Results for "Daisuke Nomura"

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The muon $g-2$ and $α(M_Z^2)$: a new data-based analysisFeb 08 2018This work presents a complete re-evaluation of the hadronic vacuum polarisation contributions to the anomalous magnetic moment of the muon, $a_{\mu}^{\rm had, \, VP}$ and the hadronic contributions to the effective QED coupling at the mass of the $Z$ ... More
Hadronic contributions to the anomalous magnetic moment of the electron and the hyperfine splitting of muoniumAug 21 2012Motivated by recent progress of theory and experiment on the anomalous magnetic moment of the electron, a_e, we update the hadronic contributions to a_e. Using our up-to-date compilation of e^+ e^- \to hadrons data, we find the leading order hadronic ... More
Solar and Atmospheric Neutrino Oscillations and Lepton Flavor Violation in Supersymmetric Models with Right-handed NeutrinosOct 26 1998Mar 19 1999Taking the solar and the atmospheric neutrino experiments into account we discuss the lepton flavor violating processes, such as $\tau\to\mu\gamma$ or $\mu\to e\gamma$, in the minimal supersymmetric standard model with right-handed neutrinos (MSSMRN) ... More
Charged Lepton Flavor Violation in the Semi-Constrained NMSSM with Right-Handed NeutrinosJan 21 2015May 21 2015We study the \mu \to e \gamma decay in the Z_3-invariant next-to-minimal supersymmetric (SUSY) Standard Model (NMSSM) with superheavy right-handed neutrinos. We assume that the soft SUSY breaking parameters are generated at the GUT scale, not universally ... More
B^0_{d,s} - \bar{B}^0_{d,s} mass-differences from QCD spectral sum rulesMay 10 2002Jun 28 2002We present the first QCD spectral sum rules analysis of the SU(3) breaking parameter \xi and an improved estimate of the renormalization group invariant (RGI) bag constant \hat{B}_{B_q} both entering into the B^0_{d,s} - \bar{B}^0_{d,s} mass-differences. ... More
Dimension-six top-Higgs interaction and its effect in collider phenomenologyJul 31 2006Measurement of the Yukawa interaction between the top quark and the Higgs boson should be useful to clarify the mechanism of fermion mass generation. We discuss the impact of non-standard interactions characterized by dimension-six operators on the effective ... More
Hunting for the Top Partner in the Littlest Higgs Model with T-parity at the LHCDec 20 2006We study the Littlest Higgs model with T-parity at the LHC through pair productions of the T-odd top quark partner (T_-) which decays into the top quark and the lightest T-odd particle. We identify the region of parameters favored by the electroweak and ... More
Constraints on radion in a warped extra dimension model from Higgs boson searches at the LHCMay 20 2013Aug 30 2013We study constraints on the radion mass and couplings in the Randall-Sundrum model from the recent LHC data on the Standard Model (SM) Higgs boson searches. When the radion is heavy enough so that it can decay into a pair of on-shell Z-bosons, we find ... More
Atmospheric Neutrino Oscillation and Large Lepton-Flavour Violation in the SUSY SU(5) GUTNov 17 1997The atmospheric neutrino anomaly reported by the super-Kamiokande collaboration suggests existence of a large flavour violating Yukawa coupling in the lepton sector. We discuss lepton-flavour violation at low energies in the framework of the supersymmetric ... More
Blow-up behavior of the scalar curvature along the conical Kähler-Ricci flow with finite time singularitiesJul 11 2016We investigate the scalar curvature behavior along the normalized conical K\"ahler-Ricci flow $\omega_t$, which is the conic version of the normalized K\"ahler-Ricci flow, with finite maximal existence time $T<\infty $. We prove that the scalar curvature ... More
Leonard pairs having zero-diagonal TD-TD formMar 18 2015Fix an algebraically closed field $\mathbb{F}$ and an integer $n \geq 1$. Let $\text{Mat}_n(\mathbb{F})$ denote the $\mathbb{F}$-algebra consisting of the $n \times n$ matrices that have all entries in $\mathbb{F}$. We consider a pair of diagonalizable ... More
Leonard pairs having specified end-entriesSep 15 2014Fix an algebraically closed field $\mathbb{F}$ and an integer $d \geq 3$. Let $V$ be a vector space over $\mathbb{F}$ with dimension $d+1$. A Leonard pair on $V$ is an ordered pair of diagonalizable linear transformations $A: V \to V$ and $A^* : V \to ... More
The end of c=1 CFTMay 11 1996Conformal field theory (CFT) with the central charge c=1 is important both in the field theory and in the condensed matter physics, since it has the continuous internal symmetry (U(1) or SU(2)) and a marginal operator, and it is an effective theory of ... More
Quantum Mechanics, Spacetime Locality, and GravityOct 20 2011May 08 2012Quantum mechanics introduces the concept of probability at the fundamental level, yielding the measurement problem. On the other hand, recent progress in cosmology has led to the "multiverse" picture, in which our observed universe is only one of the ... More
Strongly Coupled Grand Unification in Higher DimensionsAug 22 2001Mar 15 2002We consider the scenario where all the couplings in the theory are strong at the cut-off scale, in the context of higher dimensional grand unified field theories where the unified gauge symmetry is broken by an orbifold compactification. In this scenario, ... More
Constrained Standard Model from Extra DimensionMay 13 2001A five dimensional supersymmetric model is constructed which reduces to the one Higgs-doublet standard model at low energies. The radiative correction to the Higgs potential is finite and calculable, allowing the Higgs mass prediction of 127 \pm 8 GeV. ... More
Type-II seesaw model with two-Higgs doubletsApr 27 2015A study of searching for doubly charged Higgs $(\delta^{\pm\pm})$ is performed in two-Higgs-doublet extension of the type-II seesaw model. We find that a significant mixing effect between singly charged Higgs of Higgs doublet and of triplet is arisen ... More
A Note on Boltzmann BrainsFeb 18 2015Mar 02 2015Understanding the observed arrow of time is equivalent, under general assumptions, to explaining why Boltzmann brains do not overwhelm ordinary observers. It is usually thought that this provides a condition on the decay rate of every cosmologically accessible ... More
Schwarz lemma for conical Kähler metrics with general cone anglesOct 06 2016The Schwarz--Pick lemma is a fundamental result in complex analysis. It is well-known that Yau generalized it to the higher dimensional manifolds by applying his maximum principle for complete Riemannian manifolds. Jeffres obtained Schwarz lemma for volume ... More
Leonard pairs having LB-TD formApr 27 2014Fix an algebraically closed field $\mathbb{F}$ and an integer $d \geq 3$. Let $\text{Mat}_{d+1}(\mathbb{F})$ denote the $\mathbb{F}$-algebra consisting of the $(d+1) \times (d+1)$ matrices that have all entries in $\mathbb{F}$. We consider a pair of diagonalizable ... More
The MSSM confronts the precision electroweak data and the muon g-2Apr 10 2011Oct 24 2011We update the electroweak study of the predictions of the Minimal Supersymmetric Standard Model (MSSM) including the recent results on the muon anomalous magnetic moment, the weak boson masses, and the final precision data on the Z boson parameters from ... More
Predictions for g-2 of the muon and alpha_QED(M_Z^2)Dec 18 2003Apr 28 2004We calculate (g-2) of the muon and the QED coupling alpha(M_Z^2), by improving the determination of the hadronic vacuum polarization contributions and their uncertainties. We include the recently re-analysed CMD-2 data on e^+e^- -> pi^+ pi^-. We carefully ... More
Enhancement of "CP-odd" Higgs Boson Production in the Minimal Supersymmetric Standard Model with Explicit CP ViolationAug 30 2005We calculate the production cross section of the ``CP-odd'' Higgs boson via gluon fusion in the minimal supersymmetric standard model with explicit CP violation in the stop sector. We show that there is a parameter region in which the cross section is ... More
Enhancement of μ\to e γin the supersymmetric SU(5) GUT at large \tanβMay 19 1998Branching ratio of $\mu \to \e \gamma$ is evaluated in the supersymmetric SU(5) grand unified theory taking account of higher dimensional operators, which reproduce the realistic quark and lepton masses and the mixing parameters. It is shown by numerical ... More
New physics effect on the top-Yukawa coupling at ILCOct 14 2007Oct 21 2007Measurement of the top-Yukawa coupling is important to understand the fermion mass generation mechanism and dynamics of electroweak symmetry breaking. We discuss the top quark anomalous couplings which can be described by higher dimensional operators. ... More
Improved predictions for g-2 of the muon and α_{\rm QED}(M_Z^2)Nov 08 2006Apr 20 2007We update the Standard Model predictions of the anomalous magnetic moment of the muon, a_\mu = (g-2)/2, and the value of the QED coupling at the Z-boson mass, incorporating the new e^+e^- \to \pi\pi data obtained by CMD-2 and KLOE, as well as the corrected ... More
The SM prediction of g-2 of the muonSep 17 2002Sep 20 2002We calculate (g-2)/2 of the muon, by improving the determination of the hadronic vacuum polarisation contribution, a_mu^{had,LO}, and its uncertainties. The different e+e- data sets for each exclusive (and the inclusive) channel are combined in order ... More
Mesons in Nuclei and Partial Restoration of Chiral SymmetryMar 23 2016Jul 12 2016Recent topics on mesons in nuclei are discussed by especially emphasizing the role of the partial restoration of chiral symmetry in the nuclear medium. The spontaneously broken chiral symmetry in vacuum is considered to be incompletely restored in finite ... More
On fibre space structures of a projective irreducible symplectic manifoldSep 30 1997In this note, we investigate fibre space structures of a projective irreducible symplectic manifold. We prove that an 2n-dimensional projective irreducible symplectic manifold admits only an n-dimensional fibration over a Fano variety which has only Q-factorial ... More
Upper Bound for Diameter of Cosmological Black Holes and Nonexistence of Black StringsSep 29 2016The diameter of the apparent horizon, defined by the distance between furthest points on the horizon, in spacetimes with a positive cosmological constant $\varLambda$ has been investigated. It is established that the diameter of the apparent horizon on ... More
Brane-world cosmologyDec 01 1999A simple model of the brane-world cosmology has been proposed, which is characterized by four parameters, the bulk cosmological constant, the spatial curvature of the universe, the radiation strength arising from bulk space-time and the breaking parameter ... More
Recent progress in lattice supersymmetry: from lattice gauge theory to black holesJul 05 2016Supersymmetry (SUSY) is a fascinating topic in theoretical physics, because of its unique and counterintuitive properties. It is expected to emerge as new physics beyond the standard model, and it is also a building block for supergravity and superstring ... More
Diagrammatic and Kinetic Equation Analysis of Ultrasoft Fermionic Sector in Quark-Gluon PlasmaMar 26 2013At so high temperature (T) that the coupling constant (g) is small and the masses of the particles are negligible, different scheme has to be applied in each energy scale in the analysis of the quark-gluon plasma (QGP). In the soft energy region (p gT), ... More
Convergence of energy functionals and stability of lower bounds of Ricci curvature via metric measure foliationApr 02 2018Oct 26 2018The notion of the metric measure foliation is introduced by Galaz-Garc\'ia, Kell, Mondino, and Sosa. They studied the relation between a metric measure space with a metric measure foliation and its quotient space. They showed that the curvature-dimension ... More
Power variations and testing for co-jumps: the small noise approachMay 09 2016Jun 20 2016In this paper we study the effects of noise on the bipower variation (BPV), realized volatility (RV) and testing for co-jumps in high-frequency data under the small noise framework. We first establish asymptotic properties of the BPV in this framework. ... More
Effects of SNe II and SNe Ia Feedback on the Chemo-Dynamical Evolution of Elliptical GalaxiesMay 17 2001We numerically investigate the dynamical and chemical processes of the formation of elliptical galaxies in a cold dark matter (CDM) universe, in order to understand the origin of the mass-dependence of the photometric properties of elliptical galaxies. ... More
Static charged perfect fluid with the Weyl-Majumdar relationJun 17 1999Apr 12 2000Static charged perfect fluid distributions have been studied. It is shown that if the norm of the timelike Killing vector and the electrostatic potential have the Weyl-Majumdar relation, then the background spatial metric is the space of constant curvature, ... More
A basis construction for the Shi arrangement of the type $B_{\ell}$ or $C_{\ell}$May 29 2012The Shi arrangement is an affine arrangement of hyperplanes consisting of the hyperplanes of the Weyl arrangement and their parallel translations. It was introduced by J.-Y. Shi in the study of the Kazhdan-Lusztig representation of the affine Weyl groups. ... More
Metastability of R-Charged Black HolesJan 27 2007Jul 04 2007The global stability of R-charged AdS black holes in a grand canonical ensemble is examined by eliminating the constraints from the action, but without solving the equations of motion, thereby constructing the reduced action of the system. The metastability ... More
Box ball system associated with antisymmetric tensor crystalsDec 26 2003Mar 18 2007A new box ball system associated with an antisymmetric tensor crystal of the quantum affine algebra of type A is considered. This includes the so-called colored box ball system with capacity 1 as the simplest case. Infinite number of conserved quantities ... More
Lambda(1405) and kaonic few-body states in chiral dynamicsMar 14 2011Mar 18 2011The present status of the Lambda(1405) structure study in chiral dynamics is briefly reviewed. It turns out that the Lambda(1405) resonance can be described by hadronic dynamics. The idea of the hadronic molecular state is extended to kaonic few-body ... More
On singular fibres of complex Lagrangian fibrationsNov 22 1999We classify singular fibres over general points of the discriminant locus of projective complex Lagrangian fibrations on 4-dimensional holomorphic symplectic manifolds. The singular fibre F is the following either one: F is isomorphic to the product of ... More
Geometry of Multiplicative Preprojective AlgebraOct 14 2007Nov 15 2007Crawley-Boevey and Shaw recently introduced a certain multiplicative analogue of the deformed preprojective algebra, which they called the multiplicative preprojective algebra. In this paper we study the moduli space of (semi)stable representations of ... More
Quiver Varieties with Multiplicities, Weyl Groups of Non-Symmetric Kac-Moody Algebras, and Painlevé EquationsMar 18 2010Oct 26 2010To a finite quiver equipped with a positive integer on each of its vertices, we associate a holomorphic symplectic manifold having some parameters. This coincides with Nakajima's quiver variety with no stability parameter/framing if the integers attached ... More
Nonlinear electromagnetic response in quark-gluon plasmaJun 26 2014We perform the first systematic study of the nonlinear electromagnetic currents induced by external electromagnetic field in quark-gluon plasma, both in the two cases that the inhomogeneity of electromagnetic field is small (large) so that the collision ... More
The boundary state for a class of analytic solutions in open string field theoryOct 07 2011Nov 18 2011We construct a boundary state for a class of analytic solutions in the Witten's open string field theory. The result is consistent with the property of the zero limit of a propagator's length, which was claimed in [19]. And we show that our boundary state ... More
A determinant formula for relative congruence zeta functions for cyclotomic function fieldsJun 17 2009Jul 17 2009Rosen M. gave a determinant formula for relative class numbers for the P-th cyclotomic function fields in the case of the monic irreducible polynomial P, which is regarded as an analogue of the classical Maillet determinant. In this paper, we will give ... More
On the Topology of Black LensesApr 23 2009The topological structure of the black holes in 5-dimensional space-times with a horizon diffeomorphic with the lens space has been discussed. It has been shown that such a black hole can emerge from the crease set, which is composed of the plumbings ... More
Pseudoscalar mesons in nuclei and partial restoration of chiral symmetryDec 16 2010Recent theoretical developments of hadrons in nuclei are briefly reviewed in the aspect of chiral symmetry in nuclei. We show a general sum rule connecting in-medium hadronic quantities and quark condensate, emphasizing that both pionic mode and particle-hole ... More
The Role of Clustering of Sub-Clumps in Bright Elliptical Galaxy Formation from a Low-Spin Seed GalaxyOct 04 2000We reveal the role of clustering of sub-clumps, which is expected in the cold dark matter (CDM) universe, in forming a bright elliptical galaxy (BEG) from a low-spin seed galaxy. This can be done by comparing the evolution of a low-spin seed galaxy including ... More
Middle Convolution and Harnad DualityNov 19 2009Feb 08 2010We interpret the additive middle convolution operation in terms of the Harnad duality, and as an application, generalize the operation to have a multi-parameter and act on irregular singular systems.
Hadronic few-body systems in chiral dynamics, -- Few-body systems in hadron physics --Oct 06 2012Hadronic composite states are introduced as few-body systems in hadron physics. The $\Lambda(1405)$ resonance is a good example of the hadronic few-body systems. It has turned out that $\Lambda(1405)$ can be described by hadronic dynamics in a modern ... More
Galaxy Formation from a Low-Spin Density Perturbation in a CDM UniverseSep 07 1999In order to understand the formation process of elliptical galaxies which are not rotationally supported, we have carried out numerical simulations of the galaxy formation from the density perturbation with a rotation corresponding to a small spin parameter. ... More
Correlated cluster mean-field theory for spin systemsDec 22 2008Apr 27 2009A cluster mean-field method is introduced and the applications to the Ising and Heisenberg models are demonstrated. We divide the lattice sites into clusters whose size and shape are selected so that the equivalence of all sites in a cluster is preserved. ... More
No Black Hole Theorem in Three-Dimensional GravityMay 31 2000Sep 26 2000A common property of known black hole solutions in (2+1)-dimensional gravity is that they require a negative cosmological constant. In this letter, it is shown that a (2+1)-dimensional gravity theory which satisfies the dominant energy condition forbids ... More
Disorder-induced metal-insulator transitions in three-dimensional topological insulators and superconductorsSep 13 2011We discuss the effects of disorder in time-reversal invariant topological insulators and superconductors in three spatial dimensions. For three-dimensional topological insulator in symplectic (AII) symmetry class, the phase diagram in the presence of ... More
Gauge Unification in Higher DimensionsMar 12 2001Jun 14 2001A complete 5-dimensional SU(5) unified theory is constructed which, on compactification on the orbifold with two different Z_2's (Z_2 and Z_2'), yields the minimal supersymmetric standard model. The orbifold accomplishes SU(5) gauge symmetry breaking, ... More
Tridiagonal pairs of $q$-Racah type and the $μ$-conjectureAug 21 2009Let $\K$ denote a field and let $V$ denote a vector space over $\K$ with finite positive dimension. We consider a pair of linear transformations $A:V \to V$ and $A^*:V \to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; ... More
Charge-Induced Spin Torque in Anomalous Hall FerromagnetsSep 16 2015We demonstrate that spin-orbit coupled electrons in a magnetically doped system exert a spin torque on the local magnetization, without a flowing current, when the chemical potential is modulated in a magnetic field. The spin torque is proportional to ... More
Evolution of $nu=1$ Bilayer Quantum Hall FerromagnetApr 22 2002The natures of the ground state in a $\nu_{\rm T}=1$ bilayer quantum Hall system at a variety of layer spacing are investigated. At small layer separations the system exhibits spontaneous interlayer phase coherence. It is claimed that the Halperin's (1,1,1) ... More
Pairing symmetry transitions in the even-denominator FQHE systemJul 13 2001Jul 25 2001Transitions from a paired quantum Hall state to another quantum Hall state in bilayer systems are discussed in the framework of the edge theory. Starting from the edge theory for the Haldane-Rezayi state, it is shown that the charging effect of a bilayer ... More
Phase Diagram of S=1 Bond-Alternating XXZ Chains Reflecting the Hidden Z_2\times Z_2 SymmetryMay 19 1997The phase diagram of the spin-1 bond-alternating XXZ chain is studied numerically. This model is appropriate to study the VBS picture and the hidden Z_2\times Z_2 symmetry concerning to the Haldane gap problem. The possible phases are the ferromagnetic, ... More
Level spectroscopy II - application to the Gaussian model -Jun 18 1996It was a difficult problem to determine the Gaussian fixed line from the numerical data, because close to the Berezinskii-Kosterlitz-Thouless multicritical point the divergence of the correlation length becomes very slow. Considering the renormalization ... More
Critical Properties of the XXZ chain in External Staggered Magnetic FieldOct 13 1995We comment on the recent work of Alcaraz and Malvezzi [1995 {\it J. Phys. A: Math. Gen.} {\bf 19} 1521] for the critical properties of the $S=1/2$ $XXZ$ chain in staggered magnetic field. The method of determining the phase boundary from the finite-size ... More
Balanced Leonard PairsJun 12 2005Jun 15 2005Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. By a Leonard pair on $V$ we mean an ordered pair of linear transformations $A:V \to V$ and $A^*:V \to V$ that satisfy the following two conditions: (i) There ... More
Phase separation as an instability of the Tomonaga-Luttinger liquidFeb 13 1997Aug 13 1997Asymptotic behavior of the Tomonaga-Luttinger liquid in the vicinity of the phase-separated region is investigated in the one-dimensional $t$-$J$ model, to study the universal property of the $c=1$ conformal field theory with U(1) symmetry near the $K\to\infty$ ... More
Hidden Pion Varieties in Composite Models for Diphoton ResonancesMar 18 2016May 15 2016The diphoton excesses at 750 GeV seen in the LHC data may be the first hint for new physics at the TeV scale. We discuss variations of the model considered earlier, in which one or more diphoton excesses arise from composite pseudo Nambu-Goldstone bosons ... More
Supersymmetry from TypicalityJul 14 2014We argue that under a set of simple assumptions the multiverse leads to low energy supersymmetry with the spectrum often called spread or mini-split supersymmetry: the gauginos are in the TeV region with the other superpartners two or three orders of ... More
Supersymmetry, Naturalness, and Signatures at the LHCFeb 10 2006Weak scale supersymmetry is often said to be fine-tuned, especially if the matter content is minimal. This is not true if there is a large A term for the top squarks. We present a systematic study on fine-tuning in minimal supersymmetric theories and ... More
The Supersymmetric Fine-Tuning Problem and TeV-Scale Exotic ScalarsApr 26 2005A general framework is presented for supersymmetric theories that do not suffer from fine-tuning in electroweak symmetry breaking. Supersymmetry is dynamically broken at a scale \Lambda \approx (10 - 100) TeV, which is transmitted to the supersymmetric ... More
Holographic Theories of Electroweak Symmetry Breaking without a Higgs BosonDec 17 2003Dec 30 2003Recently, realistic theories of electroweak symmetry breaking have been constructed in which the electroweak symmetry is broken by boundary conditions imposed at a boundary of higher dimensional spacetime. These theories have equivalent 4D dual descriptions, ... More
Bi-Maximal Neutrino Mixing in SO(10)_{GUT}Jul 10 1998Oct 20 1998We find a grand unified SO(10) model which accommodates the bi-maximal neutrino mixing for vacuum-oscillation solutions to the atmospheric and the solar neutrino problems. This model maintains the original SO(10) mass relation between neutrino and up-type ... More
Single-Letter Characterization of Epsilon-Capacity for Mixed Memoryless ChannelsJul 01 2014For the class of mixed channels decomposed into stationary memoryless channels, single-letter characterizations of the $\varepsilon$-capacity have not been known except for restricted classes of channels such as the regular decomposable channel introduced ... More
Linear scaling calculation of a n-type GaAs quantum dotJul 31 2007A linear scale method for calculating electronic properties of large and complex systems is introduced within a local density approximation. The method is based on the Chebyshev polynomial expansion and the time-dependent method, which is tested in calculating ... More
Dust Size Growth and Settling in a Protoplanetary DiskJan 01 2006We have studied dust evolution in a quiescent or turbulent protoplanetary disk by numerically solving coagulation equation for settling dust particles, using the minimum mass solar nebular model. As a result, if we assume an ideally quiescent disk, the ... More
Tridiagonal pairs and the $μ$-conjectureAug 18 2009Let $F$ denote a field and let $V$ denote a vector space over $F$ with finite positive dimension. We consider a pair of linear transformations $A:V \to V$ and $A^*:V \to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; ... More
Tridiagonal matrices with nonnegative entriesOct 07 2010In this paper we characterize the nonnegative irreducible tridiagonal matrices and their permutations, using certain entries in their primitive idempotents. Our main result is summarized as follows. Let $d$ denote a nonnegative integer. Let $A$ denote ... More
Linear transformations that are tridiagonal with respect to both eigenbases of a Leonard pairMay 11 2006Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A : V \to V$ and $A^* : V \to V$ that satisfy (i) and (ii) below: (i) There exists a basis for $V$ with respect ... More
Fractional Quantum Hall Effects in Graphene and Its BilayerJun 05 2009Single-layer and Bilayer of graphene are new classes of two-dimensional electron systems with unconventional band structures and valley degrees of freedom. The ground states and excitations in the integer and fractional quantum Hall regimes are investigated ... More
Coupled charge and valley excitations in graphene quantum Hall ferromagnetsMar 17 2008Jul 09 2008Graphene is a two-dimensional carbon material with a honeycomb lattice and Dirac-type low-energy spectrum. In a strong magnetic field, where Coulomb interactions dominate against disorder broadening, quantum Hall ferromagnetic states realize at integer ... More
Microscopic derivation of magnon spin current in topological insulator/ferromagnet heterostructureOct 12 2016We investigate a spin-electricity conversion effect in a topological insulator/ferromagnet heterostructure. In the spin-momentum-locked surface state, an electric current generates non-equilibrium spin accumulation, which causes a spin-orbit torque that ... More
Edge State Transport of Separately Contacted Bilayer Systems in the Fractional Quantum Hall RegimeJun 14 1999Hall and diagonal resistances of bilayer fractional quantum Hall systems are discussed theoretically. The bilayers have electrodes attached separately to each layer. They are assumed to be coupled weakly by interlayer tunneling, while the interlayer Coulomb ... More
BKT transition and level spectroscopyJan 07 2002Jan 23 2002Berezinskii-Kosterlitz-Thouless (BKT) transition is one of the instability mechanisms for the Tomonaga-Luttinger liquid. But in the BKT transition, there are logarithmic-correction problems, which make it very difficult to treat BKT transitions numerically. ... More
Strong quasi-particle tunneling study in the paired quantum Hall statesMay 15 2001The quasi-particle tunneling phenomena in the paired fractional quantum Hall states are studied. A single point-contact system is first considered. Because of relevancy of the quasi-particle tunneling term, the strong tunneling regime should be investigated. ... More
Transition maps between the 24 bases for a Leonard pairMay 27 2007Let $V$ denote a vector space with finite positive dimension. We consider a pair of linear transformations $A : V \to V$ and $A^* : V \to V$ that satisfy (i) and (ii) below: (i) There exists a basis for $V$ with respect to which the matrix representing ... More
Some trace formulae involving the split sequences of a Leonard pairAug 22 2005Let $K$ denote a field, and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \to V$ and $A^*:V \to V$ that satisfy (i), (ii) below: (i) There exists a basis for $V$ with respect to ... More
Composite Models for the 750 GeV Diphoton ExcessDec 15 2015May 12 2016We present composite models explaining the diphoton excess of mass around 750 GeV recently reported by the LHC experiments.
Low-Scale See-Saw Mechanisms for Light NeutrinosJul 03 2000Jun 27 2001Alternatives to the see-saw mechanism are explored in supersymmetric models with three right-handed or sterile neutrinos. Tree-level Yukawa couplings can be drastically suppressed in a natural way to give sub-eV Dirac neutrino masses. If, in addition, ... More
Singlet Portal to the Hidden SectorAug 30 2010Ultraviolet physics typically induces a kinetic mixing between gauge singlets which is marginal and hence non-decoupling in the infrared. In singlet extensions of the minimal supersymmetric standard model, e.g. the next-to-minimal supersymmetric standard ... More
Outward Motion of Porous Dust Aggregates by Stellar Radiation Pressure in Protoplanetary DisksNov 18 2014We study the dust motion at the surface layer of protoplanetary disks. Dust grains in surface layer migrate outward due to angular momentum transport via gas-drag force induced by the stellar radiation pressure. In this study, we calculate mass flux of ... More
The universal area spectrum in single-horizon black holesMay 22 2004Jun 16 2004We investigate highly damped quasinormal mode of single-horizon black holes motivated by its relation to the loop quantum gravity. Using the WKB approximation, we show that the real part of the frequency approaches the value $T_{\rm H}\ln 3$ for dilatonic ... More
Generalized zig-zag products of regular digraphs and bounds on their spectral expansionsMar 26 2007We introduce a generalization of the zig-zag product of regular digraphs (directed graphs), which allows us to construct regular digraphs with m ore flexible choices of the degrees. In our generalization, we can control the connectivity of the resulting ... More
Matrix units associated with the split basis of a Leonard pairFeb 19 2006Let $K$ denote a field, and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \to V$ and $A^*:V \to V$ that satisfy (i), (ii) below: (i) There exists a basis for $V$ with respect to ... More
The switching element for a Leonard pairAug 25 2006Let $V$ denote a vector space with finite positive dimension. We consider a pair of linear transformations $A : V \to V$ and $A^* : V \to V$ that satisfy (i) and (ii) below: (i) There exists a basis for $V$ with respect to which the matrix representing ... More
Two-loop Induced Majorana Neutrino Mass in a Radiatively Induced Quark and Lepton Mass ModelSep 06 2016A two-loop induced radiative neutrino model is proposed as an extension of our previous work in which the first and second generation standard model fermion masses are generated at one-loop level in both quark and lepton sectors. Then we discuss current ... More
On the shape of a tridiagonal pairJun 21 2009Aug 27 2009Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider a pair of linear transformations $A:V \to V$ and $A^*:V \to V$ that satisfy the following conditions: (i) each of $A,A^*$ is diagonalizable; ... More
Phase diagram of S=1/2 XXZ chain with NNN interactionSep 20 1999We study the ground state properties of one-dimensional XXZ model with next-nearest neighbor coupling alpha and anisotropy Delta. We find the direct transition between the ferromagnetic phase and the spontaneously dimerized phase. This is surprising, ... More
Affine transformations of a Leonard pairNov 25 2006Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider an ordered pair of linear transformations $A : V \to V$ and $A^* : V \to V$ that satisfy (i) and (ii) below: (i) There exists a basis for $V$ ... More
Update of g-2 of the muon and Delta alphaJan 29 2010We update our Standard Model predictions for g-2 of the muon and for the hadronic contributions to the running of the QED coupling, Delta alpha^5_had(M_Z^2). Particular emphasis is put on recent changes in the hadronic contributions from new data in the ... More
Light MSSM Higgs boson scenario and its test at hadron collidersSep 07 2006We show that in the Minimal Supersymmetric Standard Model, the possibility for the lightest CP-even Higgs boson to be lighter than $Z$ boson (as low as about 60 GeV) is, contrary to the usual belief, not yet excluded by LEP2 data or any other existing ... More