Results for "Daigorou Hirai"

total 151took 0.13s
Fabrication of (111)-oriented Ca0.5Sr0.5IrO3/SrTiO3 superlattices; a designed playground for honeycomb physicsMar 16 2015We report the fabrication of (111)-oriented superlattice structures with alternating 2m-layers (m = 1, 2, and 3) of Ca0.5Sr0.5IrO3 perovskite and two layers of SrTiO3 perovskite on SrTiO3(111) substrates. In the case of m = 1 bilayer films, the Ir sub-lattice ... More
Semimetallic transport properties of epitaxially stabilized perovskite CaIrO3 filmsJan 07 2015We report on the synthesis and transport properties of perovskite (Pv) CaIrO3 thin films. The Pv phase of CaIrO3 was stabilized by epitaxial growth on SrTiO3, (LaAlO3)0.3(Sr2AlTaO6)0.7, and LaAlO3 substrates with strong tensile, weak tensile, and compressive ... More
Pyrochlore Oxide Superconductor Cd2Re2O7 RevisitedDec 11 2017The superconducting pyrochlore oxide Cd2Re2O7 is revisited with a particular emphasis on the sample-quality issue. The compound has drawn attention as the only superconductor (Tc = 1.0 K) that has been found in the family of {\alpha}-pyrochlore oxides ... More
Successive Symmetry Breaking in a Jeff = 3/2 Quartet in the Spin-Orbit Coupled Insulator Ba2MgReO6Jun 10 2019We report on the cubic double perovskite Ba2MgReO6 containing Re6+ ions with the 5d1 electron configuration. Resistivity, magnetization, and heat capacity measurements using single crystals show that the compound is a Mott insulator with a magnetic transition ... More
Split Fermi Surfaces of the Spin-Orbit-Coupled Metal Cd2Re2O7 Probed by de Haas-van Alphen EffectMar 28 2018The superconducting pyrochlore oxide Cd2Re2O7 shows a structural transition with inversion symmetry breaking (ISB) at Ts1 = 200 K. A recent theory [L. Fu, Phys. Rev. Lett. 115, 026401 (2015)] suggests that the origin is an electronic instability that ... More
One-dimensionalization by Geometrical Frustration in the Anisotropic Triangular Lattice of the 5d Quantum Antiferromagnet Ca3ReO5Cl2Apr 12 2019We report on the emergence of antiferromagnetic spin chains from two-dimensionally aligned spins on the anisotropic triangular lattice (ATL) in the insulating calcium rhenium oxychloride Ca3ReO5Cl2. The compound contains Re6+ ions each with one unpaired ... More
Synthesis of anti-perovskite-type carbides and nitrides from metal oxides and melamineApr 12 2019Four anti-perovskite-type compounds, ZnNNi3, ZnCNi3, SnNCo3, and SnCCo3, are synthesised through reactions between ingredient metal oxides and organic compound melamine (C3H6N6). ZnNNi3 and ZnCNi3 are selectively synthesised by choosing different reaction ... More
The emergence of superconductivity in BaNi2(Ge1-xPx)2 at a structural instabilityAug 01 2012The physical properties and structural evolution of the 122-type solid solution BaNi2(Ge1-xPx)2 are reported. The in-plane X-X (X = Ge1-xPx) dimer formation present in the end member BaNi2Ge2, which results in a structural transition to orthorhombic symmetry, ... More
Formation and Control of Twin Domains in the Pyrochlore Oxide Cd2Re2O7Sep 04 2018Sep 20 2018The successive phase transitions of the pyrochlore oxide Cd2Re2O7 are studied by polarizing microscopy and magnetic susceptibility measurements. The formation of twin domains is visualized in the polarizing images of a pristine (111) crystal surface upon ... More
Strong Electron-Phonon Coupling Superconductivity Induced by a Low-lying Phonon in IrGeMar 20 2018The physical properties of the previously reported superconductor IrGe and the Rh1-xIrxGe solid solution are investigated. IrGe has an exceptionally high superconducting transition temperature (Tc = 4.7 K) among the isostructural 1:1 late-metal germanides ... More
Superconductivity at 3.7 K in Ternary Silicide Li2IrSi3Sep 12 2014We report the discovery of superconductivity at Tc = 3.7 K in the new ternary lithium silicide Li2IrSi3. The crystal structure of Li2IrSi3 consists of IrSi6 antiprisms connected by Si triangles, giving rise to a three dimensional framework of covalent ... More
Update of HKN Nuclear PDFsMar 25 2016We discuss consistency of the nuclear effects between the electromagnetic and weak interactions. In order to study a possibility of different nuclear effects in the neutrino DIS process, double differential cross section data are compared with these values ... More
Pre-inflation models and WMAP dataApr 27 2004The effect of pre-inflation physics on the power spectrum of scalar perturbations is estimated and there is a possibility that the pre-inflation physics explains the Wilkinson Microwave Anisotropy Probe data if the length of inflation is near 60 e-folds. ... More
On uncrossing games for skew-supermodular functionsSep 29 2015Jan 18 2016In this note, we consider the uncrossing game for a skew-supermodular function $f$, which is a two-player game with players, Red and Blue, and abstracts the uncrossing procedure in the cut-covering linear program associated with $f$. Extending the earlier ... More
Shrinking of Operators in Quantum Error Correction and AdS/CFTJun 13 2019We first show that a class of operators acting on a given bipartite pure state on $\mathcal{H}_{A}\otimes\mathcal{H}_{B}$ can shrink its supports on $\mathcal{H}_{A}\otimes\mathcal{H}_{B}$ to only $\mathcal{H}_{A}$ or $\mathcal{H}_{B}$ while keeping its ... More
Discrete Convexity and Polynomial Solvability in Minimum 0-Extension ProblemsMay 20 2014Oct 17 2014For a graph G and a set V containing the vertex set of G, a 0-extension of G is a metric d on V such that d extends the shortest path metric of G and for all x in V there exists a vertex s in G with d(x, s) = 0. The minimum 0-extension problem 0-Ext[G] ... More
Initial condition of scalar perturbation in inflationDec 04 2002A formula for the power spectrum of curvature perturbations having any initial conditions in inflation is obtained. Based on the physical conditions before inflation, the possibility exists that the initial state of scalar perturbations is not only the ... More
Computing DM-decomposition of a partitioned matrix with rank-1 blocksSep 07 2016In this paper, we develop a polynomial time algorithm to compute a Dulmage-Mendelsohn-type decomposition of a matrix partitioned into submatrices of rank at most $1$.
Remarks on Föllmer's pathwise Itô calculusOct 16 2017We extend some results about F\"ollmer's pathwise It\^o calculus that have only been derived for continuous paths to c\`adl\`ag paths with quadratic variation. We study some fundamental properties of pathwise It\^o integrals with respect to c\`adl\`ag ... More
A dual descent algorithm for node-capacitated multiflow problems and its applicationsAug 28 2015Oct 29 2018In this paper, we develop an $O((m \log k) {\rm MSF} (n,m,1))$-time algorithm to find a half-integral node-capacitated multiflow of the maximum total flow-value in a network with $n$ nodes, $m$ edges, and $k$ terminals, where ${\rm MSF} (n',m',\gamma)$ ... More
Effect of Pre-inflation Conditions on Scalar and Tensor Perturbations in InflationJul 24 2003The effect of the initial conditions in inflation on scalar and tensor perturbations is investigated. Formulae for the power spectra of gravitational waves and curvature perturbations for any initial conditions in inflation are derived, and the ratio ... More
Entropy Oriented Trading: A Trading Strategy Based on the Second Law of ThermodynamicsMay 21 2007The author proposes a finance trading strategy named Entropy Oriented Trading and apply thermodynamics on the strategy. The state variables are chosen so that the strategy satisfies the second law of thermodynamics. Using the law, the author proves that ... More
L-extendable functions and a proximity scaling algorithm for minimum cost multiflow problemNov 17 2014Jul 28 2015In this paper, we develop a theory of new classes of discrete convex functions, called L-extendable functions and alternating L-convex functions, defined on the product of trees. We establish basic properties for optimization: a local-to-global optimality ... More
Computing the degree of determinants via discrete convex optimization on Euclidean buildingsMay 29 2018Jun 27 2019In this paper, we consider the computation of the degree of the Dieudonn\'e determinant of a linear symbolic matrix $A = A_0 + A_1 x_1 + \cdots + A_m x_m$, where each $A_i$ is an $n \times n$ polynomial matrix over $\mathbb{K}[t]$ and $x_1,x_2,\ldots,x_m$ ... More
Computing DM-decomposition of a partitioned matrix with rank-1 blocksSep 07 2016Feb 17 2018In this paper, we develop a polynomial time algorithm to compute a Dulmage-Mendelsohn-type decomposition of a matrix partitioned into submatrices of rank at most $1$.
A dual descent algorithm for node-capacitated multiflow problems and its applicationsAug 28 2015Oct 02 2015In this paper, we develop an $O((m \log k) {\rm MSF} (n,m,1))$-time algorithm to find a half-integral node-capacitated multiflow of the maximum total flow-value in a network with $n$ nodes, $m$ edges, and $k$ terminals, where ${\rm MSF} (n',m',\gamma)$ ... More
L-convexity on graph structuresOct 08 2016In this paper, we study classes of discrete convex functions: submodular functions on modular semilattices and L-convex functions on oriented modular graphs. They were introduced by the author in complexity classification of minimum 0-extension problems. ... More
Session Types in Abelian LogicDec 10 2013There was a PhD student who says "I found a pair of wooden shoes. I put a coin in the left and a key in the right. Next morning, I found those objects in the opposite shoes." We do not claim existence of such shoes, but propose a similar programming abstraction ... More
Computing degree of determinant via discrete convex optimization on Euclidean buildingMay 29 2018Dec 16 2018In this paper, we consider the computation of the degree of the Dieudonn\'e determinant of a linear symbolic matrix $A = A_0 + A_1 x_1 + \cdots + A_m x_m$, where each $A_i$ is an $n \times n$ polynomial matrix over $\mathbb{K}[t]$ and $x_1,x_2,\ldots,x_m$ ... More
A Nonpositive Curvature Property of Modular SemilatticesMay 04 2019The orthoscheme complex of a graded poset is a metrization of its order complex such that the simplex of each maximal chain is isometric to the Euclidean simplex of vertices $0, e_1,e_1+e_2,\ldots, e_1+e_2+ \cdots + e_n$. This notion was introduced by ... More
Remarkable suppression of Josephson current on d-wave superconductor junctionJan 08 2009Feb 23 2009Josephson current in superconductor/insulator/superconductor junction is studied theoretically. It is well known that when the zero-energy resonance state exists both side of superconducting interface, the behaver of the temperature dependence of the ... More
Uniform modular lattice and Euclidean buildingDec 31 2017In this paper, we present a simple lattice-theoretic characterization for Euclidean building of type A. We introduce a class of modular lattices, called uniform modular lattices, and show that uniform modular lattices and Euclidean buildings of type A ... More
Uniform semimodular lattices and valuated matroidsFeb 24 2018Mar 01 2019In this paper, we present a lattice-theoretic characterization for valuated matroids, which is an extension of the well-known cryptomorphic equivalence between matroids and geometric lattices ($=$ atomistic semimodular lattices). We introduce a class ... More
Superconductivity in the Cu(Ir1-xPtx)2Se4 SpinelMay 15 2013We report the observation of superconductivity in the CuIr2Se4 spinel induced by partial substitution of Pt for Ir. The optimal doping level for superconductivity in Cu(Ir1-xPtx)2Se4 is x = 0.2, where Tc is 1.76 K. A superconducting Tc vs. composition ... More
Non-Gaussianity and finite length inflationFeb 03 2010Apr 23 2010In the present paper, certain inflation models are shown to have large non-Gaussianity in special cases. Namely, finite length inflation models with an effective higher derivative interaction, in which slow-roll inflation is adopted as inflation and a ... More
Time dependence of cosmological and inflationary parameters in slow-roll inflationDec 05 2008Dec 15 2008The dependence of cosmological and inflationary parameters on time during the last 60 e-folds in inflation is investigated using a slow-roll inflation model. The time dependence of the inflaton field is calculated for the case of chaotic inflation by ... More
Effect of initial condition of inflation on power and angular power spectra in finite slow-roll inflationOct 12 2007The effect of the initial condition of inflation on the power spectra of scalar and tensor perturbations is estimated assuming a slow-roll inflation model. By defining a more general initial state in inflation particular properties of the power spectrum ... More
A Combinatorial Formula for Principal Minors of a Matrix with Tree-metric Exponents and Its ApplicationsNov 28 2013Nov 15 2014Let $T$ be a tree with a vertex set $\{ 1,2,\dots, N \}$. Denote by $d_{ij}$ the distance between vertices $i$ and $j$. In this paper, we present an explicit combinatorial formula of principal minors of the matrix $(t^{d_{ij}})$, and its applications ... More
Possible Signatures of Ejecta-Companion Interaction in iPTF 13bvnApr 08 2015May 30 2015We investigate the possible effects of the supernova ejecta hitting the companion star in iPTF 13bvn, focusing on the observable features when it becomes visible. iPTF 13bvn is a type Ib supernova that may become the first case that its progenitor is ... More
On duality and fractionality of multicommodity flows in directed networksJun 29 2010Mar 26 2011In this paper we address a topological approach to multiflow (multicommodity flow) problems in directed networks. Given a terminal weight $\mu$, we define a metrized polyhedral complex, called the directed tight span $T_{\mu}$, and prove that the dual ... More
Normalized Maximum Likelihood Coding for Exponential Family with Its Applications to Optimal ClusteringMay 16 2012May 17 2012We are concerned with the issue of how to calculate the normalized maximum likelihood (NML) code-length. There is a problem that the normalization term of the NML code-length may diverge when it is continuous and unbounded and a straightforward computation ... More
Scale dependence of the power spectrum of the curvature perturbation determined using a numerical method in slow-roll inflationAug 05 2009The Taylor expansion method has been used to investigate the scale dependence of the power spectrum of the curvature perturbation. In the present study, an alternative numerical method is used to clarify the $k$ dependence. Although there is thought to ... More
Effect of polarized gluon distribution on spin asymmetries for neutral and charged pion productionMar 09 2004Jan 13 2005A longitudinal double spin asymmetry for \pi^0 production has been measured by the PHENIX collaboration. The asymmetry is sensitive to the polarized gluon distribution and is indicated to be positive by theoretical predictions. We study a correlation ... More
Maximum vanishing subspace problem, CAT(0)-space relaxation, and block-triangularization of partitioned matrixMay 05 2017Sep 11 2017In this paper, we address the following algebraic generalization of the bipartite stable set problem. We are given a block-structured matrix (partitioned matrix) $A = (A_{\alpha \beta})$, where $A_{\alpha \beta}$ is an $m_{\alpha}$ by $n_{\beta}$ matrix ... More
On tight spans and tropical polytopes for directed distancesApr 03 2010An extension $(V,d)$ of a metric space $(S,\mu)$ is a metric space with $S \subseteq V$ and $d|_S = \mu$, and is said to be tight if there is no other extension $(V,d')$ of $(S,\mu)$ with $d' \leq d$. Isbell and Dress independently found that every tight ... More
Effect of the length of inflation on angular TT and TE power spectra in power-law inflationDec 13 2005The effect of the length of inflation on the power spectra of scalar and tensor perturbations is estimated using the power-law inflation model with a scale factor of a(t) = t^q. Considering various pre-inflation models with radiation-dominated or scalar ... More
A compact representation for minimizers of $k$-submodular functionsOct 01 2016A $k$-submodular function is a generalization of submodular and bisubmodular functions. This paper establishes a compact representation for minimizers of a $k$-submodular function by a poset with inconsistent pairs (PIP). This is a generalization of Ando--Fujishige's ... More
Shortest (A+B)-path packing via hafnianMar 26 2016Bj\"orklund and Husfeldt developed a randomized polynomial time algorithm to solve the shortest two disjoint paths problem. Their algorithm is based on computation of permanents modulo 4 and the isolation lemma. In this paper, we consider the following ... More
On k-Submodular RelaxationApr 29 2015Sep 09 2016$k$-submodular functions, introduced by Huber and Kolmogorov, are functions defined on $\{0, 1, 2, \dots, k\}^n$ satisfying certain submodular-type inequalities. $k$-submodular functions typically arise as relaxations of NP-hard problems, and the relaxations ... More
Reconstructing phylogenetic tree from multipartite quartet systemApr 03 2019A phylogenetic tree is a graphical representation of an evolutionary history of taxa in which the leaves correspond to the taxa and the non-leaves correspond to speciations. One of important problems in phylogenetic analysis is to assemble a global phylogenetic ... More
Polyhedral Clinching Auctions for Two-sided MarketsAug 15 2017Sep 14 2018In this paper, we present a new model and two mechanisms for auctions in two-sided markets of buyers and sellers, where budget constraints are imposed on buyers. Our model incorporates polymatroidal environments, and is applicable to a wide variety of ... More
Length of inflation and WMAP data in the case of power-law inflationJun 21 2005The effect of the length of inflation on the power spectra of scalar and tensor perturbations is estimated using the power-law inflation model with a scale factor of a(t) = t^q. Considering various pre-inflation models with radiation-dominated or matter-dominated ... More
Projective representations and spin characters of complex reflection groups $G(m, p, n)$ and $G(m, p, \infty)$, IIIApr 17 2018Oct 17 2018This paper is a continuation of two previous papers in MSJ Memoirs, Vol.\,29 (Math. Soc. Japan, 2013) with the same title and numbered as I and II. Based on the hereditary property given there, from mother groups $G(m,1,n)$, the generalized symmetric ... More
"Visible" 5d orbital states in a pleochroic oxychlorideApr 12 2019Transition metal compounds sometimes exhibit beautiful colors. We report here on a new oxychloride Ca3ReO5Cl2 which shows unusually distinct pleochroism; that is, the material exhibits different colors depending on viewing directions. This ple-ochroism ... More
Efficiency of metal mixing in dwarf galaxiesMar 16 2017Metal mixing plays critical roles in the enrichment of metals in galaxies. The abundance of elements such as Mg, Fe, and Ba in metal-poor stars help us understand the metal mixing in galaxies. However, the efficiency of metal mixing in galaxies is not ... More
Gauge-Invariant Cosmological Perturbations in Generalized Einstein TheoriesApr 12 1994Using the covariant approach and conformal transformations, we present a gauge-invariant formalism for cosmological perturbations in generalized Einstein theories (GETs), including the Brans-Dicke theory, theories with a non-minimally coupled scalar field ... More
Nuclear parton distribution functions and their uncertaintiesApr 09 2004Jul 15 2004We analyze experimental data of nuclear structure-function ratios F_2^A/F_2^{A'} and Drell-Yan cross section ratios for obtaining optimum parton distribution functions (PDFs) in nuclei. Then, uncertainties of the nuclear PDFs are estimated by the Hessian ... More
A possible nuclear effect on the NuTeV sin^2 theta_W anomalyJan 10 2006We investigate a possible explanation for the NuTeV anomaly in terms of a nuclear correction difference between u_v and d_v distributions. Analyzing deep elastic scattering and Drell-Yan data for nuclear targets, we try to determine the correction difference ... More
Nuclear modification of valence-quark distributions and its effects on NuTeV sin^2 theta_W anomalyDec 21 2004We investigated a nuclear modification difference between up- and down-valence quark distributions by analyzing structure function F_2 and Drell-Yan cross-section ratios. Although nuclear modifications of the valence-quark distributions themselves are ... More
Determination of polarized parton distribution functionsDec 21 2000We study parametrization of polarized parton distribution functions in the \alpha_s leading order (LO) and in the next-to-leading order (NLO). From \chi^2 fitting to the experimental data on A_1, optimum polarized distribution functions are determined. ... More
Global NLO Analysis of Nuclear Parton Distribution FunctionsNov 16 2007Nuclear parton distribution functions (NPDFs) are determined by a global analysis of experimental measurements on structure-function ratios F_2^A/F_2^{A'} and Drell-Yan cross section ratios \sigma_{DY}^A/\sigma_{DY}^{A'}, and their uncertainties are estimated ... More
Constraint on $Δg(x)$ at large $x$Jul 06 2006We investigate the polarized gluon distribution \Delta g(x) by a global analysis of current DIS data and the \pi^0 data from RHIC-Spin experiments. The \pi^0 data provide a strong constraint on \Delta g(x), so that its uncertainty is reduced. Furthermore, ... More
Global analysis of AAC for determining polarized parton distribution functionsJan 11 2006We report global analysis results for polarized parton distribution functions in the nucleon. The optimum distributions are determined by using spin asymmetry data on polarized lepton scattering on proton, neutron, and deuteron. Their uncertainties are ... More
Determination of polarized parton distribution functions with recent data on polarization asymmetriesMar 25 2006Jun 28 2006Global analysis has been performed within the next-to-leading order in Quantum Chromodynamics (QCD) to determine polarized parton distributions with new experimental data in spin asymmetries. The new data set includes JLab, HERMES, and COMPASS measurements ... More
Counting Integral Points in Polytopes via Numerical Analysis of Contour IntegrationJul 14 2018In this paper, we address the problem of counting integer points in a rational polytope described by $P(y) = \{ x \in \mathbb{R}^m \colon Ax = y, x \geq 0\}$, where $A$ is an $n \times m$ integer matrix and $y$ is an $n$-dimensional integer vector. We ... More
Nuclear effects in neutrino-nucleus DISSep 12 2009We explain the current status of nuclear parton distribution functions in connection with neutrino-nucleus interactions. Neutrino deep inelastic scattering (DIS) measurements have been done for heavy nuclear targets such as iron and lead. In order to ... More
Nuclear parton distribution functions and their effects on sin^2 theta_W anomalyAug 03 2004Nuclear parton distribution functions (NPDFs) are investigated by analyzing the data on structure functions F_2^A and Drell-Yan cross sections sigma_{DY}^{pA}. An important point of this analysis is to show uncertainties of the NPDFs by the Hessian method. ... More
Determination of nuclear parton distribution functions and their uncertainties at next-to-leading orderSep 19 2007Dec 12 2007Nuclear parton distribution functions (NPDFs) are determined by global analyses of experimental data on structure-function ratios F_2^A/F_2^{A'} and Drell-Yan cross-section ratios \sigma_{DY}^A/\sigma_{DY}^{A'}. The analyses are done in the leading order ... More
The Outcome of Supernovae in Massive Binaries; Removed Mass, and its Separation DependenceApr 16 2014Aug 01 2014The majority of massive stars are formed in binary systems. It is hence reasonable to expect that most core-collapse supernovae (CCSNe) take place in binaries and the existence of a companion star may leave some imprints in observed features. Having this ... More
Dynamics of Quiet UniversesAug 28 1996We study the stability of a contracting {\it silent universe}, which is a spacetime with irrotational dust and vanishing magnetic part of the Weyl tensor, $H_{ab}=0$. Two general relativistic backgrounds are analyzed; one is an attractor of {\it silent ... More
Nuclear modification difference between u_v and d_v distributions and its relation to NuTeV sin^2 theta_W anomalyDec 20 2004Jun 10 2005We investigate a possible nuclear correction to the NuTeV measurement of the weak-mixing angle sin^2 theta_W. In particular, a nuclear modification difference between u_v and d_v distributions contributes to the NuTeV measurement with the iron target. ... More
Nuclear corrections of parton distribution functionsAug 11 2004We report global analysis results of experimental data for nuclear structure-function ratios F_2^A/F_2^{A'} and proton-nucleus Drell-Yan cross-section ratios sigma_{DY}^{pA}/sigma_{DY}^{pA'} in order to determine optimum parton distribution functions ... More
A representation of antimatroids by Horn rules and its application to educational systemsAug 22 2015Sep 27 2016We study a representation of an antimatroid by Horn rules, motivated by its recent application to computer-aided educational systems. We associate any set $\mathcal{R}$ of Horn rules with the unique maximal antimatroid $\mathcal{A}(\mathcal{R})$ that ... More
Recent progress on nuclear parton distribution functionsFeb 17 2011Mar 22 2011We report current status of global analyses on nuclear parton distribution functions (NPDFs). The optimum NPDFs are determined by analyzing high-energy nuclear reaction data. Due to limited experimental measurements, antiquark modifications have large ... More
Determination of polarized parton distribution functions and their uncertaintiesDec 09 2003Dec 18 2003We investigate the polarized parton distribution functions (PDFs) and their uncertainties by using the world data on the spin asymmetry A_1. The uncertainties of the polarized PDFs are estimated by the Hessian method. The up and down valence-quark distributions ... More
Constraint on Δg(x) from π^0 production at RHICDec 05 2006We determine the polarized gluon distribution \Delta g(x) by a global analysis using current DIS and \pi^0 asymmetry data. The \pi^0 data from RHIC-Spin experiments provide a strong constraint on \Delta g(x), so that its uncertainty is reduced. However, ... More
Resonant magnetic X-ray scattering spectra in SDW Cr -- ab initio study -----Jun 24 2004Using ab-initio band structure calculation based on the local density approximation, Cr K-edge resonant X-ray magnetic scattering spectra are analyzed in the spin density wave (SDW) state of chromium. We perform band structure calculation, assuming an ... More
Comprehensive study of ejecta-companion interaction for core-collapse supernovae in massive binariesMar 28 2018Jul 27 2018We carry out a comprehensive study of supernova ejecta-companion interaction in massive binary systems. We aim to physically understand the kinematics of the interaction and predict observational signatures. To do this we perform simulations over a vast ... More
A representation of antimatroids by Horn rules and its application to educational systemsAug 22 2015Sep 09 2018We study a representation of an antimatroid by Horn rules, motivated by its recent application to computer-aided educational systems. We associate any set $\mathcal{R}$ of Horn rules with the unique maximal antimatroid $\mathcal{A}(\mathcal{R})$ that ... More
Determination of fragmentation functions and their uncertaintiesFeb 25 2007Apr 16 2007Fragmentation functions and their uncertainties are determined for pion, kaon, and proton by a global $\chi^2$ analysis of charged-hadron production data in electron-positron annihilation and by the Hessian method for error estimation. It is especially ... More
Performance study of SKIROC2 and SKIROC2A with BGA testboardMar 23 2017SKIROC2 is an ASIC to readout the silicon pad detectors for the electromagnetic calorimeter in the International Linear Collider. Characteristics of SKIROC2 and the new version of SKIROC2A, packaged with BGA, are measured with testboards and charge injection. ... More
Weakly modular graphs and nonpositive curvatureSep 13 2014Jan 13 2016This article investigates structural, geometrical, and topological characterizations and properties of weakly modular graphs and of cell complexes derived from them. The unifying themes of our investigation are various `nonpositive curvature' and `local-to-global' ... More
Theory of the Josephson effect in superconductor / one-dimensional electron gas / superconductor junctionFeb 26 1999Jun 11 1999We present a theory for the Josephson effect in an unconventional superconductor / one-dimensional electron gas / unconventional superconductor (s/o/s) junction, where the Josephson current is carried by components injected perpendicular to the interface. ... More
Hydrodynamical simulations and similarity relations for eruptive mass loss from massive starsFeb 17 2019Motivated by the eruptive mass loss inferred from Luminous Blue Variable (LBV) stars, we present 1D hydrodynamical simulations of the response from sudden energy injection into the interior of a very massive ($100 \, M_\odot$) star. For a fiducial case ... More
Clustering structure of nuclei in deep inelastic processesAug 04 2014A clustering aspect is explained for the $^9$Be nucleus in charged-lepton deep inelastic scattering. Nuclear modifications of the structure function $F_2$ are studied by the ratio $R_{\rm EMC} = F_2^A /F_2^D$, where $A$ and $D$ are a nucleus and the deuteron, ... More
Parity-sensitive measurements based on ferromagnet/superconductor tunneling junctionsMay 24 2001Jun 15 2001A method to identify the parity of unconventional superconductors is proposed based on tunneling spectroscopy. For a model of calculation, we adopt a ferromagnet/superconductor (F/S) junction of which tunneling current is spin polarized. The tunneling ... More
Metal-insulator transition and superconductivity induced by Rh doping in binary Ru Pnictides RuPn (Pn = P, As and Sb)Dec 02 2011Binary ruthenium pnictides, RuP and RuAs, with an orthorhombic MnP structure, were found to show a metal to a non-magnetic insulator transition at TMI = 270 K and 200 K, respectively. In the metallic region above TMI, a structural phase transition, accompanied ... More
Impacts of B-factory measurements on determination of fragmentation functions from electron-positron annihilation dataAug 14 2016Sep 27 2016Fragmentation functions are determined for the pion and kaon by global analyses of charged-hadron production data in electron-positron annihilation. Accurate measurements were reported by the Belle and BaBar collaborations for the fragmentation functions ... More
Selected topics on parton distribution functionsNov 02 2011We report recent studies on structure functions of the nucleon and nuclei. First, clustering effects are investigated in the structure function F_2 of Be-9 for explaining an unusual nuclear correction found in a JLab experiment. We propose that high densities ... More
Clustering aspects in nuclear structure functionsAug 07 2010Feb 16 2011For understanding an anomalous nuclear effect experimentally observed for the beryllium-9 nucleus at the Thomas Jefferson National Accelerator Facility (JLab), clustering aspects are studied in structure functions of deep inelastic lepton-nucleus scattering ... More
Angular Power Spectrum and Dilatonic Inflation in Modular-Invariant SupergravityJan 23 2006The angular power spectrum is investigated in the model of supergravity, incorporating the target-space duality and the non-perturbative gaugino condensation in the hidden sector. The inflation and supersymmetry breaking occur at once by the interplay ... More
Weakly modular graphs and nonpositive curvatureSep 13 2014Nov 10 2017This article investigates structural, geometrical, and topological characterizations and properties of weakly modular graphs and of cell complexes derived from them. The unifying themes of our investigation are various `nonpositive curvature' and `local-to-global' ... More
Hyperbolic Self-Gravity Solver for Large Scale Hydrodynamical SimulationsFeb 18 2016Mar 29 2016A new computationally efficient method has been introduced to treat self-gravity in mesh based hydrodynamical simulations. It is applied simply by slightly modifying the Poisson equation into an inhomogeneous wave equation. This roughly corresponds to ... More
Global analysis for determining fragmentation functions and their uncertainties in light hadronsMay 19 2007Fragmentation functions are determined for the pion, kaon, and proton by analyzing charged-hadron production data in electron-positron annihilation. It is important that uncertainties of the determined fragmentation functions are estimated in this analysis. ... More
A tractable class of binary VCSPs via M-convex intersectionJan 07 2018A binary VCSP is a general framework for the minimization problem of a function represented as the sum of unary and binary cost functions. An important line of VCSP research is to investigate what functions can be solved in polynomial time. Cooper--\v{Z}ivn\'{y} ... More
Proposal for exotic-hadron search by fragmentation functionsAug 14 2007Jan 24 2008It is proposed that fragmentation functions should be used to identify exotic hadrons. As an example, fragmentation functions of the scalar meson f_0(980) are investigated. It is pointed out that the second moments and functional forms of the u- and s-quark ... More
Determination of f_0(980) Structure by Fragmentation FunctionsFeb 19 2008We discuss internal structure of an exotic hadron by using fragmentation functions. The fragmentation functions for the f_0(980) meson are obtained by a global analysis of e^++e^- \to f_0+X data. Quark configuration of the f_0(980) could be determined ... More
Determination of fragmentation functions and their uncertainties from e+ + e- -> h + X dataDec 01 2006Fragmentation functions are determined for pions, kaons, and nucleons by a global analysis of charged-hadron production data in electron-positron annihilation. The optimum functions are obtained in both leading order (LO) and next-to-leading order (NLO) ... More
Containment for Conditional Tree PatternsMar 07 2015Jun 06 2015A Conditional Tree Pattern (CTP) expands an XML tree pattern with labels attached to the descendant edges. These labels can be XML element names or Boolean CTPs. The meaning of a descendant edge labelled by A and ending in a node labelled by B is a path ... More
Enrichment of Zinc in galactic chemodynamical evolution modelsJan 24 2018The heaviest iron-peak element, Zn has been used as an important tracer of cosmic chemical evolution. Spectroscopic observations of the metal-poor stars in Local Group galaxies show that an increasing trend of [Zn/Fe] ratios toward lower metallicity. ... More