Results for "Y. Aoki"

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Probing the microscopic structure of bound states in quantum point contactsMay 21 2007Using an approach that allows us to probe the electronic structure of strongly pinched-off quantum point contacts (QPCs), we provide evidence for the formation of self-consistently realized bound states (BSs) in these structures. Our approach exploits ... More
Detecting weak coupling in mesoscopic systems with a nonequilibrium Fano resonanceDec 28 2015Apr 26 2016A critical aspect of quantum mechanics is the nonlocal nature of the wavefunction, a characteristic that may yield unexpected coupling of nominally-isolated systems. The capacity to detect this coupling can be vital in many situations, especially those ... 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
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
Transport properties in CeOs$_{4}$Sb$_{12}$: Possibility of the ground state being semiconductingDec 22 2004Apr 03 2005We have measured both magnetoresistance and Hall effect in CeOs$_4$Sb$_{12}$ to clarify the large resistivity state ascribed to the Kondo insulating one and the origin of the phase transition near 0.9 K reported in the specific heat measurement. We found ... More
Luck is Hard to Beat: The Difficulty of Sports PredictionJun 08 2017Predicting the outcome of sports events is a hard task. We quantify this difficulty with a coefficient that measures the distance between the observed final results of sports leagues and idealized perfectly balanced competitions in terms of skill. This ... More
Transport properties of the heavy fermion superconductor PrOs$_{4}$Sb$_{12}$Apr 29 2005Jul 19 2005We have measured the electrical resistivity, thermoelectric power, Hall coefficient, and magnetoresistance (MR) on single crystals of PrOs$_{4}$Sb$_{12}$, LaOs$_{4}$Sb$_{12}$ and NdOs$_{4}$Sb$_{12}$. All the transport properties in PrOs$_{4}$Sb$_{12}$ ... 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
Specific Heat Study on Heavy-Fermion Pr compounds with filled skutterudite structureOct 27 2002Rare 4f^2-based heavy-fermion behaviors have been revealed recently in Pr-based filled skutterudites PrFe4P12 and PrOs4Sb12. Recent studies on the thermal properties on both compounds are reported, putting emphasis on the field-induced ordered phase found ... 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
Development of a Diehard GEM using PTFE insulator substrateMar 26 2014We have developed the gas electron multiplier (GEM) using polytetrafluoroethylene (PTFE) insulator substrate (PTFE-GEM). Carbonization on insulator layer by discharges shorts the GEM electrodes, causing permanent breakdown. Since PTFE is hard to be carbonized ... More
Tuning the Fano Resonance with an Intruder ContinuumMar 11 2014Through a combination of experiment and theory we establish the possibility of achieving strong tuning of Fano resonances (FRs), by allowing their usual two-path geometry to interfere with an additional, 'intruder', continuum. As the coupling strength ... 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
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
Characterizations of indicator functions and contrast representations of fractional factorial designs with multi-level factorsOct 19 2018Feb 14 2019A polynomial indicator function of designs is first introduced by Fontana, Pistone and Rogantin (2000) for two-level designs. They give the structure of the indicator function of two-level designs, especially from the viewpoints of the orthogonality of ... More
Symmetry, chaos and temperature in the one-dimensional lattice $φ^4$ theoryJan 09 2018Mar 28 2018The symmetries of the minimal $\phi^4$ theory on the lattice are systematically analyzed. We find that symmetry can restrict trajectories to subspaces, while their motions are still chaotic. The chaotic dynamics of autonomous Hamiltonian systems are discussed, ... More
Effects of new physics to the the $ρ$--parameter in the supersymmetric standard modelSep 07 1993The contribution to the $\rho$--parameter of the quark--Higgs sector of the supersymmetric standard model is computed non--perturbatively using the large--$\nf$ expansion for the case tan$\beta$=0. An explicit formula is found for the $\rho$--parameter ... More
Non-decoupling effects due to a dimensionful couplingSep 11 1997We show that the dimensionful scalar cubic coupling in 3+1 dimensions gives rise to non-decoupling effects and analyze the behavior of these effects. In the process, we clarify how it is perturbatively consistent to construct theories in which the cubic ... 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
Violations of local equilibrium and stochastic thermostatsAug 17 2006We quantitatively investigate the violations of local equilibrium in the $\phi^4$ theory under thermal gradients, using stochastic thermostats. We find that the deviations from local equilibrium can be quite well described by a behavior $\sim(\nabla T)^2$. ... More
Large--order behavior of non--decoupling effects and trivialitySep 20 1993We compute some non--decoupling effects in the standard model, such as the $\rho$ parameter, to all orders in the coupling constant expansion. We analyze their large order behavior and explicitly show how it is related to the non--perturbative cutoff ... More
Some thermal transport properties of the FPU model with quadratic pinningJan 02 2008Thermal transport properties of the FPU $\beta$ model with a quadratic pinning term are investigated for various couplings and temperatures. In particular, the size dependence of the thermal conductivity, $\kappa\propto L^\alpha$, is studied. $\alpha$ ... 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
Field-Induced Lifshitz Transition without Metamagnetism in CeIrIn$_5$Dec 23 2015We report high magnetic field measurements of magnetic torque, thermoelectric power (TEP), magnetization, and de Haas-van Alphen (dHvA) effect in CeIrIn$_5$ across 28 T, where a metamagnetic transition was suggested in previous studies. The TEP displays ... More
Gap opening with ordering in PrFe4P12 studied by local tunneling spectroscopyApr 15 2008We present measurements of the local tunneling density of states in the low temperature ordered state of PrFe4P12. The temperature dependencies of the Fermi level density of states and of the integrated density of states at low bias voltages show anomalies ... 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
Approximate degeneracy of $J=1$ spatial correlators in high temperature QCDJul 06 2017Feb 08 2019We study spatial isovector meson correlators in $N_f=2$ QCD with dynamical domain-wall fermions on $32^3\times 8$ lattices at temperatures $T=220-380$ MeV. We measure the correlators of spin-one ($J=1$) operators including vector, axial-vector, tensor ... More
Young Brown Dwarfs in the Core of the W3 Main Star-Forming RegionNov 12 2008We present the results of deep and high-resolution (FWHM ~ 0".35) JHK NIR observations with the Subaru telescope, to search for very low mass young stellar objects (YSOs) in the W3 Main star-forming region. The NIR survey covers an area of ~ 2.6 arcmin^2 ... 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
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
Afterglow spectrum of a gamma-ray burst with the highest known redshift z=6.295Dec 02 2005Gamma-ray bursts (GRBs) and their afterglows have been proposed as an excellent probe to study the evolution of cosmic star formation, the reionization of the intergalactic medium, and the metal enrichment history of the universe, since the prompt gamma-ray ... 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
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
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
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
Dynamically enhanced optical coherence tomographyDec 25 2017Feb 28 2018Optical coherence tomography (OCT) uses low-coherence reflectometry to obtain cross-sectional images of inhomogeneous media, such as biological tissue. OCT is particularly useful in the biomedical ea, since the imaging can be performed non-invasively, ... More
$K^+$-nucleus elastic scattering revisited from perspective of partial restoration of chiral symmetryMay 22 2017Sep 20 2017The $K^{+}$ meson properties in the nuclear medium are investigated by considering the wavefunction renormalization as a first step to reveal the in-medium properties of the $K^{+}$ meson in the context of partial restoration of chiral symmetry. The $K^{+}N$ ... 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
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
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
Notes on the Cauchy problem for the self-adjoint and non-self-adjoint Schroedinger equations with polynomially growing potentialsMar 12 2019The Cauchy problem is studied for the self-adjoint and non-self-adjoint Schroedinger equations. We first prove the existence and uniqueness of solutions in the weighted Sobolev spaces. Secondly we prove that if potentials are depending continuously and ... 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
Light quark masses from unquenched lattice QCDApr 16 2007Jul 21 2008We calculate the light meson spectrum and the light quark masses by lattice QCD simulation, treating all light quarks dynamically and employing the Iwasaki gluon action and the nonperturbatively O(a)-improved Wilson quark action. The calculations are ... 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
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
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
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
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
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
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
KN scattering amplitude revisited in a chiral unitary approach and a possible broad resonance in S=+1 channelJun 04 2018Dec 20 2018We revisit the $KN$ scattering amplitude in order to investigate the possibility for the existence of a broad resonance in the $I=0$ $KN$ channel around the energy of 1617 MeV with 305 MeV width. We use the chiral unitary model to describe the $KN$ scattering ... More
Observation of Reflectance Fluctuations in MetalsOct 25 2016Feb 02 2017Through the study of the power spectra of a monochromatic light beam reflected by metallic mirrors, fluctuations in their reflectance is observed. The power spectra were obtained down to a factor $10^{-6}$ below the Standard Quantum Limit, with a dynamic ... More
A small tabletop experiment for a direct measurement of the speed of lightMay 28 2007A small tabletop experiment for a direct measurement of the speed of light to an accuracy of few percent is described. The experiment is accessible to a wide spectrum of undergraduate students, in particular to students not majoring in science or engineering. ... More
Lyapunov Exponents, Transport and the Extensivity of Dimensional LossApr 10 2002An explicit relation between the dimensional loss ($\Delta D$), entropy production and transport is established under thermal gradients, relating the microscopic and macroscopic behaviors of the system. The extensivity of $\Delta D$ in systems with bulk ... 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
Two parameter flow of σ_{xx}(ω) - σ_{xy}(ω) for the graphene quantum Hall system in ac regimeAug 09 2011Apr 27 2012Flow diagram of $(\sigma_{xx}, \sigma_{xy})$ in finite-frequency ($\omega$) regime is numerically studied for graphene quantum Hall effect (QHE) system. The ac flow diagrams turn out to show qualitatively similar behavior as the dc flow diagrams, which ... 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
Hadronic matrix elements of proton decay on the latticeSep 23 2003We report on our on-going project to calculate proton decay matrix elements using domain-wall fermions on the lattice. By summarizing the history of the proton decay calculation on the lattice, we reveal the systematic errors of those calculations. Then ... More
Non--perturbative evidence for non--decoupling of heavy fermionsOct 23 1992We investigate, using a $1/N$ expansion, the behavior of a parameter in the scalar--fermion sector of the standard model that shows perturbative non--decoupling as the fermion becomes heavy. This low energy parameter is related to the $S$ parameter defined ... More
Direct optical observations of surface thermal motions at sub-shot noise levelsJan 12 2009We measure spectral properties of surface thermal fluctuations of liquids, solids, complex fluids and biological matter using light scattering methods. The random thermal fluctuations are delineated from random noise at sub-shot noise levels. The principle ... More
Vainshtein mechanism in massive gravity nonlinear sigma modelsJul 01 2016Sep 29 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
On the Violations of Local Equilibrium and Linear ResponseMay 29 2001We study how local equilibrium, and linear response predictions of transport coefficients are violated as systems move far from equilibrium. This is done by studying heat flow in classical lattice models with and without bulk transport behavior, in 1--3 ... More
Triviality, perturbation theory and $Z\to b \overline b$Jun 12 1994We compute the large-$m_t$ contributions to the $Zb\overline b$ vertex in the Standard Model non-perturbatively using both the $1/\nc$ and the $1/\nf$ expansions. Triviality and its consequences for the perturbative result are systematically analyzed. ... More
Galileon and generalized Galileon with projective invariance in a metric-affine formalismJun 07 2018Sep 21 2018We study scalar-tensor theories respecting the projective invariance in the metric-affine formalism. The metric-affine formalism is a formulation of gravitational theories such that the metric and the connection are independent variables in the first ... More
Scalar-metric-affine theories: Can we get ghost-free theories from symmetry?Apr 23 2019We reveal the existence of a certain hidden symmetry in general ghost-free scalar-tensor theories which can only be seen when generalizing the geometry of the spacetime from Riemannian. For this purpose, we study scalar-tensor theories in the metric-affine ... 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
Carbon-Enhanced Metal-Poor Stars in the Inner and Outer Halo Components of the Milky WayMar 15 2011Nov 01 2011(Abridged) Carbon-enhanced metal-poor (CEMP) stars in the halo components of the Milky Way are explored, based on accurate determinations of the carbon-to-iron ([C/Fe]) abundance ratios and kinematic quantities for over 30000 calibration stars from the ... 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
Observation of spontaneous quantum fluctuations in photon absorption by atomsJan 23 2013Fluctuations in light absorption by atoms are observed by applying laser light on rubidium atoms and measuring the transmitted light intensity fluctuations. These fluctuations are spontaneous noise, which are generic to photon atom interactions. By making ... More
Massive graviton dark matter with environment dependent mass: A natural explanation of the dark matter-baryon ratioAug 07 2017Dec 15 2017We propose a scenario that can naturally explain the observed dark matter-baryon ratio in the context of bimetric theory with a chameleon field. We introduce two additional gravitational degrees of freedom, the massive graviton and the chameleon field, ... More
Violations of local equilibrium and linear response in classical lattice theoriesOct 17 2001We study the dynamics of $\phi^4$ theory and the FPU $\beta$ model under thermal gradients, from first principles. We analyze quantitatively how local equilibrium and linear response are violated, paying special care to how we find observables that unambiguously ... More
Non-Equilibrium Steady States and Transport in the Classical Lattice $φ^4$ TheoryNov 21 1999We study the classical non-equilibrium statistical mechanics of scalar field theory on the lattice. Steady states are analyzed near and far from equilibrium. The bulk thermal conductivity is computed, including its temperature dependence. We examine the ... More
Non-perturbative Renormalization Group Approach to Dynamical Chiral Symmetry Breaking in Gauge TheoriesMay 31 1997We analyze the dynamical chiral symmetry breaking in gauge theories solely by the non-perturbative renormalization group, without recourse to the Schwinger-Dyson method. First, we briefly review the basic notions and formulation, and clarify its great ... More
Fluctuation spectroscopy of surface melting of ice without, and with impuritiesAug 30 2018Nov 27 2018Water, in its three phases, is ubiquitous, and the surface properties of ice is important to clarifying the process of melting, as well as to various other fields, including geophysics. As such, the subject has been studied both theoretically and experimentally, ... More
Spectral properties of thermal fluctuations on simple liquid surfaces below shot noise levelsDec 19 2011We study the spectral properties of thermal fluctuations on simple liquid surfaces, sometimes called ripplons. Analytical properties of the spectral function are investigated and are shown to be composed of regions with simple analytic behavior with respect ... More
On the speed of approach to equilibrium for a collisionless gasSep 15 2010We investigate the speed of approach to Maxwellian equilibrium for a collisionless gas enclosed in a vessel whose wall are kept at a uniform, constant temperature, assuming diffuse reflection of gas molecules on the vessel wall. We establish lower bounds ... More
Non-Equilibrium Statistical Mechanics of Classical Lattice $φ^4$ Field TheoryFeb 15 2000Classical $\phi^4$ theory in weak and strong thermal gradients is studied on the lattice in (1+1) dimensions. Classical $\phi^4$ theory in weak and strong thermal gradients is studied on the lattice in (1+1) dimensions. The steady state physics of the ... More
A family of pairs of imaginary cyclic fields of degree $(p-1)/2$ with both class numbers divisible by $p$Sep 21 2018We construct a new infinite family of pairs of imaginary cyclic fields of degree $(p-1)/2$ explicitly with both class numbers divisible by a given prime number $p$. For the proof, we use the fundamental unit of $\mathbb Q(\sqrt{p})$, certain units which ... More
"Dark" GRB 080325 in a Dusty Massive Galaxy at z ~ 2Mar 19 2010Jun 10 2010We present optical and near infrared observations of GRB 080325 classified as a "Dark GRB". Near-infrared observations with Subaru/MOIRCS provided a clear detection of afterglow in Ks band, although no optical counterpart was reported. The flux ratio ... 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
Light hadron spectrum in 2+1 flavor full QCD by CP-PACS and JLQCD CollaborationsSep 19 2004CP-PACS and JLQCD Collaborations are carrying out a joint project of the 2+1 flavor full QCD with the RG-improved gauge action and the non-perturbatively ${\cal O}(a)$-improved Wilson quark action. This simulation removes quenching effects of all three ... More
On The Spectrum and Spectropolarimetry of Type Ic Hypernova SN 2003dh/GRB 030329Jun 08 2003Jul 03 2003Spectroscopic and spectropolarimetric observations of SN 2003dh/GRB 030329 obtained in 2003 May using the Subaru 8.2 m telescope are presented. The properties of the SN are investigated through a comparison with spectra of the Type Ic hypernovae SNe 1997ef ... More
Probing Landau quantisation with the presence of insulator-quantum Hall transition in a GaAs two-dimensional electron systemFeb 11 2008Magneto-transport measurements are performed on the two-dimensional electron system (2DES) in an AlGaAs/GaAs heterostructure. By increasing the magnetic field perpendicular to the 2DES, magnetoresistivity oscillations due to Landau quantisation can be ... 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
Subaru Deep Spectroscopy of the Very Extended Emission-Line Region of NGC 4388: Ram Pressure Stripped Gas Ionized by the Nuclear RadiationOct 02 2003We report here the results of deep optical spectroscopy of the very extended emission-line region (VEELR) found serendipitously around the Seyfert 2 galaxy NGC 4388 in the Virgo cluster using the Subaru Telescope. The H-alpha recession velocities of most ... 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
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
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
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