Results for "A. T. Okazaki"

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A natural explanation for periodic X-ray outbursts in Be/X-ray binariesAug 02 2001When applied to Be/X-ray binaries, the viscous decretion disc model for Be stars naturally predicts the truncation of the circumstellar disc. The distance at which the circumstellar disc is truncated depends mainly on the orbital parameters and the viscosity. ... More
The Be/X-ray transient 4U 0115+63/V635 Cas I. A consistent modelNov 22 2000We present photometry and high SNR spectroscopy in the classification region of V635 Cas, the optical counterpart to the transient X-ray pulsator 4U 0115+63, taken at a time when the circumstellar envelope had disappeared. V635 Cas is classified as a ... More
Viscous Transonic Decretion in Disks of Be StarsOct 25 2000We study the characteristics of the outflow in disks of Be stars, based on the viscous decretion disk scenario. In this scenario, the matter ejected from the equatorial surface of the star drifts outward because of the effect of viscosity, and forms the ... More
Angle-resolved photoemission study of quasi-one-dimensional superconductor $β$-Na$_{0.33}$V$_2$O$_5$Aug 19 2003We have studied the electronic structure of $\beta$-Na$_{0.33}$V$_2$O$_5$, which becomes a superconductor under pressure, by angle-resolved photoemission spectroscopy. Clear band dispersions is observed only along the chain direction, indicating the quasi-one-dimensional ... More
The deformation of the interacting nucleon in the Skyrme modelMay 13 1996Changes in the nucleon shape are investigated by letting the nucleon deform under the strong interactions with another nucleon. The parameters of the axial deformations are obtained by minimizing the static energy of the two nucleon system at each internucleon ... More
The accretion regime of LS 5039: 3-D SPH simulationsNov 12 2008LS 5039 is a TeV gamma-ray binary with extended radio emission. It consists of a compact object in the mildly eccentric (e=0.35), 3.9-day orbit around a massive O star. The nature of the compact object is not yet established. In this paper, assuming that ... More
Dwarf galaxy formation induced by galaxy interactionsJun 01 2000Jun 06 2000Growing evidence has been accumulated for that some gas-rich dwarf galaxies are formed from material liberated by galaxy collisions and/or mergers. Also, gas-poor dwarf elliptical galaxies are often found in the central regions of clusters of galaxies. ... More
Accretion disc formation around the neutron star in Be/X-ray binariesNov 10 2003Feb 11 2004We study the accretion on to the neutron star in Be/X-ray binaries, using a 3D SPH code and the data imported from a simulation by \citet{oka2} for a coplanar system with a short period ($P_{\rm orb}=24.3 \rm{d}$) and a moderate eccentricity $(e=0.34)$, ... More
One-armed spiral structure of accretion discs induced by a phase-dependent mass transfer in Be/X-ray binariesMar 03 2005We study non-axisymmetric structure of accretion discs in Be/X-ray binaries, performing three dimensional Smoothed Particle Hydrodynamics simulations for a coplanar system with a short period and a moderate eccentricity. We find that ram pressure due ... More
Long-term evolution of accretion discs in Be/X-ray binariesAug 08 2006We numerically study the long-term evolution of the accretion disc around the neutron star in a coplanar Be/X-ray binary with a short period and a moderate eccentricity. From three dimensional Smoothed Particle Hydrodynamics simulations, we find that ... More
Global Disk Oscillations in Binary Be StarsSep 18 2008We study the effects of the tidal interaction with the companion, via orbital separation and binary mass ratio, on the global one-armed oscillation modes in disks around binary Be stars. Our model takes into account the three-dimensional effect that contributes ... More
The X-ray outbursts of Be/X-ray transientsNov 22 2000We present a new scenario for the behaviour of Be/X-ray binaries based on long-term multiwavelength monitoring and the decretion disc model. The circumstellar discs of the primaries are truncated because of the tidal and resonant effect of the neutron ... More
A new approach for probing circumbinary disksSep 04 2008Jan 01 2009Circumbinary disks are considered to exist in a wide variety of astrophysical objects, e.g., young binary stars, protoplanetary systems, and massive binary black hole systems in active galactic nuclei (AGNs). However, there is no definite evidence for ... More
Non-axisymmetric Structure of Accretion Disks in Be/X-ray BinariesDec 09 2004The non-axisymmetric structure of accretion disks around the neutron star in Be/X-ray binaries is studied by analyzing the results from three dimensional (3D) Smoothed Particle Hydrodynamics (SPH) simulations. It is found that ram pressure due to the ... More
2.5D global-disk oscillation models of the Be shell star ζ Tauri I. Spectroscopic and polarimetric analysisMar 02 2015Context. Various Be stars exhibit intensity variations of the violet and red emission peaks in their HI lines observed in emission. This so-called $V/R$ phenomenon is usually explained by the precession of a one-armed spiral density perturbation in the ... More
Long-term evolution of accretion disks around the neutron star in Be/X-ray binariesNov 17 2005we study the long-term evolution of the accretion disk around the neutron star in Be/X-ray binaries. We confirm the earlier result by Hayasaki & Okazaki (2004) that the disk evolves via a two-stage process, which consists of the initial developing stage ... More
Accretion onto the neutron star in Be/X-ray binariesOct 15 2003We study accretion onto the neutron star in Be/X-ray binaries, using a 3D SPH code and the data imported from a high resolution simulation by Okazaki et al.\ (2002) for a coplanar system with a short period ($P_{\rm orb}=24.3 \rm d$) and moderate eccentricity ... More
The Be/X-ray transient 4U 0115+63/V635 Cas: II. Outburst mechanismsJan 12 2001We present multi-wavelength long-term monitoring observations of V635 Cas, the optical counterpart to the transient X-ray pulsar 4U0115+63. The evolution of emission lines and photometric magnitudes indicates that the Be star undergoes relatively fast ... More
On validity of perturbative quantization of the breathing mode in the Skyrme modelDec 20 1993We present a detailed discussion of the breathing mode quantization in the Skyrme model and demonstrate that the chiral angle of the hedgehog soliton is strongly affected by the breathing motion.
Dynamical Evolution of Viscous Disks around Be Stars. I: photometryJul 11 2012Be stars possess gaseous circumstellar disks that modify in many ways the spectrum of the central B star. Furthermore, they exhibit variability at several timescales and for a large number of observables. Putting the pieces together of this dynamical ... More
Reversed anisotropy of the in-plane resistivity in the antiferromagnetic phase of iron telluridesJan 05 2015We systematically investigated the anisotropic in-plane resistivity of the iron telluride including three kinds of impurity atoms: excess Fe, Se substituted for Te, and Cu substituted for Fe. Sizable resistivity anisotropy was found in the magneto-structurally ... More
The H-alpha Variations of eta Carinae During the 2009.0 Spectroscopic EventJan 19 2010We report on H-alpha spectroscopy of the 2009.0 spectroscopic event of eta Carinae collected via SMARTS observations using the CTIO 1.5 m telescope and echelle spectrograph. Our observations were made almost every night over a two month interval around ... More
Crossover in the nature of the metallic phases in the perovskite-type RNiO_3Mar 22 2002We have measured the photoemission spectra of Nd$_{1-x}$Sm$_{x}$NiO$_{3}$, where the metal-insulator transition and the N\'{e}el ordering occur at the same temperature for $x \lesssim 0.4$ and the metal-insulator transition temperature ($T_{MI}$) is higher ... More
Quantum solitons of the nonlinear sigma-model with broken chiral symmetryAug 18 1993It is proved that the quantum-mechanical consideration of global breathing of a hedgehog-like field configuration leads to the dynamically stable soliton solutions in the nonlinear sigma-model without the Skyrme term. Such solutions exist only when chiral ... More
Viscous Effects on the Interaction between the Coplanar Decretion Disc and the Neutron Star in Be/X-Ray BinariesAug 15 2002We study the viscous effects on the interaction between the coplanar Be-star disc and the neutron star in Be/X-ray binaries, using a three-dimensional, smoothed particle hydrodynamics code. For simplicity, we assume the Be disc to be isothermal at the ... More
Photoemission study of the skutterudite compounds Co(Sb$_{1-x}$Te$_{x}$)$_3$ and RhSb$_3$Mar 16 2001Mar 19 2001We have studied the electronic structure of the skutterudite compounds Co(Sb$_{1-x}$Te$_{x}$)$_3$ (x= 0, 0.02, 0.04) by photoemission spectroscopy. Valence-band spectra revealed that Sb 5p states are dominant near the Fermi level and are hybridized with ... More
Modelling the observable behaviour of SXP 5.05Apr 12 2019SXP 5.05 is a Be/X-ray binary with a neutron star companion located in the Small Magellanic Cloud. It was first detected in 2013, and later that year, SXP 5.05 underwent a massive optical and X-ray outburst. This outburst dwarfs any other optical event ... More
LS I+61 303: microquasar or not microquasar?Dec 11 2007LS I +61 303 is a puzzling object detected from radio up to high-energy gamma-rays. Variability has recently been observed in its high-energy emission. The object is a binary system, with a compact object and a Be star as primary. The nature of the secondary ... More
Accretion vs colliding wind models for the gamma-ray binary LS I +61 303: an assessmentJun 09 2007Aug 14 2007LS I +61 303 is a puzzling Be/X-ray binary with variable gamma-ray emission at up TeV energies. The nature of the compact object and the origin of the high-energy emission are unclear. One family of models invokes particle acceleration in shocks from ... More
Modeling the RXTE light curve of $η$ Carinae from a 3-D SPH simulation of its binary wind collisionMay 13 2008The very massive star system $\eta$ Carinae exhibits regular 5.54-year (2024-day) period disruptive events in wavebands ranging from the radio to X-ray. There is a growing consensus that these events likely stem from periastron passage of an (as yet) ... More
Resonant Excitation of Disk Oscillations in Deformed Disks IV: A New Formulation Studying StabilityJan 08 2011The possibility has been suggested that high-frequency quasi-periodic oscillations observed in low-mass X-ray binaries are resonantly excited disk oscillations in deformed (warped or eccentric) relativistic disks (Kato 2004). In this paper we examine ... More
Bulk-sensitive Photoemission of Mn5Si3Sep 28 2002We have carried out a bulk-sensitive high-resolution photoemission experiment on Mn5Si3. The measurements are performed for both core level and valence band states. The Mn core level spectra are deconvoluted into two components corresponding to different ... More
High-energy observations of PSR B1259-63/LS 2883 through the 2014 periastron passage: connecting X-rays to the GeV flareDec 08 2014The binary system PSR B1259-63/LS 2883 is well sampled in radio, X-rays, and TeV gamma-rays, and shows orbital phase-dependent variability in these frequencies. The first detection of GeV gamma-rays from the system was made around the 2010 periastron ... More
Excitation of Trapped g-Mode Oscillations in Warped Disks around Black HolesApr 05 2010Apr 27 2010In order to study the origin of high-frequency quasi-periodic oscillations observed in X-ray binaries, Kato (2004) suggested a resonant excitation mechanism of disk oscillations in deformed disks. In this paper, we study numerically, following his formulation, ... More
Origin of Two Types of X-Ray Outbursts in Be/X-Ray Binaries. I. Accretion ScenariosNov 22 2012We propose the new scenario for X-ray outbursts in Be/X-ray binaries that normal and giant outbursts are respectively caused by radiatively inefficient accretion flows (RIAFs) and Bondi-Hoyle-Lyttleton (BHL) accretion of the material transferred from ... More
3D Dynamical Modeling of Wind Accretion in Cyg X-3May 19 2014Cyg X-3 is a high mass X-ray binary consisting of a Wolf-Rayet star and a compact object in a very short orbital period of 4.8h. The only confirmed microquasar with high energy gamma-ray emission, Cyg X-3 provides a unique opportunity to study the relationship ... More
Competition between unconventional superconductivity and incommensurate antiferromagnetic order in CeRh1-xCoxIn5Apr 18 2007Apr 23 2007Elastic neutron diffraction measurements were performed on the quasi-two dimensional heavy fermion system CeRh1-xCoxIn5, ranging from an incommensurate antiferromagnet for low x to an unconventional superconductor on the Co-rich end of the phase diagram. ... More
The first determination of the viscosity parameter in the circumstellar disk of a Be StarNov 30 2011Be stars possess gaseous circumstellar decretion disks, which are well described using standard $\alpha$-disk theory. The Be star 28 CMa recently underwent a long outburst followed by a long period of quiescence, during which the disk dissipated. Here ... More
Evidence for a cos(4\varphi) Modulation of the Superconducting Energy Gap of Optimally Doped FeTe_{0.6}Se_{0.4} Single Crystals Using Laser Angle-Resolved Photoemission SpectroscopyJul 27 2012Dec 10 2012We study the superconducting(SC)-gap anisotropy of the \Gamma-centered hole Fermi surface in optimally doped FeTe_{0.6}Se_{0.4} (T_c = 14.5 K), using laser-excited angle-resolved photoemission spectroscopy (ARPES). We observe sharp superconducting coherence ... More
Investigating the Circumstellar Disk of the Be Shell Star 48 LibraeAug 02 2016A global disk oscillation implemented in the viscous decretion disk (VDD) model has been used to reproduce most of the observed properties of the well known Be star $\zeta$ Tau. 48 Librae shares several similarities with $\zeta$ Tau -- they are both early-type ... More
Modeling high-energy light curves of the PSR B1259-63/LS 2883 binary based on 3-D SPH simulationsMar 09 2012Mar 13 2012Temporal changes of X-ray to very-high-energy gamma-ray emissions from the pulsar-Be star binary PSR B1259-63/LS 2883 are studied based on 3-D SPH simulations of pulsar wind interaction with Be-disk and wind. We focus on the periastron passage of the ... More
Microwave Penetration Depth and Quasiparticle Conductivity in PrFeAsO_1-y Single Crystals : Evidence for a Full-Gap SuperconductorJun 19 2008Dec 11 2008In-plane microwave penetration depth $\lambda_{ab}$ and quaiparticle conductivity at 28 GHz are measured in underdoped single crystals of the Fe-based superconductor PrFeAsO$_{1-y}$ ($T_c\approx 35$ K) by using a sensitive superconducting cavity resonator. ... More
Sulfur annealing effect for superconductivity in iron chalcogenide compoundsAug 26 2013We discovered a novel annealing method for Fe-chalcogenide superconductors. It was found that sulfur annealing deintercalated excess Fe via formation of FeS2. Due to its specifics, sulfur annealing is applicable when preparing Fe-chalcogenide-based wires ... More
Penetration depth, lower critical fields, and quasiparticle conductivity in Fe-arsenide superconductorsApr 24 2009In this article, we review our recent studies of microwave penetration depth, lower critical fields, and quasiparticle conductivity in the superconducting state of Fe-arsenide superconductors. High-sensitivity microwave surface impedance measurements ... More
SPH simulations of accretion flow via Roche lobe overflow and via mass transfer from Be diskNov 17 2005We compare the accretion flow onto the neutron star induced by Roche lobe overflow with that by the overflow from the Be disk, in a zero eccentricity, short period binary with the same mass transfer rate, performing three-dimensional Smoothed Particle ... More
High-dispersion spectroscopic monitoring of the Be/X-ray binary A0535+26/V725 Tau I: The long-term profile variabilityFeb 10 2010Feb 11 2010We report on optical high-dispersion spectroscopic monitoring observations of the Be/X-ray binary A0535+26/V725 Tau, carried out from November 2005 to March 2009. The main aim of these monitoring observations is to study spectral variabilities in the ... More
Modeling the Complete Lightcurve of omega CMaJun 29 2015We have used the radiative transfer code HDUST to analyze and interpret the long-term photometric behavior of the Be star omega CMa, considering four complete cycles of disk formation and dissipation. This is the first time in which a full lightcurve ... More
Cyclic Variability of the Circumstellar Disc of the Be Star $ζ$ Tau. II. Testing the 2D Global Disc Oscillation ModelJan 08 2009Aims. In this paper we model, in a self-consistent way, polarimetric, photometric, spectrophotometric and interferometric observations of the classical Be star $\zeta$ Tauri. Our primary goal is to conduct a critical quantitative test of the global oscillation ... More
Effect of Be Disk Evolution on Global One-Armed OscillationsApr 26 2016We study the effect of density distribution evolution on the global one-armed oscillation modes in low viscosity disks around isolated and binary Be stars. Observations show that some Be stars exhibit evidence of formation and dissipation of the equatorial ... More
Equivalence between Schwinger and Dirac schemes of quantizationFeb 13 1997Mar 01 1997This paper introduces the modified version of Schwinger's quantization method, in which the information on constraints and the choice of gauge conditions are included implicitly in the choice of variations used in quantization scheme. A proof of equivalence ... More
Tidal Interactions of Red Giants with Environment Stars in Globular ClustersJan 17 2008We investigate the tidal interactions of a red giant with a main sequence in the dense stellar core of globular clusters by Smoothed Particle Hydrodynamics method. Two models of $0.8 \msun$ red giant with the surface radii 20 and $85 R_\sun$ are used ... More
Theory of Nuclear Reactions Leading to Superheavy ElementsSep 30 1999Dynamical reaction theory is presented for synthesis of superheavy elements. Characteristic features of formation and surviving are discussed, which combinedly determine final residue cross sections of superheavy elements. Preliminary results on Z=114 ... More
In situ photoemission study of the room-temperature ferromagnet ZnGeP_2:MnApr 04 2003Apr 11 2003The chemical states of the ZnGeP$_{2}$:Mn interface, which shows ferromagnetism above room-temperature, has been studied by photoemission spectroscopy. Mn deposition on the ZnGeP$_2$ substrate heated to 400$^{\circ}$C induced Mn substitution for Zn and ... More
Hole-doping-induced changes in the electronic structure of La$_{1-x}$Sr$_x$FeO$_3$ : soft x-ray photoemission and absorption study of epitaxial thin filmsApr 19 2004We have studied the electronic structure of epitaxially grown thin films of La$_{1-x}$Sr$_x$FeO$_3$ by {\it in-situ} photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS) measurements. The Fe 2$p$ and valence-band PES spectra and the ... More
Ultrafast Melting of Spin Density Wave Order in BaFe$_{2}$As$_{2}$ Observed by Time- and Angle-Resolved Photoemission Spectroscopy with Extreme-Ultraviolet Higher Harmonic GenerationAug 22 2016Transient single-particle spectral function of BaFe$_{2}$As$_{2}$, a parent compound of iron-based superconductors, has been studied by time- and angle-resolved photoemission spectroscopy with an extreme-ultraviolet laser generated by higher harmonics ... More
The binary period and outburst behaviour of the SMC X-ray binary pulsar system SXP504May 17 2005A probable binary period has been detected in the optical counterpart to the X-ray source CXOU J005455.6-724510 = RX J0054.9-7245 = AXJ0054.8-7244 = SXP504 in the Small Magellanic Cloud. This source was detected by Chandra on 04 Jul 2002 and subsequently ... More
The semicentennial binary system PSR J2032+4127 at periastron: X-ray photometry, optical spectroscopy and SPH modellingFeb 21 2019X-ray photometry and optical spectra are presented covering the periastron passage of the highly-eccentric, ~50 year binary system PSR J2032+4127 in November 2017. This system consists of a 143 ms pulsar in orbit around a massive OB star, MT 91-213. The ... More
Evidence for superconducting gap nodes in the zone-centered hole bands of KFe2As2 from magnetic penetration-depth measurementsMar 31 2010Jun 30 2010Among the iron-based pnictide superconductors the material KFe$_2$As$_2$ is unusual in that its Fermi surface does not consist of quasi-nested electron and hole pockets. Here we report measurements of the temperature dependent London penetration depth ... More
Se content $x$ dependence of electron correlation strength in Fe$_{1+y}$Te$_{1-x}$Se$_{x}$May 28 2015The iron chalcogenide Fe$_{1+y}$Te$_{1-x}$Se$_{x}$ on the Te-rich side is known to exhibit the strongest electron correlations among the Fe-based superconductors, and is non-superconducting for $x$ < 0.1. In order to understand the origin of such behaviors, ... More
Evidence of a universal relation between electron-mode coupling and Tc in Ba1-xKxFe2As2 superconductor from Laser ARPESMar 15 2014We performed a Laser angle-resolved photoemission spectroscopy (ARPES) study on a wide doping range of Ba1-xKxFe2As2 (BaK) iron-based superconductor. We observed a robust low-binding energy (BE) kink structure in the dispersion which is doping dependent ... More
AdS2/CFT1, Whittaker vector and Wheeler-De Witt equationOct 16 2015We study the energy representation of conformal quantum mechanics as the Whittaker vector without specifying classical Lagrangian. We show that a generating function of expectation values among two excited states of the dilatation operator in conformal ... More
Superconformal Quantum Mechanics from M2-branesMar 12 2015We discuss the superconformal quantum mechanics arising from the M2-branes. We begin with a comprehensive review on the superconformal quantum mechanics and emphasize that conformal symmetry and supersymmetry in quantum mechanics contain a number of exotic ... More
The $E_6$ state sum invariant of lens spacesMar 14 2014In this paper, we calculate the values of the $E_6$ state sum invariants for the lens spaces $L(p,q)$. In particular, we show that the values of the invariants are determined by $p \mod 12$ and $q \mod (p,12)$. As a corollary, we show that the $E_6$ state ... More
Evidence for exclusion of the possibility of $d$-wave superconducting-gap symmetry in Ba-doped KFe$_2$As$_2$Jul 30 2013Feb 24 2014We have investigated the superconducting(SC)-gap anisotropy for several Ba-doped KFe$_2$As$_2$ samples using laser-based angle-resolved photoemission spectroscopy. We show that the SC-gap anisotropy and node positions drastically change with a small amount ... More
The flight of the GAPS prototype experimentJul 12 2013Dec 04 2013The General AntiParticle Spectrometer experiment (GAPS) is foreseen to carry out a dark matter search using low-energy cosmic ray antideuterons at stratospheric altitudes with a novel detection approach. A prototype flight from Taiki, Japan was carried ... More
Membrane Quantum MechanicsOct 29 2014Nov 03 2014We consider the multiple M2-branes wrapped on a compact Riemann surface and study the arising quantum mechanics by taking the limit where the size of the Riemann surface goes to zero. The IR quantum mechanical models resulting from the BLG-model and the ... More
Local Whittaker-Newforms for GSp(4) matching to Langlands parametersFeb 20 2019We extend the local newform theory of B. Roberts and R. Schmidt for generic, irreducible, admissible representations of PGSp(4) to that for GSp(4). The newform matches to the Langlands parameter.
L-functions of $S_3(\G_2(2,4,8))$Aug 09 2010The space of Siegel cuspforms of degree $2$ of weight $3$ with respect to the congruence subgroup $\G_2(2,4,8)$ was studied by van Geemen and van Straten in Math. computation. {\bf 61} (1993). They showed the space is generated by six-tuple products of ... More
Cyclic variability of the circumstellar disk of the Be star zetaTau - I. Long-term monitoring observationsJul 13 2009Emission lines formed in decretion disks of Be stars often undergo long-term cyclic variations, especially in the violet-to-red (V/R) ratio of their primary components. From observations of the bright Be-shell star zeta Tau, the possibly broadest and ... More
Theoretical predictions of residues cross sections of superheavy elementsJul 01 1999Dynamical reaction theories are reviewed for synthesis of superheavy elements. Characteristic features of formation and surviving are discussed with reference to possible incident channels. Theoretical predictions are presented on favorable incident channels ... More
Lower Critical Fields of Superconducting PrFeAsO$_{1-y}$ Single CrystalsNov 22 2008Jan 14 2009We have studied the lower critical fields H_{c1} of superconducting iron oxipnictide PrFeAsO_{1-y} single crystals for H parallel and perpendicular to the ab-planes. Measurements of the local magnetic induction at positions straddling the sample edge ... More
Temperature Dependence of the Electrical Transport Properties of Multilayer GrapheneJul 04 2013Aug 23 2014Multilayer graphene (MLG) thin films are deposited on silicon oxide substrates by mechanical exfoliation (or 'scotch-tape method') from Kish graphite. The thickness and number of layers are determined from both Atomic Force Microscopy (AFM) and Raman ... More
X-ray Modeling of η Carinae and WR140 from SPH SimulationsOct 08 2011The colliding wind binary (CWB) systems \eta\ Carinae and WR140 provide unique laboratories for X-ray astrophysics. Their wind-wind collisions produce hard X-rays that have been monitored extensively by several X-ray telescopes, including RXTE. To interpret ... More
The Dynamical Evolution of Be star disksOct 12 2010We present a novel theoretical tool to analyze the dynamical behaviour of a Be disk fed by non-constant decretion rates. It is mainly based on the computer code HDUST, a fully three-dimensional radiative transfer code that has been successfully applied ... More
Interplay of the inverse proximity effect and magnetic field in out-of-equilibrium single-electron devicesDec 13 2016The magnetic field is shown to affect significantly non-equilibrium quasiparticle (QP) distributions under conditions of inverse proximity effect on the remarkable example of a single-electron hybrid turnstile. This effect suppresses the gap in the superconducting ... More
Common Origin of the Circular-dichroism Pattern in ARPES of SrTiO3 and CuxBi2Se3Aug 22 2011Circular dichroism in the angular distribution (CDAD) of photoelectrons from SrTiO3:Nb and CuxBi2Se3 is investigated by 7-eV laser ARPES. In addition to the well-known node that occurs in CDAD when the incidence plane matches the mirror plane of the crystal, ... More
Superconducting pairing and the pseudogap in nematic striped La2-xSrxCuO4Feb 26 2013The individual k\parallel and k\perp stripe excitations in fluctuating spin-charge stripes have not been observed yet. In Raman scattering if we set, for example, incident and scattered light polarizations to two possible stripe directions, we can observe ... More
Field-induced quantum critical route to a Fermi liquid in high-temperature superconductorsMay 15 2008In high transition temperature (T_c) superconductivity, charge doping is a natural tuning parameter that takes copper oxides from the antiferromagnet to the superconducting region. In the metallic state above T_c the standard Landau's Fermi-liquid theory ... More
Warped Circumbinary Disks in Active Galactic NucleiJun 09 2014We study a warping instability of a geometrically thin, non-self-gravitating disk surrounding binary supermassive black holes on a circular orbit. Such a circumbinary disk is subject to not only tidal torques due to the binary gravitational potential ... More
Current-Induced Gap Suppression in the Mott Insulator Ca$_2$RuO$_4$Sep 04 2013We present nonlinear conduction phenomena in the Mott insulator Ca2RuO4 investigated with a proper evaluation of self-heating effects. By utilizing a non-contact infrared thermometer, the sample temperature was accurately determined even in the presence ... More
Warping and tearing of misaligned circumbinary disks around eccentric SMBH binariesFeb 01 2015We study the warping and tearing of a geometrically thin, non-self-gravitating disk surrounding binary supermassive black holes on an eccentric orbit. The circumbinary disk is significantly misaligned with the binary orbital plane, and is subject to the ... More
Radiation-Driven Warping of Circumbinary Disks Around Eccentric Young Star BinariesOct 29 2014We study a warping instability of a geometrically thin, non-self-gravitating, circumbinary disk around young binary stars on an eccentric orbit. Such a disk is subject to both the tidal torques due to a time-dependent binary potential and the radiative ... More
3-D SPH simulations of colliding winds in eta CarinaeMar 27 2008We study colliding winds in the superluminous binary eta Carinae by performing three-dimensional, Smoothed Particle Hydrodynamics (SPH) simulations. For simplicity, we assume both winds to be isothermal. We also assume that wind particles coast without ... More
Radiative transfer on decretion discs of Be binariesOct 28 2016In this work we explore the effect of binarity in the decretion disc of Be stars, in order to explain their variability. To this aim, we performed smoothed particle hydrodynamics (SPH) simulations on Be binary systems, following the matter ejected isotropically ... More
Be discs in binary systems: II. Misaligned orbitsJun 21 2017We use a smoothed particle hydrodynamics (SPH) code to examine the effects of misaligned binary companions on Be star discs. We systematically vary the degree of misalignment between the disc and the binary orbit, as well as the disc viscosity and orbital ... More
Hydrodynamic Interaction between the Be Star and the Pulsar in the TeV Binary PSR B1259-63/LS 2883May 08 2011May 15 2011We study the interaction between the Be star and the pulsar in the TeV binary PSR B1259-63/LS 2883, using 3-D SPH simulations of the tidal and wind interactions in this Be-pulsar system. We first run a simulation without pulsar wind nor Be wind, taking ... More
Atomic-like behaviors and orbital-related Luttinger liquid in carbon nano-peapod quantum dotsAug 14 2007We report influence of encapsulated C60 molecules on electron transport in carbon-nanotube peapod quantum dots. We find atomic-like behaviors with doubly degenerate electronic levels, which exist only around ground states, by single electron spectroscopy ... More
Atomic-like behaviors and orbital-related Tomonaga-Luttinger liquid in peapod quantum dotsOct 01 2005Nov 29 2005We report encapsulated C60 molecules on electron transport in carbon-nanotube peapod quantum dots. We find atomic-like behaviors with doubly degenerate electronic levels, which exist only around ground states, by single electron spectroscopy measured ... More
X-ray Modeling of η Carinae and WR140 from SPH SimulationsNov 01 2011The colliding wind binary (CWB) systems \eta\ Carinae and WR140 provide unique laboratories for X-ray astrophysics. Their wind-wind collisions produce hard X-rays that have been monitored extensively by several X-ray telescopes, including RXTE. To interpret ... More
Fractal Properties in EconomicsAug 03 2000Aug 06 2000Scaling properties in financial fluctuations are reviewed from the standpoint of statistical physics. We firstly show theoretically that the balance of demand and supply enhances fluctuations due to the underlying phase transition mechanism. By analyzing ... More
The 2011 Periastron Passage of the Be Binary delta ScorpiiFeb 17 2013We describe the results of the world-wide observing campaign of the highly eccentric Be binary system delta Scorpii 2011 periastron passage which involved professional and amateur astronomers. Our spectroscopic observations provided a precise measurement ... More
Phase diagram and oxygen annealing effect of FeTe1-xSex iron-based superconductorNov 28 2011Jun 02 2012Phase diagrams of as-grown and O2-annealed FeTe1-xSex determined from magnetic susceptibility measurement were obtained. For as-grown samples, the antiferromagnetic order was fully suppressed in the range region x \geq 0.15, and weak superconductivity ... More
Photoemission study of the metal-insulator transition in VO_2/TiO_2(001) : Evidence for strong electron-electron and electron-phonon interactionDec 04 2003We have made a detailed temperature-dependent photoemission study of VO_2/TiO_2(001) thin films, which show a metal-insulator transition at \sim 300 K. Clean surfaces were obtained by annealing the films in an oxygen atmosphere. Spectral weight transfer ... More
Unusual nodal behaviors of the superconducting gap in the iron-based superconductor Ba(Fe$_{0.65}$Ru$_{0.35}$)$_2$As$_2$: Effects of spin-orbit couplingNov 14 2016We have investigated the superconducting gap of optimally doped Ba(Fe$_{0.65}$Ru$_{0.35}$)$_2$As$_2$ by angle-resolved photoemission spectroscopy (APRES) using bulk-sensitive 7 eV laser and synchrotron radiation. It was found that the gap is isotropic ... More
Rotational Symmetry Breaking in the Hidden-Order Phase of URu2Si2Jul 27 2011A second-order phase transition is characterized by spontaneous symmetry breaking. The nature of the broken symmetry in the so-called "hidden order" phase transition in the heavy fermion compound URu2Si2, at transition temperature T_h=17.5 K, has posed ... More
In-plane electronic anisotropy in the antiferromagnetic-orthorhombic phase of isovalent-substituted Ba(Fe$_{1-x}$Ru$_x$)$_2$As$_2$Mar 10 2015We have studied the anisotropy in the in-plane resistivity and the electronic structure of isovalent Ru-substituted BaFe$_2$As$_2$ in the antiferromagnetic-orthorhombic phase using well-annealed crystals. The anisotropy in the residual resistivity component ... More
Suppression of the antiferromagnetic pseudogap in the electron-doped high-temperature superconductor by "protect annealing"Feb 11 2015In the hole-doped cuprates, a small amount of carriers suppresses antiferromagnetism and induces superconductivity. In the electron-doped cuprates, on the other hand, superconductivity appears only in a narrow range of high electron concentration ($\sim$ ... More
Development of the poloidal Charge eXchange Recombination Spectroscopy system in Heliotron JMar 22 2018A Charge eXchange Recombination Spectroscopy (CXRS) system designed to measure the poloidal rotation velocity is developed in Heliotron J. The poloidal CXRS system measures the carbon emission line (C VI, n=8-7, 529.05nm) and the Doppler shift of the ... More
Constraining the Absolute Orientation of Eta Carinae's Binary Orbit: A 3-D Dynamical Model for the Broad [Fe III] EmissionNov 09 2011We present a three-dimensional (3-D) dynamical model for the broad [Fe III] emission observed in Eta Carinae using the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS). This model is based on full 3-D Smoothed Particle Hydrodynamics ... More
Be discs in coplanar circular binaries: Phase-locked variations of emission linesApr 22 2017Sep 22 2017The first results of radiative transfer calculations on decretion discs of binary Be stars are presented. A smoothed particle hydrodynamics code computes the structure of Be discs in coplanar circular binary systems for a range of orbital and disc parameters. ... More