Results for "Yoshiaki Tsujimoto"

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Implications of Elemental Abundances in Dwarf Spheroidal GalaxiesSep 28 2005Sep 29 2005Unusual elemental abundance patterns observed for stars belonging to nearby dwarf spheroidal (dSph) galaxies are discussed. Analysis of the [alpha/H] vs. [Fe/H] diagrams where alpha represents Mg or average of alpha-elements reveals that Fe from Type ... More
Turn-off of Deuterium Astration in the Recent Star Formation of the Galaxy DiskSep 05 2010Chemical features of the local stellar disk have firmly established that long-term, continuous star formation has been accompanied by a steady rate of accretion of low-metallicity gas from the halo. We now argue that the recent discovery of an enhanced ... More
Chemical Signature Indicating A Lack of Massive Stars in Dwarf GalaxiesMay 16 2011Growing evidence supports an unusual elemental feature appearing in nearby dwarf galaxies, especially dwarf spheroidals (dSphs), indicating a key process of galaxy evolution that is different from that of the Galaxy. In addition to the well-known deficiency ... More
Fossil Imprints of Outflow from the Galactic Bulge in Elemental Abundances of Metal-Rich Disk StarsJul 09 2007We explore the elemental abundance features of metal-rich disk stars, highlighting the comparisons made with those of the recently revealed Galactic bulge stars. A similarity between two of the comparisons leads to a new theoretical picture of the bulge-disk ... More
A New Contributor to Chemical Evolution in High-Redshift GalaxiesJun 29 2004The recent discovery of a new population of stars exhibiting unusual elemental abundance patterns characterized by enhanced Ti to Ga elements and low alpha and n-capture elements suggests the contribution of a new class of supernovae, probably a kind ... More
Twisted period relations for Lauricella's hypergeometric function F_AOct 23 2013We study Lauricella's hypergeometric function $F_A$ of $m$-variables and the system $E_A$ of differential equations annihilating $F_A$, by using twisted (co)homology groups. We construct twisted cycles with respect to an integral representation of Euler ... More
Effective non-vanishing of global sections of multiple adjoint bundles for polarized 4-foldsOct 22 2010Let X be a smooth complex projective variety of dimension 4 and let L be an ample line bundle on X. In this paper, we study a natural number m such that h^{0}(m(K_{X}+L))>0 for any polarized 4-folds (X,L) with \kappa(K_{X}+L)\geq 0.
A technique for loop calculations in non-Abelian gauge theories - with application to five gluon amplitudeNov 24 1999A powerful tool for calculations in non-Abelian gauge theories is obtained by combining the background field gauge, the helicity basis and the color decomposition methods. It has reproduced the one-loop calculation of the five-gluon amplitudes in QCD, ... More
Analysis of the spin structure function $g_2(x,Q^2)$ and twist-3 operatorsJan 25 1995We discuss the spin-dependent structure function $g_2(x,Q^2)$ in the framework of the operator product expansion. It is noted that the anomalous dimensions and coefficient functions for the twist-3 gluon-field-dependent operators depend on the choice ... More
Third Quantization of Kaluza-Klein Cosmology and CompactificationDec 08 1997We study on the third quantization of a Kaluza-Klein toy model. In this model time ($x$) is defined by the scale factor of universe, and the space coordinate ($y$) is defined by the ratio of the scales of the ordinary space and the internal space. We ... More
Decoherence Functional and Probability InterpretationJan 09 1993We confirm that the diagonal elements of the Gell-Mann and Hartle's decoherence decoherence functional are equal to the relative frequencies of the results of many identical experiments, when a set of alternative histories decoheres. We consider both ... More
Discovery of Active Galactic Nuclei in Mid- and Far-Infrared Deep Surveys with ISONov 01 2001We present a summary on the discovery of active galactic nuclei in mid- and far-infrared deep surveys with use of the Infrared Space Observatory.
Electric magnetic duality of the confining flux tube in Abelian-projected gluodynamicsDec 30 2002The structure of the Abelian-projected (AP) flux tube in SU(2) gauge theory in the maximally Abelian gauge is studied by applying the Hodge decomposition to the Abelian Wilson loop. It is shown that the profile of the AP flux tube has the same structure ... More
Deriving the factor endowment--commodity output relationship for Thailand (1920-1927) using a three-factor two-good general equilibrium trade modelOct 11 2018Feeny (1982, pp. 26-28) referred to a three-factor two-good general equilibrium trade model, when he explained the relative importance of trade and factor endowments in Thailand 1880-1940. For example, Feeny (1982) stated that the growth in labor stock ... More
A lower bound for $K_{X}L$ of quasi-polarized surfaces $(X,L)$ with non-negative Kodaira dimensionJul 15 1996Let $X$ be a smooth projective surface over the complex number field and let $L$ be a nef-big divisor on $X$. Here we consider the following conjecture; If the Kodaira dimension $\kappa(X)\geq 0$, then $K_{X}L\geq 2q(X)-4$, where $q(X)$ is the irregularity ... More
Intersection numbers and twisted period relations for the generalized hypergeometric function ${}_{m+1} F_m$Jun 29 2014We study the generalized hypergeometric function ${}_{m+1} F_m$ and the differential equation ${}_{m+1}E_m$ satisfied by it. We use the twisted (co)homology groups associated with an integral representation of Euler type. We evaluate the intersection ... More
Formation of the Galactic bulge from a two-component stellar disk: Explaining cylindrical rotation and vertical metallicity gradientJun 22 2011Recent observational studies have revealed that the Galactic bulge has cylindrical rotation and a steeper vertical metallicity gradient. We adopt two representative models for the bulge formation and thereby investigate whether the two models can explain ... More
Origin of chemical and dynamical properties of the Galactic thick diskMay 30 2011We adopt a scenario in which the Galactic thick disk was formed by minor merging between the first generation of the Galactic thin disk (FGTD) and a dwarf galaxy about 9 Gyr ago and thereby investigate chemical and dynamical properties of the Galactic ... More
Fossil Imprints of the First Generation Supernova Ejecta in Extremely Metal-Deficient StarsSep 16 1998Using results of nucleosynthesis calculations for theoretical core-collapse supernova models with various progenitor's masses, it is shown that abundance patterns of C, Mg, Si, Ca, and H seen in extremely metal-deficient stars with [Fe/H] < -2.5 follow ... More
Origin of the unusually low nitrogen abundances in young populations of the Large Magellanic CloudAug 07 2010It is a longstanding problem that HII regions and very young stellar populations in the Large Magellanic Cloud (LMC) have the nitrogen abundances ([N/H]) by a factor of ~7 lower than the solar value. We here discuss a new scenario in which the observed ... More
Five-parton amplitudes with two-quark and two-photon at Next-to-Leading OrderMar 18 2002Apr 26 2002We discuss one-loop five-parton amplitudes with two-quark two-photon or three-photon external legs. The amplitudes are required to evaluate the NLO corrections for the $\gamma\gamma jet$ production process at hadron colliders. The results have been already ... More
Twisted cycles and twisted period relations for Lauricella's hypergeometric function F_CAug 26 2013Oct 24 2013We study Lauricella's hypergeometric function F_C by using twisted (co)homology groups. We construct twisted cycles with respect to an Euler-type integral representation of F_C. These cycles correspond to 2^m linearly independent solutions to the system ... More
The monodromy representation of Lauricella's hypergeometric function F_CMar 07 2014Oct 14 2015We study the monodromy representation of the system $E_C$ of differential equations annihilating Lauricella's hypergeometric function $F_C$ of $m$ variables. Our representation space is the twisted homology group associated with an integral representation ... More
Factor endowment -- commodity output relationships in a three-factor, two-good general equilibrium trade modelNov 28 2017We analyze the Rybczynski sign pattern, which expresses the factor endowment - commodity output relationships in a three-factor, two-good general equilibrium trade model. The relationship determines whether a strong Rybczynski result holds. We search ... More
2:3 Twin Quasi-Periodic Oscillations in Magnetohydrodynamic Accretion FlowsAug 02 2004We study the radial and vertical oscillations in the three-dimensional magnetohydrodynamic (MHD) accretion flows around black holes. General relativistic effects are taken into account by using pseudo-Newtonian potential. We find that the structure of ... More
Rotation and Mass in the Milky Way and Spiral GalaxiesAug 30 2016[PASJ Review Paper] Rotation curves are the basic tool for deriving the distribution of mass in spiral galaxies. In this review, we describe various methods to measure rotation curves in the Milky Way and spiral galaxies. We then describe two major methods ... More
Metamagnetism and Fermi Surface in the Anderson Lattice ModelOct 18 1995We investigate magnetization as functions of external magnetic field $H$ in the $U$-infinite Anderson lattice model within the leading order approximation in the $1/N$-expansion. At $T=0$, at $H=H_M$ where the Zeeman energy is equal to a certain characteristic ... More
Twisted cycles and twisted period relations for Lauricella's hypergeometric function F_CAug 26 2013Apr 02 2017We study Lauricella's hypergeometric function F_C by using twisted (co)homology groups. We construct twisted cycles with respect to an Euler-type integral representation of F_C. These cycles correspond to 2^m linearly independent solutions to the system ... More
Diagnostics of Gaseous Halo of the Milky Way by a Shock Wave from the Galactic CentreJan 03 2019Jan 04 2019A method to diagnose the gas distribution in the Galactic halo using a shock wave from the Galactic Centre (GC) is presented. Propagation of a shock wave caused by central explosion with released energy $\sim 10^{55}$ erg is calculated for various models ... More
Rotation Curve and Mass Distribution in the Galactic Center --- From Black Hole to Entire Galaxy ---Jul 31 2013Analyzing high-resolution longitude-velocity (LV) diagrams of the Galactic Center observed with the Nobeyama 45-m telescope in the CO and CS line emissions, we obtain a central rotation curve of the Milky Way. We combine it with the data for the outer ... More
Semiclassical Quantization of Two-Dimensional Dilaton GravityAug 23 1992Quantization of the dilaton gravity in two dimensions is discussed by a semiclassical approximation. We compute the fixed-area partition function to one-loop order and obtain the string susceptibility on Riemann surfaces of arbitrary genus. Our result ... More
Continuum Cascade Model: Branching Random Walk for Traveling WaveJul 15 2015Jan 26 2016The food web is a directed graph in which nodes label species and directed links represent the predation between species. The cascade model generates random food webs. The continuum cascade model is a Poisson approximation of the cascade model. The recursion ... More
Random Sequential Generation of Intervals for the Cascade Model of Food WebsJun 23 2011The cascade model generates a food web at random. In it the species are labeled from 0 to $m$, and arcs are given at random between pairs of the species. For an arc with endpoints $i$ and $j$ ($i<j$), the species $i$ is eaten by the species labeled $j$. ... More
A Provocative Summary: Is There Any Unified Model for Triggering Active Galactic Nuclei ?Dec 09 2013A provocative summary of the conference on "Galaxy Mergers in an Evolving Universe" is presented. The conference includes the following issues; 1) Mergers at low redshift, 2) Merger dynamics and numerical simulations, 3) Mergers in galaxy evolution, 4) ... More
The Minor-Merger Driven Nuclear Activity in Seyfert Galaxies: A Step toward the Simple Unified Formation Mechanism of Active Galactic Nuclei in the Local UniverseMay 27 1999Seyfert nuclei are typical active galactic nuclei (AGNs) in the local universe, which are thought to be powered by gas accretion onto a supermassive black hole (SMBH). The dynamical effect exerted either by non-axisymmetric gravitational potential (such ... More
Does the Radiative Avalanche Fueling Work in Any Active Galactic Nuclei ?Jul 17 1997Recently Umemura, Fukue, & Mineshige (1997) proposed the radiative avalanche fueling to active galactic nuclei; gas accretion is driven by radiation drag exerted by stellar radiation from circumnuclear starburst regions. This mechanism is also interesting ... More
Generalized flux-tube solution in Abelian-projected SU(N) gauge theoryAug 07 2002Aug 09 2002The [U(1)]^{N-1} dual Ginzburg-Landau (DGL) theory as a low-energy effective theory of Abelian-projected SU(N) gauge theory is formulated in a Weyl symmetric way. The string tensions of flux-tube solutions of the DGL theory associated with color-electric ... More
The effects of energy and commodity prices on commodity output in a three-factor, two-good general equilibrium trade modelNov 28 2017Nov 28 2018We analyze the effects of energy and commodity prices on commodity output using a three-factor, two-good general equilibrium trade model with three factors: capital, labor, and imported energy. We derive a sufficient condition for each sign pattern of ... More
A numerical characterization of polarized manifolds (X,L) with K_{X}=-(n-i)L by the ith sectional geometric genus and the ith Δ-genusMay 26 2010Let (X,L) be a polarized manifold of dimension n. In this paper, by using the ith sectional geometric genus and the ith \Delta-genus, we will give a numerical characterization of (X,L) with K_{X}=-(n-i)L for the following cases (i) i=2, (ii) i=3 and n ... More
A function field analogue of the Rasmussen-Tamagawa conjecture: The Drinfeld module caseJun 22 2017Nov 06 2018In the arithmetic of function fields, Drinfeld modules play the role that elliptic curves play in the arithmetic of number fields. The aim of this paper is to study a non-existence problem of Drinfeld modules with constrains on torsion points at places ... More
Chemical Signature of a Major Merger in the Early Formation of Small Magellanic CloudJun 18 2009The formation history of the Small Magellanic cloud (SMC) is unraveled based on the results of our new chemical evolution models constructed for the SMC, highlighting the observed anomaly in the age-metallicity relation for star clusters in the SMC. We ... More
Supernova SN1987A Revisited as a Major Production Site for r-Process ElementsSep 20 2001The origin of nucleosynthesis products of rapid neutron capture reactions (the r-process) is a longstanding astrophysical problem. Recent analyses of elemental abundances for extremely metal-poor stars shed light on the elemental abundances of individual ... More
Galactic r-process abundance feature shaped by radial migrationMay 20 2019Growing interests in the chemical feature of r-process elements among nearby disk stars represented by the [Eu/Fe] vs. [Fe/H] diagram have sprouted since it can assess the origin of r-process elements through the comparison with theoretical models, including ... More
Enrichment history of r-process elements shaped by a merger of neutron star pairsMay 06 2014The origin of r-process elements remains unidentified and still puzzles us. The recent discovery of evidence for the ejection of r-process elements from a short-duration gamma-ray burst singled out neutron star mergers (NSMs) as their origin. In contrast, ... More
Formation of anomalous globular clusters with metallicity spreads: A unified pictureAug 29 2016Recent observations have revealed that at least 8 globular clusters (GCs) in the Galaxy show internal abundance spreads in [Fe/H]. We investigate the origin of these `anomalous' GCs using numerical simulations of GCs in the dwarfs orbiting around the ... More
First Evidence of Globular Cluster Formation from the Ejecta of Prompt Type Ia SupernovaeApr 18 2012Recent spectroscopic observations of globular clusters (GCs) in the Large Magellanic Cloud (LMC) have discovered that one of the intermediate-age GC, NGC 1718 with [Fe/H]=-0.7 has an extremely low [Mg/Fe] ratio of ~-0.9. We propose that NGC 1718 was formed ... More
Can the Feynman-Hellmann theorem be used to separate the connected- and disconnected-diagram contributions to the nucleon sigma term ?Oct 30 2009In recent lattice QCD studies, the Feynman-Hellmann theorem is often used to estimate separate contributions of the connected and disconnected diagrams to the nucleon sigma term. We demonstrate through a simple analysis within an effective model of QCD ... More
The origins of light and heavy r-process elements identified by chemical tagging of metal-poor starsOct 07 2014Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration gamma-ray burst. The hypothesis of a NS merger origin is reinforced ... More
Chemical evolution of the Large Magellanic CloudOct 15 2012We adopt a new chemical evolution model for the Large Magellanic Cloud (LMC) and thereby investigate its past star formation and chemical enrichment histories. The delay time distribution of type Ia supernovae recently revealed by type Ia supernova surveys ... More
Implications of a non-universal IMF from C, N, and O abundances in very metal-poor Galactic stars and damped Lyman-alpha absorbersFeb 28 2011Mar 03 2011Recently revealed C, N, and O abundances in the most metal-poor damped Lyman-alpha (DLA) absorbers are compared with those of extremely metal-poor stars in the Galactic halo, as well as extragalactic H II regions, to decipher nucleosynthesis and chemical ... More
Accretion of dust grains as a possible origin of metal-poor stars with low alpha/Fe ratiosOct 08 2003Oct 10 2003The origin of low alpha/Fe ratios in some metal-poor stars, so called low-alpha stars, is discussed. It is found that most of low-alpha stars in the Galaxy are on the main-sequence. This strongly suggests that these stars suffered from external pollution. ... More
New Insights into the Early Stage of the Galactic Chemical EvolutionOct 05 1998The supernova yields of several heavy elements including alpha-, iron-group, and r-process elements are obtained as a function of the mass of their progenitor main-sequence stars M_ms from the abundance patterns of extremely metal-poor stars with a procedure ... More
Chemical evolution of galaxies with radiation-driven dust windAug 22 2014We discuss how the removal of interstellar dust by radiation pressure of stars influences the chemical evolution of galaxies by using a new one-zone chemical evolution models with dust wind. The removal efficiency of an element (e.g., Fe, Mg, and Ca) ... More
Diversity of Type Ia Supernovae Imprinted in Chemical AbundancesOct 29 2012A time delay of Type Ia supernova (SN Ia) explosions hinders the imprint of their nucleosynthesis on stellar abundances. However, some occasional cases give birth to stars that avoid enrichment of their chemical compositions by massive stars and thereby ... More
Two-Component Galactic Bulge Probed with Renewed Galactic Chemical Evolution ModelJan 04 2012Results of recent observations of the Galactic bulge demand that we discard a simple picture of its formation, suggesting the presence of two stellar populations represented by two peaks of stellar metallicity distribution (MDF) in the bulge. To assess ... More
Relics of subluminous supernovae in metal-poor starsJan 14 2003The unique elemental abundance pattern of the carbon-rich stars CS29498-043 and CS22949-037 is characterized by a large excess of magnesium and silicon in comparison with iron. This excess is investigated in the context of a supernova-induced star formation ... More
History of Milky Way Dwarf Spheroidal Galaxies Imprinted on Abundance Patterns of Neutron-Capture ElementsMay 02 2002Stellar abundance pattern of neutron-capture elements such as barium is used as a powerful tool to infer how star formation proceeded in dwarf spheroidal (dSph) galaxies. It is found that the abundance correlation of barium with iron in stars belonging ... More
Elliptic Hypergeometric Laurent Biorthogonal Polynomials with a Dense Point Spectrum on the Unit CircleSep 15 2008Mar 19 2009Using the technique of the elliptic Frobenius determinant, we construct new elliptic solutions of the $QD$-algorithm. These solutions can be interpreted as elliptic solutions of the discrete-time Toda chain as well. As a by-product, we obtain new explicit ... More
A rough analytic relation on partial differential equationsApr 28 2010We introduce some analytic relations on the set of partial differential equations of two variables. It relies on a new comparison method to give rough asymptotic estimates for solutions which obey different partial differential equations. It uses a kind ... More
Suzaku Spectroscopy of the Extended X-Ray Emission in M17Jul 27 2007Jul 27 2007We present the results of a Suzaku spectroscopic study of the soft extended X-ray emission in the HII region M17. The spectrum of the extended emission was obtained with a high signal-to-noise ratio in a spatially-resolved manner using the X-ray Imaging ... 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
X-Ray Observations of the Sagittarius D HII Region toward the Galactic Center with SuzakuMay 14 2008We present a Suzaku X-ray study of the Sagittarius D (Sgr D) HII region in the Galactic center region. Two 18'x18' images by the X-ray Imaging Spectrometer (XIS) encompass the entire Sgr D complex. Thanks to the low background, XIS discovered two diffuse ... More
Optimal conditions for Bell test using spontaneous parametric down-conversion sourcesAug 25 2018We theoretically and experimentally investigate the optimal conditions for the Bell experiment using spontaneous parametric down conversion (SPDC) sources. In theory, we show that relatively large average photon number (typically $\sim$0.5) is desirable ... More
Extracting an entangled photon pair from collectively decohered pairs at a telecommunication wavelengthMar 10 2015We experimentally demonstrated entanglement extraction scheme by using photons at the telecommunication band for optical-fiber-based quantum communications. We generated two pairs of non-degenerate polarization entangled photons at 780~nm and 1551~nm ... More
Calibration of Chaotic Models for Interest RatesJun 13 2011In this paper we calibrate chaotic models for interest rates to market data using a polynomial-exponential parametrization for the chaos coefficients. We identify a subclass of one-variable models that allow us to introduce complexity from higher order ... More
Mass of the Galaxy Inferred from Outer Rotation CurveNov 20 1996Using an outer rotation curve of the Galaxy, we explore the galactic constants and the mass of the Galaxy. We show that \Theta_0 of 200 km/s is more favorable than the IAU standard value of 220 km/s, and also show that if \Theta_0 is smaller than 207 ... More
First Order Bipolaronic Transition at Finite Temperature in the Holstein ModelMay 03 2010Oct 14 2010We investigate the Holstein model by using the dynamical mean-field theory combined with the exact diagonalization method. Below a critical temperature Tcr, a coexistence of the polaronic and the bipolaronic solutions is found for the same value of the ... More
Superconductivity and Spin gap in the zigzag chain t-J model simulating a CuO double chain in Pr_2Ba_4Cu_7O_15-deltaSep 08 2007Using the numerical diagonalization method, we examine the one-dimensional t_1-t_2-J_1-J_2 model (zigzag chain t-J model) which represents an effective model for metallic CuO double chain in the superconductor Pr_2Ba_4Cu_7O_15-\delta. Based on the Tomonaga-Luttinger ... More
Decoherence of localized spins interacting via RKKY interactionAug 17 2004May 17 2005We theoretically study decoherence of two localized spins interacting via the RKKY interaction in one-, two-, and three-dimensional electron gas. We derive the kinetic equation for the reduced density matrix of the localized spins and show that energy ... More
Superconductivity of the One-Dimensional d-p Model with p-p transferAug 29 1997Using the numerical diagonalization method, we investigate the one-dimensional $d$-$p$ model, simulating a Cu-O linear chain with strong Coulomb repulsions. Paying attention to the effect of the transfer energy $t_{pp}$ between the nearest neighbor oxygen-sites, ... More
Generation of dark radiation in the bulk inflaton modelJan 05 2003Apr 21 2003We investigate the dynamics of a bulk scalar field with various decay channels in the Randall-Sundrum infinite braneworld scenario. A bulk scalar field in this scenario has a quasi-localized mode which dominates the late-time behavior near the brane. ... More
Irreducibility of the monodromy representation of Lauricella's $F_C$Mar 28 2017Apr 16 2018Let $E_C$ be the hypergeometric system of differential equations satisfied by Lauricella's hypergeometric series $F_C$ of $m$ variables. We show that the monodromy representation of $E_C$ is irreducible under our assumption consisting of $2^{m+1}$ conditions ... More
Vortex Flows in the Solar Chromosphere -- I. Automatic detection methodFeb 20 2017Solar "magnetic tornadoes" are produced by rotating magnetic field structures that extend from the upper convection zone and the photosphere to the corona of the Sun. Recent studies show that such rotating features are an integral part of atmospheric ... More
LRG J0239-0134: A Ring Galaxy or a Pair of Superbubbles at z=1 ?Nov 03 2000The unusual morphology of LRG J0239$-$0134 at $z$ =1.062 has been interpreted as a ring galaxy. Here we propose an alternative idea that the ring-like morphology is attributed to a pair of superbubbles driven by the intense starburst in the central region ... More
Picard-Vessiot groups of Lauricella's hypergeometric systems $E_C$ and Calabi-Yau varieties arising integral representationsJul 28 2018We study the Zariski closure of the monodromy group $\mathbf{Mon}$ of Lauricella's hypergeometric function $F_C$. If the identity component $\mathbf{Mon}^0$ acts irreducibly, then $\overline{\mathbf{Mon}} \cap \mathbf{SL}_{2^n}(\mathbb{C})$ must be one ... More
Cooperative Effect of Coulomb Interaction and Electron-Phonon Coupling on the Heavy Fermion State in the Two-Orbital Periodic Anderson ModelJan 13 2010Mar 01 2010We investigate the two-orbital periodic Anderson model, where the local orbital fluctuations of f-electrons couple with a two-fold degenerate Jahn-Teller phonon, by using the dynamical mean-field theory. It is found that the heavy fermion state caused ... More
Origin of dielectric relaxation observed in complex perovskite oxides Ba(1-x)La(x)Ti(1-x)Cr(x)O3Apr 04 2005Frequency dependence of the dielectric constant of complex perovskite oxide Ba(1-x)La(x)Ti(1-x)Cr(x)O3 (BLTC) ceramics with the composition ratio 0.4<= x <= 0.7 is precisely measured in the temperature range from 20 K to 300 K, and the dielectric relaxation ... More
Braneworld inflation driven by dynamics of a bulk scalar fieldFeb 13 2003Feb 21 2003We review a viable alternative scenario of the inflationary universe in the context of the Randall-Sundrum (RS) braneworld. In this scenario, the dynamics of a 5-dimensional scalar field, which we call a bulk scalar field, plays the central role. Focusing ... More
Operator Product Expansion and Topological States in $c = 1$ Matter Coupled to 2-D GravityNov 25 1991Factorization of the $N$-tachyon amplitudes in two-dimensional $c=1$ quantum gravity is studied by means of the operator product expansion of vertex operators after the Liouville zero mode integration. Short-distance singularities between two tachyons ... More
Factorization and Topological States in $c=1$ Matter Coupled to 2-D GravityAug 30 1991Sep 02 1991Factorization of the $N$-point amplitudes in two-dimensional $c=1$ quantum gravity is understood in terms of short-distance singularities arising from the operator product expansion of vertex operators after the Liouville zero mode integration. Apart ... More
On the canonical formalism of $f(R)$-type gravity using Lie derivativesDec 15 2014Jun 25 2015We present a canonical formalism of the $f(R)$-type gravity using the Lie derivatives instead of the time derivatives by refining the formalism of our group. The previous formalism is a direct generalization of the Ostrogradski's formalism. However the ... More
Subaru Spectroscopy of the Giant Ly$α$ Nebula Associated with the High-$z$ Powerful Radio Galaxy 1243+036Dec 20 2003We report results of our new spatially-resolved, optical spectroscopy of the giant Ly$\alpha$ nebula around a powerful radio galaxy 1243+036 (4C+03.24) at $z=3.57$. The nebula is extended over $\sim 30$ kpc from the nucleus, and forms a pair of cones ... More
The Electron Scattering Region in Seyfert NucleiJun 27 1999The electron scattering region (ESR) is one of important ingredients in Seyfert nuclei because it makes possible to observe the hidden broad line region (hereafter HBLR) in some type 2 Seyfert nuclei (hereafter S2s). However, little is known about its ... More
Noncommutative Deformation of InstantonsMay 22 2008Jul 08 2008We construct instanton solutions on noncommutative Euclidean 4-space which are deformations of instanton solutions on commutative Euclidean 4-space. We show that the instanton numbers of these noncommutative instanton solutions coincide with the commutative ... More
Submillimeter CO emission from shock-heated gas in the L1157 outflowMar 02 2001We present the CO J=6-5, 4-3, and 3-2 spectra from the blueshifted gas of the outflow driven by the low-mass class 0 protostar in the L1157 dark cloud. Strong submillimeter CO emission lines with T_mb > 30 K have been detected at 63" (~0.13 pc) south ... More
The monodromy representation and twisted period relations for Appell's hypergeometric function F_4Oct 16 2013Jan 12 2014We consider the system $\mathcal{F}_4(a,b,c)$ of differential equations annihilating Appell's hypergeometric series $F_4(a,b,c;x)$. We find the integral representations for four linearly independent solutions expressed by the hypergeometric series $F_4$. ... More
Convex Pentagon Tilings and Heptiamonds, IApr 13 2017Mar 08 2018In 1995, Marjorie Rice discovered an interesting tiling by using convex pentagons. The authors discovered novel properties of the tilings of convex pentagon which Rice used in the discovery. As a result, many new convex pentagon tilings (tessellations) ... More
Physical Degrees of Freedom in 2-D String Field TheoriesJul 20 1992States in the absolute (semi-relative) cohomology but not in the relative cohomology are examined through the component decomposition of the string field theory action for the 2-D string. It is found that they are auxiliary fields without kinetic terms, ... More
Brane-world inflation without inflaton on the braneOct 10 2000Jan 26 2001Inspired by the Randall-Sundrum brane-world scenario, we investigate the possibility of brane-world inflation driven not by an inflaton field on the brane, but by a bulk, dilaton-like gravitational field. As a toy model for the dilaton-like gravitational ... More
Superwind model of extended Lyman alpha emitters at high redshiftJan 31 2000We propose a new model for the extended Ly alpha blobs found recently at high redshift z ~ 3. The observational properties of these blobs are; 1) the observed Ly alpha luminosities are ~ 10^{43} h^{-2} ergs s^{-1}, 2) they appear elongated morphologically, ... More
The equivalence theorem in the generalized gravity of f(R)-type and canonical quantization IIApr 11 2012We first review the equivalence theorem of the f(R)-type gravity to Einstein gravity with a scalar field by deriving it in a self-contained and pedagogical way. Then we describe the problem of to what extent the equivalence holds. Main problems are (i) ... More
Wave Packet in Quantum Cosmology and Definition of Semiclassical TimeJun 05 1996We consider a quantum cosmology with a massless background scalar field $\pb$ and adopt a wave packet as the wave function. This wave packet is a superposition of the WKB form wave functions, each of which has a definite momentum of the scalar field $\pb$. ... More
Refined form of the paper "Canonical formalism of the f(R)-type gravity in terms of Lie derivatives"Apr 12 2013Sep 16 2013We refine the presentation of the previous paper of our group, Y.Ezawa et al., Class. Quantum Grav. {\bf 23} (2006), 3205 [arXiv:gr-qc/0507060]. In that paper, we proposed a canonical formalism of f(R)-type generalized gravity by using the Lie derivatives ... More
Are Vortex Numbers Preserved?Dec 14 2006Apr 11 2008We study noncommutative vortex solutions that minimize the action functional of the Abelian Higgs model in 2-dimensional noncommutative Euclidean space. We first consider vortex solutions which are deformed from solutions defined on commutative Euclidean ... More
Superconductivity in a Two-Orbital Hubbard Model with Electron and Hole Fermi Pockets: Application in Iron Oxypnictide SuperconductorsDec 11 2009We investigate the electronic states of a one-dimensional two-orbital Hubbard model with band splitting by the exact diagonalization method. The Luttinger liquid parameter $K_{\rho}$ is calculated to obtain superconducting (SC) phase diagram as a function ... More
Combined Analysis of Numerical Diagonalization and Renormalization Group methods for the One-Dimensional $U$-$V$ Model at Quarter fillingJan 15 2004Apr 29 2004The one-dimensional extended Hubbard model with both the on-site $U$ and the nearest neighbor $V$ interactions at quarter filling is studied by using a novel finite size scaling. We diagonalize finite size systems numerically and calculate the Luttinger-liquid ... More
Finite size mass shift formula for stable particles revisitedSep 01 2004Luescher's finite size mass shift formula in a periodic finite volume, involving forward scattering amplitudes in the infinite volume, is revisited for the two stable distinguishable particle system. The generalized mass shift formulae for the boson and ... More
Successive Phase Transitions in Na_{0.5}CoO_{2} based on the Triangular Lattice d-p ModelOct 14 2008We investigate the electronic states of the CoO_2 plane in the layered cobalt oxides Na_{0.5}CoO_{2} using the realistic 11 band d-p model on a two-dimensional triangular lattice. Effects of the Coulomb interaction on a Co site: the intra- and inter-orbital ... More
Braneworld reheating in the bulk inflaton modelDec 27 2002Mar 17 2003In the context of the braneworld inflation driven by a bulk scalar field, we study the energy dissipation from the bulk scalar field into the matter on the brane in order to understand the reheating after inflation. Deriving the late-time behavior of ... More
Pfaffian equations and contiguity relations of the hypergeometric function of type $(k+1, k+n+2)$ and their applicationsFeb 04 2016We study the structures of Pfaffian equations and contiguity relations of the hypergeometric function of type $(k+1,k+n+2)$ by using twisted cohomology groups and the intersection form on them. We apply our results to algebraic statistics; numerical evaluation ... More