Results for "Takeshi Yajima"

total 1358took 0.10s
On wave operators for Schrödinger operators with threshold singuralities in three dimensionsJun 11 2016We show that wave operators for three dimensional Schr\"odinger operators $H=-\Delta + V$ with threshold singularities are bounded in $L^1({\mathbb R}^3)$ if and only if zero energy resonances are absent from $H$ and the existence of zero energy eigenfunctions ... More
Remarks on $L^p$-boundedness of wave operators for Schrödinger operators with threshold singularitiesFeb 23 2016We consider the continuity property in Lebesgue spaces $L^p(\R^m)$ of wave operators $W_\pm$ of scattering theory for Schr\"odinger operator $H=-\lap + V$ on $\R^m$, $|V(x)|\leq C\ax^{-\delta}$ for some $\delta>2$ when $H$ is of exceptional type, i.e. ... 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
Massive fermion production in nonsingular superstring cosmologyMar 14 2001We study massive spin-1/2 fermion production in nonsingular superstring cosmology, taking into account one-loop quantum corrections to a superstring effective action with dilaton and modulus fields. While no creation occurs in the massless limit, massive ... More
Frustrated Magnetism of Pharmacosiderite Comprising Tetrahedral Clusters Arranged in the Primitive Cubic LatticeAug 07 2018We show that pharmacosiderite is a novel cluster antiferromagnet comprising frustrated regular tetrahedra made of spin-5/2 Fe3+ ions that are arranged in the primitive cubic lattice. The connectivity of the tetrahedra and the inter-cluster interaction ... More
A CA Hybrid of the Slow-to-Start and the Optimal Velocity Models and its Flow-Density RelationMar 30 2015Jul 31 2015The s2s-OVCA is a cellular automaton (CA) hybrid of the optimal velocity (OV) model and the slow-to-start (s2s) model, which is introduced in the framework of the ultradiscretization method. Inverse ultradiscretization as well as the time continuous limit, ... More
Instability of resonances under Stark perturbationsApr 16 2018Let $H^{\varepsilon}=-\frac{d^2}{dx^2}+\varepsilon x +V$, $\varepsilon\geq0$, on $L^2(\mathbf{R})$. Let $V=\sum_{k=1}^Nc_k|\psi_k\rangle\langle\psi_k|$ be a rank $N$ operator, where the $\psi_k\in L^2(\mathbf{R})$ are real, compactly supported, and even. ... More
Orbital Arrangements and Magnetic Interactions in the Quasi-One-Dimensional Cuprates ACuMoO_4(OH) (A = Na, K)May 20 2015A new spin-1/2 quasi-one-dimensional antiferromagnet KCuMoO_4(OH) is prepared by the hydrothermal method. The crystal structures of KCuMoO_4(OH) and the already-known Na-analogue, NaCuMoO_4(OH), are isotypic, comprising chains of Cu^{2+} ions in edge-sharing ... More
The $L^p$ boundedness of wave operators for Schrödinger operators with threshold singularities II. Even dimensional caseMay 10 2006In this paper we consider the wave operators $W_{\pm}$ for a Schr\"odinger operator $H$ in ${\bf{R}}^n$ with $n\geq 4$ even and we discuss the $L^p$ boundedness of $W_{\pm}$ assuming a suitable decay at infinity of the potential $V$. The analysis heavily ... More
Perturbative Analysis of Potential Scattering Problems in the Lieb-Liniger ModelJul 12 2013Feb 12 2014The Lieb-Liniger model which has a weak external potential term under the periodic boundary condition is investigated. By exploiting the Bethe states as bases, we perform a perturbation analysis up to the first order to obtain the shifts of eigenenergies ... More
Stochastic Process Associated with Traveling Wave Solutions of the Sine-Gordon EquationSep 20 2008Oct 05 2008Stochastic processes associated with traveling wave solutions of the sine-Gordon equation are presented. The structure of the forward Kolmogorov equation as a conservation law is essential in the construction and so is the traveling wave structure. The ... More
Max-Plus Algebra for Complex Variables and Its Application to Discrete Fourier TransformationMay 26 2005A generalization of the max-plus transformation, which is known as a method to derive cellular automata from integrable equations, is proposed for complex numbers. Operation rules for this transformation is also studied for general number of complex variables. ... More
Superconductivity in 122-type antimonide BaPt$_2$Sb$_2$Sep 25 2014The crystal structure, superconducting properties, and electronic structure of a novel superconducting 122-type antimonide, BaPt$_2$Sb$_2$, have been investigated by measurements of powder X-ray diffraction patterns, electrical resistivity, ac magnetic ... More
Anisotropy of Dirac cones and van Hove singularity in an organic Dirac fermion systemOct 31 2018We propose an experimental method to examine the in-plane anisotropy of electronic structure in layered conductors. In the method, we measure the interlayer magnetoresistance as a function of in-plane magnetic field orientation. We applied it to an organic ... More
Weak ferromagnetic order breaking the threefold rotational symmetry of the underlying kagomé lattice in CdCu$_3$(OH)$_6$(NO$_3$)$_2\cdot$H$_2$OMar 28 2017Novel magnetic phases are expected to occur in highly frustrated spin systems. Here we study the structurally perfect kagom\'e antiferromagnet CdCu$_3$(OH)$_6$(NO$_3$)$_2\cdot$H$_2$O by magnetization, magnetic torque, and heat capacity measurements using ... More
General Spin Precession and Betatron Oscillation in Storage RingFeb 25 2016We give the geralized expression of spin precession of extended bunch particles having both anomalous magnetic and electric dipole moments in storage ring. The transversal betatron oscillation formula of the bunch is also given. The latter is the generalization ... More
Higher dimensional examples of manifolds whose adjoint bundles are not spannedMar 28 1996Let $(X,L)$ be an $n$-dimensional polarized variety. Fujita's conjecture says that if $L^n>1$ then the adjoint bundle $K_X+nL$ is spanned and $K_X+(n+1)L$ is very ample. There are some examples such that $K_X+nL$ is not spanned or $K_X+(n+1)L$ is not ... More
On freeness theorem of the adjoint bundle on a normal surfaceMar 28 1996We extend Reider's freeness criterion to normal surfaces of characteristic 0. Let Y be a normal surface. Let D be a nef divisor on Y such that K_Y+D is a Cartier divisor. Let x be a point on Y. If x is a base point of |K_Y+D| and D^2>\delta_x (\delta_x ... More
w and w' of Scalar Field Models of Dark EnergyOct 20 2005Nov 06 2009Important observables to reveal the nature of dark energy are the equation of state $w$ and its time derivative in units of the Hubble time $w'$. Recently, it is shown that the simplest scalar field models of dark energy (quintessence) occupy rather narrow ... More
Scalar-Tensor Gravity in Two 3-brane SystemJan 11 2000Jun 01 2000We derive the low-energy effective action of four-dimensional gravity in the Randall-Sundrum scenario in which two 3-branes of opposite tension reside in a five-dimensional spacetime. The dimensional reduction with the Ansatz for the radion field by Charmousis ... More
Generalized Gravity and a GhostFeb 15 2005Mar 22 2005We show that generalized gravity theories involving the curvature invariants of the Ricci tensor and the Riemann tensor as well as the Ricci scalar are equivalent to multi- scalar-tensor gravities with four derivatives terms. By expanding the action around ... More
1/R gravity and Scalar-Tensor GravityJul 18 2003Sep 09 2003We point out that extended gravity theories, the Lagrangian of which is an arbitrary function of scalar curvature $R$, are equivalent to a class of the scalar tensor theories of gravity. The corresponding gravity theory is $\omega=0$ Brans-Dicke gravity ... More
Resolving the singularity of the Hawking-Turok type instantonOct 01 1998Nov 14 1998We point out that the singular instanton of Hawking-Turok type, in which the singularity occurs due to the divergence of a massless scalar field, can be generated by Euclideanized regular $p$-brane solutions in string (or M-) theory upon compactification ... More
AF-embeddability of crossed products of Cuntz algebrasOct 09 2001We investigate crossed products of Cuntz algebras by quasi-free actions of abelian groups. We prove that our algebras are AF-embeddable when actions satisfy a certain condition. We also give a necessary and sufficient condition that our algebras become ... More
On quasi-categories of comodules and Landweber exactnessDec 10 2016In this paper we study quasi-categories of comodules over coalgebras in a stable homotopy theory. We show that the quasi-category of comodules over the coalgebra associated to a Landweber exact S-algebra depends only on the height of the associated formal ... More
Cylindrical Combinatorics and Representations of Cherednik Algebras of type ASep 30 2006We investigate the representation theory of the rational and trigonometric Cherednik algebra of type $GL_n$ by means of combinatorics on periodic (or cylindrical) skew diagrams. We introduce and study standard tableaux and plane partitions on periodic ... More
Rogawski's conjecture on the Jantzen filtration for the degenerate affine Hecke algebra of type AMay 07 1998The functors constructed by Arakawa and the author relate the representation theory of gl_n and that of the degenerate affine Hecke algebra H_l of GL_l. They transform the Verma modules over gl_n to the standard modules over H_l. They transform the simple ... More
Supervising Unsupervised Learning with Evolutionary Algorithm in Deep Neural NetworkMar 28 2018A method to control results of gradient descent unsupervised learning in a deep neural network by using evolutionary algorithm is proposed. To process crossover of unsupervisedly trained models, the algorithm evaluates pointwise fitness of individual ... More
Bilayer Quantum Hall System as a Macroscopic QubitMay 02 2001Sep 25 2001In the bilayer quantum Hall system, a spontaneously charge imbalance state appears at the ground energy level. Gap in the collective excitation energy makes it stable against decoherence in macroscopic level. This state behaves as a spin 1/2 representation ... More
Ideal structure of $C^*$-algebras associated with $C^*$-correspondencesSep 18 2003Oct 02 2003We study the ideal structure of $C^*$-algebras arising from $C^*$-correspondences. We prove that gauge-invariant ideals of our $C^*$-algebras are parameterized by certain pairs of ideals of original $C^*$-algebras. We show that our $C^*$-algebras have ... More
Non-planar Diagrams and Non-commutative Superspace in Dijkgraaf-Vafa theoryMar 25 2004Oct 27 2005We consider the field theory on non-commutative superspace and non-commutative spacetime that arises on D-branes in Type II superstring theory with a constant self-dual graviphoton and NS-NS $B$ field background. $\N=1$ supersymmetric field theories on ... More
Characteristic cycle of the exterior product of constructible sheavesJul 11 2016We show that the characteristic cycle of the exterior product of constructible complexes is the exterior product of the characteristic cycles of factors. This implies the compatibility of characteristic cycles with smooth pull-back which is a first step ... More
On the proper push-forward of the characteristic cycle of a constructible sheafJul 11 2016We study the compatibility with proper push-forward of the characteristic cycles of a constructible complex on a smooth variety over a perfect field.
Wild Ramification and the Cotangent BundleJan 20 2013Apr 10 2014We define the characteristic cycle of a locally constant \'etale sheaf on a smooth variety in positive characteristic ramified along boundary as a cycle in the cotangent bundle of the variety, at least on a neighborhood of the generic point of the divisor ... More
Escape fraction of ionizing photons from high-redshift galaxies in cosmological SPH simulationsFeb 17 2010Nov 11 2010Combing the three-dimensional radiative transfer (RT) calculation and cosmological SPH simulations, we study the escape fraction of ionizing photons (f_esc) of high-redshift galaxies at z=3-6. Our simulations cover the halo mass range of M_h = 10^9 - ... More
Effect of radiative transfer on damped Lyman-alpha and Lyman limit systems in cosmological SPH simulationsDec 24 2011Sep 12 2012We study the effect of local stellar radiation and UVB on the physical properties of DLAs and LLSs at z=3 using cosmological SPH simulations. We post-process our simulations with the ART code for radiative transfer of local stellar radiation and UVB. ... More
Effects of Ultraviolet Background and Local Stellar Radiation on the H_I Column Density DistributionJun 28 2010Nov 29 2010We study the impact of ultraviolet background (UVB) radiation field and the local stellar radiation on the H_I column density distribution f(N_HI) of damped Ly-alpha systems (DLAs) and sub-DLAs at z=3 using cosmological smoothed particle hydrodynamics ... More
Relativistic dissipative hydrodynamics with extended matching conditions for ultra-relativistic heavy-ion collisionsApr 05 2012Jun 05 2012Recently we proposed a novel approach to the formulation of relativistic dissipative hydrodynamics by extending the so-called matching conditions in the Eckart frame [Phys. Rev. {\bf C 85}, (2012) 14906]. We extend this formalism further to the arbitrary ... More
Odd-frequency pairing and Ising spin susceptibility in time-reversal invariant superfluids and superconductorsAug 28 2014We here examine the relation between odd-frequency spin-triple even-parity (OTE) Cooper pairs and anomalous surface magnetic response in time-reversal invariant (TRI) spin-triplet superfluids and superconductors. The spin susceptibility generally consists ... More
Variational and perturbative formulations of QM/MM free energy with mean-field embedding and its analytical gradientsSep 13 2008Dec 30 2008Conventional quantum chemical solvation theories are based on the mean-field embedding approximation. That is, the electronic wavefunction is calculated in the presence of the mean field of the environment. In this paper a direct quantum mechanical/molecular ... More
Primordial Magnetic Fields from the Post-Inflationary UniverseMar 20 2014May 28 2014We explore cosmological magnetogenesis in the post-inflationary universe, when the inflaton oscillates around its potential minimum and the universe is effectively dominated by cold matter. During this epoch prior to reheating, large-scale magnetic fields ... More
Two-point correlation functions in perturbed minimal modelsApr 07 1998Two point correlation functions of the off-critical primary fields \phi_{1, 1+s} are considered in the perturbed minimal models M_{2, 2N+3} + \phi_{1,3}. They are given as infinite series of form factor contributions. The form factors of \phi_{1, 1+s} ... More
Functional Equations of Form Factors for Diagonal Scattering TheoriesOct 24 1995Form factor bootstrap approach is applied for diagonal scattering theories. We consider the ADE theories and determine the functional equations satisfied by the minimal two-particle form factors. We also determine the parameterization of the singularities ... More
Reconstructing the inflaton potential from the spectral indexApr 29 2015Jul 21 2015Recent cosmological observations are in good agreement with the scalar spectral index $n_s$ with $n_s-1\sim -2/N$, where $N$ is the number of e-foldings. Quadratic chaotic model, Starobinsky model and Higgs inflation or $\alpha$-attractors connecting ... More
Apparent Horizon Formation and Hoop Conjecture in Non-axisymmetric SpacesApr 21 1999Jul 04 1999We investigate the validity of Thorne's hoop conjecture in non-axisymmetric spacetimes by examining the formation of apparent horizons numerically. If spaces have a discrete symmetry about one axis, we can specify the boundary conditions to determine ... More
Slow-Roll Thawing QuintessenceFeb 23 2009Sep 25 2009We derive slow-roll conditions for thawing quintessence. We solve the equation of motion of $\phi$ for a Taylor expanded potential (up to the quadratic order) in the limit where the equation of state $w$ is close to -1 to derive the equation of state ... More
Extended Quintessence and its Late-time DominationJun 29 2001Various astronomical observations point towards the evidence for dark energy. One of the most mysterious problem is the coincidence problem: why dark energy becomes dominant only recently. We present a scenario based on extended quintessence models to ... More
Quintessence, the Gravitational Constant, and GravityMar 25 1999Aug 01 1999Dynamical vacuum energy or quintessence, a slowly varying and spatially inhomogeneous component of the energy density with negative pressure, is currently consistent with the observational data. One potential difficulty with the idea of quintessence is ... More
Anomaly of discrete family symmetries and gauge coupling unificationOct 24 2006Anomaly of discrete symmetries can be defined as the Jacobian of the path-integral measure. We assume that an anomalous discrete symmetry at low energy is remnant of an anomaly free discrete symmetry, and that its anomaly is cancelled by the Green-Schwarz(GS) ... More
Addenda to General Spin Precession and Betatron Oscillation in Storage RingAug 20 2016We give the geralized expression of spin precession of extended bunch particles having both anomalous magnetic and electric dipole moments in storage ring in higher order than the previous work and in the presence of ${\bf E}$ field as well as ${\bf B}$ ... More
C^*-algebras generated by scaling elementsApr 27 2004We investigate C^*-algebras generated by scaling elements. We generalize the Wold decomposition and Coburn's theorem on isometries to scaling elements. We also completely determine when the C^*-algebra generated by a scaling element contains an infinite ... More
Gauge Field on Brane in M-atrix TheoryOct 03 2001In this ultra short note, gauge field propagation in D-brane configuration of M theory in the BFSS matrix formulation is considered. Noncommutativity of the space plays a key role for appearance of gauge fields as physical degrees of freedom.
A connection formula of a divergent bilateral basic hypergeometric functionFeb 17 2014We give the new connection formula for the divergent bilateral basic hypergeometric series ${}_2\psi_2(a_1,a_2;b_1;q,x)$ by the using of the $q$-Borel-Laplace resummation method and Slater's formula. The connection coefficients are given by elliptic functions. ... More
The Stokes phenomenon for the Ramanujan's $q$-difference equation and its higher order extensionApr 09 2014We show connection formulae of local solutions of the Ramanujan equation between the origin and the infinity. These solutions are given by the Ramanujan function, the $q$-Airy function and the divergent basic hypergeometric series ${}_2\varphi_0(0,0;-;q,x)$. ... More
Automorphism groups of smooth plane curvesJun 25 2013Jun 07 2014The author determines the structure of automorphism groups of smooth plane curves of degree at least four. Furthermore, he gives some upper bounds for the order of automorphism groups of smooth plane curves and classifies the cases with large automorphism ... More
A Connection Formula of the Hahn-Exton $q$-Bessel FunctionMay 10 2011Dec 16 2011We show a connection formula of the Hahn-Exton $q$-Bessel function around the origin and the infinity. We introduce the $q$-Borel transformation and the $q$-Laplace transformation following C. Zhang to obtain the connection formula. We consider the limit ... More
Hilbert modular forms and p-adic Hodge theoryDec 04 2006Dec 11 2006We consider the p-adic Galois representation associated to a Hilbert modular form. We show the compatibility with the local Langlands correspondence at a place divising p under a certain assumption. We also prove the monodromy-weight conjecture. The prime-to-p ... More
Wild ramification and the characteristic cycle of an l-adic sheafMay 19 2007Feb 01 2008We propose a geometric method to measure the wild ramification of a smooth etale sheaf along the boundary. Using the method, we study the graded quotients of the logarithmic ramification groups of a local field of positive characteristic with arbitrary ... More
A class of C^*-algebras generalizing both graph algebras and homeomorphism C^*-algebras II, examplesMay 14 2004Sep 16 2005We show that the method to construct C^*-algebras from topological graphs, introduced in our previous paper, generalizes many known constructions. We give many ways to make new topological graphs from old ones, and study the relation of C^*-algebras constructed ... More
A class of $C^*$-algebras generalizing both graph algebras and homeomorphism $C^*$-algebras IV, pure infinitenessSep 15 2005This is the final one in the series of papers where we introduce and study the $C^*$-algebras associated with topological graphs. In this paper, we get a sufficient condition on topological graphs so that the associated $C^*$-algebras are simple and purely ... More
Cahn-Hilliard approach to some degenerate parabolic equations with dynamic boundary conditionsAug 29 2016In this paper the well-posedness of some degenerate parabolic equations with a dynamic boundary condition is considered. To characterize the target degenerate parabolic equation from the Cahn-Hilliard system, the nonlinear term coming from the convex ... More
The Constancy of the Constants of Nature: UpdatesNov 01 2011Dec 23 2011The current observational and experimental bounds on the time variation of the constants of nature (the fine structure constant $\alpha$, the gravitational constant $G$ and the proton-electron mass ratio $\mu=m_p/m_e$) are reviewed.
The ideal structures of crossed products of Cuntz algebras by quasi-free actions of abelian groupsAug 07 2001We completely determine the ideal structures of the crossed products of Cuntz algebras by quasi-free actions of abelian groups and give another proof of A. Kishimoto's result on the simplicity of such crossed products. We also give a necessary and sufficient ... More
Thermal emission from semi-classical dynamical systemFeb 19 2019Recently the bound on the Lyapunov exponent $\lambda_L \le 2\pi T/ \hbar$ in thermal quantum systems was conjectured by Maldacena, Shenker and Stanford. If we naively apply this bound to a system with a fixed Lyapunov exponent $\lambda_L$, it might predict ... More
On dimensional reductions of the M-9-braneMar 27 2000Sep 08 2000We discuss the relations of the M-9-brane with other branes via dimensional reductions, mainly focusing on their Wess-Zumino (WZ) actions. It is shown that on three kinds of dimensional reductions, the WZ action of the M-9-brane respectively gives those ... More
Differential Equations Associated to The SU(2) WZNW Model on Elliptic CurvesDec 26 1994Jan 24 1995We study the $SU(2)$ WZNW model over a family of elliptic curves. Starting from the formulation developed by Tsuchiya, Ueno and Yamada, we derive a system of differential equations which contains the Knizhnik-Zamolodchikov-Bernard equations. Our system ... More
On local solutions of the Ramanujan equation and their connection formulaeMar 15 2012We show connection formulae of local solutions of the Ramanujan equation between the origin and the infinity. These solutions are given by the Ramanujan function, the $q$-Airy function and the divergent basic hypergeometric series ${}_2\varphi_0(0,0;-;q,x)$. ... More
An asymptotic formula of the divergent bilateral basic hypergeometric seriesMay 07 2012May 09 2012We show an asymptotic formula of the divergent bilateral basic hypergeometric series ${}_1\psi_0 (a;-;q,\cdot)$ with using the $q$-Borel-Laplace method. We also give the limit $q\to 1-0$ of our asymptotic formula.
A connection formula between the Ramanujan function and the $q$-Airy functionApr 05 2011Jul 01 2011We show a connection formula between two different $q$-Airy functions. One is called the Ramanujan function which appears in Ramanujan's "Lost notebook". Another one is called the $q$-Airy function that obtained in the study of the second $q$-Painlev\'e ... More
Thermal Emission from Semi-classical Dynamical SystemsFeb 19 2019Mar 31 2019Recently the bound on the Lyapunov exponent $\lambda_L \le 2\pi T/ \hbar$ in thermal quantum systems was conjectured by Maldacena, Shenker, and Stanford. If we naively apply this bound to a system with a fixed Lyapunov exponent $\lambda_L$, it might predict ... More
The Stokes phenomenon for the $q$-difference equation satisfied by the basic hypergeometric series ${}_3\varphi_1(a_1,a_2,a_3;b_1;q,x)$Feb 17 2014We show the connection formula for the basic hypergeometric series ${}_3\varphi_1(a_1,a_2,a_3;b_1;q,x)$ between around the origin and infinity by the using of the $q$-Borel-Laplace transformations. We also show the limit $q\to 1-0$ of the new connection ... More
Modification of Gravitational Anomaly Method in Hawking RadiationFeb 23 2009May 23 2009We discuss an ambiguity of the derivation of the Hawking radiation through the gravitational anomaly method and propose modifications of this method such that it reproduces the correct thermal fluxes. In this modified gravitational anomaly method, we ... More
Discrete G-Spectra and embeddings of module spectraFeb 27 2015Sep 03 2016In this paper we study the category of discrete G-spectra for a profinite group G. We consider an embedding of module objects in spectra into a category of module objects in discrete G-spectra, and study the relationship between the embedding and the ... More
Permutation presentations of modules over finite groupsAug 03 2006We introduce a notion of permutation presentations of modules over finite groups, and completely determine finite groups over which every module has a permutation presentation. To get this result, we prove that every coflasque module over a cyclic p-group ... More
Characteristic cycles and the conductor of direct imageApr 16 2017Apr 25 2017We prove the functoriality for proper push-forward of the characteristic cycles of constructible complexes by morphisms of smooth projective schemes over a perfect field, under the assumption that the direct image of the singular support has the dimension ... More
q-deformed Coxeter element in Non-simply-laced Affine Toda Field TheoriesJun 09 1997The Lie algebraic structures of the S-matrices for the affine Toda field theories based on the dual pairs (X_N^{(1)}, Y_M^{(l)}) are discussed. For the non-simply-laced horizontal subalgebra X_N and the simply-laced horizontal subalgebra Y_M, we introduce ... More
Recent results from Telescope ArrayJan 31 2014The Telescope Array (TA) observatory, located in midwest Utah, USA, is designed to detect ultra high energy cosmic rays whose energy is greater than 1 EeV. TA mainly consists of two types of detector. The first type is the atmospheric Fluorescence Detector ... More
The Equation of State of Tracker FieldsSep 24 2009Jan 07 2010We derive the equation of state of tracker fields, which are typical examples of freezing quintessence (quintessence with the equation of state approaching toward -1), taking into account of the late-time departure from the tracker solution due to the ... More
Tracking K-essenceJun 18 2002Jul 25 2002We derive a condition for converging a common evolutionary track for k-essence (a scalar field dark energy with non-canonical kinetic terms). For the Lagrangian density V(phi)W(X) with X=dot{phi}^2/2, we find tracker solutions with w_{phi} < w_B exist ... More
Initial Conditions for Vector InflationMay 30 2008Aug 05 2008Recently, a model of inflation using non-minimally coupled massive vector fields has been proposed. For a particular choice of non-minimal coupling parameter and for a flat FRW model, the model is reduced to the model of chaotic inflation with massive ... More
Constancy of the Constants of NatureOct 27 2001Mar 17 2002The current observational and experimental bounds on time variation of the constants of Nature are briefly reviewed.
Schubert classes in the equivariant cohomology of the Lagrangian GrassmannianAug 05 2005May 11 2006Let $LG_n$ denote the Lagrangian Grassmannian parametrizing maximal isotropic (Lagrangian) subspaces of a fixed symplectic vector space of dimension $2n.$ For each strict partition $\lambda=(\lambda_1,...,\lambda_k)$ with $\lambda_1\leq n$ there is a ... More
Is θ_{13}^{PMNS} correlated with θ_{23}^{PMNS} or not?May 01 2013Sep 11 2013By postulating the relation \theta_{23} \simeq 45^\circ + \eta\theta_{13}, we seek preferable correction terms to tri-bi-maximal mixing and discuss their origins. Global analyses of the neutrino oscillation parameters favor \eta=\pm 1/\sqrt{2}; this corresponds ... More
Non-zero θ_13 in models for hierarchical neutrino mass spectrumApr 09 2011Sep 04 2011We introduce three right-handed Majorana neutrinos and combine the type-I seesaw and inert doublet mechanisms. The resultant (active) neutrino mass matrix is divided into rank=1 and =2 parts with different energy scales. The different energy scales are ... More
The Spacetime Superalgebras from M-branes in M-brane BackgroundsApr 30 1998Jun 14 1998We derive the spacetime superalgebras explicitly from ``test'' M-brane actions in M-brane backgrounds to the lowest order in $\theta$ via canonical formalism, and discuss various BPS saturated configurations on the basis of their central charges which ... More
Superalgebras in Many Types of M-Brane Backgrounds and Various Supersymmetric Brane ConfigurationsDec 02 1998Feb 02 1999We derive superalgebras in many types of supersymmetric M-brane backgrounds. The backgrounds examined here include the cases of the M-wave and the M-Kaluza-Klein monopole. On the basis of the obtained algebras, we deduce all the supersymmetric non-orthogonal ... More
Rational and trigonometric degeneration of the double affine Hecke algebra of type $A$Feb 25 2005Aug 08 2005We study a connection between the representation theory of the rational Cherednik algebra of type $GL_n$ and the representation theory of the degenerate double affine Hecke algebra (the degenerate DAHA). We focus on an algebra embedding from the rational ... More
Classification of simple modules over degenerate double Affine Hecke algebras of type AApr 29 2003We study a class of representations over the degenerate double affine Hecke algebra of gl_n by an algebraic method. As fundamental objects in this class, we introduce certain induced modules and study some of their properties. In particular, it is shown ... More
On crossed products of the Cuntz algebra ${\mathcal O}_\infty$ by quasi-free actions of abelian groupsDec 15 2001We investigate the structures of crossed products of the Cuntz algebra ${\mathcal O}_\infty$ by quasi-free actions of abelian groups. We completely determine their ideal structures and compute the strong Connes spectra and K-groups.
Ramification of local fields with imperfect residue fields IIIMay 17 2010May 19 2010The graded quotients of the logarithmic ramification groups of a local field of mixed characteristic is killed by the residue characteristic. Its characters are described by differential forms.
Semi-classical bound on Lyapunov exponent and acoustic Hawking radiation in $c=1$ matrix modelJan 03 2018Jan 15 2018A classical particle motion in an inverse harmonic potential shows the exponential sensitivity of the initial condition, and the Lyapunov exponent $\lambda_L$ is uniquely fixed by the shape of the potential. Hence, if we naively apply the bound on the ... More
Thermodynamics of Large N Gauge Theories with Chemical Potentials in a 1/D ExpansionMay 12 2010Aug 03 2010In order to understand thermodynamical properties of N D-branes with chemical potentials associated with R-symmetry charges, we study a one dimensional large N gauge theory (bosonic BFSS type model) as a first step. This model is obtained through a dimensional ... More
Hawking Radiation and Quantum Anomaly in AdS2/CFT1 CorrespondenceNov 11 2008Jan 21 2009In order to understand a boundary description of Hawking radiation in the AdS/CFT correspondence, we investigate the trace anomaly method in AdS$_2$ space. In this method, Hawking radiation is derived from the trace anomaly of the energy-momentum tensor ... More
Surjective isometries on a Banach space of analytic functions on the open unit discJan 09 2019Let $H(\mathbb{D})$ be the linear space of all analytic functions on the open unit disc $\mathbb{D}$. We define $\mathcal{S}^\infty$ by the linear subspace of all $f \in H(\mathbb{D})$ with bounded derivative $f'$ on $\mathbb{D}$. We give the characterization ... More
Notes on the characteristic cycle of a constructible sheafMar 25 2016Jul 13 2016We study some properties of the characteristic cycle of a constructible complex on a smooth variety over a perfect field, push-forward and product.
Effective base point freeness on normal surfacesJul 02 1998We give the new effective criterion for the global generation of the adjoint bundle on normal surfaces with a boundary. We could make the invariant \delta small a bit more on log-terminal singular point, and then we could prove the theorem described in ... More
A construction of actions on Kirchberg algebras which induce given actions on their K-groupsAug 03 2006Jun 18 2007We prove that every action of a finite group all of whose Sylow subgroups are cyclic on the K-theory of a Kirchberg algebra can be lifted to an action on the Kirchberg algebra. The proof uses a construction of Kirchberg algebras generalizing the one of ... More
$J_1-J_2$ Square-Lattice Heisenberg Antiferromagnets with 4$d^1$ spins: AMoOPO$_4$Cl (A = K, Rb)Feb 09 2017Magnetic properties of AMoOPO$_4$Cl (A = K, Rb) with Mo$^{5+}$ ions in the 4$d^1$ electronic configuration are investigated by magnetization, heat capacity and NMR measurements on single crystals, combined with powder neutron diffraction experiments. ... More
Magnetoelastic couplings in the deformed Kagomé quantum spin lattice of volborthiteMar 12 2019Microscopic spin interactions on a deformed Kagom\'{e} lattice of volborthite are investigated through magnetoelastic couplings. A negative longitudinal magnetostriction $\Delta L<0$ in the $b$ axis is observed, which depends on the magnetization $M$ ... More
Effective base point freeness on a normal surfaceDec 20 1996Jan 20 1997This treats the base-point-freeness of the adjoint bundles on normal surfaces with a boundary. This is an extension of the non-relative version of the theorem of Ein-Lazarsfeld-Masek and the theorem of Kawachi-Masek.