Results for "Ryo Nagai"

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Tree level unitarity and finiteness of electroweak oblique correctionsApr 29 2015We study perturbative unitarity and electroweak oblique corrections in the electroweak symmetry breaking models including an arbitrary number of neutral Higgs bosons. Requiring the perturbative unitarity of the high energy scattering amplitudes of weak ... More
Classification of simple heavy vector triplet modelsJul 13 2016We classify models beyond the standard model with extra spin-1 particles ($V'$) based on the dominant decay mode of $V'$. We find two categories in which $V'$ mainly decay into fermions or bosons. We study simple renormalizable models where the electroweak ... More
Renormalization Effects on Electric Dipole Moments in Electroweakly Interacting Massive Particle ModelsFeb 14 2019We study the renormalization effects on electric dipole moments in the models with new electroweakly interacting massive fermions. The electric dipole moments are generated by the effective operators which arise from integrating out heavy particles at ... More
Does unitarity imply finiteness of electroweak oblique corrections at one-loop? - constraining extra neutral Higgs bosons -Sep 05 2014Jan 09 2015Introducing arbitrary number of neutral Higgs bosons in the electroweak symmetry breaking sector, we derive a set of conditions among Higgs couplings which need to be satisfied to maintain the unitarity of the high energy scattering amplitudes of weak ... More
Effective Theories for Dark Matter Nucleon ScatteringFeb 08 2015May 11 2015We reformulate the calculation of the dark matter-nucleon scattering cross sections based on the method of effective field theories. We assume that the scatterings are induced by the exchange of colored mediators, and construct the effective theories ... More
Heavy Gravitino from Dynamical Generation of Right-Handed Neutrino Mass Scale, and Gravitational WavesMay 11 2018Jul 31 2018The absence of supersymmetric particles at the weak scale is a puzzle if supersymmetry solves the gauge hierarchy problem. We show that, if the right-handed neutrino masses arise from hidden gaugino condensation via GUT-suppressed operators, successful ... More
Teleportation stretching for lossy Gaussian channelsMar 16 2016If a quantum channel is commutable with a certain set of operators, a Choi state of the channel becomes a sufficient resource for any entanglement generation achieved by a single use of the channel with the help of local operation and classical communications ... More
Contravariantly finite resolving subcategories over commutative ringsFeb 02 2010Contravariantly finite resolving subcategories of the category of finitely generated modules have been playing an important role in the representation theory of algebras. In this paper we study contravariantly finite resolving subcategories over commutative ... More
A new approximation theory which unifies spherical and Cohen-Macaulay approximationsMar 13 2006This paper gives a new approximation theory for finitely generated modules over commutative Noetherian rings, which unifies two famous approximation theorems; one is due to Auslander and Bridger and the other is due to Auslander and Buchweitz. Modules ... More
Classifying thick subcategories of the stable category of Cohen-Macaulay modulesAug 02 2009Jun 21 2010Various classification theorems of thick subcategories of a triangulated category have been obtained in many areas of mathematics. In this paper, as a higher-dimensional version of the classification theorem of thick subcategories of the stable category ... More
Revisit on How to Derive Asymptotic Profiles to Some Evolution EquationsJun 16 2015We consider the Cauchy problem in ${\bf R}^{n}$ for heat and damped wave equations. We derive asymptotic profiles to those solutions with weighted $L^{1,1}({\bf R}^{n})$ data by presenting a simple method.
A New Expression of Soliton Solution to the Ultradiscrete Toda EquationApr 15 2008A new type of multi-soliton solution to the ultradiscrete Toda equation is proposed. The solution can be transformed into another expression of solution in a perturbation form. A direct proof of the solution is also given.
Downside risk minimization via a large deviations approachMay 03 2012We consider minimizing the probability of falling below a target growth rate of the wealth process up to a time horizon $T$ in an incomplete market model, and then study the asymptotic behavior of minimizing probability as $T\to\infty$. This problem can ... More
Birational geometry of O'Grady's six dimensional example over the Donaldson-Uhlenbeck compactificationJul 09 2010We determine the birational geometry of O'Grady's six dimensional example over the Donaldson-Uhlenbeck compactification, by looking at the locus of non-locally-free sheaves on the relevant moduli space.
Neural-network Kohn-Sham exchange-correlation potential and its out-of-training transferabilityFeb 08 2018We incorporate in the Kohn-Sham self consistent equation a trained neural-network projection from the charge density distribution to the Hartree-exchange-correlation potential $n \rightarrow V_{\rm Hxc}$ for possible numerical approach to the exact Kohn-Sham ... More
Unitarity sum rules, three site moose model, and the ATLAS 2 TeV diboson anomaliesJul 05 2015Aug 25 2015We investigate $W'$ interpretations for the ATLAS 2 TeV diboson anomalies. The roles of the unitarity sum rules, which ensure the perturbativity of the longitudinal vector boson scattering amplitudes, are emphasized. We find the unitarity sum rules and ... More
Symmetry and geometry in generalized Higgs effective field theory -- Finiteness of oblique corrections v.s. perturbative unitarityApr 16 2019We formulate a generalization of Higgs effective field theory (HEFT) including arbitrary number of extra neutral and charged Higgs bosons (generalized HEFT, GHEFT) to describe non-minimal electroweak symmetry breaking models. Using the geometrical form ... More
Contour deformation trick in hybrid NLIEFeb 17 2012Jun 15 2012The hybrid NLIE of AdS_5 x S^5 is applied to a wider class of states. We find that the Konishi state of the orbifold AdS_5 x (S^5/Z_S) satisfies A_1 NLIE with the source terms which are derived from contour deformation trick. For general states, we construct ... More
Giant Magnons on CP^3 by Dressing MethodFeb 19 2009May 18 2009We consider classical string spectrum of R x CP^3, and construct a family of solutions with residual SU(2) symmetry by the dressing method on SU(4)/U(3) sigma model. All of them obey the square-root type dispersion relation, as is expected from the su(2|2) ... More
An intrinsic non-triviality of graphsApr 26 2008Feb 01 2009We say that a graph is intrinsically non-trivial if every spatial embedding of the graph contains a non-trivial spatial subgraph. We prove that an intrinsically non-trivial graph is intrinsically linked, namely every spatial embedding of the graph contains ... More
A refinement of the Conway-Gordon theoremsJul 01 2009Aug 12 2009In 1983, Conway-Gordon showed that for every spatial complete graph on 6 vertices, the sum of the linking numbers over all of the constituent 2-component links is congruent to 1 modulo 2, and for every spatial complete graph on 7 vertices, the sum of ... More
A characterization of modules locally of finite injective dimensionSep 25 2006In this note, finite modules locally of finite injective dimension over commutative Noetherian rings are characterized in terms of vanishing of Ext modules.
Reconstruction from Koszul homology and applications to module and derived categoriesOct 06 2012Jan 11 2014Let R be a commutative noetherian ring. Let M be a finitely generated R-module. In this paper, we reconstruct M from its Koszul homology with respect to a suitable sequence of elements of R by taking direct summands, syzygies and extensions, and count ... More
Equivalences between weight modules via $\mathcal{N}=2$ coset constructionsMay 08 2016Nov 07 2016In this paper we introduce a variant of weight modules for certain conformal vertex superalgebras as an appropriate framework of the $\mathcal{N}=2$ supersymmetric coset construction. We call them weight-wise admissible modules. Motivated by the work ... More
Hybrid NLIE for the Mirror AdS_5 x S^5Jan 26 2011Oct 07 2011We revisit the derivation of hybrid nonlinear integral equations of the XXX model starting from the linearization of the T-system related to spinon variables. We obtain two sets of equations, corresponding to two linearly independent solutions of A_1 ... More
Separate seesaw and its applications to dark matter and baryogenesisMar 01 2013Jul 02 2013We propose a new seesaw model in an extra-dimensional setup where only right-handed neutrinos are bulk fields. In the model, localizations of an extra-dimensional wave function and brane Majorana mass of the right-handed neutrinos can be different among ... More
An uncountably infinite number of indecomposable totally reflexive modulesJul 13 2006Oct 10 2006A few years ago, Huneke and Leuschke proved a theorem which solved a conjecture of Schreyer. It asserts that an excellent Cohen-Macaulay local ring of countable Cohen-Macaulay type which is complete or has uncountable residue field has at most a one-dimensional ... More
Finiteness of the number of minimal atoms in Grothendieck categoriesMar 07 2015Dec 22 2017For a Grothendieck category having a noetherian generator, we prove that there are only finitely many minimal atoms. This is a noncommutative analogue of the fact that every noetherian scheme has only finitely many irreducible components. It is also shown ... More
Delta edge-homotopy invariants of spatial graphs via disk-summing the constituent knotsMar 12 2007Aug 20 2007In this paper we construct some invariants of spatial graphs by disk-summing the constituent knots and show the delta edge-homotopy invariance of them. As an application, we show that there exist infinitely many slice spatial embeddings of a planar graph ... More
On the number of indecomposable totally reflexive modulesJul 13 2006Sep 25 2006In this note, it is proved that over a commutative noetherian henselian non-Gorenstein local ring there are infinitely many isomorphism classes of indecomposable totally reflexive modules, if there is a nonfree cyclic totally reflexive module.
Remarks on modules approximated by G-projective modulesSep 27 2005Let $R$ be a commutative Noetherian Henselian local ring. Denote by $\mathrm{mod} R$ the category of finitely generated $R$-modules, and by ${\mathcal G}$ the full subcategory of $\mathrm{mod} R$ consisting of all G-projective $R$-modules. In this paper, ... More
Finiteness of the number of minimal atoms in Grothendieck categoriesMar 07 2015May 26 2019For a Grothendieck category having a noetherian generator, we prove that there are only finitely many minimal atoms. This is a noncommutative analogue of the fact that every noetherian scheme has only finitely many irreducible components. It is also shown ... More
Asymptotic profile of solutions for strongly damped Klein-Gordon equationsMay 29 2018We consider the Cauchy problem in the whole space for strongly damped Klein-Gordon equations. We derive asymptotic profles of solutions with weighted initial data by a simple method introduced by R. Ikehata. The obtained results show that the wave effect ... More
Equivalences between weight modules via $\mathcal{N}=2$ coset constructionsMay 08 2016Sep 17 2016In this paper we introduce a variant of weight modules for certain conformal vertex superalgebras as an appropriate framework of the $\mathcal{N}=2$ supersymmetric coset construction. We call them weight-wise admissible modules. Motivated by the work ... More
Relation between dispersion lines and conductance of telescoped armchair double-wall nanotubes analyzed using perturbation formulas and first-principles calculationsMar 15 2012Oct 18 2012The Landauer's formula conductance of the telescoped armchair nanotubes is calculated with the Hamiltonian defined by first-principles calculations (SIESTA code). Herein, partially extracting the inner tube from the outer tube is called 'telescoping'. ... More
Resonant spin current in nanotube double junctionsDec 02 2002Zero bias conductance per spin of nanotube double junction (NTDJ) is investigated theoretically using the tight binding model, unrestricted Hartree-Fock approximation and non-equilibrium Green's functions. NTDJ consists of two metallic nanotubes joined ... More
Backward diode composed of a metallic and semiconducting nanotubeJun 04 2001The conditions necessary for a nanotube junction connecting a metallic and semiconducting nanotube to rectify the current are theoretically investigated. A tight binding model is used for the analysis, which includes the Hartree-Fock approximation and ... More
Functional equations of Nekrasov functions proposed by Ito-Maruyoshi-OkudaApr 03 2018We prove functional equations of Nekrasov partition functions for $A_{1}$-singularity, suggested by Ito-Maruyoshi-Okuda. Our proof uses the method by Nakajima-Yoshioka based on the theory of wall-crossing formula developed by Mochizuki.
Modules in resolving subcategories which are free on the punctured spectrumJan 09 2009Let R be a commutative noetherian local ring, and let X be a resolving subcategory of the category of finitely generated R-modules. In this paper, we study modules in X by relating them to modules in X which are free on the punctured spectrum of R. We ... More
The existence of finitely generated modules of finite Gorenstein injective dimensionJun 13 2005In this note, we study commutative Noetherian local rings having finitely generated modules of finite Gorenstein injective dimension. In particular, we consider whether such rings are Cohen-Macaulay.
Classification of categorical subspaces of locally noetherian schemesMay 18 2014Mar 14 2016We classify the prelocalizing subcategories of the category of quasi-coherent sheaves on a locally noetherian scheme. In order to give the classification, we introduce the notion of a local filter of subobjects of the structure sheaf. The essential part ... More
Extension groups between atoms in abelian categoriesOct 10 2018We introduce the extension groups between atoms in an abelian category. For a locally noetherian Grothendieck category, the localizing subcategories closed under injective envelopes are characterized in terms of those extension groups. We also introduce ... More
Construction of Grothendieck categories with enough compressible objects using colored quiversFeb 10 2018We introduce a new method to construct a Grothendieck category from a given colored quiver. This is a variant of the construction used to prove that every partially ordered set arises as the atom spectrum of a Grothendieck category. Using the new method, ... More
Non-fragile superconductivity with nodes in the superconducting topological insulator CuxBi2Se3: Zeeman orbital field and non-magnetic impuritiesOct 17 2014Jan 26 2015We study the robustness against non-magnetic impurities in the topological superconductor with point nodes, focusing on an effective model of Cu$_{x}$Bi$_{2}$Se$_{3}$. We find that the topological superconductivity with point-nodes is not fragile against ... More
Non-locally-free locus of O'Grady's ten dimensional exampleJul 09 2010We give a completely explicit description of the fibers of the natural birational morphism from O'Grady's ten dimensional singular moduli space of sheaves on a K3 surface to the corresponding Donaldson-Uhlenbeck compactification.
Conductance of telescoped double-walled nanotubes from perturbation calculationsMar 23 2009Aug 06 2010In a telescoped double-walled nanotube (TDWNT), with the inner tube partially extracted from the outer tube, the total current is forced to flow between the layers. Considering the interlayer Hamiltonian as a perturbation, we can obtain an analytic formula ... More
On the Wu invariants for immersions of a graph into the planeAug 21 2009Feb 14 2010We give an explicit calculation of the Wu invariants for immersions of a finite graph into the plane and classify all generic immersions of a graph into the plane up to regular homotopy by the Wu invariant. This result is a generalization of the fact ... More
Homotopy on spatial graphs and generalized Sato-Levine invariantsOct 19 2007Dec 27 2008Edge-homotopy and vertex-homotopy are equivalence relations on spatial graphs which are generalizations of Milnor's link-homotopy. Fleming and the author introduced some edge (resp. vertex)-homotopy invariants of spatial graphs by applying the Sato-Levine ... More
Classifying subcategories of modules over a commutative noetherian ringAug 01 2008Let R be a quotient ring of a commutative coherent regular ring by a finitely generated ideal. Hovey gave a bijection between the set of coherent subcategories of the category of finitely presented R-modules and the set of thick subcategories of the derived ... More
On localizing subcategories of derived categoriesDec 12 2007Jul 14 2009Let A be a commutative noetherian ring. In this paper, we interpret localizing subcategories of the derived category of A by using subsets of Spec A and subcategories of the category of A-modules. We unify theorems of Gabriel, Neeman and Krause.
Stabilizer group of generalized determinantJan 25 2017In this paper, we consider linear combination of determinant and permanent, which we call generalized determinant, and determine the stabilizer group of it.
Asymptotic Profiles for wave equations with strong dampingFeb 25 2014We consider the Cauchy problem in ${\bf R}^{n}$ for strongly damped wave equations. We derive asymptotic profiles of these solutions with weighted $L^{1,1}({\bf R}^{n})$ data by using a method introduced in [10].
The gonality and the Clifford index of curves on a toric surfaceOct 19 2013We determine the gonality and the Clifford index for curves on a compact smooth toric surface. Moreover, it is shown that their gonality are computed by pencils on the ambient surface. From the geometrical view point, this means that the gonality can ... More
Classifying Serre subcategories via atom spectrumDec 29 2011Sep 13 2012In this paper, we introduce the atom spectrum of an abelian category as a topological space consisting of all the equivalence classes of monoform objects. In terms of the atom spectrum, we give a classification of Serre subcategories of an arbitrary noetherian ... More
Thick subcategories over Gorenstein local rings that are locally hypersurfaces on the punctured spectraSep 14 2011Let R be a Gorenstein local ring which is locally a hypersurface on the punctured spectrum. In this paper, we classify thick subcategories of the bounded derived category of finitely generated R-modules. Moreover, using this classification, we also classify ... More
Discovery of a new subparsec counterjet in NGC 1275: the inclination angle and the environmentSep 13 2016We report the detection of a new feature at the centre of NGC 1275 in the Perseus cluster, hosting the radio source 3C 84. This feature emerges 2 mas (~ 0.7 pc) north of the central core in recent 15 and 43 GHz VLBA images, and seems to be the counterjet ... More
Discrete soliton equations and convergence acceleration algorithmsNov 07 1995Some of the well-known convergence acceleration algorithms, when viewed as two-variable difference equations, are equivalent to discrete soliton equations. It is shown that the $\eta-$algorithm is nothing but the discrete KdV equation. In addition, one ... More
Kramer-Pesch approximation for analyzing field-angle-resolved measurements made in unconventional superconductors: A calculation of the zero-energy density of statesFeb 12 2008Aug 29 2008By measuring angular-oscillation behavior of the heat capacity with respect to the applied field direction, one can detect the details of the gap structure. We introduce the Kramer-Pesch approximation (KPA) as a new method to analyze the field-angle-dependent ... More
Helium Sedimentation and the UV Upturn in Brightest Cluster GalaxiesOct 01 2009Oct 20 2009Recent observations with Galaxy Evolution Explorer (GALEX) show strong unexpected UV excess in the spectrum of brightest cluster galaxies (BCGs). It is believed that the excess UV signal is produced by old and evolved core-He burning stars, and the UV ... More
Ultradiscrete Plücker Relation Specialized for Soliton SolutionsDec 11 2010We propose an ultradiscrete analogue of Pl\"ucker relation specialized for soliton solutions. It is expressed by an ultradiscrete permanent which is obtained by ultradiscretizing the permanent, that is, the signature-free determinant. Using this relation, ... More
Bilinear Equations and Bäcklund Transformation for Generalized Ultradiscrete Soliton SolutionMar 10 2010Ultradiscrete soliton equations and B\"acklund transformation for a generalized soliton solution are presented. The equations include the ultradiscrete KdV equation or the ultradiscrete Toda equation in a special case. We also express the solution by ... More
Predictions via large theta13 from cascadesJun 29 2011Aug 11 2011We investigate a relation among neutrino observables, three mixing angles and two mass squared differences, from a cascade texture of neutrino mass matrix. We show an allowed region of the correlation by use of current data of neutrino oscillation experiments. ... More
Renormalization of Extended QCD$_2$Jul 09 2015Sep 10 2015Extended QCD (XQCD) proposed by Kaplan [1] is an interesting reformulation of QCD with additional bosonic auxiliary fields. While its partition function is kept exactly the same as that of original QCD, XQCD naturally contains properties of low energy ... More
A Perspective on Classical Strings from Complex Sine-Gordon SolitonsSep 04 2006Oct 02 2007We study a family of classical string solutions with large spins on R x S^3 subspace of AdS_5 x S^5 background, which are related to Complex sine-Gordon solitons via Pohlmeyer's reduction. The equations of motion for the classical strings are cast into ... More
A critical shock Mach number for particle acceleration in the absence of pre-existing cosmic rays: $M=\sqrt 5$Jul 17 2013Nov 28 2013It is shown that, under some generic assumptions, shocks cannot accelerate particles unless the overall shock Mach number exceeds a critical value M > sqrt(5). The reason is that for M <= sqrt(5) the work done to compress the flow in a particle precursor ... More
Quantum Benchmark via an Uncertainty Product of Canonical VariablesApr 09 2014Mar 27 2015We present an uncertainty-relation-type quantum benchmark for continuous-variable (CV) quantum channels that works with an input ensemble of Gaussian distributed coherent states and homodyne measurements. It determines an optimal trade-off relation between ... More
Superconducting proximity effect on a two-dimensional Dirac electron systemJan 21 2014The superconducting proximity effect on two-dimensional massless Dirac electrons is usually analyzed using a simple model consisting of the Dirac Hamiltonian and an energy-independent pair potential. Although this conventional model is plausible, it is ... More
More anomaly-free models of six-dimensional gauged supergravityDec 01 2005Sep 04 2006We construct a huge number of anomaly-free models of six-dimensional N = (1,0) gauged supergravity. The gauge groups are products of U(1) and SU(2), and every hyperino is charged under some of the gauge groups. It is also found that the potential may ... More
Finite-Size Effects for Dyonic Giant MagnonsJan 06 2008Oct 15 2008We compute finite-size corrections to dyonic giant magnons in two ways. One is by examining the asymptotic behavior of helical strings of hep-th/0609026 as elliptic modulus k goes to unity, and the other is by applying the generalized Luscher formula ... More
On equivariant maps related to the space of pairs of exceptional Jordan algebrasMar 02 2016Let $\mathcal{J}$ be the exceptional Jordan algebra and $V=\mathcal{J}\oplus \mathcal{J}$. We construct an equivariant map from $V$ to $\mathrm{Hom}_k(\mathcal{J}\otimes \mathcal{J},\mathcal{J})$ defined by homogeneous polynomials of degree $8$ such that ... More
Probing circular polarization in stochastic gravitational wave background with pulsar timing arraysDec 30 2015We study the detectability of circular polarization in a stochastic gravitational wave background from various sources such as supermassive black hole binaries, cosmic strings, and inflation in the early universe with pulsar timing arrays. We calculate ... More
Pre-reheating Magnetogenesis in the Kinetic Coupling ModelFeb 18 2016Apr 04 2016Recent blazar observations provide growing evidence for the presence of magnetic fields in the extragalactic regions. While a natural speculation is to associate the production to inflationary physics, it has been known that magnetogenesis solely from ... More
A Unified Scheme of Measurement and Amplification Processes based on Micro-Macro Duality -- Stern-Gerlach experiment as a typical exampleOct 19 2008A unified scheme for quantum measurement processes is formulated on the basis of Micro-Macro duality as a mathematical expression of the general idea of quantum-classical correspondence. In this formulation, we can naturally accommodate the amplification ... More
Nonsticky Ice at the Origin of the Uniformly Polarized Submillimeter Emission from the HL Tau DiskApr 08 2019May 08 2019Recent (sub)millimeter polarimetric observations toward the young star HL Tau have successfully detected polarization emission from its circumstellar disk. The polarization pattern observed at 0.87 mm is uniform and parallel to the disk's minor axis, ... More
Algorithmic canonical stratifications of simplicial complexesAug 20 2018We introduce a new algorithm for the structural analysis of finite abstract simplicial complexes based on local homology. Through an iterative and top-down procedure, our algorithm computes a stratification $\pi$ of the poset $P$ of simplices of a simplicial ... More
The radius of a subcategory of modulesNov 12 2011Sep 23 2013We introduce a new invariant for subcategories X of finitely generated modules over a local ring R which we call the radius of X. We show that if R is a complete intersection and X is resolving, then finiteness of the radius forces X to contain only maximal ... More
D-modules over rings with finite F-representation typeJun 26 2007Dec 19 2007Smith and Van den Bergh introduced the notion of finite F-representation type as a characteristic $p$ analogue of the notion of finite representation type. In this paper, we prove two finiteness properties of rings with finite F-representation type. The ... More
The discrete Toda equation revisited, dual $β$-Grothendieck polynomial, ultradiscretization and static solitonAug 31 2017Oct 30 2017This paper presents a study of the discrete Toda equation $(\tau_n^t)^2+\tau_{n-1}^t\tau_{n+1}^t=\tau_n^{t-1}\tau_n^{t+1}$, that was introduced in 1977. In this paper, it has been proved that the algebraic solution of the discrete Toda equation, obtained ... More
Electromagnetic Response of a $k_x\pm ik_y$ Superconductor: Effect of Order Parameter Collective ModesMar 14 2000Effects of order parameter collective modes on electromagnetic response are studied for a clean spin-triplet superconductor with $k_x\pm ik_y$ orbital symmetry, which has been proposed as a candidate pairing symmetry for Sr$_2$RuO$_4$. It is shown that ... More
The domain-wall model in an asymptotic-free dynamicsNov 30 1997We investigate a possibility that the rough gauge problem, which have appeared to be a main reason for failures of lattice chiral gauge theories, is cured by an asymptotic-free dynamics. Taking the domain-wall model in 2(+1) dimensions with SU(2) gauge ... More
Domain-wall fermions with U(1) dynamical gauge fields in (4+1)-dimensionsSep 02 1996We carry out a numerical simulation of a domain-wall model in (4+1) dimensions, in the presence of a quenched U(1) dynamical gauge field only in an extra dimension, corresponding to the weak coupling limit of a (4-dimensional) physical gauge coupling. ... More
Direct/indirect detection signatures of nonthermally produced dark matterJul 10 2008Sep 22 2008We study direct and indirect detection possibilities of neutralino dark matter produced non-thermally by e.g. the decay of long-lived particles, as is easily implemented in the case of anomaly or mirage mediation models. In this scenario, large self-annihilation ... More
New Detections of Galactic Molecular Absorption Systems toward ALMA Calibrator SourcesOct 16 2015We report on Atacama Large Millimeter/submillimeter Array (ALMA) detections of molecular absorption lines in Bands 3, 6 and 7 toward four radio-loud quasars, which were observed as the bandpass and complex gain calibrators. The absorption systems, three ... More
Efficient-phase-encoding protocols for continuous-variable quantum key distribution using coherent states and postselectionAug 18 2006We propose efficient-phase-encoding protocols for continuous-variable quantum key distribution using coherent states and postselection. By these phase encodings, the probability of basis mismatch is reduced and total efficiency is increased. We also propose ... More
Security of Continuous-variable quantum cryptography using coherent states: Decline of postselection advantageJun 23 2005We investigate the security of continuous-variable (CV) quantum key distribution (QKD) using coherent states in the presence of quadrature excess noise. We consider an eavesdropping attack which uses a linear amplifier and beam splitter. This attack makes ... More
Quasi-stationary States of Two-Dimensional Electron Plasma Trapped in Magnetic FieldSep 09 2005May 11 2006We have performed numerical simulations on a pure electron plasma system under a strong magnetic field, in order to examine quasi-stationary states that the system eventually evolves into. We use ring states as the initial states, changing the width, ... More
Slow relaxation in the two dimensional electron plasma under the strong magnetic fieldNov 28 2006We study slow relaxation processes in the point vortex model for the two-dimensional pure electron plasma under the strong magnetic field. By numerical simulations, it is shown that, from an initial state, the system undergoes the fast relaxation to a ... More
Effects of Velocity Correlation on Early Stage of Free Cooling Process of Inelastic Hard Sphere SystemSep 05 2003Oct 29 2003The free cooling process in the inelastic hard sphere system is studied by analysing the data from large scale molecular dynamics simulations on a three dimensional system. The initial energy decay, the velocity distribution function, and the velocity ... More
Spin and orbital ordering in double-layered manganitesApr 29 1999We study theoretically the phase diagram of the double-layered perovskite manganites taking into account the orbital degeneracy, the strong Coulombic repulsion, and the coupling with the lattice deformation. Observed spin structural changes as the increased ... More
Relationship Between Gravity and Gauge Scattering in the High Energy LimitOct 30 2012Nov 12 2012Investigations of high-energy graviton-graviton and gluon-gluon scattering are performed in the leading eikonal approximation for the kinematic regime of large center of mass energy and low momentum transfer. We find a double copy relation between the ... More
Sequential optimizing investing strategy with neural networksFeb 11 2010In this paper we propose an investing strategy based on neural network models combined with ideas from game-theoretic probability of Shafer and Vovk. Our proposed strategy uses parameter values of a neural network with the best performance until the previous ... More
Lensing reconstruction from a patchwork of polarization mapsMay 26 2014Aug 23 2014The lensing signals involved in CMB polarization maps have already been measured with ground-based experiments such as SPTpol and POLARBEAR, and would become important as a probe of cosmological and astrophysical issues in the near future. Sizes of polarization ... More
On Conway-Gordon type theorems for graphs in the Petersen familySep 10 2012Jul 11 2013For every spatial embedding of each graph in the Petersen family, it is known that the sum of the linking numbers over all of the constituent 2-component links is congruent to 1 modulo 2. In this paper, we give an integral lift of this formula in terms ... More
Regular projections of graphs with at most three double pointsAug 29 2008May 07 2009A generic immersion of a planar graph into the 2-space is said to be knotted if there does not exist a trivial embedding of the graph into the 3-space obtained by lifting the immersion with respect to the natural projection from the 3-space to the 2-space. ... More
Resolving subcategories closed under certain operations and a conjecture of Dao and TakahashiOct 27 2017Let R be a commutative Noetherian local ring with residue field k. Let X be a resolving subcategory of finitely generated R-modules. This paper mainly studies when X contains k or consists of totally reflexive modules. It is proved that X does so if X ... More
Frobenius morphisms and derived categories on two dimensional toric Deligne-Mumford stacksMay 31 2012Jun 15 2013For a toric Deligne-Mumford (DM) stack, we can consider a certain generalization of the Frobenius endomorphism. For such an endomorphism on a two-dimensional toric DM stack, we show that the push-forward of the structure sheaf generates the bounded derived ... More
Rational orbits of the space of pairs of exceptional Jordan algebrasMar 02 2016Let $k$ be a field of characteristic not equal to $2,3$, $\mathbb{O}$ an octonion over $k$ and $\mathcal{J}$ the exceptional Jordan algebra defined by $\mathbb{O}$. We consider the prehomogeneous vector space $(G,V)$ where $G=GE_6\times \mathrm{GL}(2)$ ... More
The FFRT property of two-dimensional normal graded rings and orbifold curvesJun 01 2017Oct 31 2018This study examines the finite $F$-representation type (abbr. FFRT) property of a two-dimensional normal graded ring $R$ in characteristic $p>0$, using notions from the theory of algebraic stacks. Given a graded ring $R$, we consider an orbifold curve ... More
Products of Greek letter elements dug up from the third Morava stabilizer algebraFeb 12 2012Oka and the second author considered the cohomology of the second Morava stabilizer algebra to study nontriviality of the products of beta elements of the stable homotopy groups of spheres. In this paper, we use the cohomology of the third Morava stabilizer ... More
Structure of irreducible homomorphisms to/from free modulesJun 08 2016Jul 01 2017The primary goal of this paper is to investigate the structure of irreducible monomorphisms to and irreducible epimorphisms from finitely generated free modules over a noetherian local ring. Then we show that over such a ring, self-vanishing of Ext and ... More