Results for "M. Takata"

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Evolution of the gravity offset of mixed modes in RGB starsMay 14 2019Observations of mixed modes in evolved low-mass stars enable us to probe the properties of not only the outer envelope of these stars, but also their deep layers. Among the seismic parameters associated with mixed modes, the gravity offset, denoted with ... More
Modelling the multi-wavelength emissions from PSR B1259-63/LS 2883: the effects of the stellar disc on shock radiationsApr 16 2019PSR B1259-63/LS 2883 is an elliptical pulsar/Be star binary and emits broadband emissions from radio to TeV $\gamma$-rays. The massive star possesses an equatorial disc, which is inclined with the orbital plane of the pulsar. The non-thermal emission ... More
Revisiting the valence-band and core-level photoemission spectra of NiOAug 02 2007May 20 2008We have re-examined the valence-band (VB) and core-level electronic structure of NiO by means of hard and soft x-ray photoemission spectroscopy (PES). The spectral weight of the lowest energy state found to be enhanced in the bulk sensitive Ni 2p core-level ... More
Photoemission evidence for a Mott-Hubbard metal-insulator transition in VO$_2$Jul 27 2006Jul 30 2008The temperature ($T$) dependent metal-insulator transition (MIT) in VO$_2$ is investigated using bulk sensitive hard x-ray ($\sim$ 8 keV) valence band, core level, and V 2$p-3d$ resonant photoemission spectroscopy (PES). The valence band and core level ... More
Period spacings in red giants; III. Coupling factors of mixed modesDec 26 2016The power of asteroseismology relies on the capability of global oscillations to infer the stellar structure. For evolved stars, we benefit from unique information directly carried out by mixed modes that probe their radiative cores. This third article ... More
An Analytic LT-equivariant Index and Noncommutative GeometryJan 21 2017Let $T$ be a circle and $LT$ be its loop group. Let $\mathcal{M}$ be an infinite dimensional manifold equipped with a nice $LT$-action. We construct an analytic $LT$-equivariant index for $\mathcal{M}$, and justify it in terms of noncommutative geometry. ... More
Naturality of FHT isomorphismFeb 12 2015Freed, Hopkins and Teleman constructed an isomorphism between twisted equivariant K-theory of compact Lie group $G$ and the "Verlinde ring" of the loop group of $G$. We call this isomorphism FHT isomorphism. However, it does not hold naturality with respect ... More
LT-equivariant Index from the Viewpoint of KK-theorySep 18 2017Let $T$ be a circle group, and $LT$ be its loop group. We hope to establish an index theory for infinite-dimensional manifolds which $LT$ acts on, including Hamiltonian $LT$-spaces, from the viewpoint of $KK$-theory. We have already constructed several ... More
Kinetic theory for a simple modeling of phase transition: Dynamics out of local equilibriumJul 11 2018Oct 30 2018This is a continuation of the previous work (Takata & Noguchi, J. Stat. Phys., 2018) that introduces the presumably simplest model of kinetic theory for phase transition. Here, main concern is to clarify the stability of uniform equilibrium states in ... More
4 D Quantum N-Dilaton Gravity and One-Loop Divergence of Effective Action on Constant DilatonMay 04 1996We consider 4D quantum gravity with N-dilatons with the most general couplings. Especially, on constant dilaton and arbitrary metric background, we show the structure of the divergent terms. We show the constraint between the couplings necessary to cancel ... More
Deligne's conjecture on the Lefschetz trace formula for $p^n$-torsion étale cohomologyMay 08 2012Deligne's conjecture is the Lefschetz trace formula for correspondences defined over a finite field. In this paper, we prove an analogous statement of Deligne's conjecture with respect to $p^n$-torsion \'etale cohomology under certain conditions, where ... More
The infinite base change lifting associated to an APF extension of a $p$-adic fieldSep 05 2015In this paper, the author proved that the base change lifting associated to a totally ramified extension of a non-archimedean local field coincides with a map coming from the close fields theory of Kazhdan under some conditions. As a corollary, we can ... More
The colored Jones polynomial and the A-polynomial for twist knotsJan 08 2004We show that for a twist knot, the A-polynomial can be obtained from recurrences for the summand in Masbaum's formula of the colored Jones polynomial. Our result supports the AJ conjecture due to S.Garoufalidis.
4-D Quantum Dilaton Gravity During Inflation and Renormalization at One loopApr 26 1996We consider 4D quantum-dilaton gravity with the most general coupling in a homogeneous and isotropic universe, especially an inflationary one, which is essentially characterized by an exponentially expanding scale factor with time. We show that on the ... More
Electric-Magnetic Duality in IIB Matrix Model with D-braneAug 02 2000We consider electric-magnetic duality(S-duality) in IIB matrix model with a D3-brane background. We propose the duality transformation by considering that of noncommutative Yang-Mills theory(NCYM) in four dimension. NCYM derived from the matrix model ... More
Maxwell Theory from Matrix ModelOct 31 2000Nov 01 2000We present a scenario for deriving Maxwell theory from IIB matrix model. Four dimensional spacetime and theories on it relate different dimensional ones by applying appropriate limits of the backgrounds of matrix model. It is understood by looking at ... More
An infinite-dimensional index theorem and the Higson-Kasparov-Trout algebraNov 16 2018We have been studying the index theory for some special infinite-dimensional manifolds with a "proper cocompact" actions of the loop group LT of the circle T, from the viewpoint of the noncommutative geometry. In this paper, we will introduce the LT-equivariant ... More
Bonding Nature in MgB2May 29 2001The accurate charge density of MgB2 was observed at room temperature(R.T.) and 15K by the MEM(Maximum Entropy Method)/Rietveld analysis using synchrotron radiation powder data. The obtained charge density clearly revealed the covalent bonding feature ... More
Out-of-plane nesting driven spin spiral in ultrathin Fe/Cu(001) filmsNov 12 2009Epitaxial ultrathin Fe films on fcc Cu(001) exhibit a spin spiral (SS), in contrast to the ferromagnetism of bulk bcc Fe. We study the in-plane and out-of-plane Fermi surfaces (FSs) of the SS in 8 monolayer Fe/Cu(001) films using energy dependent soft ... More
Roles of two successive phase transitions in new spin-Peierls system TiOBrSep 14 2005In this sturdy, we determine the roles of two successive phase transitions in the new spin-Peierls system TiOBr by electron and synchrotron X-ray diffraction analyses. Results show an incommensurate superstructure along the h- and k-directions between ... More
Nearly-uniform internal rotation of solar-like main-sequence stars revealed by space-based asteroseismology and spectroscopic measurementsJul 04 2015The rotation rates in the deep interior and at the surface of 22 main-sequence stars with masses between $1.0$ and $1.6\,{\rm M}_{\odot}$ are constrained by combining asteroseismological analysis with spectroscopic measurements. The asteroseismic data ... More
High-energy emissions from the gamma-ray binary 1FGL J1018.6-5856Mar 23 2017The gamma-ray binary 1FGL J1018.6-5856 is known to be composed of a massive star with a compact object with an orbital period of 16.54 days. We study mechanisms of high-energy emissions (X-ray, GeV, and TeV $\gamma$-rays) from this binary system. The ... More
Model on pulsed GeV radiation from magnetarsFeb 27 2013We discuss a possible scenario for radiation mechanism of pulsed GeV gamma-rays from magnetars. The magnetars have shown frequent X-ray bursts, which would be triggered by crust fractures and could release the energy of order of ~10^{41-42}erg. If the ... More
Chandra Phase-Resolved Spectroscopy of the High Magnetic Field Pulsar B1509-58Apr 03 2017We report on a timing and spectral analysis of the young, high magnetic field rotation-powered pulsar (RPP) B1509-58 using Chandra continuous-clocking mode observation. The pulsar's X-ray light curve can be fit by the two Gaussian components and the pulsed ... More
Study of KIC 8561221 observed by Kepler: an early red giant showing depressed dipolar modesNov 27 2013The continuous high-precision photometric observations provided by the CoRoT and Kepler space missions have allowed us to better understand the structure and dynamics of red giants using asteroseismic techniques. A small fraction of these stars shows ... More
The Metal-Insulator Transition in Y1-xCaxTiO3 Caused by Phase SeparationApr 10 2002In order to explore the origin of the Metal-Insulator (M-I) transition, the precise crystal structures of the hole-doped Mott insulator system, Y1-XCaXTiO3 (x=0.37, 0.39 and 0.41), are studied for the temperature range between 20K and 300K by the synchrotron ... More
Dipole modes with depressed amplitudes in red giants are mixed modesOct 12 2016Seismic observations have shown that a number of evolved stars exhibit low-amplitude dipole modes, which are referred to as depressed modes. Recently, these low amplitudes have been attributed to the presence of a strong magnetic field in the stellar ... More
A simple kinetic model for the phase transition of the van der Waals fluidNov 02 2017May 27 2018A simple kinetic model, which is presumably minimum, for the phase transition of the van der Waals fluid is presented. In the model, intermolecular collisions for a dense gas has not been treated faithfully. Instead, the expected interactions as the non-ideal ... More
Data Search by a Laser Ising Machine with Gradual Pumping or CouplingNov 11 2013Feb 06 2014We study two operational schemes for a coherent Ising machine based on an injection-locked laser network. These schemes gradually increase the pumping rate or the mutual coupling among the slave lasers. We numerically simulate the two schemes against ... More
Enhanced ferromagnetic transition temperature induced by a microscopic structural rearrangement in the diluted magnetic semiconductor Ge$_{1-x}$Mn$_{x}$TeJun 19 2017The correlation between magnetic properties and microscopic structural aspects in the diluted magnetic semiconductor Ge$_{1-x}$Mn$_{x}$Te is investigated by x-ray diffraction and magnetization as a function of the Mn concentration $x$. The occurrence ... More
Bayesian Inference on the Radio-quietness of Gamma-ray PulsarsMar 22 2018We demonstrate for the first time using a robust Bayesian approach to analyse the populations of radio-quiet (RQ) and radio-loud (RL) gamma-ray pulsars. We quantify their differences and obtain their distributions of the radio-cone opening half-angle ... More
Photonic Topological Insulating Phase Induced Solely by Gain and LossOct 25 2017Jul 04 2018We reveal a one-dimensional topological insulating phase induced solely by gain and loss control in non-Hermitian optical lattices. The system comprises units of four uniformly coupled cavities, where successive two have loss, the others experience gain ... More
One loop renormalization of the 4-D Quantum Dilaton Gravity in Spherical symmetric backgroundMay 08 1996We study the one loop renormalization in the most general metric-dilaton theory with second derivative only. In constant background dilaton theory, there are two types of gravity background which enable the theory renormalizable at one-loop level. We ... More
On the Origin of Lyman-$α$ Blobs at High Redshift: Kinematic Evidence for a Hyperwind Galaxy at z = 3.1May 01 2003We present deep optical spectroscopy of an extended Ly$\alpha$ emission-line blob located in an over-dense region at redshift $z \approx 3.1$; `blob 1' of Steidel et al. (2000). The origin of such Ly$\alpha$ blobs has been debated for some time; two of ... More
Babinet's principle in the Fresnel regime studied using ultrasoundApr 08 2009Dec 07 2009The diffraction of ultrasound by a circular disk and an aperture of the same size have been investigated as a demonstration of Babinet's principle in the Fresnel regime. The amplitude and the phase of diffracted ultrasonic waves have been measured, and ... More
D-brane Scattering in IIB String Theory and IIB Matrix ModelOct 01 1998Jan 26 1999We consider two Dirichlet p-branes with lower dimensional brane charges and their scattering. We first calculate the cylinder amplitude of open string with suitable boundary conditions. We compare this result with that in the IIB matrix model. We find ... More
Interaction between two Fuzzy SpheresAug 01 2001We have calculated interactions between two fuzzy spheres in 3 dimension. It depends on the distance r between the spheres and the radii rho_1, rho_2. There is no force between the spheres when they are far from each other (long distance case). We have ... More
The slope conjecture for graph knotsJan 06 2015Jan 30 2015The slope conjecture proposed by Garoufalidis asserts that the Jones slopes given by the sequence of degrees of the colored Jones polynomials are boundary slopes. We verify the slope conjecture for graph knots, i.e. knots whose Gromov volume vanish.
XMM-Newton observation of PSR B2224+65 and its jetDec 26 2011We have investigated the pulsar PSR B2224+65 and its X-ray jet with XMM-Newton. Apart from the long X-ray jet which is almost perpendicular to the direction of proper motion, a putative extended feature at the pulsar position, which oriented in the opposite ... More
Two-dimensional Heisenberg behavior of Jeff = 1/2 isospins in the paramagnetic state of spin-orbital Mott insulator Sr2IrO4Mar 09 2012Dynamical correlations of Jeff = 1/2 isospins in the paramagnetic state of spin-orbital Mott insu- lator Sr2IrO4 was revealed by resonant magnetic x-ray diffuse scattering. We found two-dimensional antiferromagnetic fluctuation with a large in-plane correlation ... More
An astrophysical interpretation of the remarkable g-mode frequency groups of the rapidly rotating $γ$ Dor star, KIC 5608334Mar 23 2018The Fourier spectrum of the $\gamma$-Dor variable KIC 5608334 shows remarkable frequency groups at $\sim$3, $\sim$6, $\sim$9, and 11--12\,d$^{-1}$. We explain the four frequency groups as prograde sectoral g modes in a rapidly rotating star. Frequencies ... More
Restframe Optical Spectroscopic Classifications for Submillimeter GalaxiesJul 26 2006We report the results of a systematic near-infrared spectroscopic survey using the Subaru, VLT and Keck Telescopes of a sample of high redshift Ultra-luminous Infrared Galaxies (ULIRGs) mainly composed of submillimeter-selected galaxies. Our observations ... More
Weak antiferromagnetism of J_eff=1/2 band in bilayer iridate Sr3Ir2O7Jul 31 2012The antiferromagnetic structure of Sr3Ir2O7, the bilayer analogue of a spin-orbital Mott insulator Sr2IrO4, was revealed by resonant magnetic x-ray diffraction. Contrasting intensities of the magnetic diffraction at the Ir LIII and LII edges show a Jeff=1/2 ... More
Spin and Orbital Contributions to Magnetically Ordered Moments in 5d Layered Perovskite Sr2IrO4Aug 05 2013The ratio of orbital (L) and spin (S) contributions to the magnetically ordered moments of a 5d transition metal oxide, Sr2IrO4 was evaluated by non-resonant magnetic x-ray diffraction. We applied a new experimental setting to minimize the error in which ... More
Pressure evolution of low-temperature crystal structure and bonding of 37 K $T_c$ FeSe superconductorMar 12 2009FeSe with the PbO structure is a key member of the family of new high-$T_c$ iron pnictide and chalcogenide superconductors, as while it possesses the basic layered structural motif of edge-sharing distorted FeSe$_4$ tetrahedra, it lacks interleaved ion ... More
Pressure/temperature/substitution-induced melting of A-site charge disproportionation in Bi_(1-x)La_(x)NiO_3 (0 =< x =< 0.5)Feb 02 2005May 13 2005Metal-insulator transitions strongly coupled with lattice were found in Bi1-xLaxNiO3. Synchrotron X-ray powder diffraction revealed that pressure (P ~ 3 GPa, T = 300 K), temperature (T ~ 340 K, x = 0.05), and La-substitution (x ~ 0.075, T = 300 K) caused ... More
Photoemission Evidence for Valence Fluctuations and Kondo Resonance in YbAl2Jun 08 2012We use hard x-ray photoemission spectroscopy (HAXPES) to investigate the electronic structure of YbAl2, for which the Yb valence has not been consistently reported to date. The bulk sensitivity and the analytical simplicity provided by the Yb 3d core-level ... More
Nanoscale Dichotomy of Ti 3d Carriers Mediating the Ferromagnetism in Co:TiO2 Anatase Thin FilmsAug 11 2010We study the surface and bulk electronic structure of the room-temperature ferromagnet Co:TiO2 anatase films using soft and hard x-ray photoemission spectroscopy with probe sensitivities of ~1 nm and ~10 nm, respectively. We obtain direct evidence of ... More
Asteroseismic detection of latitudinal differential rotation in 13 Sun-like starsSep 21 2018The differentially rotating outer layers of stars are thought to play a role in driving their magnetic activity, but the underlying mechanisms that generate and sustain differential rotation are poorly understood. We report the measurement of latitudinal ... More
Tetrahedral Magnetic Order and the Metal-Insulator Transition in the Pyrochlore Lattice of Cd2Os2O7Apr 21 2012Cd2Os2O7 shows a peculiar metal-insulator transition at 227 K with magnetic ordering in a frustrated pyrochlore lattice, but its magnetic structure in the ordered state and the transition origin are yet uncovered. We observed a commensurate magnetic peak ... More
Probing the Pulsar Wind in the gamma-ray Binary System PSR B1259-63/SS 2883Jul 01 2009Jul 22 2009The spectral energy distribution from the X-ray to the very high energy regime ($>100$ GeV) has been investigated for the $\gamma$-ray binary system PSR B1259-63/SS2883 as a function of orbital phase within the framework of a simple model of a pulsar ... More
Face changing companion of the redback millisecond pulsar PSR J1048+2339Jan 07 2019We present optical observations of the redback millisecond pulsar PSR J1048+2339, which is a 4.66 ms radio pulsar in a compact binary with an orbital period of six hours. We obtained high-quality light curves of PSR J1048+2339 with the Lulin 1 m Telescope. ... 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
Temperature dependent Eu 3d-4f X-ray Absorption and Resonant Photoemission Study of the Valence Transition in $EuNi_2(Si_{0.2}Ge_{0.8})_2$Jul 22 2005We study the mixed valence transition ($T$$_{v}$ $\sim$80 K) in EuNi$_{2}$(Si$_{0.2}$Ge$_{0.8}$)$_{2}$ using Eu 3$d-4f$ X-ray absorption spectroscopy (XAS) and resonant photoemission spectroscopy (RESPES). The Eu$^{2+}$ and Eu$^{3+}$ main peaks show a ... More
A medium deep Chandra and Subaru survey of the 13hr XMM/ROSAT deep survey areaFeb 26 2003We present the results of a Chandra ACIS-I survey of a high latitude region at 13h +38 which was earlier observed with ROSAT (McHardy et al. 1998) and which has recently been observed by XMM-Newton for 200ksec. XMM-Newton will provide good quality X-ray ... More
Conformal Transformation in GravityApr 30 1995The conformal transformation in the Einstein - Hilbert action leads to a new frame where an extra scalar degree of freedom is compensated by the local conformal-like symmetry. We write down a most general action resulting from such transformation and ... More
One loop renormalization of the four-dimensional theory for quantum dilaton gravity.Feb 17 1995We study the one loop renormalization in the most general metric-dilaton theory with the second derivative terms only. The general theory can be divided into two classes, models of one are equivalent to conformally coupled with gravity scalar field and ... More
X-ray/GeV emissions from Crab-like pulsars in LMCDec 01 2016We discuss X-ray and gamma-ray emissions from Crab-like pulsars, PSRs~J0537-6910 and~J0540-6919, in Large Magellanic Cloud. Fermi-LAT observations have resolved the gamma-ray emissions from these two pulsars and found the pulsed emissions from PSR~J0540-6919. ... More
On the Polarized Nonthermal Emission from AR ScorpiiApr 11 2019We study linear polarization of optical emission from white dwarf (WD) binary system AR~Scorpii. The optical emission from this binary is modulating with the beat frequency of the system, and it is highly polarized, with the degree of the polarization ... More
[OII]3727 Emission from the Companion to the Quasar BR 1202-0725 at z=4.7Mar 08 2000Results of a narrow-band imaging for the redshifted [OII]3727 emission around a quasar at z=4.7 obtained with the Subaru telescope and CISCO (a Cassegrain near infrared camera) are presented. A significant emission line is detected in the narrow-band ... More
Non-thermal emissions from outer magnetospheric accelerators of middle-aged pulsarsOct 21 2008We discuss $\gamma$-ray emissions from the outer gap accelerators of middle-aged pulsars for part of the series of our studies. A two-dimensional electrodynamic model is used to solve the distribution of accelerating electric fields with electron and ... More
Pulse Profiles, Spectra and Polarization Characteristics of Non-Thermal Emissions from the Crab-Like PulsarsJul 23 2007We discuss non-thermal emission mechanism of the Crab-like pulsars with both a two-dimensional electrodynamical study and a three-dimensional model. We investigate the emission process in the outer gap accelerator. In the two-dimensional electrodynamical ... More
Reshetikhin-Turaev invariants of Seifert 3-manifolds for classical simple Lie algebras, and their asymptotic expansionsSep 30 2002Feb 02 2003We derive formulas for the Reshetikhin-Turaev invariants of all oriented Seifert manifolds associated to an arbitrary complex finite dimensional simple Lie algebra $\mathfrak g$ in terms of the Seifert invariants and standard data for $\mathfrak g$. A ... More
Quantum invariants of Seifert 3-manifolds and their asymptotic expansionsOct 01 2002We report on recent results of the authors concerning calculations of quantum invariants of Seifert 3-manifolds. These results include a derivation of the Reshetikhin-Turaev invariants of all oriented Seifert manifolds associated with an arbitrary complex ... More
Order by quenched disorder in the model triangular antiferromagnet RbFe(MoO4)2Jul 22 2017We observe a disappearance of the 1/3 magnetization plateau and a striking change of the magnetic configuration under a moderate doping of the model triangular antiferromagnet RbFe(MoO4)2. The reason is an effective lifting of degeneracy of mean-field ... More
Hard x-ray photoemission study of LaAlO3/LaVO3 multilayersApr 13 2007We have studied the electronic structure of multilayers composed of a band insulator LaAlO$_3$ (LAO) and a Mott insulator LaVO$_3$ (LVO) by means of hard x-ray photoemission spectroscopy, which has a probing depth as large as $\sim 60 {\AA}$. The Mott-Hubbard ... More
Pressure-induced unconventional superconductivity in the heavy-fermion antiferromagnet CeIn3: An 115In-NQR study under pressureFeb 15 2008We report on the pressure-induced unconventional superconductivity in the heavy-fermion antiferromagnet CeIn3 by means of nuclear-quadrupole-resonance (NQR) studies conducted under a high pressure. The temperature and pressure dependences of the NQR spectra ... 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
X-ray and optical properties of X-ray sources in the 13hr XMM-Newton/Chandra deep surveyDec 02 2002The 13hr XMM-Newton/Chandra deep survey is the first of two extremely deep XMM-Newton fields observed by the XMM-OM consortium. A 120 ks Chandra mosaic, covering 0.2 square degrees, provides sensitive, confusion-free point source detection with sub-arcsecond ... More
Heat-Treatment-Induced Switching of Magnetic States in the Doped Polar Semiconductor Ge$_{1-x}$Mn$_x$TeMay 18 2016Cross-control of a material property - manipulation of a physical quantity (e.g., magnetisation) by a nonconjugate field (e.g., electrical field) - is a challenge in fundamental science and also important for technological device applications. It has ... More
A Vigorous Starburst in the SCUBA Galaxy N2 850.4Mar 06 2003We present optical and near-IR spectroscopy of a z=2.38 hyperluminous IR galaxy, covering the restframe wavelength range from 1000-5000A. It appears to comprise two components separated by less than 1" on the sky (<8kpc); one component (B) is blue, the ... More
Magnetically-Driven Ferroelectric Atomic Displacements in perovskite like YMnO3Jul 13 2011Magnetically-driven ferroelectric atomic displacements of the order of 10$^{-3} Angstrom have been observed in orthorhombic (perovskite like) YMnO$_3$ by a single-crystal synchrotron x-ray diffraction. The refined polar structure shows the characteristic ... More
Search for pulsed gamma-ray emission from globular cluster M28Feb 04 2013Using the data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope, we have searched for the gamma-ray pulsations from the direction of globular cluster M28 (NGC 6626). We report the discovery of a signal with the frequency consistent ... More
Orbital Phase Dependent Gamma-ray emissions from the Black Widow PulsarOct 26 2012We report on evidence for orbital phase-dependence of the gamma-ray emission from PSR B1957+20 black widow system by using the data of the Fermi Large Area Telescope. We divide an orbital cycle into two regions: a region containing the inferior conjunction, ... More
Compressibility of the MgB2 SuperconductorFeb 28 2001Considerable excitement has been caused recently by the discovery that the binary boride system with stoichiometry MgB2 is superconducting at the remarkably high temperature of 39 K (1). This potentially opens the way to even higher Tc values in a new ... More
Discovery of γ-ray pulsation and X-ray emission from the black widow pulsar PSR J2051-0827Jan 28 2012We report the discovery of pulsed {\gamma}-ray emission and X-ray emission from the black widow millisecond pulsar PSR J2051-0827 by using the data from the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope and the Advanced CCD Imaging ... More
Doping Dependent Changes in Nitrogen 2$p$ States in the Diluted Magnetic Semiconductor Ga$_{1-x}$Cr$_{x}$NSep 30 2004We study the electronic structure of the recently discovered diluted magnetic semiconductor Ga$_{1-x}$Cr$_{x}$N ($x$ = 0.01-0.10). A systematic study of the changes in the $occupied$ and $unoccupied$ ligand (N) partial density of states (DOS) of the host ... More
Exploring the X-ray and gamma-ray properties of the redback millisecond pulsar PSR J1723-2837Nov 01 2013Dec 24 2013We have investigated the X-ray and $\gamma$-ray properties of the redback millisecond pulsar PSR J1723-2837 with XMM-Newton, Chandra and Fermi. We have discovered the X-ray orbital modulation of this binary system with the minimum that coincides with ... More
Deep-Imaging Observations of a Candidate of an Absorbed QSO at z=0.653, AX J131831+3341Dec 27 2000The results of deep-imaging observations of a candidate of an absorbed QSO at z=0.653, AX J131831+3341, are presented. AX J131831+3341 was found during the course of optical follow-up observations of the ASCA Large Sky Survey, and has an X-ray luminosity ... More
Problems on invariants of knots and 3-manifoldsJun 09 2004This is a list of open problems on invariants of knots and 3-manifolds with expositions of their history, background, significance, or importance. This list was made by editing open problems given in problem sessions in the workshop and seminars on `Invariants ... More
Nature of Well-Screened State in Hard X-ray Mn 2$p$ Core-Level Photoemission of La$_{1-x}$Sr$_x$MnO$_3$ FilmsMay 19 2004Oct 22 2004Using hard x-ray (HX ; $h\nu$ = 5.95 keV) synchrotron photoemission spectroscopy (PES), we study the intrinsic electronic structure of La$_{1-x}$Sr$_x$MnO$_3$ (LSMO) thin films. Comparison of Mn 2$p$ core-levels with Soft x-ray (SX ; $h\nu$ $\sim$ 1000 ... More
The Discovery of Primeval Large-Scale Structures with Forming Clusters at Redshift 6Dec 29 2004We report the discovery of primeval large-scale structures (LSSs) including two proto-clusters in a forming phase at z=5.7. We carried out extensive deep narrow-band imaging in the 1 deg^2 sky of the Subaru/XMM-Newton Deep Field, and obtained a cosmic ... More
Fermi Study of 5-300 GeV emission from the high-mass pulsar binary PSR B1259-63/LS 2883Apr 18 2016We report the results from our detailed analysis of the Fermi Large Area Telescope (LAT) data for the pulsar binary PSR B1259-63/LS 2883. During the GeV flares that occurred when the pulsar was in the periastron passages, we have detected a 5--300 GeV ... More
Modeling the Variability of Active Galactic Nuclei by Infinite Mixture of Ornstein-Uhlenbeck(OU) ProcessesNov 09 2018We develop an infinite mixture model of Ornstein-Uhlenbeck(OU) processes for describing the optical variability of QSOs based on treating the variability as a stochastic process. This enables us to get the parameters of the power spectral densities(PSDs) ... More
Quantum correction to tiny vacuum expectation value in two Higgs doublet model for Dirac neutrino massJul 06 2011Apr 03 2014We study a Dirac neutrino mass model of Davidson and Logan. In the model, the smallness of the neutrino mass is originated from the small vacuum expectation value of the second Higgs of two Higgs doublets. We study the one loop effective potential of ... More
Quantum correlation in degenerate optical parametric oscillators with mutual injectionsMay 30 2015Nov 01 2015We theoretically and numerically study the quantum dynamics of two degenerate optical parametric oscillators with mutual injections. The cavity mode in the optical coupling path between the two oscillator facets is explicitly considered. Stochastic equations ... More
Population study for gamma-ray pulsars with the outer gap modelOct 28 2010Inspired by increase of population of $\gamma$-ray emitting pulsars by the $Fermi$ telescope, we perform a population study for $\gamma$-ray emitting canonical pulsars. We use a Monte-Carlo technique to simulate the Galactic population of neutron stars ... More
Multi-fermion interaction models in curved spacetimeDec 04 2008A model with a scalar type eight-fermion interaction is investigated in curved spacetime. The ground state of the model can be obtained by observing the effective potential. Applying the Riemann normal coordinate expansion, we calculate an effective potential ... More
Effective Lagrangian for a Technicolor Model without Exact Custodial SymmetryMar 23 1994May 06 1994Effective Lagrangian including technimesons is constructed for a realistic one-family Technicolor model without exact custodial symmetry. Tree level contribution to oblique correction parameters $S$ and $U$ due to spin 1 technimesons are computed with ... More
A Model for AR~Scorpii: Emission from Relativistic Electrons Trapped by Closed Magnetic Field Lines of Magnetic White DwarfsDec 10 2017AR~Scorpii is an intermediate polar system composed of a magnetic white dwarf (WD) and an M-type star, and shows non-thermal, pulsed, and highly linearly polarized emission. The radio/optical emission modulates with the WD's spin and show the double peak ... More
Electronic Structure of Strained Manganite Thin Films with Room Temperature Ferromagnetism Investigated by Hard X-ray Photoemission SpectroscopyOct 09 2004We report the bulk sensitive Hard X-ray (hv=5.95keV) core level photoemission spectroscopy to investigate the intrinsic electronic structure of strained (La0.85Ba0.15)MnO3 thin films. In a 20nm thick well-strained film with strongly enhanced ferromagnetism, ... More
The Strong Slope Conjecture for twisted generalized Whitehead doublesNov 28 2018The Slope Conjecture proposed by Garoufalidis asserts that the degree of the colored Jones polynomial determines a boundary slope, and its refinement, the Strong Slope Conjecture proposed by Kalfagianni and Tran asserts that the linear term in the degree ... More
The strong slope conjecture for graph knotsSep 04 2018We prove the Strong Slope Conjecture for graph knots. Along the way we propose some variants of the Strong Slope Conjecture and discuss their inheritance under cablings and connected sums.
Evidence for a correlated insulator to antiferromagnetic metal transition in CrNApr 01 2010We investigate the electronic structure of Chromium Nitride (CrN) across the first-order magneto-structural transition at T_N ~ 286 K. Resonant photoemission spectroscopy shows a gap in the 3d partial density of states at the Fermi level and an On-site ... More
Strong valence fluctuation in the quantum critical heavy fermion superconductor beta-YbAlB4: A hard x-ray photoemission studyJun 26 2009Jun 14 2010Electronic structures of the quantum critical superconductor beta-YbAlB4 and its polymorph alpha-YbAlB4 are investigated by using bulk-sensitive hard x-ray photoemission spectroscopy. From the Yb 3d core level spectra, the values of the Yb valence are ... More
Three-dimensional Two-Layer Outer Gap Model: the Third Peak of Vela PulsarOct 23 2011We extend the two-dimensional two-layer outer gap model to a three-dimensional geometry and use it to study the high-energy emission of the Vela pulsar. We apply this three-dimensional two-layer model to the Vela pulsar and compare the model light curves, ... More
Universal valence-band picture of the ferromagnetic semiconductor GaMnAsSep 12 2010The origin of ferromagnetism in the prototype ferromagnetic semiconductor GaMnAs is still controversial due to the insufficient understanding of its band structure and Fermi level position. Here, we show the universal valence-band (VB) picture of GaMnAs ... More
Gamma-ray emission from Outer-Gap of pulsar magnetosphereDec 03 2002We develop a model for gamma-ray emission from the outer magnetosphere of pulsars (the outer-gap model). The charge depletion causes a large electric field which accelerates electrons and positrons. We solve the electric field with radiation and pair ... More
Time variation of particle and anti-particle asymmetry in an expanding universeMar 04 2014Jun 25 2014Particle number violating interactions wash out the primordial asymmetry of particle number density generated by some interaction satisfying Sakharov conditions for baryogenesis. In this paper, we study how the primordial asymmetry evolves in time under ... More
Particle number production and time variation with non-equilibrium quantum field theoryOct 06 2012Oct 11 2012We study the particle number production and its time variation using non-equilibrium quantum field theory. We study the model proposed by Hotta \cite{Hotta:2012hi} for particle number production with a heavy neutral scalar and a light complex scalar. ... More