Results for "Takayoshi Kusune"

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Test Result of Time-Of-Propagation Cherenkov CounterJan 27 2000Feb 14 2000A new concept concerning Cherenkov detector for particle identification by means of measuring both the Time-of-Propagation (TOP) and horizontal emission angle ($\Phi$) of Cherenkov photons is described here. Some R&D works are also reported.
Magnetic stability of massive star forming clumps in RCW 106Apr 12 2019The RCW~106 molecular cloud complex is an active massive star-forming region where a ministarburst is taking place. We examined its magnetic structure by near-IR polarimetric observations with the imaging polarimeter SIRPOL on the IRSF 1.4 m telescope. ... More
Magnetic stability of massive star forming clumps in RCW 106Apr 12 2019Apr 16 2019The RCW 106 molecular cloud complex is an active massive star-forming region where a ministarburst is taking place. We examined its magnetic structure by near-IR polarimetric observations with the imaging polarimeter SIRPOL on the IRSF 1.4 m telescope. ... More
Near-IR Imaging Polarimetry toward a Bright-Rimmed Cloud: Magnetic Field in SFO 74Nov 07 2014We have made near-infrared (JHKs) imaging polarimetry of a bright-rimmed cloud (SFO 74). The polarization vector maps clearly show that the magnetic field in the layer just behind the bright rim is running along the rim, quite different from its ambient ... More
Spin(7) holonomy manifold and SuperconnectionOct 09 2000We discuss the higher dimensional generalization of gravitational instantons by using volume-preserving vector fields. We give special attention to the case of 8-dimensions and present a new construction of the Ricci flat metric with holonomy in Spin(7). ... More
Mass ratio of elementary excitations in frustrated antiferromagnetic chains with dimerizationJan 10 2012Oct 17 2012Excitation spectra of S=1/2 and S=1 frustrated Heisenberg antiferromagnetic chains with bond alternation (explicit dimerization) are studied using a combination of analytical and numerical methods. The system undergoes a dimerization transition at a critical ... More
Characterizing a Set of Popular Matchings Defined by Preference Lists with TiesJan 14 2016In this paper, we give a simple characterization of a set of popular matchings defined by preference lists with ties. By employing our characterization, we propose a polynomial time algorithm for finding a minimum cost popular matching.
Spontaneous Formation of Surface Magnetic Structure from Large-scale Dynamo in Strongly-stratified ConvectionApr 18 2016We report the first successful simulation of spontaneous formation of surface magnetic structures from a large-scale dynamo by strongly-stratified thermal convection in Cartesian geometry. The large-scale dynamo observed in our strongly-stratified model ... More
A short guide to topological terms in the effective theories of condensed matterFeb 19 2015This article is meant as a gentle introduction to the "topological terms" that often play a decisive role in effective theories describing topological quantum effects in condensed matter systems. We first take up several prominent examples, mainly from ... More
Coefficients of bosonized dimer operators in spin-1/2 XXZ chains and their applicationsMay 11 2010Dec 21 2010Comparing numerically evaluated excitation gaps of dimerized spin-1/2 XXZ chains with the gap formula for the low-energy effective sine-Gordon theory, we determine coefficients d_xy and d_z of bosonized dimerization operators in spin-1/2 XXZ chains, which ... More
Generation and characterization of a source of wavelength division multiplexing quantum key distributionApr 05 2004Apr 06 2004Using spontaneous parametric down-conversion, photon pairs entangled in frequency and polarization were generated. After frequency resolving the photon pairs, the polarization correlations were measured on several polarization basis, and it was confirmed ... More
Numerical study of t2g orbital system with ferromagnetic polarizationMay 23 2008Finite temperature orbital state in a ferromagnetic Mott insulator with triply-degenerate $t_{2g}$ orbital is investigated numerically. We employ the quantum Monte Carlo simulation with the loop algorithm. Indications for conventional staggered-type orbital ... More
Mean-Field Modeling of $α^2$-Dynamo Coupled with Direct Numerical Simulations of Rigidly Rotating ConvectionSep 10 2014Sep 22 2014The mechanism of large-scale dynamos in rigidly rotating stratified convection is explored by direct numerical simulations (DNS) in Cartesian geometry. A mean-field dynamo model is also constructed using turbulent velocity profiles consistently extracted ... More
Global well-posedness for one dimensional Chern-Simons-Dirac system in $L^p$Jan 28 2016Time global wellposedness in L^p for the Chern-Simons-Dirac equation in 1+1 dimension is discussed.
Spectroscopy by frequency entangled photon pairsJun 23 2003Jan 05 2004Quantum spectroscopy was performed using the frequency-entangled broadband photon pairs generated by spontaneous parametric down-conversion. An absorptive sample was placed in front of the idler photon detector, and the frequency of signal photons was ... More
Finsler connection for general Lagrangian systemsAug 11 2014Feb 24 2016We give a Finsler non-linear connection by a new simplified definition for not only regular case but also singular case. In regular case, it corresponds to non-linear connection part of Berwald's connection, but our connection is expressed not in line ... More
Long-term Evolution of Large-scale Magnetic Fields in Rotating Stratified ConvectionMar 25 2014Convective dynamo simulations are performed in local Cartesian geometry. We report the first successful simulation of a large-scale oscillatory dynamo in rigidly rotating convection without stably stratified layers. A key requirement for exciting the ... More
A Local One-Zone Model of MHD Turbulence in Dwarf Nova DisksDec 03 2002The evolution of the magnetorotational instability (MRI) during the transition from outburst to quiescence in a dwarf nova disk is investigated using three-dimensional MHD simulations. The shearing box approximation is adopted for the analysis, so that ... More
The Effect of the Hall Term on the Nonlinear Evolution of the Magnetorotational Instability: I. Local Axisymmetric SimulationsJan 11 2002The effect of the Hall term on the evolution of the magnetorotational instability (MRI) in weakly ionized accretion disks is investigated using local axisymmetric simulations. First, we show that the Hall term has important effects on the MRI when the ... More
Axisymmetric Magnetorotational Instability in Viscous Accretion DisksAug 18 2008Axisymmetric magnetorotational instability (MRI) in viscous accretion disks is investigated by linear analysis and two-dimensional nonlinear simulations. The linear growth of the viscous MRI is characterized by the Reynolds number defined as $R_{\rm MRI} ... More
Dilution Effects in Two-dimensional Quantum Orbital SystemOct 10 2006We study dilution effects in a Mott insulating state with quantum orbital degree of freedom, termed the two-dimensional orbital compass model. This is a quantum and two-dimensional version of the orbital model where the interactions along different bond ... More
Dilution effect in correlated electron system with orbital degeneracyAug 18 2008Theory of dilution effect in orbital ordered system is presented. The $e_g$ orbital model without spin degree of freedom and the spin-orbital coupled model in a three-dimensional simple-cubic lattice are analyzed by the Monte-Carlo simulation and the ... More
The Effect of the Hall Term on the Nonlinear Evolution of the Magnetorotational Instability: II. Saturation Level and Critical Magnetic Reynolds NumberMay 22 2002The nonlinear evolution of the magnetorotational instability (MRI) in weakly ionized accretion disks, including the effect of the Hall term and ohmic dissipation, is investigated using local three-dimensional MHD simulations and various initial magnetic ... More
Self-Sustained Ionization and Vanishing Dead Zones in Protoplanetary DisksJun 07 2005Jul 12 2005We analyze the ionization state of the magnetohydrodynamically turbulent protoplanetary disks and propose a new mechanism of sustaining ionization. First, we show that in the quasi-steady state of turbulence driven by magnetorotational instability in ... More
In situ TEM observation of oxygen evolution reaction in GDC-Pt half cell at elevated temperaturesJun 04 2015Gadolinium-doped ceria was studied in a half SOFCs at elevated temperatures. In situ electron holography could reveal ionic activity in a single GDC-Pt interface at the elevated temperatures that result in further oxidation of the GDC. In situ EELS measurements ... More
Saturation and Thermalization of the Magnetorotational Instability: Recurrent Channel Flows and ReconnectionsOct 05 2001The nonlinear evolution and the saturation mechanism of the magnetorotational instability (MRI) are investigated using three-dimensional resistive MHD simulations. A local shearing box is used for our numerical analysis and the simulations begin with ... More
Symmetry-protected topological order in magnetization plateau states of quantum spin chainsDec 12 2014Apr 23 2015A symmetry-protected topologically ordered phase is a short-range entangled state, for which some imposed symmetry prohibits the adiabatic deformation into a trivial state which lacks entanglement. In this paper we argue that magnetization plateau states ... More
Correlations of measurement information and noise in quantum measurements with finite resolutionMar 17 2000The original purpose of measurements is to provide us with information about a previously unknown physical property of the system observed. In the Hilbert space formalism of quantum mechanics, this physical meaning of measurement information is not immediately ... More
Quantum nondemolition measurement of a light field component by a feedback compensated beam splitterMar 19 2001In conventional quantum nondemolition measurements, the interaction between signal and probe preserves the measured variable. Alternatively, it is possible to restore the original value of the variable by feedback. In this paper, we describe a quantum ... More
Quantum jumps in backaction evasion measurements of a light field componentMay 25 2000Backaction evasion measurements of a quadrature component of the light field vacuum necessarily induce quantum jumps in the photon number. The correlation between measurement results and quantum jump events reveals fundamental nonclassical aspects of ... More
Nonaxisymmetric Magnetorotational Instability in Proto-Neutron StarsDec 13 2005We investigate the stability of differentially rotating proto-neutron stars (PNSs) with a toroidal magnetic field. Stability criteria for nonaxisymmetric MHD instabilities are derived using a local linear analysis. PNSs are expected to have much stronger ... More
Field theory of symmetry protected valence bond solid states in (2+1) dimensionsSep 05 2016Oct 04 2016This paper describes a semiclassical field theory approach to the topological properties of spatially featureless Affleck-Kennedy-Lieb-Tasaki type valence bond solid ground states of antiferromagnets in spatial dimensions one to three. Using nonlinear ... More
Thermopower analysis of metal-insulator transition temperature modulations in vanadium dioxide thin films with lattice distortionJul 10 2015Insulator-to-metal (MI) phase transition in vanadium dioxide (VO2) thin films with controlled lattice distortion was investigated by thermopower measurements. VO2 epitaxial films with different crystallographic orientations, grown on (0001) alpha-Al2O3, ... More
Field theory of symmetry protected valence bond solid states in (2+1) dimensionsSep 05 2016This paper describes a semiclassical field theory approach to the topological properties of spatially featureless Affleck-Kennedy-Lieb-Tasaki type valence bond solid ground states of antiferromagnets in spatial dimensions one to three. Using nonlinear ... More
Evolution and Nucleosynthesis of Metal-Free Massive StarsDec 13 1999We calculate presupernova evolutions and supernova explosions of massive stars (M=13-25 Mo) for various metallicities. We find the following characteristic abundance patterns of nucleosynthesis in the metal-free (Pop III) stars. (1) The alpha-nuclei (from ... More
Killing Symmetry on Finsler ManifoldSep 09 2016Killing vector fields $K$ are defined on Finsler manifold. The Killing symmetry is reformulated simply as $\delta K^\flat =0$ by using the Killing non-linear 1-form $K^\flat$ and the spray operator $\delta$ with the Finsler non-linear connection. $K^\flat$ ... More
Spontaneous population imbalance in two-component Bose and Fermi gasesNov 17 2009May 11 2010We study two-component (or pseudo-spin-1/2) Bose or Fermi gases in one dimension, in which particles are convertible between the components. Through bosonization and numerical analyses of a simple lattice model, we demonstrate that, in such gases, a strong ... More
Photon echo signature of vibrational cat states created by femtosecond excitation of moleculesJul 28 2000Jan 19 2001A pair of coherent femtosecond pulse excitations applied to a molecule with strong electron-phonon coupling creates a coherent superposition of a low momentum and a high momentum wavepacket in the vibrational states of both the excited state and the ground ... More
Magnetization and phase transition induced by circularly polarized laser in quantum magnetsFeb 18 2013Sep 09 2014We theoretically predict a nonequilibrium phase transition in quantum spin systems induced by a laser, which provides a purely quantum-mechanical way of coherently controlling magnetization. Namely, when a circularly polarized laser is applied to a spin ... More
Laser-Driven Multiferroics and Ultrafast Spin Current GenerationFeb 11 2016Oct 03 2016We propose an ultrafast way to generate spin chirality and spin current in a class of multiferroic magnets using a terahertz circularly polarized laser. Using the Floquet formalism for periodically driven systems, we show that it is possible to dynamically ... More
Reversibly switchable electromagnetic device with leakage-free electrolyteApr 04 2016Electrical control of oxygen off-stoichiometry of transition-metal oxides at room temperature is a desired strategy to simultaneously switch the electrical conductance and magnetism of the device. Although the use of the electrochemical redox reaction ... More
Infrared-transmittance tunable metal-insulator conversion device with thin-film-transistor-type structure on a glass substrateApr 29 2017Infrared (IR) transmittance tunable metal-insulator conversion was demonstrated on glass substrate by using thermochromic vanadium dioxide (VO2) as the active layer in three-terminal thin-film-transistor-type device with water-infiltrated glass as the ... More
High-harmonic generation in quantum spin systemsJan 22 2019We theoretically study the high-harmonic generation (HHG) in one-dimensional spin systems. While in electronic systems the driving by AC electric fields produces radiation from the dynamics of excited charges, we consider here the situation where spin ... More
The Effect of Neutrino Radiation on Magnetorotational Instability in Proto-Neutron StarsOct 02 2006Neutrino radiation takes a major role in the momentum, heat, and lepton transports in proto-neutron stars (PNSs). These diffusive processes affect the growth of magnetorotational instability (MRI) in PNSs. We perform a local linear analysis for the axisymmetric ... More
Nonclassical correlations of photon number and field components in the vacuum stateDec 15 1999Apr 05 2000It is shown that the quantum jumps in the photon number n from zero to one or more photons induced by backaction evasion quantum nondemolition measurements of a quadrature component x of the vacuum light field state are strongly correlated with the quadrature ... More
Macroscopic quantum tunneling of the Bose-Einstein condensate trapped in cylindrically symmetric potentialNov 21 2000We investigate the macroscopic quantum tunneling of the attractive Bose-Einstein condensate. Within the effective Lagrangian framework, we find bounce solutions and explicitly calculate the decay rate of the condensate trapped in a cylindrically symmetric ... More
Spin-chain description of fractional quantum Hall states in the Jain seriesMay 22 2012Oct 09 2012We discuss the relationship between fractional quantum Hall (FQH) states at filling factor $\nu=p/(2p+1)$ and quantum spin chains. This series corresponds to the Jain series $\nu=p/(2mp+1)$ with $m=1$ where the composite fermion picture is realized. We ... More
Thermopower analysis of the electronic structure around metal-insulator transition in V1-xWxO2Oct 07 2014Electronic structure across the metal-insulator (MI) transition of electron-doped V1-xWxO2 epitaxial films (x = 0-0.06) grown on alfa-Al2O3 substrates was studied by means of thermopower (S) measurements. Significant increase of |S|-values accompanied ... More
Dependence of the saturation level of magnetorotational instability on gas pressure and magnetic Prandtl numberJun 11 2015A large set of numerical simulations of magnetohydrodynamic (MHD) turbulence induced by the magnetorotational instability (MRI) is presented. Revisiting the previous survey conducted by Sano et al. (2004), we investigate the gas pressure dependence of ... More
Magnetism and Superconductivity in Ferromagnetic Heavy Fermion System UCoGe under In-plane Magnetic FieldsMay 21 2016We study the ferromagnetic superconductor UCoGe at ambient pressure under $ab$-plane magnetic fields $\vec{H}$ which are perpendicular to the ferromagnetic easy axis. It is shown that, by taking into account the Dyaloshinskii-Moriya interaction arising ... More
Laser-induced magnetization curveFeb 04 2014Dec 11 2014We propose an all optical ultrafast method to highly magnetize general quantum magnets using a circularly polarized terahertz laser. The key idea is to utilize a circularly polarized laser and its chirping. Through this method, one can obtain magnetization ... More
Critical Magnetic Field Strength for Suppression of the Richtmyer-Meshkov Instability in PlasmasOct 23 2013Oct 25 2013The critical strength of a magnetic field required for the suppression of the Richtmyer-Meshkov instability (RMI) is investigated numerically by using a two-dimensional single-mode analysis. For the cases of MHD parallel shocks, the RMI can be stabilized ... More
A flux tube model for glueballsMay 09 2003We calculate the mass spectrum and the decay widths of glueballs in the flux tube model. The glueball is assumed to be a closed flux tube. The breathing motion and the rotational motion are investigated using the WKB approximation. The calculated spectra ... More
Superconducting Properties and Phase Diagram of Indirectly Electron-Doped (Sr1-xLax)Fe2As2 Epitaxial Films Grown by Pulsed Laser DepositionFeb 02 2013A non-equilibrium phase (Sr1-xLax)Fe2As2 was formed by epitaxial film-growth. The resulting films emerged superconductivity along with suppression of the resistivity anomaly that is associated with magnetic and structural phase transitions. The maximum ... More
Unusual pressure effects on the superconductivity of indirectly electron-doped (Ba1-xLax)Fe2As2 epitaxial filmsSep 27 2013Oct 11 2013Applying an external pressure to indirectly electron-doped 122-type (Ba1-xLax)Fe2As2 epitaxial films enhances the superconducting critical temperature (Tc) up to 30.3 K. Different from the other family compounds, the Tc is enhanced not only in the under-doped ... More
Spin-Echo Measurements for an Anomalous Quantum Phase of 2D Helium-3Jul 01 2008Nov 19 2008Previous heat-capacity measurements of our group had shown the possible existence of an anomalous quantum phase containing the zero-point vacancies (ZPVs) in 2D $^{3}$He. The system is monolayer $^{3}$He adsorbed on graphite preplated with monolayer $^{4}$He ... More
ASCA Identification of SMC X-2 with the 2.37-s Pulsar Discovered by RXTEFeb 27 2001May 23 2001This paper has been withdrawn because the class file must not be uploaded.
Energy-momentum conservation laws in Finsler/Kawaguchi Lagrangian formulationJun 09 2014Jun 16 2015We reformulate the standard Lagrangian formalism to a reparameterisation invariant Lagrangian formalism by means of Finsler and Kawaguchi geometry. In our formalism, various types of symmetries that appears in theories of physics are expressed geometrically ... More
Electric double-layer transistor using layered iron selenide Mott insulator TlFe1.6Se2Feb 12 2014Mar 04 2014A1-xFe2-ySe2 (A = K, Cs, Rb, Tl) are recently discovered iron-based superconductors with critical temperatures (Tc) ranging up to 32 K. Their parent phases have unique properties when compared with other iron-based superconductors; e.g., their crystal ... More
Heteroepitaxial growth and optoelectronic properties of layered iron oxyarsenide, LaFeAsOAug 14 2008Sep 19 2008Epitaxial thin films of LaFeAsO were fabricated on MgO (001) and mixed-perovskite (La, Sr)(Al, Ta)O3 (001) single-crystal substrates by pulsed laser deposition using a Nd:YAG second harmonic source and a 10 at.% F-doped LaFeAsO disk target. Temperature ... More
Continuous variable teleportation of single photon states (Proceedings version)Dec 04 2001We investigate the changes to a single photon state caused by the non-maximal entanglement in continuous variable quantum teleportation. It is shown that the teleportation measurement introduces field coherence in the output.
Fidelity and information in the quantum teleportation of continuous variablesMar 15 2000Jun 06 2000Ideally, quantum teleportation should transfer a quantum state without distortion and without providing any information about that state. However, quantum teleportation of continuous electromagnetic field variables introduces additional noise, limiting ... More
Spontaneous atomic ordering and magnetism in epitaxially stabilized double perovskitesDec 19 2012We have studied the atomic ordering of B-site transition metals and magnetic properties in the pulsed-laser deposited films of La2CrFeO6 (LCFO) and La2VMnO6 (LVMO), whose bulk materials are known to be single perovskites with random distribution of the ... More
A 168-s X-Ray Pulsar in the SMC Observed with ASCAApr 13 2001May 23 2001This paper has been withdrawn because the class file must not be uploaded.
Light Curve and Spectral Models for the Hypernova SN 1998bw associated with GRB980425Jul 03 2000Nov 21 2000A refined model for the unusual Type Ic supernova 1998bw, discovered as the optical counterpart of GRB980425, is presented, and synthetic light curves and spectra are compared with the observations. The first 30 days of the light curve and the broad line ... More
Continuous variable teleportation of single photon statesApr 03 2001Jul 25 2001The properties of continuous variable teleportation of single photon states are investigated. The output state is different from the input state due to the non-maximal entanglement in the EPR beams. The photon statistics of the teleportation output are ... More
Critical factor for epitaxial growth of cobalt-doped BaFe2As2 films by pulsed laser depositionApr 22 2014May 02 2014We heteroepitaxially grew cobalt-doped BaFe2As2 films on (La,Sr)(Al,Ta)O3 single-crystal substrates by pulsed laser deposition using four different wavelengths and investigated how the excitation wavelength and pulse energy affected growth. Using the ... More
Cusp singularity in mean field Ising modelFeb 08 2017An entropy of the Ising model in the mean field approximation is derived by the Hamilton-Jacobi formalism. We consider a grand canonical ensemble with respect to the temperature and the external magnetic field. A cusp arises at the critical point, which ... More
Thin Film Growth and Device Fabrication of Iron-Based SuperconductorsNov 02 2011Iron-based superconductors have received much attention as a new family of high-temperature superconductors owing to their unique properties and distinct differences from cuprates and conventional superconductors. This paper reviews progress in thin film ... More
Two-photon interference of multimode two-photon pairs with an unbalanced interferometerMar 25 2003Aug 31 2003Two-photon interference of multimode two-photon pairs produced by an optical parametric oscillator has been observed for the first time with an unbalanced interferometer. The time correlation between the multimode two photons has a multi-peaked structure. ... More
Variational principle of relativistic perfect fluidMay 30 2016We reformulate the relativistic perfect fluid system on curved space-time. Using standard variables, the velocity field $u$,energy density $\rho$ and pressure $p$, the covariant Euler-Lagrange equation is obtained from variational principle. This leads ... More
Magnetorotational Instability in Protoplanetary Disks. II. Ionization State and Unstable RegionsMay 23 2000We investigate where in protoplanetary disks magnetorotational instability operates, which can cause angular momentum transport in the disks. We investigate the spatial distribution of various charged particles and the unstable regions for a variety of ... More
Phase diagram and pair Tomonaga-Luttinger liquid in a Bose-Hubbard model with flat bandsSep 24 2013Dec 09 2013To explore superfluidity in flat-band systems, we consider a Bose-Hubbard model on a cross-linked ladder with $\pi$ flux, which has a flat band with a gap between the other band for noninteracting particles, where we study the effect of the on-site repulsion ... More
Identical effects of indirect and direct electron doping of superconducting BaFe2As2 thin filmsSep 30 2011Apr 26 2012Electron doping of a 122-type iron pnictide BaFe2As2 by substituting the Ba site with an aliovalent ion (indirect doping), which had been unsuccessful by conventional solid-state synthesis methods, was achieved by a non-equilibrium film growth process. ... More
High Critical Current Density 4 MA/cm2 in Co-Doped BaFe2As2 Epitaxial Films Grown on (La, Sr)(Al, Ta)O3 Substrates without Buffer LayersMay 12 2010High critical current densities Jc of 4 MA/cm2 at 4 K were obtained in Co-doped BaFe2As2 (BaFe2As2:Co) epitaxial films grown directly on (La, Sr)(Al, Ta)O3 substrates by pulsed laser deposition. Use of a highly pure target and improvement of film homogeneity ... More
Superconductivity in Epitaxial Thin Films of Co-Doped SrFe2As2 with Bilayered FeAs Structures and their Magnetic AnisotropyAug 14 2008Sep 03 2008Superconducting epitaxial films of Fe-based layered arsenide, Co-doped SrFe2As2, were grown at 700oC on mixed perovskite (La, Sr)(Al, Ta)O3 (001) single-crystal substrates by pulsed-laser deposition. Both the epitaxial film and an (001)-oriented film ... More
Magnetic scattering and electron pair breaking by rare-earth-ion substitution in BaFe2As2 epitaxial filmsJul 01 2013The effect of electron doping by trivalent charge state rare-earth ion (RE = La, Ce, Pr, and Nd) substitutions on the superconductivity in BaFe2As2 was examined using epitaxial films. Each of the RE substitutions suppressed the resistivity anomaly associated ... More
Thin film growth by pulsed laser deposition and properties of 122-type iron-based superconductor AE(Fe1--xCox)2As2 (AE = alkaline earth)May 18 2012This paper reports comprehensive results on thin-film growth of 122-type iron-pnictide superconductors, AE(Fe1-xCox)2As2 (AE = Ca, Sr, and Ba, AEFe2As2:Co) by a pulsed laser deposition method using a neodymium-doped yttrium aluminum garnet laser as an ... More
Water-induced superconductivity in SrFe2As2Mar 22 2009It has been considered that FeAs-based high transition temperature (high-Tc) superconductors need electron or hole doping by aliovalent ion substitution or large off-stoichiometry in order to induce superconductivity. We report that exposure of undoped ... More
Observation of an oscillatory correlation function of multimode two-photon pairsMar 17 2003Apr 19 2003An oscillatory correlation function has been observed by the coincidence counting of multimode two-photon pairs produced with a degenerate optical parametric oscillator far below threshold. The coherent superposition of the multimode two-photon pairs ... More
Gain tuning and fidelity in continuous variable quantum teleportationNov 24 2001Mar 28 2002The fidelity of continuous variable teleportation can be optimized by changing the gain in the modulation of the output field. We discuss the gain dependence of fidelity for coherent, vacuum and one photon inputs and propose optimal gain tuning strategies ... More
Information extraction and quantum state distortions in continuous variable quantum teleportationOct 22 2001We analyze the loss of fidelity in continuous variable teleportation due to non-maximal entanglement. It is shown that the quantum state distortions correspond to the measurement back-action of a field amplitude measurement. Results for coherent states ... More
Information losses in continuous variable quantum teleportationFeb 20 2001Jul 05 2001It is shown that the information losses due to the limited fidelity of continuous variable quantum teleportation are equivalent to the losses induced by a beam splitter of appropriate reflectivity.
Molecular photon echoes as a signature of vibrational cat statesMay 25 2000Jul 28 2000Quantum interference between two distinct vibrational trajectories induced by two pulse femtosecond excitation in molecules is shown to result in a photon echo, providing direct evidence of the cat state superposition of Gaussian vibrational wavepackets. ... More
Dead Zone Formation and Nonsteady Hyperaccretion in Collapsar Disks : A Possible Origin of Short-Term Variability in the Prompt Emission of Gamma-Ray BurstsDec 21 2006Mar 16 2007The central engine of gamma-ray bursts (GRBs) is believed to be a hot and dense disk with hyperaccretion onto a few solar-mass black hole. We investigate where the magnetorotational instability (MRI) actively operates in the hyperaccretion disk, which ... More
Temperature-Dependent Cycloidal Magnetic Structure in GdRu$_{2}$Al$_{10}$ Studied by Resonant X-ray DiffractionAug 10 2017We have performed resonant X-ray diffraction experiments on the antiferromagnet GdRu$_{2}$Al$_{10}$ and have clarified that the magnetic structure in the ordered state is cycloidal with the moments lying in the $bc$ plane and propagating along the $b$ ... More
Magnetic Field Amplification Associated with the Richtmyer-Meshkov InstabilitySep 05 2012The amplification of a magnetic field due to the Richtmyer-Meshkov instability (RMI) is investigated by two-dimensional MHD simulations. Single-mode analysis is adopted to reveal definite relation between the nonlinear evolution of RMI and the field enhancement. ... More
The JCMT BISTRO Survey: The Magnetic Field In The Starless Core $ρ$ Ophiuchus CFeb 20 2019We report 850~$\mu$m dust polarization observations of a low-mass ($\sim$12 $M_{\odot}$) starless core in the $\rho$ Ophiuchus cloud, Ophiuchus C, made with the POL-2 instrument on the James Clerk Maxwell Telescope (JCMT) as part of the JCMT B-fields ... More
Discovery of 101-s Pulsations from AX J0057.4-7325 in the SMC with ASCANov 02 2000The results from two ASCA observations of AX J0057.4-7325 = RX J0057.3-7325 are presented. Coherent pulsations with a barycentric period of 101.45 +/- 0.07 s were discovered in the second observation. The X-ray spectrum was found to be hard (photon index ... More
Advantageous grain boundaries in iron pnictide superconductorsNov 26 2010Jul 11 2011High critical temperature superconductors have zero power consumption and could be used to produce ideal electric power lines. The principal obstacle in fabricating superconducting wires and tapes is grain boundaries-the misalignment of crystalline orientations ... More
DC superconducting quantum interference devices fabricated using bicrystal grain boundary junctions in Co-doped BaFe2As2 epitaxial filmsMay 12 2010Jul 05 2010DC superconducting quantum interference devices (dc-SQUIDs) were fabricated in Co-doped BaFe2As2 epitaxial films on (La, Sr)(Al, Ta)O3 bicrystal substrates with 30deg misorientation angles. The 18 x 8 micro-meter^2 SQUID loop with an estimated inductance ... More
Convection Causes Enhanced Magnetic Turbulence in Accretion Disks in OutburstMar 12 2014Apr 11 2014We present the results of local, vertically stratified, radiation MHD shearing box simulations of MRI turbulence appropriate for the hydrogen ionizing regime of dwarf nova and soft X-ray transient outbursts. We incorporate the frequency-integrated opacities ... More
Transport and magnetic properties of Co-doped BaFe_{2}As_{2} epitaxial thin filmsAug 02 2010Aug 03 2010We report resistivity, Hall coefficient, current-voltage characteristics, and magneto-optical imaging measurements of epitaxial Co-doped BaFe_{2}As_{2} thin films deposited on MgO(001) substrate. The Hall resistivity of the films has a substantial contribution ... More
Anomalous scaling behavior in a mixed-state Hall effect of a cobalt-doped BaFe2As2 epitaxial film with a high critical current density over 1 MA/cm2Feb 15 2013The mixed-state Hall effect was examined in a Ba(Fe1-xCox)2As2 epitaxial film with a high critical current density. The transverse resistivity {\rho}xy and the longitudinal resistivity {\rho}xx follow power law scaling {\rho}xy = A{\rho}xx{\beta}. In ... More
$^{17}$O NMR Measurements on Superconducting Na$_{0.35}$CoO$_{2} \cdot y$H$_{2}$OJun 29 2005An $^{17}$O NMR measurement was performed on nonoriented polycrystalline Na$_{0.35}$CoO$_2 \cdot y$H$_2$O with superconducting (SC) transition temperature $T_\text{c} = 4.6$ K. A weak temperature dependence was observed in the Knight shift at the O site ... More
Nucleosynthesis in Type II supernovae and the abundances in metal-poor starsSep 24 1998Dec 15 1998We explore the effects on nucleosynthesis in Type II supernovae of various parameters (mass cut, neutron excess, explosion energy, progenitor mass) in order to explain the observed trends of the iron-peak element abundance ratios ([Cr/Fe], [Mn/Fe], [Co/Fe] ... More
Can differences in the nickel abundance in Chandrasekhar mass models explain the relation between brightness and decline rate of normal Type Ia Supernovae?Sep 29 2000The use of Type Ia supernovae as distance indicators relies on the determination of their brightness. This is not constant, but it can be calibrated using an observed relation between the brightness and the properties of the optical light curve (decline ... More
Atomically-flat, chemically-stable, superconducting epitaxial thin film of iron-based superconductor, cobalt-doped BaFe$_2$As$_2$Jul 03 2009Epitaxial growth of Fe-based superconductors such as Co-doped SrFe$_2$As$_2$ (SrFe$_2$As$_2$:Co) was reported recently, but has still insufficient properties for device application because they have rough surfaces and are decomposed by reactions with ... More
Pseudo-perturbation-based Broadcast Control of Multi-agent SystemsMay 20 2018Jul 31 2018The present paper proposes a novel broadcast control (BC) law for multi-agent coordination. A BC framework has been developed to achieve global coordination tasks with low communication volume. The BC law uses broadcast communication, which transmits ... More
Anisotropic pressure effects on superconductivity in Fe1+yTe1-xSxMar 02 2018Mar 22 2018We have investigated uniaxial and hydrostatic pressure effects on superconductivity in Fe1.07Te0.88S0.12 through magnetic-susceptibility measurements down to 1.8 K. The superconducting transition temperature Tc is enhanced by out-of-plane pressure (uniaxial ... More