Results for "Shogo Nishiyama"

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Spectroscopically Identified Intermediate Age Stars at 0.5 - 3 pc Distance from Sgr A*Nov 05 2015<Context.> Nuclear star clusters (NSCs) at the dynamical center of galaxies appear to have a complex star formation history. This suggests repeated star formation even in the influence of the strong tidal field from supermassive black holes. <Aim.> In ... More
Near-Infrared Counterparts to Chandra X-ray Sources toward the Galactic Center. I. Statistics and a Catalog of CandidatesJul 11 2009Aug 21 2009We present a catalog of 5184 candidate infrared counterparts to X-ray sources detected towards the Galactic center. The X-ray sample contains 9017 point sources detected in this region by the Chandra X-ray Observatory, including data from a recent deep ... More
Young, Massive Star Candidates Detected throughout the Nuclear Star Cluster of the Milky WayOct 23 2012Aims. Young, massive stars have been found at projected distances R < 0.5 pc from supermassive black hole, Sgr A* at the center of our Galay. In recent years, increasing evidence has been found for the presence of young, massive stars also at R > 0.5 ... 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
Radial Velocity Measurements of an Orbiting Star Around Sgr A*Sep 05 2017Sep 07 2017During the next closest approach of the orbiting star S2/S0-2 to the Galactic supermassive black hole (SMBH), it is estimated that RV uncertainties of ~ 10 km/s allow us to detect post-Newtonian effects throughout 2018. To evaluate an achievable uncertainty ... More
Magnetically Confined Interstellar Hot Plasma in the Nuclear Bulge of our GalaxyMay 02 2013The origin of the Galactic center diffuse X-ray emission (GCDX) is still under intense investigation. In particular, the interpretation of the hot (kT ~ 7 keV) component of the GCDX, characterised by the strong Fe 6.7 keV line emission, has been contentious. ... More
Classical Exchange Algebra of the Superstring on S^5 with the AdS-timeSep 25 2007May 21 2014A classical exchange algebra of the superstring on S^5 with the AdS-time is shown on the light-like plane. To this end we use the geometrical method of which consistency is guaranteed by the classical Yang-Baxter equation. The Dirac method does not work, ... More
Top-antitop charge asymmetry measurements in the dilepton channel with the ATLAS detectorJan 14 2019We report a measurement of the charge asymmetry $A_C$ in top quark pair production with the ATLAS experiment. The measurement focuses on dilepton channels ($ee$, $e\mu$, $\mu\mu$). The data are unfolded to parton level at full phase space using a fully ... More
Photon detection operator and complementarity between electric detector and magnetic detectorSep 03 2013Nov 21 2013It had been a long standing problem that there is no consistent definition of photon position operator nor photon number density in the context of quantum theory. In this paper we derive the photon detection operator, which defines location of photon ... More
Superselection Rules from Measurement TheoryDec 24 2011In quantum theory, physically measurable quantities of a microscopic system are represented by self-adjoint operators. However, not all of the self-adjoint operators correspond to measurable quantities. The superselection rule is a criterion to distinguish ... More
Path Integrals on Riemannian Manifolds with Symmetry and Induced Gauge StructureJun 20 2000Jan 16 2001We formulate path integrals on any Riemannian manifold which admits the action of a compact Lie group by isometric transformations. We consider a path integral on a Riemannian manifold M on which a Lie group G acts isometrically. Then we show that the ... More
Topology and Inequivalent Quantizations of Abelian Sigma ModelFeb 28 1995The abelian sigma model in (1+1) dimensions is a field theoretical model which has a field $ \phi : S^1 \to S^1 $. An algebra of the quantum field is defined respecting the topological aspect of the model. It is shown that the zero-mode has an infinite ... More
Quantum Mechanics on ManifoldsJun 28 1993A definition of quantum mechanics on a manifold $ M $ is proposed and a method to realize the definition is presented. This scheme is applicable to a homogeneous space $ M = G / H $. The realization is a unitary representation of the transformation group ... More
Uncertainty relation between angle and orbital angular momentum: interference effect in electron vortex beamsNov 04 2014Apr 06 2015The uncertainty relation between angle and orbital angular momentum had not been formulated in a similar form as the uncertainty relation between position and linear momentum because the angle variable is not represented by a quantum mechanical self-adjoint ... More
More on the Triplet Killing Potentials of Quaternionic Kaehler ManifoldsJun 29 2005We show the properties of the triplet Killing potentials of quaternionic Kaehler manifolds which have been missing in the literature. It is done by means of the metric formula of the manifolds. We compute the triplet Killing potentials for the quaternionic ... More
A distribution for a pair of unit vectors generated by Brownian motionSep 07 2009We propose a bivariate model for a pair of dependent unit vectors which is generated by Brownian motion. Both marginals have uniform distributions on the sphere, while the conditionals follow so-called ``exit'' distributions. Some properties of the proposed ... More
Complementarity and the nature of uncertainty relations in Einstein-Bohr recoiling slit experimentMar 14 2007Jul 16 2015A model of the Einstein-Bohr double-slit experiment is formulated in a fully quantum theoretical setting. In this model, the state and dynamics of a movable wall that has the double slits in it, as well as the state of a particle incoming to the double ... More
Quantization on a torus without position operatorsSep 09 2003Oct 11 2003We formulate quantum mechanics in the two-dimensional torus without using position operators. We define an algebra with only momentum operators and shift operators and construct irreducible representation of the algebra. We show that it realizes quantum ... More
Zero-mode, Winding Number and Quantization of Abelian Sigma Model in (1+1) DimensionsDec 20 1994We consider the $ U(1) $ sigma model in the two dimensional space-time which is a field-theoretical model possessing a nontrivial topology. It is pointed out that its topological structure is characterized by the zero-mode and the winding number. A new ... More
Isoholonomic Problem and Holonomic Quantum ComputationMay 06 2005Geometric phases accompanying adiabatic processes in quantum systems can be utilized as unitary gates for quantum computation. Optimization of control of the adiabatic process naturally leads to the isoholonomic problem. The isoholonomic problem in a ... More
Path Integrals on Riemannian Manifolds with Symmetry and Stratified Gauge StructureOct 02 2001We study a quantum system in a Riemannian manifold M on which a Lie group G acts isometrically. The path integral on M is decomposed into a family of path integrals on a quotient space Q=M/G and the reduced path integrals are completely classified by ... More
Near-infrared Polarimetry toward the Galactic Center - Magnetic Field Configuration in the Central One Degree Region -Jan 29 2010We present a NIR polarimetric map of the 1deg by 1deg region toward the Galactic center. Comparing Stokes parameters between highly reddened stars and less reddened ones, we have obtained a polarization originating from magnetically aligned dust grains ... More
Intrinsically Polarized Stars and Implication for Star Formation in the Central Parsec of Our GalaxyOct 11 2013We have carried out adaptive-optics assisted observations at the Subaru telescope, and have found 11 intrinsically polarized sources in the central parsec of our Galaxy. They are selected from 318 point sources with Ks<15.5, and their interstellar polarizations ... More
Topology and quantization of abelian sigma model in (1+1) dimensionsAug 17 1994It is known that there exist an infinite number of inequivalent quantizations on a topologically nontrivial manifold even if it is a finite-dimensional manifold. In this paper we consider the abelian sigma model in (1+1) dimensions to explore a system ... More
Algebra and Twisted Algebra in Toroidal Target SpaceJan 16 1996Mar 01 1996Target space duality is reconsidered from the viewpoint of quantization in a space with nontrivial topology. An algebra of operators for the toroidal bosonic string is defined and its representations are constructed. It is shown that there exist an infinite ... More
The Berkovits Method for Conformally Invariant Non-linear Sigma-models on G/HFeb 21 2006We discuss 2-dimmensional non-linear sigma-models on the Kaehler manifold G/H in the first order formalisim. Using the Berkovits method we explicitly construct the G-symmetry currents and primaries, when G/H are irreducible. It is a variant of the Wakimoto ... More
The Disc Amplitude of the Dijkgraaf-Vafa Theory:1/N Expansion vs Complex Curve AnalysisApr 20 2005May 02 2005According to Dijkgraaf and Vafa the effective glueball superpotential of the N=1 supersymmetric QCD coupled with an adjoint chiral multiplet is given by the planar amplitude in the 1/N expansion of a matrix model. It was shown that, when the N=1 supersymmetric ... More
Entropy production in 2D $λφ^4$ theory in the Kadanoff-Baym approachOct 28 2008Jan 13 2010We study non-equilibrium quantum dynamics of the single-component scalar field theory in 1+1 space-time dimensions on the basis of the Kadanoff-Baym equation including the next-to-leading-order (NLO) skeleton diagrams. As an extension of the non-relativistic ... More
Remarks on the asymptotic behavior of the solution of an abstract damped wave equationMay 06 2015Sep 30 2015We study an abstract damped wave equation. We prove that the solution of the damped wave equation becomes closer to the solution of a heat type equation as time tend to infinity. As an application of our approach, we also study the asymptotic behavior ... More
Universal critical behavior of the two-magnon-bound-state mass gap for the (2+1)-dimensional Ising modelJul 31 2014The two-magnon-bound-state mass gap m_2 for the two-dimensional quantum Ising model was investigated by means of the numerical diagonalization method; the low-lying spectrum is directly accessible via the numerical diagonalization method. It has been ... More
Transfer-matrix approach to the three-dimensional bond percolation: An application of Novotny's formalismDec 18 2005A transfer-matrix simulation scheme for the three-dimensional (d=3) bond percolation is presented. Our scheme is based on Novotny's transfer-matrix formalism, which enables us to consider arbitrary (integral) number of sites N constituting a unit of the ... More
Stiffening of fluid membranes due to thermal undulations: density matrix renormalization group studyOct 22 2002It has been considered that the effective bending rigidity of fluid membranes should be reduced by thermal undulations. However, recent thorough investigation by Pinnow and Helfrich revealed significance of measure factors for the partition sum. Accepting ... More
Deconfined criticality for the two-dimensional quantum S=1-spin model with the three-spin and biquadratic interactionsMar 28 2015The criticality between the nematic and valence-bond-solid (VBS) phases was investigated for the two-dimensional quantum S=1-spin model with the three-spin and biquadratic interactions by means of the numerical diagonalization method. It is expected that ... More
Criticality of the (2+1)-dimensional S=1 transverse-field Ising model with extended interactions: Suppression of corrections to scalingMar 09 2010The criticality of the (2+1)-dimensional S=1 transverse-field Ising model is investigated with the numerical diagonalization method. The scaling behavior is improved by tuning the coupling-constant parameters; the S=1 spin model allows us to incorporate ... More
Resolution of null fiber and conormal bundles on the Lagrangian GrassmannianJan 26 2007Dec 28 2007We study the null fiber of a moment map related to dual pairs. We construct an equivariant resolution of singularities of the null fiber, and get conormal bundles of closed $ K_C $-orbits in the Lagrangian Grassmannian as the categorical quotient. The ... More
Inequalities between $L^p$-norms for log-concave distributionsMar 25 2019Log-concave distributions include some important distributions such as normal distribution, exponential distribution and so on. In this note, we show inequalities between two Lp-norms for log-concave distributions on the Euclidean space. These inequalities ... More
$L^p$-norm inequality using q-moment and its applicationsFeb 04 2019Feb 20 2019For a measurable function on a set which has a finite measure, an inequality holds between two Lp-norms. In this paper, we show similar inequalities for the Euclidean space and the Lebesgue measure by using a q-moment which is a moment of an escort distribution. ... More
Asymptotic cone of semisimple orbits for symmetric pairsDec 15 2010Let G be a reductive algebraic group over the complex field and O_h be a closed adjoint orbit through a semisimple element h. By a result of Borho and Kraft (1979), it is known that the asymptotic cone of the orbit O_h is the closure of a Richardson nilpotent ... More
YSO search toward the boundary of the Central Molecular Zone with near-infrared polarimetryJun 11 2014We have carried out near-infrared polarimetry toward the boundary of the Central Molecular Zone, in the field of (-1.4 deg $\lesssim l \lesssim$ -0.3 deg and 1.0 deg $\lesssim l \lesssim$ 2.9 deg, $|b|\lesssim$ 0.1 deg), using the near-infrared polarimetric ... More
Photometric Observations of 107P/Wilson-HarringtonJun 26 2011We present lightcurve observations and multiband photometry for 107P/Wilson-Harrington using five small- and medium-sized telescopes. The lightcurve has shown a periodicity of 0.2979 day (7.15 hour) and 0.0993 day (2.38 hour), which has a commensurability ... More
Criticalities of the transverse- and longitudinal-field fidelity susceptibilities for the d=2 quantum Ising modelJul 13 2013The inner product between the ground-state eigenvectors with proximate interaction parameters, namely, the fidelity, plays a significant role in the quantum dynamics. In this paper, the critical behaviors of the transverse- and longitudinal-field fidelity ... More
Critical behavior of the fidelity susceptibility for the d=2 transverse-field Ising modelMay 17 2013The overlap (inner product) between the ground-state eigenvectors with proximate interaction parameters, the so-called fidelity, plays a significant role in the quantum-information theory. In this paper, the critical behavior of the fidelity susceptibility ... More
Crumpling transition of the triangular lattice without open edges: effect of a modified folding ruleMar 10 2010Folding of the triangular lattice in a discrete three-dimensional space is investigated by means of the transfer-matrix method. This model was introduced by Bowick and co-workers as a discretized version of the polymerized membrane in thermal equilibrium. ... More
Deconfinement criticality for the spatially anisotropic triangular antiferromagnet with the ring exchangeFeb 12 2009The spatially anisotropic triangular antiferromagnet is investigated with the numerical diagonalization method. As the anisotropy varies, the model changes into a variety of systems such as the one-dimensional, triangular, and square-lattice antiferromagnets. ... More
Bound-state energy of the d=3 Ising model in the broken-symmetry phase: Suppressed finite-size correctionsApr 09 2008The low-lying spectrum of the three-dimensional Ising model is investigated numerically; we made use of an equivalence between the excitation gap and the reciprocal correlation length. In the broken-symmetry phase, the magnetic excitations are attractive, ... More
Quantum-fluctuation-induced repelling interaction of quantum string between wallsFeb 07 2001Quantum string, which was brought into discussion recently as a model for the stripe phase in doped cuprates, is simulated by means of the density-matrix-renormalization-group method. String collides with adjacent neighbors, as it wonders, owing to quantum ... More
Revisiting Unit Fractions That Sum To 1Mar 23 2016This paper is a continuation of a previous paper. Here, as there, we examine the problem of finding the maximum number of terms in a partial sequence of distinct unit fractions larger than 1/100 that sums to 1. In the previous paper, we found that the ... More
Finite-size-scaling analysis of the XY universality class between two and three dimensions: An application of Novotny's transfer-matrix methodFeb 03 2005Based on Novotny's transfer-matrix method, we simulated the (stacked) triangular Ising antiferromagnet embedded in the space with the dimensions variable in the range 2 \le d \le 3. Our aim is to investigate the criticality of the XY universality class ... More
Multi-criticality of the three-dimensional Ising model with plaquette interactions: An extension of Novotny's transfer-matrix formalismJul 12 2004Three-dimensional Ising model with the plaquette-type (next-nearest-neighbor and four-spin) interactions is investigated numerically. This extended Ising model, the so-called gonihedric model, was introduced by Savvidy and Wegner as a discretized version ... More
Electron trajectory in the hydrogen atomOct 10 2001Dec 27 2001A trajectory in the Schroedinger wave for an electron in an attractive Coulomb potential with the dynamical behavior is proposed and illustrated for a scattering and a bound state. The scattering cross section derived from the trajectories is almost exactly ... More
Numerical analysis of the dissipative two-state system with the density-matrix Hilbert-space-reduction algorithmApr 19 1999Ground state of the dissipative two-state system is investigated by means of the Lanczos diagonalization method. We adopted the Hilbert-space-reduction scheme proposed by Zhang, Jeckelmann and White so as to reduce the overwhelming reservoir Hilbert space ... More
Numerical diagonalization analysis of the ground-state superfluid-localization transition in two dimensionsDec 20 1998Ground state of the two-dimensional hard-core-boson system in the presence of the quenched random chemical potential is investigated by means of the exact-diagonalization method for the system sizes up to L=5. The criticality and the DC conductivity at ... More
Deconfined-critical behavior of the VBS- and nematic-order parameters for the spatially anisotropic S=1-spin modelAug 23 2012The phase transition between the valence-bond-solid (VBS) and nematic phases, the so-called deconfined criticality, was investigated for the quantum S=1-spin model on the spatially anisotropic triangular lattice with the biquadratic interaction by means ... More
d=2 transverse-field Ising model under the screw-boundary condition: An optimization of the screw pitchSep 02 2011A length-N spin chain with the \sqrt{N}(=v)-th neighbor interaction is identical to a two-dimensional (d=2) model under the screw-boundary (SB) condition. The SB condition provides a flexible scheme to construct a d\ge2 cluster from an arbitrary number ... More
Crumpling transition of the discrete planar folding in the negative-bending-rigidity regimeJul 13 2010The folding of the triangular lattice embedded in two dimensions (discrete planar folding) is investigated numerically. As the bending rigidity K varies, the planar folding exhibits a series of crumpling transitions at K \approx -0.3 and K \approx 0.1. ... More
Numerical diagonalization analysis of the criticality of the (2+1)-dimensional XY model: Off-diagonal Novotny's methodAug 27 2008The criticality of the (2+1)-dimensional XY model is investigated with the numerical diagonalization method. So far, it has been considered that the diagonalization method would not be very suitable for analyzing the criticality in large dimensions (d ... More
Multicriticality of the (2+1)-dimensional gonihedric model: A realization of the (d,m)=(3,2) Lifshitz pointApr 30 2007Multicriticality of the gonihedric model in 2+1 dimensions is investigated numerically. The gonihedric model is a fully frustrated Ising magnet with the finely tuned plaquette-type (four-body and plaquette-diagonal) interactions, which cancel out the ... More
Folding of the triangular lattice in a discrete three-dimensional space: Crumpling transitions in the negative-bending-rigidity regimeAug 12 2005Folding of the triangular lattice in a discrete three-dimensional space is studied numerically. Such ``discrete folding'' was introduced by Bowick and co-workers as a simplified version of the polymerized membrane in thermal equilibrium. According to ... More
Folding of the triangular lattice in a discrete three-dimensional space: Density-matrix-renormalization-group studyMar 31 2004Folding of the triangular lattice in a discrete three-dimensional space is investigated numerically. Such ``discrete folding'' has come under through theoretical investigation, since Bowick and co-worker introduced it as a simplified model for the crumpling ... More
Quantum-fluctuation-induced collisions and subsequent excitation gap of an elastic string between wallsFeb 18 2002An elastic string embedded between rigid walls is simulated by means of the density-matrix renormalization group. The string collides against the walls owing to the quantum-mechanical zero-point fluctuations. Such ``quantum entropic'' interaction has ... More
Numerical analyses of the nonequilibrium electron transport through the Kondo impurity beside the Toulouse pointFeb 23 2000Nonequilibrium electron transport through the Kondo impurity is investigated numerically for the system with twenty conduction-electron levels. The electron current under finite voltage drop is calculated in terms of the `conductance viewed as transmission' ... More
Universal scaled Higgs-mass gap for the bilayer Heisenberg model in the ordered phaseJan 19 2016The spectral properties for the bilayer quantum Heisenberg model were investigated with the numerical diagonalization method. In the ordered phase, there appears the massive Higgs excitation embedded in the continuum of the Goldstone excitations. Recently, ... More
Neel-VBS phase boundary of the extended J_1-J_2 model with biquadratic interactionJan 04 2012The J_1-J_2 model with the biquadratic (plaquette-four-spin) interaction was simulated with the numerical-diagonalization method. Some limiting cases of this model have been investigated thoroughly. Taking the advantage of the extended parameter space, ... More
Random-field-driven phase transitions in the ground state of the S=1 XXZ spin chainMay 10 1998Ground-state of the S=1 XXZ spin chain under the influence of the random magnetic field is studied by means of the exact-diagonalization method. The S=1/2 counterpart has been investigated extensively so far. The easy-plane area, including the Haldane ... More
On the paper ``Weak convergence of some classes of martingales with jumps''Jul 31 2007This note extends some results of Nishiyama [Ann. Probab. 28 (2000) 685--712]. A maximal inequality for stochastic integrals with respect to integer-valued random measures which may have infinitely many jumps on compact time intervals is given. By using ... More
Enhanced orbit embeddingOct 09 2014Nov 23 2014Let $ \tilde{G} $ be an algebraic group acting on a variety $ \tilde{L} $, and $ G \subset \tilde{G} $ a subgroup which leaves a subvariety $ L \subset \tilde{L} $ stable. For a $ G $-orbit $ O_G = G u (u \in L) $ in $ L $, we can associate an orbit $ ... More
A note on affine quotients and equivariant double fibrationsJan 26 2007Jan 30 2007We consider two linear reductive algebraic groups $ G $ and $ G' $ over $ C $. Take a finite dimensional rational representation $ W $ of $ G \times G' $. Let $ Y = W // G := Spec C[W]^G $ and $ X = W // G' := \Spec C[W]^{G'} $ be the affine quotients. ... More
Asymptotic theory of semiparametric $Z$-estimators for stochastic processes with applications to ergodic diffusions and time seriesSep 02 2009This paper generalizes a part of the theory of $Z$-estimation which has been developed mainly in the context of modern empirical processes to the case of stochastic processes, typically, semimartingales. We present a general theorem to derive the asymptotic ... More
A Sepak Takraw - Based Molecular Model For C60 - A Mathematical Study Of A 60-Atom MoleculeApr 15 2015We mathematically investigate four molecular models of buckminsterfullerene (C60) discussing the strengths and weaknesses of each, and a new orthorhombic 20-dodecahedron model is proposed to replace the traditional truncated icosahedron model. This representation ... More
A stochastic maximal inequality, strict countability, and related topicsJul 05 2013Feb 10 2016As an alternative to the well-known methods of "chaining" and "bracketing" that have been developed in the study of random fields, a new method, which is based on a stochastic maximal inequality derived by using It\^o's formula and on a new concept named ... More
Divergence Network: Graphical calculation method of divergence functionsOct 30 2018Nov 01 2018In this paper, we introduce directed networks called `divergence network' in order to perform graphical calculation of divergence functions. By using the divergence networks, we can easily understand the geometric meaning of calculation results and grasp ... More
A remark on the Schrödinger equation on Zoll manifoldsMar 27 2011On the one dimensional sphere, the support of the fundamental solution to the Schr$\rm \ddot o$dinger equation consists of finite points at the time $t\in 2\pi\Q$. The paper \cite{Ka} generalized this fact to compact symmetric spaces. In this paper, we ... More
Sum decomposition of divergence into three divergencesOct 03 2018Oct 06 2018Divergence functions play a key role as to measure the discrepancy between two points in the field of machine learning, statistics and signal processing. Well-known divergences are the Bregman divergences, the Jensen divergences and the f-divergences. ... More
Generalized Bregman and Jensen divergences which include some f-divergencesAug 19 2018Sep 20 2018In this paper, we introduce new classes of divergences by extending the definitions of the Bregman divergence and the skew Jensen divergence. These new divergence classes (g-Bregman divergence and skew g-Jensen divergence) satisfy some properties similar ... More
Possible Pairing Symmetry of Three-dimensional Superconductor UPt$_3$ -- Analysis Based on a Microscopic Calculation --Jan 24 2005Stimulated by the anomalous superconducting properties of UPt$_3$, we investigate the pairing symmetry and the transition temperature in the two-dimensional(2D) and three-dimensional(3D) hexagonal Hubbard model. We solve the Eliashberg equation using ... More
The Whitham Deformation of the Dijkgraaf-Vafa TheorySep 25 2003Apr 06 2004We discuss the Whitham deformation of the effective superpotential in the Dijkgraaf-Vafa (DV) theory. It amounts to discussing the Whitham deformation of an underlying (hyper)elliptic curve. Taking the elliptic case for simplicity we derive the Whitham ... More
Robustness of scale-free networks to cascading failures induced by fluctuating loadsJul 01 2015Taking into account the fact that overload failures in real-world functional networks are usually caused by extreme values of temporally fluctuating loads that exceed the allowable range, we study the robustness of scale-free networks against cascading ... More
Distribution of Dust around Galaxies: An Analytic ModelMar 29 2012Apr 22 2012We develop an analytic halo model for the distribution of dust around galaxies. The model results are compared with the observed surface dust density profile measured through reddening of background quasars in the Sloan Digital Sky Survey (SDSS) reported ... More
Consistently Constrained SL(N) WZWN Models and Classical Exchange AlgebraJan 14 2013May 21 2014Currents of the SL(N) WZWN model are constrained so that the remaining symmetry is a symmetry of constrained currents as well. Such consistency enables us to study the Poisson structure of constrained SL(N) WZWN models properly. We establish the Poisson ... More
Characterization of Geometric Structures of Biaxial Nematic PhasesMay 16 2008May 22 2008The ordering matrix, which was originally introduced by de Gennes, is a well-known mathematical device for describing orientational order of biaxial nematic liquid crystal. In this paper we propose a new interpretation of the ordering matrix. We slightly ... More
Inequivalent Quantizations and Holonomy Factor from the Path-Integral ApproachSep 11 1996A path-integral quantization on a homogeneous space G/H is proposed based on the guiding principle `first lift to G and then project to G/H'. It is then shown that this principle gives a simple procedure to obtain the inequivalent quantizations (superselection ... More
The Fuzzy Kaehler Coset Space by the Fedosov FormalismMay 28 2001Jun 27 2001We discuss deformation quantization of the Kaehler coset space by using the Fedosov formalism. We show that the Killing potentials of the Kaehler coset space satisfy the fuzzy algebrae, when the coset space is irreducible.
Möbius transformation and a Cauchy family on the sphereOct 26 2015Aug 28 2018We present some properties of a Cauchy family of distributions on the sphere, which is a spherical extension of the wrapped Cauchy family on the circle. The spherical Cauchy family is closed under the M\"obius transformation on the sphere and there is ... More
Robustness analysis of bimodal networks in the whole range of degree correlationJul 13 2016We present exact analysis of the physical properties of bimodal networks specified by the two peak degree distribution fully incorporating the degree-degree correlation between node connection. The structure of the correlated bimodal network is uniquely ... More
Topological Landau-Ginzburg theory with a rational potential and the dispersionless KP hierarchyMay 19 1995Based on the dispersionless KP (dKP) theory, we give a comprehensive study of the topological Landau-Ginzburg (LG) theory characterized by a rational potential. Writing the dKP hierarchy in a general form, we find that the hierarchy naturally includes ... More
Spin-chain with PSU(2|2)xU(1)^3 and Non-linear Sigma-model with D(2,1;gamma)Feb 12 2015We propose that the spin-chain with the PSU(2|2)xU(1)^3 symmetry is equivalent to the non-linear sigma-model on PSU(2|2)xU(1)^3/{HxU(1)} with a certain subgroup. To this end we show that the spin-variable of the former theory is identified as the Killing ... More
Constrained WZWN Models on G/{S x U(1)^n} and Exchange Algebra of G-PrimariesJun 04 2013May 23 2014Consistently constrained WZWN models on G/{S x U(1)^n} is given by constraining currents of the WZWN models with G. Poisson brackets are set up on the light-like plane. Using them we show the Virasoro algebra for the energy-momentum tensor of constrained ... More
A Successive LP Approach with C-VaR Type Constraints for IMRT OptimizationDec 05 2016Radiation therapy is considered to be one of important treatment protocols for cancers. Radiation therapy employs several beams of ionizing radiation to kill cancer tumors, but such irradiation also causes damage to normal tissues. Therefore, a treatment ... More
Violent Relaxation of Spherical Stellar SystemsJan 31 1997Violent relaxation process of spherical stellar systems is examined by numerical simulations of shell model. The collapse of uniform density sphere both with and without external force is investigated. It is found that time variation of mean gravitational ... More
Conformal mapping for multivariate Cauchy familiesOct 26 2015We discuss some statistical properties of the multivariate Cauchy families on the Euclidean space and on the sphere. It is seen that the two multivariate Cauchy families are closed under conformal mapping called the M\"obius transformation and that, for ... More
A characterization of a Cauchy family on the complex spaceFeb 09 2014It is shown that a family of distributions on the complex space is characterized as the only family such that the orbit of one distribution under a certain group of transformations on the complex space is the same as that under the group of affine transformations. ... More
Robust estimation of location and concentration parameters for the von Mises-Fisher distributionJan 31 2012Robust estimation of location and concentration parameters for the von Mises-Fisher distribution is discussed. A key reparametrisation is achieved by expressing the two parameters as one vector on the Euclidean space. With this representation, we first ... More
Fuzzy Algebrae of the General Kaehler Coset Space G/H\otimesU(1)^kSep 10 2002We study the fuzzy structure of the general Kaehler coset space G/S\otimes{U(1)}^k deformed by the Fedosov formalism. It is shown that the Killing potentials satisfy the fuzzy algebrae working in the Darboux coordinates.
The Fuzzy Kaehler Coset Space with the Darboux CoordinatesSep 04 2001The Fedosov deformation quantization of the symplectic manifold is determined by a 1-form differential r. We identify a class of r for which the $\star$ product becomes the Moyal product by taking appropriate Darboux coordinates, but invariant by canonically ... More
Duality between front and rear mutations in cluster algebrasAug 06 2018We study the duality between the mutations and the rear mutations in cluster algebras, where the rear mutations are the transformations of rational expressions of cluster variables in terms of the initial cluster under the change of the initial cluster. ... More
Near-infrared Polarimetry of flares from Sgr A* with Subaru/CIAOJul 31 2009Aug 07 2009We have performed near-infrared monitoring observations of Sgr A*, the Galactic center radio source associated with a supermassive black hole, with the near-infrared camera CIAO and the 36-element adaptive optics system on the Subaru telescope. We observed ... More
Near-Infrared Polarimetry toward the Galactic CenterSep 29 2008Near-infrared polarimetry of point sources reveals the presence of a toroidal magnetic field in the central 20' x 20' region of our Galaxy. Comparing the Stokes parameters between high extinction stars and relatively low extinction ones, we have obtained ... More
Suzaku X-Ray Spectroscopy of a Peculiar Hot Star in the Galactic Center RegionDec 03 2007We present the results of a Suzaku study of a bright point-like source in the 6.7 keV intensity map of the Galactic center region. We detected an intense FeXXV 6.7 keV line with an equivalent width of ~1 keV as well as emission lines of highly ionized ... More
Impact of distance determinations on Galactic structure. I. Young and intermediate-age tracersApr 13 2018Here we discuss impacts of distance determinations on the Galactic disk traced by relatively young objects. The Galactic disk, about 40 kpc in diameter, is a cross-road of studies on the methods of measuring distances, interstellar extinction, evolution ... More
IRSF SIRIUS JHKs Simultaneous Transit Photometry of GJ1214bOct 11 2012We report high precision transit photometry of GJ1214b in JHKs bands taken simultaneously with the SIRIUS camera on the IRSF 1.4m telescope at Sutherland, South Africa. Our MCMC analyses show that the observed planet-to-star radius ratios in JHKs bands ... More