial strain in Sr2IrO4 thin filmsFeb 05 2013Mar 30 2013We have synthesized epitaxial Sr2IrO4 thin-films on various substrates and studied their electronic structures as a function of lattice-strains. Under tensile (compressive) strains, increased (decreased) Ir-O-Ir bond-angles are expected to result in increased ... More
Optical Signatures of Spin-Orbit Exciton in Bandwidth Controlled Sr$_2$IrO$_4$ Epitaxial Films via High-Concentration Ca and Ba DopingJun 12 2017We have investigated the electronic and optical properties of (Sr$_{1-x}$Ca$_{x}$)$_2$IrO$_4$ (x= 0 - 0.375) and (Sr$_{1-y}$Ba$_y$)$_2$IrO$_4$ (y= 0 - 0.375) epitaxial thin-films, in which the bandwidth is systematically tuned via chemical substitutions ... More
Electronic and optical properties of La-doped Sr$_3$Ir$_2$O$_7$ epitaxial thin-filmsFeb 08 2018We have investigated structural, transport, and optical properties of tensile strained (Sr$_{1-x}$La$_x$)$_3$Ir$_2$O$_7$ (x = 0, 0.025, 0.05) epitaxial thin-films. While High-T$_c$ superconductivity is predicted theoretically in the system, we have observed ... More
Multiband superconductivity in NbSe_2 from heat transportApr 22 2003The thermal conductivity of the layered s-wave superconductor NbSe_2 was measured down to T_c/100 throughout the vortex state. With increasing field, we identify two regimes: one with localized states at fields very near H_c1 and one with highly delocalized ... More
Heat Conduction in the Vortex State of NbSe_2: Evidence for Multi-Band SuperconductivityNov 15 2002Mar 18 2003The thermal conductivity kappa of the layered s-wave superconductor NbSe_2 was measured down to T_c/100 throughout the vortex state. With increasing field, we identify two regimes: one with localized states at fields very near H_c1 and one with highly ... More
Direct measurement of stellar angular diameters by the VERITAS Cherenkov TelescopesApr 12 2019The angular size of a star is a critical factor in determining its basic properties. Direct measurement of stellar angular diameters is difficult: at interstellar distances stars are generally too small to resolve by any individual imaging telescope. ... More
Instantons For Black Hole Pair ProductionNov 23 1998Dec 04 1998We address the issue of constructing continuous instantons representing the pair creation of black holes in a cosmological context. The recent attempt at constructing such solutions using virtual domain walls is reviewed first. We then explore the existence ... More
The Computational Complexity of Random Serial DictatorshipApr 11 2013Apr 23 2013In social choice settings with linear preferences, random dictatorship is known to be the only social decision scheme satisfying strategyproofness and ex post efficiency. When also allowing indifferences, random serial dictatorship (RSD) is a well-known ... More
Gravitational Geons RevisitedOct 31 1996Sep 03 1997A careful analysis of the gravitational geon solution found by Brill and Hartle is made. The gravitational wave expansion they used is shown to be consistent and to result in a gauge invariant wave equation. It also results in a gauge invariant effective ... More
Horizons in 2+1-dimensional collapse of particlesJul 12 2007A simple, geometrical construction is given for three-dimensional spacetimes with negative cosmological constant that contain two particles colliding head-on. Depending on parameters like particle masses and distance, the combined geometry will the that ... More
Thermodynamics of (3+1)-dimensional black holes with toroidal or higher genus horizonsMay 07 1997Aug 04 1997We examine counterparts of the Reissner-Nordstrom-anti-de Sitter black hole spacetimes in which the two-sphere has been replaced by a surface Sigma of constant negative or zero curvature. When horizons exist, the spacetimes are black holes with an asymptotically ... More
An Ordinal Minimax TheoremDec 13 2014Jan 07 2016In the early 1950s Lloyd Shapley proposed an ordinal and set-valued solution concept for zero-sum games called \emph{weak saddle}. We show that all weak saddles of a given zero-sum game are interchangeable and equivalent. As a consequence, every such ... More
Multiwinner Approval Rules as Apportionment MethodsNov 26 2016We establish a link between multiwinner elections and apportionment problems by showing how approval-based multiwinner election rules can be interpreted as methods of apportionment. We consider several multiwinner rules and observe that they induce apportionment ... More
Dynamics of the Electro-Reflective Response of TaS3Apr 28 2004We have observed a large (~1%) change in infrared reflectance of the charge-density-wave (CDW) conductor, orthorhombic TaS3, when its CDW is depinned. The change is concentrated near one current contact. Assuming that the change in reflectance is proportional ... More
Testing Substitutability of Weak PreferencesJan 02 2012In many-to-many matching models, substitutable preferences constitute the largest domain for which a pairwise stable matching is guaranteed to exist. In this note, we extend the recently proposed algorithm of Hatfield et al. [3] to test substitutability ... More
Torque and temperature dependence of the hysteretic voltage-induced torsional strain in tantalum trisulfideJul 12 2011Sep 09 2011We have measured the dependence of the hysteretic voltage-induced torsional strain (VITS) in crystals of orthorhombic tantalum trisulfide on temperature and applied torque. In particular, applying square-wave voltages above the charge-density-wave (CDW) ... More
Engineering One-Dimensional Quantum Stripes from Superlattices of Two-Dimensional Layered MaterialsOct 24 2016One-dimensional (1D) quantum systems, which are predicted to exhibit novel states of matter in theory, have been elusive in experiment. Here we report a superlattice method of creating artificial 1D quantum stripes, which offers dimensional tunability ... More
Knots in Macromolecules in Constraint SpaceJul 01 2005We find a power law for the number of knot-monomers with an exponent $0.39 \pm0.13$ in agreement with previous simulations. For the average size of a knot we also obtain a power law $N_m=2.56\cdot N^{0.20\pm0.04}$. We further present data on the average ... More
Black Holes and Wormholes in 2+1 DimensionsJul 15 1997A large variety of spacetimes---including the BTZ black holes---can be obtained by identifying points in 2+1 dimensional anti-de Sitter space by means of a discrete group of isometries. We consider all such spacetimes that can be obtained under a restriction ... More
Consistent distribution-free $K$-sample and independence tests for univariate random variablesOct 24 2014Jun 18 2015A popular approach for testing if two univariate random variables are statistically independent consists of partitioning the sample space into bins, and evaluating a test statistic on the binned data. The partition size matters, and the optimal partition ... More
Electro-Optic Search for Critical Divergence of the Charge-Density-Wave Diffusion Constant at the Onset of DepinningJul 25 2007Sep 09 2007We have used electro-reflectance measurements to study charge-density-wave (CDW) polarization dynamics at voltages near the CDW depinning onset (Von) in the quasi-one-dimensional conductor K0.3MoO3 ("blue bronze"). For low voltages, where the phase-slip ... More
Web-Based Question Answering: A Decision-Making PerspectiveOct 19 2012We describe an investigation of the use of probabilistic models and cost-benefit analyses to guide resource-intensive procedures used by a Web-based question answering system. We first provide an overview of research on question-answering systems. Then, ... More
Dynamics of Charge Flow in the Channel of a Thin-Film Field-Effect TransistorMay 01 2012Sep 24 2012The local conductivity in the channel of a thin-film field-effect transistor is proportional to the charge density induced by the local gate voltage. We show how this determines the frequency- and position-dependence of the charge induced in the channel ... More
Possible quantum criticality and coexistence of spontaneous ferromagnetism and field-induced metamagnetism in triple-layered Sr4Ru3O10May 30 2006A thermodynamic and transport study of Sr4Ru3O10 as a function of temperature and magnetic field are presented. The central results include a growing specific heat C with increasing field B, a divergent magnetic contribution to C/T at low temperatures, ... More
Dynamics of the hysteretic voltage-induced torsional strain in tantalum trisulfideOct 30 2009Jan 07 2010We have studied how the hysteretic voltage-induced torsional strain, associated with charge-density-wave depinning, in orthorhombic tantalum trisulfide depends on square-wave and triangle-wave voltages of different frequencies and amplitudes. The strains ... More
Testing Cosmic Censorship with Black Hole CollisionsJul 12 1993There exists an upper limit on the mass of black holes when the cosmological constant $\Lambda$ is positive. We study the collision of two black holes whose total mass exceeds this limit. Our investigation is based on a recently discovered exact solution ... More
Motion of free spins and NMR imaging without a radio-frequency magnetic fieldApr 19 2015NMR imaging without any radio-frequency magnetic field is explained by a quantum treatment of independent spin~$\tfrac 12$. The total magnetization is determined by means of their individual wave function. The theoretical treatment, based on fundamental ... More
Anomalous itinerant magnetism in single crystal Sr4Ru3O10: A thermodynamic and transport investigationMar 14 2007A thermodynamic and transport study of Sr4Ru3O10 as a function of temperature and magnetic field is presented. The central results include a growing specific heat C with increasing field B, a magnetic contribution to C/T at low temperatures proportional ... More
Electro-optic measurement of carrier mobility in an organic thin-film transistorApr 29 2010Jun 15 2010We have used an electro-optic technique to measure the position-dependent infrared absorption of holes injected into a thin crystal of the organic semiconductor, 6,13-bis(triisopropylsilylethynyl)-pentacene incorporated in a field-effect transistor. By ... More
Proportional RankingsDec 05 2016In this paper we extend the principle of proportional representation to rankings. We consider the setting where alternatives need to be ranked based on approval preferences. In this setting, proportional representation requires that cohesive groups of ... More
Dynamic Infrared Electro-Optic Response of Soluble Organic Semiconductors in Thin Film TransistorsDec 19 2012We use a frequency-dependent electro-optic technique to measure the hole mobility in small molecule organic semiconductors, such as 6,13 bis(triisopropylsilylethynyl)-pentacene. Measurements are made on semiconductor films in bottom gate, bottom contact ... More
Production of K+ and of K- Mesons in Heavy-Ion Collisions from 0.6 to 2.0 AGeV Incident EnergyJan 08 2007This paper summarizes the yields and the emission patterns of K+ and of K- mesons measured in inclusive C+C, Ni+Ni and Au+Au collisions at incident energies from 0.6 AGeV to 2.0 AGeV using the Kaon Spectrometer KaoS at GSI. For Ni+Ni collisions at 1.5 ... More
Enhanced Out-of-plane Emission of K+ Mesons observed in Au+Au Collisions at 1 AGeVJul 10 1998The azimuthal angular distribution of K+ mesons has been measured in Au + Au collisions at 1 AGeV. In peripheral and semi-central collisions, K+ mesons preferentially are emitted perpendicular to the reaction plane. The strength of the azimuthal anisotropy ... More
Evidence for Different Freeze-Out Radii of High- and Low-Energy Pions Emitted in Au+Au Collisions at 1 GeV/nucleonDec 11 1997Double differential production cross sections of negative and positive pions and the number of participating protons have been measured in central Au+Au collisions at 1 GeV per nucleon incident energy. At low pion energies the pi^- yield is strongly enhanced ... More
Phase transitions in LaFeAsO: structural, magnetic, elastic, and transport properties, heat capacity and Mossbauer spectraJun 23 2008Aug 21 2008We present results from a detailed experimental investigation of LaFeAsO, the parent material in the series of "FeAs" based oxypnictide superconductors. Upon cooling this material undergoes a tetragonal-orthorhombic crystallographic phase transition at ... More
On the cylindrically symmetric wormholes WhCR^e: The motion of test particlesFeb 28 2016In this article we partially implement the program outlined in the previous paper of the authors [A. V. Aminova and P. I. Chumarov, Phys. Rev. D 88, 044005 (2013)]. The program owes its origins to the following comment in paper [M. Cveti\v{c} and D. Youm, ... More
Low-Field Anomaly in the Specific Heat of s-wave Superconductors due to the Expansion of the Vortex CoresNov 30 1998Oct 26 1999The magnetic field dependence of the electronic specific heat C(H) in the s-wave superconductor NbSe_2 shows curvature at low fields, resembling the near H^1/2 term in C(H) which has been reported in high-T_c superconductors and attributed to a d-wave ... More
Thermal Resistances of Thin-Films of Small Molecule Organic SemiconductorsJul 06 2016Sep 02 2016We have measured the thermal resistances of thin films of the small molecule organic semiconductors bis(triisopropylsilylethynyl) pentacene (TIPS-pn), bis(triethylsilylethynyl) anthradithiophene (TES-ADT) and difluoro bis(triethylsilylethynyl) anthradithiophene ... More
A Search for Dark Matter Axions with the Orpheus ExperimentMar 12 2014Feb 20 2015Axions are well motivated particles that could make up most or all of the dark matter if they have masses below 100 $\mu$eV. Microwave cavity techniques comprised of closed resonant structures immersed in solenoid magnets are sensitive to dark matter ... More
Exact Mean Computation in Dynamic Time Warping SpacesOct 24 2017May 31 2018Dynamic time warping constitutes a major tool for analyzing time series. In particular, computing a mean series of a given sample of series in dynamic time warping spaces (by minimizing the Fr\'echet function) is a challenging computational problem, so ... More
Specific Heat of (Ca1-xSrx)3Ru2O7 Single CrystalsNov 09 2006We have measured the specific heat of crystals of (Ca1-xSrx)3Ru2O7 using ac- and relaxation-time calorimetry. Special emphasis was placed on the characterization of the Neel (TN=56 K) and structural (Tc = 48 K) phase transitions in the pure, x=0 material. ... More
Dynamics of the Electro-Optic response of Blue BronzeMay 19 2006Jul 09 2006We have studied the charge density wave (CDW) repolarization dynamics in blue bronze by applying square-wave voltages of different frequencies to the sample and measuring the changes in infrared transmittance, proportional to CDW strain. The frequency ... More
Nuclear spin interferences in bulk water at room temperatureMar 29 2007Nuclear spin interference effects generated in a macroscopic sample of 10ml degassed water are detected in a simple NMR experiment. A \pi/2 - \tau - \pi/2 RF double pulse sequence (Ramsey sequence) is applied to the water sample immersed in a static magnetic ... More
Thermal and Magnetic Properties of the Spin-Chain Material, Pr3RuO7Mar 09 2005May 17 2005We present measurements of the magnetic moment and specific heat of single crystals of the spin-chain insulator, Pr3RuO7. The susceptibility indicates that three-dimensional antiferromagnetic order sets in at TN = 54 K, with spin polarization approximately ... More
Holographic description of strongly correlated electrons in external magnetic fieldsApr 13 2013We study the Fermi level structure of (2+1)-dimensional strongly interacting electron systems in external magnetic field using the AdS/CFT correspondence. The gravity dual of a finite density fermion system is a Dirac field in the background of the dyonic ... More
Holographic fermions in external magnetic fieldsNov 17 2010Dec 13 2011We study the Fermi level structure of 2+1-dimensional strongly interacting electron systems in external magnetic field using the AdS/CFT correspondence. The gravity dual of a finite density fermion system is a Dirac field in the background of the dyonic ... More
Gravitational wave detectors based on matter wave interferometers (MIGO) are no better than laser interferometers (LIGO)Aug 31 2004Dec 17 2004We show that a recent claim that matter wave interferometers have a much higher sensitivity than laser interferometers for a comparable physical setup is unfounded. We point out where the mistake in the earlier analysis is made. We also disprove the claim ... More
Thermal Diffusivities of Functionalized Pentacene SemiconductorsJun 04 2014Aug 14 2014We have measured the interlayer and in-plane (needle axis) thermal diffusivities of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn). The needle axis value is comparable to the phonon thermal conductivities of quasi-one dimensional organic metals ... More
Effects of hydrostatic pressure on the magnetic susceptibility of ruthenium oxide Sr3Ru2O7: Evidence for pressure-enhanced antiferromagnetic instabilityMar 11 2003Hydrostatic pressure effects on the temperature- and magnetic field dependencies of the in-plane and out-of-plane magnetization of the bi-layered perovskite Sr3Ru2O7 have been studied by SQUID magnetometer measurements under a hydrostatic helium-gas pressure. ... More
Justified Representation in Approval-Based Committee VotingJul 31 2014Sep 12 2016We consider approval-based committee voting, i.e. the setting where each voter approves a subset of candidates, and these votes are then used to select a fixed-size set of winners (committee). We propose a natural axiom for this setting, which we call ... More
Field-tuned Collapse of an Orbital Ordered and Spin-polarized State: Colossal Magnetoresistance in Bilayered RuthenateJul 03 2003Ca3Ru2O7 with a Mott-like transition at 48 K features different in-plane anisotropies of magnetization and magnetoresistance. Applying magnetic field along the magnetic easy-axis precipitates a spin-polarized state via a first-order metamagnetic transition, ... More
Frequency-Dependent Photothermal Measurement of Transverse Thermal Diffusivity of Organic SemiconductorsAug 13 2015Nov 30 2015We have used a photothermal technique, in which chopped light heats the front surface of a small ( ~ 1 mm2) sample and the chopping frequency dependence of thermal radiation from the back surface is measured with a liquid nitrogen cooled infrared detector. ... More
VERITAS observations of the BL Lac object TXS 0506+056Jul 12 2018On 2017 September 22, the IceCube Neutrino Observatory reported the detection of the high-energy neutrino event \icnu, of potential astrophysical origin. It was soon determined that the neutrino direction was consistent with the location of the gamma-ray ... More
Charge Order Superstructure with Integer Iron Valence in Fe2OBO3Jul 18 2007Solution-grown single crystals of Fe2OBO3 were characterized by specific heat, Mossbauer spectroscopy, and x-ray diffraction. A peak in the specific heat at 340 K indicates the onset of charge order. Evidence for a doubling of the unit cell at low temperature ... More
Anisotropic electron mobility studies on Cl2-NDI single crystals and the role of static and dynamic lattice deformations upon temperature variationJan 08 2015Jun 09 2016The anisotropic electron transport in the (001) plane of sublimation-grown Cl$_{2}$-NDI (naphthalene diimide) single crystals is analysed over a temperature range between 175 K and 300 K. Upon cooling from room temperature to 175 K the electron mobility ... More
Monte Carlo studies for the optimisation of the Cherenkov Telescope Array layoutApr 02 2019The Cherenkov Telescope Array (CTA) is the major next-generation observatory for ground-based very-high-energy gamma-ray astronomy. It will improve the sensitivity of current ground-based instruments by a factor of five to twenty, depending on the energy, ... More
Ambiguity-free formulation of the Higgs-Kibble modelOct 05 2010A renormalizable ambiguity-free formulation of the Higgs-Kibble model is proposed.
Quantum-Limited Amplification via Reservoir EngineeringNov 01 2013Apr 08 2014We describe a new kind of phase-preserving quantum amplifier which utilizes dissipative interactions in a parametrically-coupled three-mode bosonic system. The use of dissipative interactions provides a fundamental advantage over standard cavity-based ... More
Crossed Andreev reflection in diffusive contactsNov 06 2006Crossed Andreev reflection in multiterminal structures in the diffusive regime is addressed within the quasiclassical Keldysh-Usadel formalism. The elastic cotunneling and crossed Andreev reflection of quasiparticles give nonlocal currents and voltages ... More