Results for "Y. Aoki"

total 34048took 0.12s
Proton decay matrix elements on the latticeApr 28 2013Jan 13 2014Hadronic matrix elements of proton decay are essential ingredients to bridge the grand unification theory to low energy observables like proton lifetime. In this paper we non-perturbatively calculate the matrix elements, relevant for the process of a ... More
Universality of the Nf=2 Running CouplingMar 06 2009We investigate universality of the Nf=2 running coupling in the Sch\"odinger functional scheme, by calculating the step scaling function in lattice QCD with the renorm alization group (RG) improved gauge action at both weak(u=0.9796) and strong(u=3.3340) ... More
Chemical composition of UV-bright star ZNG 4 in the globular cluster M13Feb 12 2004We present a detailed model-atmosphere analysis of ZNG 4, a UV-bright star in the globular cluster M13. From the analysis of a high resolution ($ R \approx 45,000 $) spectrum of the object, we derive the atmospheric parameters to be $\rm T_{eff} = 8500\pm ... More
Coexistence of Antiferromagnetism and Superconductivity near the Quantum Criticality in Heavy Fermion Compound CeRhIn$_5$Nov 26 2002We report a study on the interplay between antiferromagnetism (AFM) and superconductivity (SC) in a heavy-fermion compound CeRhIn$_5$ under pressure $P=1.75$ GPa. The onset of the magnetic order is evidenced from a clear split of $^{115}$In-NQR spectrum ... More
Unusual behaviors in the transport properties of REFe$_{4}$P$_{12}$ (RE: La, Ce, Pr, and Nd)Oct 02 2000We have investigated the resistivity ($\rho$), thermoelectric power (TEP) and Hall coefficient ($R_{H}$) on high quality single crystals of REFe$_{4}$P$_{12}$. TEP in CeFe$_{4}$P$_{12}$ is extremely large ($\sim$ 0.5mV/K at 290K) with a peak of $\sim$ ... More
Thermodynamical Study on the Heavy-Fermion Superconductor PrOs4Sb12: Evidence for Field-Induced Phase TransitionJun 11 2002Sep 10 2002We report measurements of low-temperature specific heat on the 4f^2-based heavy-fermion superconductor PrOs4Sb12. In magnetic fields above 4.5 T in the normal state, distinct anomalies are found which demonstrate the existence of a field-induced ordered ... More
One loop calculation in lattice QCD with domain-wall quarksNov 05 1997One loop corrections to the domain-wall quark propagator are calculated in massless QCD. It is shown that no additative counter term to the current quark mass is generated in this theory, and the wave function renormalization factor of the massless quark ... More
Chiral properties of domain-wall fermions from eigenvalues of 4 dimensional Wilson-Dirac operatorSep 21 2001Oct 03 2001We investigate chiral properties of the domain-wall fermion (DWF) system by using the four-dimensional hermitian Wilson-Dirac operator. We first derive a formula which connects a chiral symmetry breaking term in the five dimensional DWF Ward-Takahashi ... More
Anomaly through Gauge Invariant Regularization with Infinite Number of Pauli-Villars FieldsJun 15 1993Jun 17 1993Abelian anomaly is examined by means of the recently proposed gauge invariant regularization for SO(10) chiral gauge theory and its generalization for a theory of arbitrary gauge group with anomaly-free chiral fermion contents. For both cases it is shown ... More
Prospects of Very Long Base-Line Neutrino Oscillation Experiments with the KEK-JAERI High Intensity Proton AcceleratorDec 27 2001We study physics potential of Very Long Base-Line (VLBL) Neutrino-Oscillation Experiments with the High Intensity Proton Accelerator (HIPA), which will be completed by the year 2007 in Tokai-village, Japan, as a joint project of KEK and JAERI (Japan Atomic ... More
The effect of uniaxial pressure on the magnetic anomalies of the heavy-fermion metamagnet CeRu2Si2Jun 11 2002The effect of uniaxial pressure (P_u) on the magnetic susceptibility (X), magnetization (M), and magnetoresistance (MR) of the heavy-fermion metamagnet CeRu2Si2 has been investigated. For the magnetic field along the tetragonal c axis, it is found that ... More
One loop calculation of QCD with domain-wall quarksSep 26 1997We calculate one loop corrections to the domain-wall quark propagator in QCD. We show how the wave function is renormalized in this theory. Especially we are interested in the behavior of the massless fermion mode, which exists near the domain wall at ... More
Structure and magnetism in nanocrystalline Ca(La)B$_6$ filmsFeb 14 2004Nanocrystalline films of La-doped CaB$_6$ have been fabricated by using a rf-magnetron sputtering. Lattice expansion of up to 6% with respect to the bulk value was observed along the direction perpendicular to the film plane, which arises from the trapping ... More
The Origin of Carbon-Enhancement and Initial Mass Function of Extremely Metal-Poor Stars in the Galactic HaloOct 23 2006It is known that the carbon-enhanced, extremely metal-poor (CEMP) stars constitute a substantial proportion in the extremely metal-poor (EMP) stars of the Galactic Halo, by far larger than CH stars in Population II stars. We investigate their origin with ... More
The order of the quantum chromodynamics transition predicted by the standard model of particle physicsNov 10 2006We determine the nature of the QCD transition using lattice calculations for physical quark masses. Susceptibilities are extrapolated to vanishing lattice spacing for three physical volumes, the smallest and largest of which differ by a factor of five. ... More
Histograms in heavy-quark QCD at finite temperature and densitySep 10 2013Feb 07 2014We study the phase structure of lattice QCD with heavy quarks at finite temperature and density by a histogram method. We determine the location of the critical point at which the first-order deconfining transition in the heavy-quark limit turns into ... More
Application of fixed scale approach to static quark free energies in quenched and 2+1 flavor lattice QCD with improved Wilson quark actionDec 13 2011Oct 24 2012Free energies between static quarks and Debye screening masses in the quark-gluon plasma are studied on the basis of Polyakov-line correlations in lattice simulations of 2+1 flavors QCD with the renormalization-group improved gluon action and the $O(a)$-improved ... More
Towards the equation of state in 2+1 flavor QCD with improved Wilson quarks in the fixed scale approachOct 28 2009We report on the status of our study towards the equation of state in 2+1 flavor QCD with improved Wilson quarks. To reduce the computational cost which is quite demanding for Wilson-type quarks, we adopt the fixed scale approach, i.e. the temperature ... More
Reverberation Measurements of the Inner Radius of the Dust Torus in Nearby Seyfert 1 GalaxiesNov 24 2005The most intense monitoring observations yet made in the optical (UBV) and near-infrared (JHK) wave bands were carried out for nearby Seyfert1 galaxies of NGC 5548, NGC 4051, NGC 3227, and NGC 7469. Over three years of observations with MAGNUM telescope ... More
Broad Balmer-line Absorption in SDSS J172341.10+555340.5Mar 24 2010Aug 03 2010I present the discovery of Balmer-line absorption from H alpha to H9 in iron low-ionizaton broad absorption line (FeLoBAL) quasar, SDSS~J172341.10+555340.5 by near-infrared spectroscopy with the Cooled Infrared Spectrograph and Camera for OHS (CISCO) ... More
Stable and unstable periodic orbits in the one dimensional lattice $φ^4$ theoryJun 10 2016Aug 28 2016Periodic orbits for the classical $\phi^4$ theory on the one dimensional lattice are systematically constructed by extending the normal modes of the harmonic theory, for periodic, fixed and free boundary conditions. Through the process, we clarify, in ... More
The estimate of the wind energy potential and insolationSep 20 2009The concise letter points out that the estimates of the global potential of wind power exceeds the amount of kinetic energy in the relevant layer of atmosphere by far more than an order of magnitude. Originally submitted to the Letters section of the ... More
Boson--fermion bound states in two dimensional QCDJul 12 1993We derive the boson--fermion bound state equation in a two dimensional gauge theory in the large--$\nc$ limit. We analyze the properties of this equation and in particular, find that the mass trajectory is linear with respect to the bound state level ... More
An introduction to computational algebraic statisticsJul 26 2016In this paper, we introduce the fundamental notion of a Markov basis, which is one of the first connections between commutative algebra and statistics. The notion of a Markov basis is first introduced by Diaconis and Sturmfels (1998) for conditional testing ... More
The "devil's staircase" type phase transition in NaV2O5 under high pressureApr 17 2001The "devil's staircase" type phase transition in the quarter-filled spin-ladder compound NaV2O5 has been discovered at low temperature and high pressure by synchrotron radiation x-ray diffraction. A large number of transitions are found to successively ... More
Symmetries of spatial meson correlators in high temperature QCDFeb 08 2019Based on a complete set of $J = 0$ and $J=1$ spatial isovector correlation functions calculated with $N_F = 2$ domain wall fermions we identify an intermediate temperature regime of $T \sim 250 - 550$ MeV where chiral symmetry is restored but the correlators ... More
Spin-Orbit Force from Lattice QCDMay 10 2013Jun 19 2014We present a first attempt to determine nucleon-nucleon potentials in the parity-odd sector, which appear in 1P1, 3P0, 3P1, 3P2-3F2 channels, in Nf=2 lattice QCD simulations. These potentials are constructed from the Nambu-Bethe-Salpeter wave functions ... More
Kaon-Nucleon potential from lattice QCDFeb 11 2010Mar 03 2010We study the KN interactions in the I(J^{\pi})=0(1/2^-) and 1(1/2^-) channels and associated exotic state \Theta^+ from 2+1 flavor full lattice QCD simulation for relatively heavy quark mass corresponding to m_{\pi}=871 MeV. The s-wave KN potentials are ... More
The PACS-CS ProjectOct 02 2005We describe our plan to develop a large-scale cluster system with a peak speed of 14.3Tflops for lattice QCD at the Center for Computational Sciences, University of Tsukuba, as a successor to the current 0.6Tflops CP-PACS computer. The system consist ... More
$ρ$ meson decay from the latticeOct 03 2006We present preliminary results on the $\rho$ meson decay width estimated from the scattering phase shift of the I=1 two-pion system. The phase shift is calculated by the finite size formula for non-zero total momentum frame (the moving frame) derived ... More
Lattice QCD Calculation of the $ρ$ Meson Decay WidthAug 28 2007We present a lattice QCD calculation of the $\rho$ meson decay width via the $P$-wave scattering phase shift for the I=1 two-pion system. Our calculation uses full QCD gauge configurations for $N_f=2$ flavors generated using a renormalization group improved ... More
Chiral Symmetry and Electron-Electron Interaction in Many-Body Gap Formation in GrapheneAug 08 2011We study a many-body ground state of graphene in perpendicular magnetic fields. Chiral symmetry in graphene enables us to determine the many-body ground state, which turns out to be a doubly degenerate chiral condensate for the half-filled (undoped) case. ... More
New Dissipation Relaxation Phenomenon in Oscillating Solid He-4Mar 19 2008We describe the first observations on the time-dependent dissipation when the drive level of a torsional oscillator containing solid He-4 is abruptly changed. The relaxation of dissipation in solid He-4 shows rich dynamical behavior including exponential ... More
Oscillation Frequency Dependence of Non-Classical Rotation Inertia of Solid $^4$HeMay 04 2007May 07 2007The non-classical rotational inertia fraction of the identical cylindrical solid $^4$He below 300 mK is studied at 496 and 1173 Hz by a double resonance torsional oscillator. Below 35 mK, the fraction is the same at sufficiently low rim velocities. Above ... More
Flat bands in Weaire-Thorpe model and siliceneOct 29 2014Jan 31 2015In order to analytically capture and identify peculiarities in the electronic structure of silicene, Weaire-Thorpe(WT) model, a standard model for treating three-dimensional (3D) silicon, is applied to silicene with the buckled 2D structure. In the original ... More
Fermion spectrum in the quenched U(1) chiral Wilson-Yukawa modelNov 11 1992Nature of charged fermion state is investigated in the quenched U(1) chiral Wilson-Yukawa model. Fitting the charged fermion propagator with a single hyperbolic cosine does not yield reliable result. On the other hand the behaviour of the propagator including ... More
Lattice realization of the generalized chiral symmetry in two dimensionsSep 24 2016While it has been pointed out that the chiral symmetry, which is important for the Dirac fermions in graphene, can be generalized to tilted Dirac fermions as in organic metals, such a generalized symmetry was so far defined only for a continuous low-energy ... More
Manipulation of the Dirac cones and the anomaly in the graphene related quantum Hall effectSep 10 2010The quantum Hall effect in graphene is regarded to be involving half-integer topological numbers associated with the massless Dirac particle, this is usually not apparent due to the doubling of the Dirac cones. Here we theoretically consider two classes ... More
Topological analysis of the quantum Hall effect in graphene: Dirac-Fermi transition across van Hove singularities and the edge vs bulk quantum numbersJul 26 2006Inspired by a recent discovery of a peculiar integer quantum Hall effect (QHE) in graphene, we study QHE on a honeycomb lattice in terms of the topological quantum number, with two-fold interests: First, how the zero-mass Dirac QHE around the center of ... More
Nucleon axial charge in 2+1 flavor dynamical lattice QCD with domain wall fermionsJan 25 2008Jul 03 2008We present results for the nucleon axial charge g_A at a fixed lattice spacing of 1/a=1.73(3) GeV using 2+1 flavors of domain wall fermions on size 16^3x32 and 24^3x64lattices (L=1.8 and 2.7 fm) with length 16 in the fifth dimension. The length of the ... More
The Kaon B-parameter from Quenched Domain-Wall QCDAug 15 2005May 15 2006We present numerical results for the kaon B-parameter, B_K, determined in the quenched approximation of lattice QCD. Our simulations are performed using domain-wall fermions and the renormalization group improved, DBW2 gauge action which combine to give ... More
Domain wall fermions with improved gauge actionsNov 12 2002Nov 26 2002We study the chiral properties of quenched domain wall fermions with several gauge actions. We demonstrate that the residual chiral symmetry breaking, which is present for a finite number of lattice sites in the fifth dimension ($L_s$), can be substantially ... More
Direct Observation of Quadrupolar Excitons in the Heavy-Fermion Superconductor PrOs$_{4}$Sb$_{12}$Feb 28 2005Sep 07 2005We report inelastic neutron scattering experiments performed to investigate the low energy magnetic excitations on single crystals of the heavy-fermion superconductor PrOs$_{4}$Sb$_{12}$. The observed excitation clearly softens at a wave vector Q = (1,0,0), ... More
Transition of the Stellar Initial Mass Function Explored with Binary Population SynthesisMar 09 2013The stellar initial mass function (IMF) plays a crucial role in determining the number of surviving stars in galaxies, the chemical composition of the interstellar medium, and the distribution of light in galaxies. A key unsolved question is whether the ... More
Chiral zero modes on the domain-wall model in 4+1 dimensionsOct 24 1996We investigate an original domain-wall model in 4+1 dimensions numerically in the presence of U(1) dynamical gauge field only in an extra dimension, corresponding to a weak coupling limit of 4-dimensional physical gauge coupling. Using a quenched approximation ... More
Markov bases for two-way change-point models of ladder determinantal tablesAug 30 2016Feb 03 2017To evaluate a fitting of a statistical model to given data, calculating a conditional $p$ value by a Markov chain Monte Carlo method is one of the effective approaches. For this purpose, a Markov basis plays an important role because it guarantees the ... More
Application of chiral perturbation theory to 2+1 flavor lattice QCD with O(a)-improved Wilson quarksOct 18 2007We apply chiral perturbation theory to the pseudoscalar meson mass and decay constant data obtained in the PACS-CS Project toward 2+1 flavor lattice QCD simulations with the O(a)-improved Wilson quarks. We examine the existence of chiral logarithms in ... More
Spin-squeezed Ground States in the Bilayer Quantum Hall FerromagnetNov 05 1997A "squeezed-vacuum" state considered in quantum optics is shown to be realized in the ground-state wavefunction for the bilayer quantum Hall system at the total Landau level filling of $\nu=1/m$ (m: odd integer). This is derived in the boson approximation, ... More
Strong coupling between a trapped single atom and an all-fiber cavityMay 25 2015Aug 26 2015We demonstrate an all-fiber cavity QED system with a trapped single atom in the strong coupling regime. We use a nanofiber Fabry-Perot cavity, that is, an optical nanofiber sandwiched by two fiber-Bragg-grating mirrors. Measurements of the cavity transmission ... More
Mass inequalities in two dimensional gauged four fermi modelsAug 17 2001We quantitatively analyze the meson mass inequality relations of two dimensional gauged four fermi models in the large N limit. The class of models we study includes the 't Hooft model, the chiral and non-chiral Gross-Neveu models as special points in ... More
Molecular dynamics study of a classical two-dimensional electron system: Positional and orientational ordersJun 15 1999Dec 07 1999Molecular dynamics simulation is used to investigate the crystallization of a classical two-dimensional electron system, in which electrons interact with the Coulomb repulsion. From the positional and the orientational correlation functions, we have found ... More
Persistence of Vibrational Modes in a Classical Two-Dimensional Electron LiquidJan 04 2000Vibrational density of states of a classical two-dimensional electron system obtained with a molecular-dynamics simulation is shown to have a peak in both solid and liquid phases. From an exact diagonalisation of the dynamical matrix, the peak is identified ... More
Noise reduction and hyperfine level coherence in spontaneous noise spectroscopy of atomic vaporSep 12 2013We develop a system for measurements of power spectra of transmitted light intensity fluctuations, in which the extraneous noise, including shot noise, is reduced. In essence, we just apply light, measure the power of the transmitted light and derive ... More
Michelson interferometry with quantum noise reductionJun 18 2012A Michelson interferometer with noise reduction to sub-shot noise levels is proposed and realized. Multiple measurements of a single signal beam are taken and the quantum property of light plays an essential role in the principle underlying this interferometry. ... More
Massive gravitons as dark matter and gravitational wavesApr 22 2016Jul 18 2016We consider the possibility that the massive graviton is a viable candidate of dark matter in the context of bimetric gravity. We first derive the energy-momentum tensor of the massive graviton and show that it indeed behaves as that of dark matter fluid. ... More
Bulk Properties of Anharmonic Chains in Strong Thermal Gradients: Non-Equilibrium $φ^4$ TheoryOct 09 1999We study nonequilibrium properties of a one-dimensional lattice Hamiltonian with quartic interactions in strong thermal gradients. Nonequilibrium temperature profiles, T(x), are found to develop significant curvature and boundary jumps. From the determination ... More
Classical $φ^4$ Lattice Field Theory in Strong Thermal GradientsNov 22 1999The dynamics of classical $\phi^4$ theory under weak and strong thermal gradients is studied. We obtain the thermal conductivity of the theory including its temperature dependence. Under moderately strong thermal gradients, the temperature profiles become ... More
Physics of the gauged four fermi model in $(1+1)$ dimensionsMay 12 1999We analyze a two dimensional model of gauged fermions with quartic couplings in the large-N limit. This combines the 't Hooft model and the Gross-Neveu model where the coupling constants of both theories are arbitrary. Analytic equations describing the ... More
1+1 dimensional QCD with fundamental bosons and fermionsJun 09 1995We analyze the properties of mesons in 1+1 dimensional QCD with bosonic and fermionic ``quarks'' in the large $\nc$ limit. We study the spectrum in detail and show that it is impossible to obtain massless mesons including boson constituents in this model. ... More
Topological aspects of graphene: Dirac fermions and the bulk-edge correspondence in magnetic fieldsJan 18 2007We discuss topological aspects of electronic properties of graphene, including edge effects, with the tight-binding model on a honeycomb lattice and its extensions to show the following: (i) Appearance of the pairn of massless Dirac dispersions, which ... More
Charged fermion states in the quenched U(1) chiral Wilson-Yukawa modelApr 08 1993Apr 13 1993Property of charged fermion states is investigated in the quenched U(1) chiral Wilson-Yukawa model. Fitting the charged fermion propagator with a single hyperbolic cosine does not yield reliable results. On the other hand the behavior of the propagator ... More
Full QCD calculation of neutron electric dipole moment with the external electric field methodMar 06 2008Jul 22 2008We have calculated the neutron electric dipole moment (NEDM) in the presence of the CP violating $\theta$ term in lattice QCD with 2-flavor dynamical clover quarks, using the external electric field method. Accumulating a large number of statistics by ... More
High-Resolution Spectroscopy of Extremely Metal-Poor Stars from SDSS/SEGUE: I. Atmospheric Parameters and Chemical CompositionsOct 06 2012Chemical compositions are determined based on high-resolution spectroscopy for 137 candidate extremely metal-poor (EMP) stars selected from the Sloan Digital Sky Survey (SDSS) and its first stellar extension, the Sloan Extension for Galactic Understanding ... More
Scale-Free Structure Emerging from Co-Evolution of a Network and the Concentration of Diffusive Resources on ItAug 04 2011Nov 13 2012Co-evolution exhibited by a network system, involving the intricate interplay between the dynamics of the network itself and the subsystems connected by it, is a key concept for understanding the self-organized, flexible nature of real-world network systems. ... More
Effect of Synchronous Incoming Spikes on Activity Pattern in A Network of Spiking NeuronsOct 25 2004Although recent neurophysiological experiments suggest that synchronous neural activity is involved in some perceptual and cognitive processes, the functional role of such coherent neuronal behavior is not well understood. As a first step in clarifying ... More
Light hadron spectrum with 2+1 flavor dynamical $O(a)$-improved Wilson quarksOct 18 2007We present preliminary results for the light harden spectrum in $N_f=2+1$ lattice QCD obtained with the nonperturbatively $O(a)$-improved Wilson quark action and the Iwasaki gauge action. Simulations are carried out at $\beta=1.90$ on a $32^3 \times 64$ ... More
Manifestation of spin degrees of freedom in the double fractional quantum Hall systemAug 03 1994The double fractional quantum Hall system of spin 1/2 electrons is numerically studied to predict that there exists a novel spin-unpolarized quantum liquid specific to the multi-species system, which exemplifies a link between the spin state and the inter-layer ... More
Vainshtein mechanism in massive gravity nonlinear sigma modelsJul 01 2016We study the stability of the Vainshtein screening solution of the massive/bi-gravity based on the massive nonlinear sigma model as the effective action inside the Vainshtein radius. The effective action is obtained by taking the $\Lambda_2$ decoupling ... More
More on DBI action in 4D $\mathcal{N}=1$ supergravityNov 25 2016Dec 03 2016We construct a Dirac-Born-Infeld (DBI) action coupled to a two-form field in four dimensional $\mathcal{N}=1$ supergravity. Our superconformal formulation of the action shows a universal way to construct it in various Poincar\'e supergravity formulations. ... More
FPU $β$ model: Boundary Jumps, Fourier's Law and ScalingMar 06 2001We examine the interplay of surface and volume effects in systems undergoing heat flow. In particular, we compute the thermal conductivity in the FPU $\beta$ model as a function of temperature and lattice size, and scaling arguments are used to provide ... More
Non--decoupling, triviality and the $ρ$ parameterJul 02 1992Nov 04 1992The dependence of the $\rho$ parameter on the mass of the Higgs scalar and the top quark is computed non--perturbatively using the $1/N_F$ expansion in the standard model. We find an explicit expression for the $\rho$ parameter that requires the presence ... More
The Correlation between Si III] 1892/ C III] 1909 and Fe II 4500/ H beta in low redshift QSOsDec 19 1998HST archival FOS spectra of 40 QSOs with z <= 0.5 in the Bright Quasar Survey have been analyzed. The spectra cover the region 1800-2000 A in the QSOs' rest frames, including the Al III 1859, Si III] 1892, C III] 1909, and Fe III UV34 emission-lines. ... More
Observing random walks of atoms in buffer gas through resonant light absorptionMay 25 2016Jul 01 2016Using resonant light absorption, random walk motions of rubidium atoms in nitrogen buffer gas are observed directly. The transmitted light intensity through atomic vapor is measured and its spectrum is obtained, down to orders of magnitude below the shot ... More
Hadron Spectrum for Quenched Domain-Wall Fermions with DBW2 Gauge ActionOct 16 2001We investigate basic physical quantities for quenched simulation with domain-wall fermions and the DBW2 gauge action. Masses and decay constant of pseudoscalar mesons are measured. Scaling properties are tested.
Mesonic and nonmesonic weak decay widths of medium-heavy lambda hypernucleiSep 12 2004Mar 15 2005We have measured the energy spectra of pions and protons emitted in the weak decay of 12_Lambda_C, 28_Lambda_Si, and Lambda_Fe hypernuclei produced via the (pi+, K+) reaction. The decay widths of the pi- mesonic decay (Lambda -> p + pi-) and the nonmesonic ... More
On-shell improvement of the massive Wilson quark actionSep 01 2004We review a relativistic approach to the heavy quark physics in lattice QCD by applying a relativistic $O(a)$ improvement to the massive Wilson quark action on the lattice. After explaining how power corrections of $m_Q a$ can be avoided and remaining ... More
Chiral symmetry and its manifestation in optical responses in graphene: interaction and multi-layersOct 02 2012Chiral symmetry, fundamental in the physics of graphene, guarantees the existence of topologically stable doubled Dirac cones and anomalous behaviors of the zero-energy Landau level in magnetic fields. The crucial role is inherited in the optical responses ... More
Lattice QCD with Domain-Wall FermionsSep 24 1999We study the quenched lattice QCD using domain-wall fermions at $\beta=6.0$. Behaviors of both pion mass and the explicit breaking term in the axial Ward-Takahashi identity support the existence of the chiral zero modes. We observe a good agreement between ... More
The Optical/Near-Infrared Light Curves of SN 2002ap for the First 140 Days after DiscoveryApr 01 2003Supernova (SN) 2002ap in M74 was observed in the $UBVRIJHK$ bands for the first 40 days following its discovery (2002 January 29) until it disappeared because of solar conjunction, and then in June after it reappeared. The magnitudes and dates of peak ... More
Nucleon decay matrix elements with the Wilson quark action: an updateOct 04 1999We present preliminary results of a new lattice computation of hadronic matrix elements of baryon number violating operators which appear in the low-energy effective Lagrangian of (SUSY-)Grand Unified Theories. The contribution of irrelevant form factor ... More
Hadron matrix elements for nucleon decay with the Wilson quark actionSep 20 1998We report preliminary results of our study of matrix elements of baryon number violating operators which appear in the low-energy effective Lagrangian of (SUSY-)Grand Unified Theories. The calculation is performed on a $32^{3}\times80$ lattice at $\beta=6.1$ ... More
Cosmology in ghost-free bigravity theory with twin matter fluids: The origin of "dark matter"Dec 26 2013Jan 08 2014We study dynamics of Friedmann-Lemaitre-Robertson-Walker (FLRW) spacetime based on the ghost-free bigravity theory. Assuming the coupling parameters guaranteeing the existence of de Sitter space as well as Minkowski spacetime, we find two stable attractors ... More
Phase transition of the dissipative double-well quantum mechanicsSep 26 2012We investigate the critical dissipation of the double-well quantum mechanics. We adopt two-state approximation to define effective Ising models and apply the block decimation renormalization group and the finite range scaling method recently proposed ... More
Non-critical strings at high energySep 10 1996We consider scattering amplitudes in non-critical string theory of $N$ external states in the limit where the energy of all external states is large compared to the string tension. We argue that the amplitudes are naturally complex analytic in the matter ... More
High energy scattering of non-critical stringsSep 28 1996We summarize recent work, in which we consider scattering amplitudes of non-critical strings in the limit where the energy of all external states is large compared to the string tension. We show that the high energy limit is dominated by a saddle point ... More
The JHF-Kamioka neutrino projectJun 05 2001The JHF-Kamioka neutrino project is a second generation long base line neutrino oscillation experiment that probes physics beyond the Standard Model by high precision measurements of the neutrino masses and mixing. A high intensity narrow band neutrino ... More
Geometrical origin of integrability for Liouville and Toda theoryMar 17 1993We generalize the Lax pair and B\"acklund transformations for Liouville and Toda field theories as well as their supersymmetric generalizations, to the case of arbitrary Riemann surfaces. We make use of the fact that Toda field theory arises naturally ... More
Weak solution method of the non-perturbative renormalization group equation to describe dynamical chiral symmetry breaking and its application to beyond the ladder analysis in QCDApr 18 2013The method of non-perturbative renormalization group (NPRG) is applied to the analysis of dynamical chiral symmetry breaking (DCSB) in QCD. We show that the DCSB solution of the NPRG flow equation can be obtained without the bosonization. The solution, ... More
Damping of the Collective Amplitude Mode in Superconductors with Strong Electron-Phonon CouplingApr 27 2016Sep 18 2016We study the effect of strong electron-phonon interactions on the damping of the Higgs amplitude mode in superconductors by means of non-equilibrium dynamical mean-field simulations of the Holstein model. In contrast to the BCS dynamics, we find that ... More
The endpoint of the first-order phase transition of the SU(2) gauge-Higgs model on a 4-dimensional isotropic latticeJan 27 1999We study the first-order finite-temperature electroweak phase transition of the SU(2) gauge-Higgs model defined on a 4-dimensional isotropic lattice with temporal extension N_t=2. Finite-size scaling study of Lee-Yang zeros yields the value of the Higgs ... More
The end point of the first-order phase transition of the SU(2) gauge-Higgs model on a four-dimensional isotropic latticeSep 16 1998We report results of a study of the end point of the electroweak phase transition of the SU(2) gauge-Higgs model defined on a four-dimensional isotropic lattice with N_t=2. Finite-size scaling study of Lee-Yang zeros yields lambda_c=0.00116(16) for the ... More
Novel features in the flux-flow resistivity of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$Apr 16 2005Jul 19 2005We have investigated the electrical resistivity of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$ in the mixed state. We found unusual double minima in the flux-flow resistivity as a function of magnetic field below the upper critical field for ... More
Proton decay matrix elements with domain-wall fermionsJul 04 2006Sep 18 2006Hadronic matrix elements of operators relevant to nucleon decay in grand unified theories are calculated numerically using lattice QCD. In this context, the domain-wall fermion formulation, combined with non-perturbative renormalization, is used for the ... More
Trigger Merging Module for the J-PARC E16 ExperimentJun 25 2018An experiment to measure an invariant mass of {\phi} mesons in nuclear medium is planned as the J-PARC E16 experiment. A trigger merging module (TRG-MRG) has been developed to detect leading-edges from 256 channels of discriminator-output signals and ... More
Spin Fluid Dynamics Observed by Magnetic Fountain Effect and Mechano-Spin Effect in the Ferromagnetic Superfluid $^3$He A$_1$ PhaseAug 10 2010Systematic observations of the magnetically generated fountain pressure in the superfluid $^3$He A$_1$ have been carried out in a newly built apparatus designed to reduce the effect of thermal gradients. In the same apparatus, mechanical pumping and filtering ... More
Perturbative Renormalization Factors of Baryon Number Violating Operators for Improved Quark and Gauge Actions in Lattice QCDJan 05 2000We calculate one-loop renormalization factors of three-quark operators, which appear in the low energy effective Lagrangian of the nucleon decay, for $O(a)$-improved quark action and gauge action including six-link loops. This calculation is required ... More
Tensor Charge of the Nucleon in Lattice QCDAug 22 1996First results of lattice QCD simulation on the nucleon tensor-charge $\delta q$ are presented. From the quenched QCD simulations with the Wilson quark action at $\beta = 5.7$ on a 16$^3\times$ 20 lattice and on a $12^3\times 20$ lattice, we find (i) the ... More
Magnetic Phase Diagram of the Heavy-Fermion Superconductor PrOs4Sb12Mar 26 2003We investigated the magnetic phase diagram of the first Pr-based heavy fermion superconductor PrOs4Sb12 by means of high-resolution dc magnetization measurements in low temperatures down to 0.06K. The temperature dependence of the magnetization M(T) at ... More
The QCD transition temperature: results with physical masses in the continuum limitSep 28 2006Nov 28 2006The transition temperature ($T_c$) of QCD is determined by Symanzik improved gauge and stout-link improved staggered fermionic lattice simulations. We use physical masses both for the light quarks ($m_{ud}$) and for the strange quark ($m_s$). Four sets ... More
The equation of state in lattice QCD: with physical quark masses towards the continuum limitOct 17 2005Mar 07 2006The equation of state of QCD at vanishing chemical potential as a function of temperature is determined for two sets of lattice spacings. Coarser lattices with temporal extension of N_t=4 and finer lattices of N_t=6 are used. Symanzik improved gauge and ... More