Results for "Makoto Watanabe"

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Spin and Charge Fluctuations near Metal-Insulator Transition in Dimer-Type Molecular SolidFeb 28 2017Spin and charge fluctuations at vicinity of metal-to-Mott insulator transitions are studied in an organic solid with molecular dimers. The extended Hubbard model taking account of the internal electronic degree of freedom in a molecular dimer is analyzed ... 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
Significantly high polarization degree of the very low-albedo asteroid (152679) 1998 KU$_\mathrm{2}$Dec 05 2017We present a unique and significant polarimetric result regarding the near-Earth asteroid (152679) 1998 KU$_\mathrm{2}$ , which has a very low geometric albedo. From our observations, we find that the linear polarization degrees of 1998 KU$_\mathrm{2}$ ... More
Clustering of Emission-line Stars in the W5E HII regionFeb 19 2008We have made a new survey of emission-line stars in the W5E HII region to investigate the population of PMS stars near the OB stars by using the Wide Field Grism Spectrograph 2 (WFGS2). A total of 139 H-alpha emission stars were detected and their g'i'-photometry ... More
Stochastic Modeling of 3-D Compositional Distribution in the Crust with Bayesian Inference and Application to Geoneutrino Observation in JapanJan 05 2019Geoneutrino observations, first achieved by KamLAND in 2005 and followed by Borexino in 2010, have accumulated statistics and improved sensitivity for more than ten years. The uncertainty of the geoneutrino flux at the surface is now reduced to a level ... More
Buffering Time Strategies for Wireless Full-duplex Systems under Poisson TrafficNov 14 2016May 17 2018Full-duplex wireless communication has the potential to double the capacity of wireless networks by reducing the band occupancy of transmissions. However, a full-duplex capability cannot always reduce the band occupancy because the real traffic is not ... More
Buffering Time Strategies for Wireless Full-duplex Systems under Poisson TrafficNov 14 2016Full-duplex wireless communication has the potential to double the capacity of wireless networks by reducing the band occupancy of transmissions. However, a full-duplex capability cannot always reduce the band occupancy because the real traffic is not ... More
17P/Holmes: Contrast in activity between before and after the 2007 outburstSep 17 2013A Jupiter-family comet, 17P/Holmes, underwent outbursts in 1892 and 2007. In particular, the 2007 outburst is known as the greatest outburst over the past century. However, little is known about the activity before the outburst because it was unpredicted. ... More
Evolution of the Relativistic Plasmoid-Chain in the Poynting-Dominated PlasmaJul 22 2013In this paper, we investigate the evolution of the plasmoid-chain in a Poynting-dominated plasma. We model the relativistic current sheet with cold background plasma using the relativistic resistive magnetohydrodynamic approximation, and solve its temporal ... More
Why do we need instantons in strangeness hadron physics?Nov 24 2004Roles of instantons in strangeness hadron physics are discussed. After introducing general features of instantons, hadron spectroscopy under the influence of instanton-quark effective interactions is discussed. Emphases are on the H dibaryon, spin-orbit ... More
QCD Sum Rules of PentaquarksSep 25 2004QCD sum rule is applied to the pentaquark spectroscopy. It is concluded that no positive parity state is seen in low energy region, while there may exist negative parity states at around 1.5 GeV. Choice of interpolating local operators and relation to ... More
Models of the Nonmesonic Weak DecayMar 15 2004I review the current status of understanding the mechanism of the nonmesonic weak decays (NMWD) of hypernuclei. Long standing problem on the Gamma_n/Gamma_p ratio has been solved by considering short-range weak interactions properly. This leaves a few ... More
$π^+$ Emission from Hypernuclei and the Weak $ΔI=3/2$ TransitionsNov 25 1997Jan 05 1999Low energy $\pi^+$ emission in hypernuclear weak decays is studied in the soft pion limit. It is found that the $\pi^+$ decay amplitude is dominated by the $\Delta I=3/2$ part of nonmesonic weak decays according to the soft pion theorem. The ratios, $R(\pi^+/soft ... More
Theoretical Overview of the Pentaquark BaryonsJun 21 2004A review is given of the theoretical ideas concerning the mysterious pentaquark baryons proposed during the first year after its discovery. We focus on the difficulties involved with the constituent quark models and the discrepancy between the QCD predictions ... More
Direct Quark Mechanism for Weak $\Lam N \leftrightarrow NN$ ProcessesJan 16 1998Two body weak processes $\Lambda N \leftrightarrow NN$ are studied from the viewpoint of quark substructure of baryons.They can be studied in nonmesonic weak decays of hypernuclei and also hyperon production in the $NN$ scattering. The direct quark mechanism ... More
Roles of Quark Degrees of Freedom in HypernucleiJul 31 1997The quark model description of the hyperon nucleon forces, especially the antisymmetric spin-orbit forces, is studied from the spin-flavor SU(6) and the flavor SU(3) symmetry point of view. It is pointed out that the quark exchange interaction predicts ... More
Clustering Analysis of Periodic Point Vortices with the $L$ FunctionAug 28 2006Mar 01 2007A motion of point vortices with periodic boundary conditions is studied by using Weierstrass zeta functions. Scattering and recoupling of a vortex pair by a third vortex becomes remarkable when the vortex density is large. Clustering of vortices with ... More
Bifurcations and Chaos in the Six-Dimensional Turbulence Model of GledzerMay 19 2006May 26 2006The cascade-shell model of turbulence with six real variables originated by Gledzer is studied numerically using Mathematica 5.1. Periodic, doubly-periodic and chaotic solutions and the routes to chaos via both frequency-locking and period-doubling are ... More
Determinantal Martingales and Interacting Particle SystemsJul 09 2013Determinantal process is a dynamical extension of a determinantal point process such that any spatio-temporal correlation function is given by a determinant specified by a single continuous function called the correlation kernel. Noncolliding diffusion ... More
Bessel process, Schramm-Loewner evolution, and Dyson modelMar 24 2011Bessel process is defined as the radial part of the Brownian motion (BM) in the $D$-dimensional space, and is considered as a one-parameter family of one-dimensional diffusion processes indexed by $D$, BES$^{(D)}$. It is well-known that $D_{\rm c}=2$ ... More
Survival probability of mutually killing Brownian motions and the O'Connell processDec 17 2011Mar 23 2012Recently O'Connell introduced an interacting diffusive particle system in order to study a directed polymer model in 1+1 dimensions. The infinitesimal generator of the process is a harmonic transform of the quantum Toda-lattice Hamiltonian by the Whittaker ... More
The singularity problem in string theoryAug 24 2001Dec 26 2001We review the current status of the singularity problem in string theory for non-experts. After the problem is discussed from the point of view of supergravity, we discuss classic examples and recent examples of singularity resolution in string theory. ... More
Slope equality of plane curve fibrations and its application to Durfee's conjectureApr 28 2017Apr 17 2018We give a slope equality for fibered surfaces whose general fiber is a smooth plane curve. As a corollary, we prove a "strong" Durfee-type inequality for isolated hypersurface surface singularities, which implies Durfee's strong conjecture for such singularities ... More
Hasse principle for character group of finitely generated field over the rational number fieldOct 16 2012In this paper, we show the Hasse principle for the character group of a finitely generated field over the rational number field. By applying this result, we obtain an algebraic proof of unramified class field theory of arithmetical schemes.
Determinantal Martingales and Noncolliding Diffusion ProcessesMay 19 2013Jul 09 2014Two aspects of noncolliding diffusion processes have been extensively studied. One of them is the fact that they are realized as harmonic Doob transforms of absorbing particle systems in the Weyl chambers. Another aspect is integrability in the sense ... More
Mixed anomalies of chiral algebras compactified to smooth quasi-projective surfacesDec 14 2007Feb 25 2015Some time ago, the chiral algebra theory of Beilinson-Drinfeld was expected to play a central role in the convergence of divergence in mathematical physics of superstring theory for quantization of gauge theory and gravity. Naively, this algebra plays ... More
AdS/CFT Duality User GuideSep 11 2014Aug 31 2016This is the draft/updated version of a textbook on "real-world" applications of the AdS/CFT duality for beginning graduate students in particle physics and for researchers in the other fields. The aim of this book is to provide background materials such ... More
Critical phenomena in the AdS/CFT dualityJun 25 2010We review black holes with second-order phase transition in string theory (R-charged black holes and holographic superconductors) and review their static and dynamic critical phenomena. Holographic superconductors have conventional mean-field values for ... More
Hyperon-Nucleon Interaction in a Quark ModelOct 13 1993A lecture given at the International School Seminar on {\sl Hadrons and Nuclei from QCD}, Tsuruga-Vladivostok-Sapporo, August-September, 1993. A realistic hyperon ($Y$)-nucleon ($N$) interaction based on the quark model and the one-boson-exchange potential ... More
On the nonrelativistic limit of a semilinear field equation in a uniform and isotropic spaceDec 26 2015The nonrelativistic limit of a semilinear field equation is considered in a uniform and isotropic space.The scale-function of the space is constructed based on the Einstein equation.The Cauchy problem of the limit-equation is considered,and global and ... More
Topological Aspects of an Antisymmetric Background Field on OrbifoldsJan 14 1993We study string theory on orbifolds in the presence of an antisymmetric constant background field in detail and discuss some of new aspects of the theory. It is pointed out that the term with the antisymmetric background field can be regarded as a topological ... More
Elliptic Bessel processes and elliptic Dyson models realized as temporally inhomogeneous processesMay 10 2016Sep 22 2016The Bessel process with parameter $D>1$ and the Dyson model of interacting Brownian motions with coupling constant $\beta >0$ are extended to the processes in which the drift term and the interaction terms are given by the logarithmic derivatives of Jacobi's ... More
Clustering of point vortices in a periodic boxOct 31 2007The Monte Carlo simulation of $N$ point vortices with square periodic boundary conditions is performed where $N$ is order of 100. The clustering property is examined by computing the $L$ function familiar in the field of spatial ecology. The case of a ... More
A note on Gersten's conjecture for étale cohomology over two-dimensional henselian regular local ringsMar 05 2019We show the Gersten's conjecture for \'etale cohomology over two dimensional henselian regular local rings without assuming equi-characteristic. As application, we obtain the local-global principle for Galois cohomology over mixed characteristic two-dimensional ... More
On the Hasse Principle for the Brauer group of a purely transcendental extension field in one variable over an arbitrary fieldJan 11 2012In this paper we show the Hasse principle for the Brauer group of a purely transcendental extension field in one variable over an arbitrary field.
A remark on the bound for the free energy of directed polymers in random environment in 1+2 dimensionJun 18 2014We consider the behavior of the quantity $p(\beta)$; the free energy of directed polymers in random environment in $1+2$ dimension, where $\beta$ is inverse temperature. We know that the free energy is strictly negative when $\beta$ is not zero. In this ... More
Spectroscopy of Pentaquark BaryonsSep 07 2005A review is given to pentaquark mass predictions in quark models and QCD. It is pointed out that no successful quark model prediction is available for low-lying pentaquark states. Some new results of direct application of QCD, QCD sum rules and lattice ... More
On the derivation of several second order partial differential equations from a generalization of the Einstein equationMar 15 2016A generalization of the Einstein equation is considered for complex line elements. Several second order semilinear partial differential equations are derived from it as semilinear field equations in uniform and isotropic spaces. The nonrelativistic limits ... More
Double Periodicity and Frequency-Locking in the Langford EquationJul 05 2007The bifurcation structure of the Langford equation is studied numerically in detail. Periodic, doubly-periodic, and chaotic solutions and the routes to chaos via coexistence of double periodicity and period-doubling bifurcations are found by the Poincar\'e ... More
System of Complex Brownian Motions Associated with the O'Connell ProcessJun 11 2012Sep 15 2012The O'Connell process is a softened version (a geometric lifting with a parameter $a>0$) of the noncolliding Brownian motion such that neighboring particles can change the order of positions in one dimension within the characteristic length $a$. This ... More
Non-colliding system of Brownian particles as Pfaffian processJun 10 2005In the paper [7] we studied the temporally inhomogeneous system of non-colliding Brownian motions and proved that multi-time correlation functions are generally given by the quaternion determinants in the sense of Dyson and Mehta. In this report we give ... More
Peculiarity of String Theory on Orbifolds in the Presence of an Antisymmetric Background FieldOct 09 1992We study string theory on orbifolds in the presence of an antisymmetric constant background field and discuss some of new aspects of the theory. It is shown that the term with the antisymmetric field has a topological nature like a Chern-Simons term or ... More
Fibers of Cyclic Covering Fibrations of a Ruled SurfaceMay 14 2015Apr 17 2016We give an algorithm to classify singular fibers of finite cyclic covering fibrations of a ruled surface by using singularity diagrams. As the first application, we classify all fibers of 3-cyclic covering fibrations of genus 4 of a ruled surface and ... More
Non-adiabatic dynamics in 10Be with the microscopic alpha+alpha+N+N modelAug 17 2005Mar 02 2006The alpha+6He low-energy reactions and the structural changes of 10Be in the microscopic alpha+alpha+N+N model are studied by the generalized two-center cluster model with the Kohn-Hulthen-Kato variation method. It is found that, in the inelastic scattering ... More
Equivariant comparison of quantum homogeneous spacesSep 14 2011May 02 2013We prove the deformation invariance of the quantum homogeneous spaces of the q-deformation of simply connected simple compact Lie groups over the Poisson-Lie quantum subgroups, in the equivariant KK-theory with respect to the translation action by maximal ... More
Durfee-type inequality for complete intersection surface singularitiesMay 14 2018We prove that the signature of the Milnor fiber of smoothings of a $2$-dimensional isolated complete intersection singularity does not exceed the negative number determined by the geometric genus, the embedding dimension and the number of irreducible ... More
Linear independence of values of logarithms revisitedApr 03 2019Let $m\ge 2$ be an integer, $K$ an algebraic number field and $\alpha\in K\setminus \{0,-1\}$ with sufficiently small absolute value. In this article, we provide a new lower bound for linear form in $1,{\rm{log}}(1+\alpha),\ldots,{\rm{log}}^{m-1}(1+\alpha)$ ... More
Branching random walks in random environment and super-Brownian motion in random environmentApr 23 2013Jun 27 2013We focus on the existence and characterization of the limit for a certain critical branching random walks in time-space random environment in one dimension which was introduced by M. Birnkenr Each particle performs simple random walk on $\mathbb{Z}$ ... More
Unknotting submanifolds of the 3-sphere by twistingsSep 21 2016Dec 01 2016By the Fox's re-embedding theorem, any compact submanifold of the 3-sphere can be re-embedded in the 3-sphere so that it is unknotted. It is unknown whether the Fox's re-embedding can be replaced with twistings. In this paper, we will show that any closed ... More
Non-minimal bridge positions of torus knots are stabilizedJun 05 2010We show that any non-minimal bridge decomposition of a torus knot is stabilized and that $n$-bridge decompositions of a torus knot are unique for any integer $n$. This implies that a knot in a bridge position is a torus knot if and only if there exists ... More
Additivity of free genus of knotsNov 08 1998We show that free genus of knots is additive under connected sum.
The Heterotic EnhanconNov 06 2001Mar 12 2002The enhancon mechanism is studied in the heterotic string theory. We consider the N_L=0 winding strings with momentum (NS1-W*) and the Kaluza-Klein dyons (KK5-NS5*). The NS1-W* and KK5-NS5* systems are dualized to the D4-D0* and D6-D2* systems, respectively, ... More
Natural Generalization of Bosonic String AmplitudesFeb 26 1993Jun 04 1993The similarity between tree-level string theory scalar amplitudes, the Koba-Nielsen form ($S^{1}$) and the Virasoro-Shapiro form ($S^{2}$) suggests a natural $S^{n}$ generalization for a scalar amplitude. It is shown that the $S^{n}$ amplitude shares ... More
Pregeometrical Formulation of Berkovits' Open RNS Superstring Field TheoriesDec 15 2001We propose a pregeometrical formulation of Berkovits' open Ramond-Neveu-Schwarz (RNS) superstring field theories. We show that Berkovits' open RNS superstring field theories arise by expanding around particular solutions of the classical equations of ... More
Super-Brownian motion in random environment as a limit point of critical branching random walks in random environmentJul 07 2012Apr 24 2013We focus on the existence and its characterization of limit for a certain critical branching random walks in time-space random environment in 1 dimension which was introduced by Birkner Each particle performs simple random walk on $\mathbb{Z}$ ... More
Nuclear Force in the Skyrme Model: Quasistatic ApproachApr 13 1993Dynamics of two-Skyrmion systems is studied in the quasistatic approach. The quasistatic approach enables us to formulate the collective coordinate quantization of two-Skyrmion systems consistently with the 1/Nc expansion. By constructing quasistatic ... More
QCD Analysis of the H dibaryonOct 20 1995The status of theoretical studies of the $H$ dibaryon is reviewed. Some recent developments including the effect of the instanton induced interaction and the QCD sum rule results are discussed in detail.
Point Process Analysis of Vortices in a Periodic BoxJun 07 2007The motion of assemblies of point vortices in a periodic parallelogram can be described by the complex position $z_j(t)$ whose time derivative is given by the sum of the complex velocities induced by other vortices and the solid rotation centered at $z_j$. ... More
Determinantal Martingales and Correlations of Noncolliding Random WalksJul 07 2013Dec 20 2014We study the noncolliding random walk (RW), which is a particle system of one-dimensional, simple and symmetric RWs starting from distinct even sites and conditioned never to collide with each other. When the number of particles is finite, $N < \infty$, ... More
Characteristic Polynomials of Random Matrices and Noncolliding Diffusion ProcessesFeb 23 2011Dec 17 2015We consider the noncolliding Brownian motion (BM) with $N$ particles starting from the eigenvalue distribution of Gaussian unitary ensemble (GUE) of $N \times N$ Hermitian random matrices with variance $\sigma^2$. We prove that this process is equivalent ... More
Dissipative Abelian Sandpile ModelsMay 02 2015We introduce a family of abelian sandpile models with two parameters $n, m \in {\bf N}$ defined on finite lattices on $d$-dimensional torus. Sites with $2dn+m$ or more grains of sand are unstable and topple, and in each toppling $m$ grains dissipate from ... More
O'Connell's process as a vicious Brownian motionOct 09 2011Dec 10 2011Vicious Brownian motion is a diffusion scaling limit of Fisher's vicious walk model, which is a system of Brownian particles in one dimension such that if two of them meet they kill each other. We consider the vicious Brownian motion conditioned never ... More
Determinantal process starting from an orthogonal symmetry is a Pfaffian processApr 11 2011Oct 03 2011When the number of particles $N$ is finite, the noncolliding Brownian motion (BM) and the noncolliding squared Bessel process with index $\nu > -1$ (BESQ$^{(\nu)}$) are determinantal processes for arbitrary fixed initial configurations. In the present ... More
Deformation of algebras associated to group cocyclesJul 13 2011We define a deformation of algebras endowed with coaction of the reduced group algebras. The deformation parameter is given by a 2-cocycle over the group. We prove K-theory isomorphisms for the cocycles which can be perturbed to the trivial one.
Operator algebra of foliations with projectively invariant transverse measureNov 06 2007Apr 18 2013We study the structure of operator algebras associated with the foliations which have projectively invariant measures. When a certain ergodicity condition on the measure preserving holonomies holds, the lack of holonomy invariant transverse measure can ... More
Baryon-Baryon Interaction in the Quark Cluster ModelJun 19 2003The quark cluster model approach to the baryon-baryon interaction is reviewed and recent application to the charge symmetry breaking in nuclear force is discussed.
Summary of the YITP-RCNP Workshop on Chiral Restoration in Nuclear MediumJun 19 2003This is a personal summary of the workshop. I overview the topics of the workshop and itemize what we learned at the workshop.
Strong and Weak Interactions of Strange HadronsFeb 15 1995I review hadronic processes involving strange hadrons, especially hyperons from the quark structure point of view. The strong interaction of quarks expects several important new features when the strangeness is introduced upon the non-strange degrees ... More
Dynamics of Multiquark Systems: Mass, Width and ExoticsOct 27 2006Exotic multi-quark states are examined in the quark model and in QCD. Current status of theoretical studies of the pentaquark Theta^+ is reported. We show recent analyses of multi-quark components of baryons. A novel method to extract a compact excited ... More
Chiral Symmetry and Weak Decay of HypernucleiJun 15 1999The weak decays of hyperons and hypernuclei are studied from the chiral symmetry viewpoint. The soft pion relations are useful in understanding the isospin properties of the weak hyperon decays. Recent development on the short-range part of the $\Lam ... More
Unknotting submanifolds of the 3-sphere by twistingsSep 21 2016By the Fox's re-embedding theorem, any compact submanifold of the 3-sphere can be re-embedded in the 3-sphere so that it is unknotted. It is unknown whether the Fox's re-embedding can be replaced with twistings. In this paper, we will show that any closed ... More
Ground state property of Bose-Einstein gas for arbitrary power low interactionJan 16 2002We study Bose-Einstein gas for an arbitrary power low interaction $C_{\alpha}r^{-\alpha}$. This is done by the Hartree Fock Bogoliubov (HFB) approach at $T \le T_{c}$ and the mean field approach at $T>T_{c}$. Especially, we investigate the ground state ... More
On the Probability Distribution of Velocity Circulation in Three-Dimensional TurbulenceJul 23 1993The probability distribution functions of the circulation of velocity in three-dimensional decaying isotropic turbulence are examined by the database of the numerical simulation based on the pseudospectral method. It is shown that the standard deviation ... More
Reciprocal Time Relation of Noncolliding Brownian Motion with DriftApr 25 2012Jun 15 2012We consider an $N$-particle system of noncolliding Brownian motion starting from $x_1 \leq x_2 \leq ... \leq x_N$ with drift coefficients $\nu_j, 1 \leq j \leq N$ satisfying $\nu_1 \leq \nu_2 \leq ... \leq \nu_N$. When all of the initial points are degenerated ... More
Elliptic Determinantal Process of Type ANov 17 2013Sep 29 2014We introduce an elliptic extension of Dyson's Brownian motion model, which is a temporally inhomogeneous diffusion process of noncolliding particles defined on a circle. Using elliptic determinant evaluations related to the reduced affine root system ... More
Coexistence of coiled surfaces and spanning surfaces for knots and linksNov 26 2012It is a well-known procedure for constructing a torus knot or link that first we prepare an unknotted torus and meridian disks in the complementary solid tori of it, and second smooth the intersections of the boundary of meridian disks uniformly. Then ... More
Higher Order Correction to the GHS String Black HoleJun 14 1994We study the order $\alpha'$ correction to the string black hole found by Garfinkle, Horowitz, and Strominger. We include all operators of dimension up to four in the Lagrangian, and use the field redefinition technique which facilitates the analysis. ... More
Zero Mode Divergence Problem in String TheoryJan 06 1994For $2D$ string theory, the perturbative $S$-matrices are not well-defined due to a zero mode divergence. Although there exist formal procedures to make the integral convergent, their physical meanings are unclear. We describe a method to obtain finite ... More
Connes-Landi Deformation of Spectral TriplesJun 23 2010We describe a way to deform spectral triples with a 2-torus action and a real deformation parameter, motivated by deformation of manifolds after Connes-Landi. Such deformations are shown to have naturally isomorphic $K$-theoretic invariants independent ... More
Monodromy of the Gauss-Manin connection for deformation by group cocyclesJul 28 2012Mar 02 2017We consider the 2-cocycle deformation of algebras graded by discrete groups. The action of the Maurer-Cartan form on cyclic cohomology is shown to be cohomologous to the cup product action of the group cocycle. This allows us to compute the monodromy ... More
Gorenstein polytopes obtained from bipartite graphsMar 07 2008Mar 11 2008Beck et. al. characterized the grid graphs whose perfect matching polytopes are Gorenstein and they also showed that for some parameters, perfect matching polytopes of torus graphs are Gorenstein. In this paper, we complement their result, that is, we ... More
Durfee-type inequality for hypersurface surface singularitiesApr 28 2017May 14 2018We prove a "strong" Durfee-type inequality for isolated hypersurface surface singularities, which implies Durfee's strong conjecture for such singularities with non-negative topological Euler number of the exceptional set of the minimal resolution.
Subaru Telescope adaptive optics observations of gravitationally lensed quasars in the Sloan Digital Sky SurveyJun 16 2015Feb 02 2016We present the results of an imaging observation campaign conducted with the Subaru Telescope adaptive optics system (IRCS+AO188) on 28 gravitationally lensed quasars (23 doubles, 1 quad, and 1 possible triple, and 3 candidates) from the SDSS Quasar Lens ... More
Phase diagram and collective excitation in excitonic insulator: from the orbital physics viewpointFeb 25 2016May 06 2016Excitonic insulating system is studied from the viewpoints of the orbital physics in strongly correlated electron systems. An effective model Hamiltonian for low-energy electronic states is derived from the two-orbital Hubbard model with a finite energy ... More
Polarimetric Study of Near-Earth Asteroid (1566) IcarusSep 05 2017We conducted a polarimetric observation of the fast-rotating near-Earth asteroid (1566) Icarus at large phase (Sun-asteroid-observer's) angles $\alpha$= 57 deg--141deg around the 2015 summer solstice. We found that the maximum values of the linear polarization ... More
Wireless Full-duplex Medium Access Control for Enhancing Energy EfficiencyMar 31 2017Recent years have witnessed a proliferation of battery-powered mobile devices, e.g., smartphones, tablets, sensors, and laptops, which leads a significant demand for high capacity wireless communication with high energy efficiency. Among technologies ... More
2014-2015 Multiple Outbursts of 15P/FinlaySep 03 2016Multiple outbursts of a Jupiter-family comet, 15P/Finlay, occurred from late 2014 to early 2015. We conducted an observation of the comet after the first outburst and subsequently witnessed another outburst on 2015 January 15.6-15.7. The gas, consisting ... More
Optical and Near-Infrared Polarimetry for a Highly Dormant Comet 209P/LINEAROct 17 2015We conducted an optical and near-infrared polarimetric observation of the highly dormant Jupiter-Family Comet, 209P/LINEAR. Because of its low activity, we were able to determine the linear polarization degrees of the coma dust particles and nucleus independently, ... More
Smoothness of the Gap Function in the BCS-Bogoliubov Theory of SuperconductivityJun 07 2010We deal with the gap equation in the BCS-Bogoliubov theory of superconductivity, where the gap function is a function of the temperature $T$ only. We show that the squared gap function is of class $C^2$ on the closed interval $[\,0,\,T_c\,]$. Here, $T_c$ ... More
Exact Hausdorff measure on the boundary of a Galton--Watson treeJul 30 2007A necessary and sufficient condition for the almost sure existence of an absolutely continuous (with respect to the branching measure) exact Hausdorff measure on the boundary of a Galton--Watson tree is obtained. In the case where the absolutely continuous ... More
An operator theoretical proof for the second-order phase transition in the BCS-Bogoliubov model of superconductivityJul 01 2016Sep 14 2018We first show some properties such as smoothness and monotone decreasingness of the solution to the BCS-Bogoliubov gap equation for superconductivity. Moreover we give the behavior of the solution with respect to the temperature near the transition temperature. ... More
Observations of Umbral Dots and their Physical ModelsJul 17 2014The Hinode satellite opens a new era to the sunspots research, because of its high spatial resolution and temporal stability. Fine scale structures in sunspots, called umbral dots (UDs), have become one of the hottest topics in terms of the close observation ... More
The h-expansion of Macdonald operators and their expression by Dunkl operatorsApr 11 2012Apr 12 2012Macdonald operators are well known as the 'commutative family' acting on the symmetric functions over Q(q,t). If we suppose that q=exp(h) and t=exp(beta h) and observe the Taylor expansion around h=0, we can see the second-degree Dunkl operator appear ... More
Triviality of hierarchical O(N) spin model in four dimensions with large NNov 04 2003The renormalization group transformation for the hierarchical O(N) spin model in four dimensions is studied by means of characteristic functions of single-site measures, and convergence of the critical trajectory to the Gaussian fixed point is shown for ... More
On the sections of universal hyperelliptic curvesSep 14 2016In this paper, we will give an algebraic proof for determining the sections for the universal pointed hyperelliptic curves, when $g\geq 3$ and the image of the $\ell$-adic cyclotomic character $G_k\to \Z^\times$ is infinite. Furthermore, we will study ... More
An invariant of fiberwise Morse functions on surface bundle over $S^1$ by counting graphsMar 30 2015May 07 2015We apply Lescop's construction of $\mathbb{Z}$-equivariant perturbative invariant of knots and 3-manifolds to the explicit equivariant propagator of "AL-paths" given in arXiv:1403.8030. We obtain an invariant $\hat{Z}_n$ of certain equivalence classes ... More
On the splitting of Lazarsfeld-Mukai bundles on K3 surfaces IIMay 10 2017In this paper, we say that a rank 2 bundle splits if it is given by an extension of two line bundles. In the previous works, we gave a necessary condition for Lazarsfeld-Mukai bundles of rank 2 to split, under a numerical condition ([W2], Theorem 3.1). ... More
An operator-theoretical proof for the second-order phase transition in the BCS-Bogoliubov model of superconductivity (final version)Dec 14 2017Apr 09 2019We show that the transition from a normal conducting state to a superconducting state is a second-order phase transition in the BCS-Bogoliubov model of superconductivity from the viewpoint of operator theory. Here we have no magnetic field. Moreover we ... More
The solution to the BCS gap equation and the second-order phase transition in superconductivityJun 04 2010May 17 2011The existence and the uniqueness of the solution to the BCS gap equation of superconductivity is established in previous papers, but the temperature dependence of the solution is not discussed. In this paper, in order to show how the solution varies with ... More
Mean field approximation for biased diffusion on Japanese inter-firm trading networkDec 31 2013Feb 15 2014By analysing the financial data of firms across Japan, a nonlinear power law with an exponent of 1.3 was observed between the number of business partners (i.e. the degree of the inter-firm trading network) and sales. In a previous study using numerical ... More