Results for "Taka-hisa Arima"

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Magnon dispersion shift in the induced-ferromagnetic phase of the noncentrosymmetric MnSiSep 30 2016Small angle neutron inelastic scattering measurement has been performed to study the magnon dispersion relation in the field-induced-ferromagnetic phase of the noncentrosymmetric binary compound MnSi. For the magnons propagating parallel or anti-parallel ... More
"Visible" 5d orbital states in a pleochroic oxychlorideApr 12 2019Transition metal compounds sometimes exhibit beautiful colors. We report here on a new oxychloride Ca3ReO5Cl2 which shows unusually distinct pleochroism; that is, the material exhibits different colors depending on viewing directions. This ple-ochroism ... More
Magnetization-polarization cross-control near room temperature in hexaferrite single crystalsApr 10 2019Mutual control of the electricity and magnetism in terms of magnetic (H) and electric (E) fields, the magnetoelectric (ME) effect, offers versatile low power-consumption alternatives to current data storage, logic gate, and spintronic devices. Despite ... More
Piezo-Magnetoelectric Effect of Spin Origin in Dysprosium OrthoferriteJul 02 2015Piezo-magnetoelectric effect, namely simultaneous induction of both the ferromagnetic moment and electric polarization by an application of uniaxial stress, was achieved in the non-ferroelectric and antiferromagnetic ground state of DyFeO$_3$. The induced ... More
Néel-type skyrmion lattice in tetragonal polar magnet VOSe$_2$O$_5$Oct 11 2017Formation of the triangular skyrmion-lattice is found in a tetragonal polar magnet VOSe$_2$O$_5$. By magnetization and small-angle neutron scattering measurements on the single crystals, we identify a cycloidal spin state at zero field and a N\'eel-type ... More
All-in/all-out magnetic domains: X-ray diffraction imaging and magnetic field controlJul 21 2014Long-range non-collinear all-in/all-out magnetic order has been directly observed for the first time in real space in the pyrochlore Cd$_2$Os$_2$O$_7$ using resonant magnetic microdiffraction at the Os L$_3$ edge. Two different antiferromagnetic domains ... More
Resonant X-Ray Diffraction Study of Strongly Spin-Orbit-Coupled Mott Insulator CaIrO3Aug 23 2011We performed resonant x-ray diffraction experiments at the $L$ absorption edges for the post-perovskite-type compound CaIrO$_{3}$ with $(t_{2g})^5$ electronic configuration. By observing the magnetic signals, we could clearly see that the magnetic structure ... More
Anomalous Heat Conduction in Quasi-One-Dimensional GasesSep 04 2006Nov 16 2007From three-dimensional linearized hydrodynamic equations, it is found that the heat conductivity is proportional to $(L_x/(L_y^2 L_z^2))^{1/3}$, where $L_x$, $L_y$ and $L_z$ are the lengths of the system along the $x$, $y$ and $z$ directions, and we consider ... More
Skyrmion lattice with a giant topological Hall effect in a frustrated triangular-lattice magnetMay 28 2018Geometrically frustrated magnets provide abundant opportunities for discovering complex spin textures, which sometimes yield unconventional electromagnetic responses in correlated electron systems. It is theoretically predicted that magnetic frustration ... More
Effect of Group Means on the Probability of ConsensusJun 29 2014In this study, groups who could not reach a consensus were investigated using the group polarization paradigm. The purpose was to explore the conditions leading to intragroup disagreement and attitude change following disagreement among 269 participants. ... More
Formulations of the Einstein equations for numerical simulationsMay 01 2008We review recent efforts to re-formulate the Einstein equations for fully relativistic numerical simulations. In order to complete a long-term and accurate simulations of binary compact objects, people seek a robust set of equations against the violation ... More
Efficient Call Path Detection for Android-OS Size of Huge Source CodeFeb 12 2016Today most developers utilize source code written by other parties. Because the code is modified frequently, the developers need to grasp the impact of the modification repeatedly. A call graph and especially its special type, a call path, help the developers ... More
Truncated post-Newtonian neutron star modelJul 03 1998Jul 28 1998As a preliminary step towards simulating binary neutron star coalescing problem, we test a post-Newtonian approach by constructing a single neutron star model. We expand the Tolman-Oppenheimer-Volkov equation of hydrostatic equilibrium by the power of ... More
On certain constructions of p-adic families of Siegel modular forms of even genusNov 28 2010Suppose that p > 5 is a rational prime. Starting from a well-known p-adic analytic family of ordinary elliptic cusp forms of level p due to Hida, we construct a certain p-adic analytic family of holomorphic Siegel cusp forms of arbitrary even genus and ... More
On certain constructions of p-adic families of Siegel modular forms of even genusNov 30 2010Suppose that p > 5 is a rational prime. Starting from a well-known p-adic analytic family of ordinary elliptic cusp forms of level p due to Hida, we construct a certain p-adic analytic family of holomorphic Siegel cusp forms of arbitrary even genus and ... More
A semi-ordinary p-stabilization of Siegel Eisenstein series for symplectic groups and its p-adic interpolationJul 01 2012Mar 28 2013For a given rational prime p, we define a certain p-stabilization of holomorphic Siegel Eisenstein series for the symplectic group of arbitrary genus. In addition, we derive an explicit formula for the Fourier coefficients and conclude their p-adic interpolation ... More
Existence of solutions for a fractional semilinear parabolic equation with singular initial dataJul 05 2016In this paper we obtain necessary conditions and sufficient conditions on the initial data for the solvability of the Cauchy problem $$ \partial_t u+(-\Delta)^{\frac{\theta}{2}}u=u^p,\quad x\in{\bf R}^N,\,\,t>0, \qquad u(0)=\mu\ge 0\quad\mbox{in}\quad{\bf ... More
A semi-ordinary $p$-stabilization of Siegel Eisenstein series for symplectic groups and its $p$-adic interpolationJul 01 2012Oct 11 2018For any rational prime $p$, we define a certain $p$-stabilization of holomorphic Siegel Eisenstein series for the symplectic group ${\rm Sp}(2n)_{/\mathbb{Q}}$ of an arbitrary genus $n \ge 1$. In addition, we derive an explicit formula for the Fourier ... More
Skyrmion phase and competing magnetic orders on a breathing kagome latticeDec 06 2018Magnetic skyrmion textures are realized mainly in non-centrosymmetric, e.g. chiral or polar, magnets. Extending the field to centrosymmetric materials is a rewarding challenge, where the released helicity / vorticity degree of freedom and higher skyrmion ... More
Constraint propagation in N+1-dimensional space-timeFeb 24 2004Higher dimensional space-time models provide us an alternative interpretation of nature, and give us different dynamical aspects than the traditional four-dimensional space-time models. Motivated by such recent interests, especially for future numerical ... More
Re-formulating the Einstein equations for stable numerical simulations: Formulation Problem in Numerical RelativitySep 30 2002Dec 02 2002We review recent efforts to re-formulate the Einstein equations for fully relativistic numerical simulations. The so-called numerical relativity (computational simulations in general relativity) is a promising research field matching with ongoing astrophysical ... More
Numerical experiments of adjusted BSSN systems for controlling constraint violationsNov 22 2007Jan 07 2008We present our numerical comparisons between the BSSN formulation widely used in numerical relativity today and its adjusted versions using constraints. We performed three testbeds: gauge-wave, linear wave, and Gowdy-wave tests, proposed by the Mexico ... More
Adjusted ADM systems and their expected stability properties: constraint propagation analysis in Schwarzschild spacetimeOct 01 2001Jan 15 2002In order to find a way to have a better formulation for numerical evolution of the Einstein equations, we study the propagation equations of the constraints based on the Arnowitt-Deser-Misner formulation. By adjusting constraint terms in the evolution ... More
A FDR-preserving field theory of glass transition in terms of the fluctuating hydrodynamicsMar 12 2008Oct 22 2008A field theoretical method for the fluctuating hydrodynamics with preserving fluctuation-dissipation relations (FDR) is reformulated. It is shown that the long time behavior within the first-loop order perturbation under the assumption that the correlations ... More
Knudsen Effect in a Nonequilibrium GasJun 20 2005Nov 16 2007From the molecular dynamics simulation of a system of hard-core disks in which an equilibrium cell is connected with a nonequilibrium cell, it is confirmed that the pressure difference between two cells depends on the direction of the heat flux. From ... More
A unit-level small area model with misclassified covariatesNov 09 2016Oct 22 2018Small area models are mixed effects regression models that link the small areas and borrow strength from similar domains. When the auxiliary variables used in the models are measured with error, small area estimators that ignore the measurement error ... More
Neutrino Mass Bounds from Neutrinoless Double Beta Decays and Large Scale StructuresMar 17 2008Mar 20 2008We investigate the way how the total mass sum of neutrinos can be constrained from the neutrinoless double beta decay and cosmological probes with cosmic microwave background (WMAP 3-year results), large scale structures including 2dFGRS and SDSS data ... More
Black Objects and Hoop Conjecture in Five-dimensional Space-timeJul 15 2009Jan 14 2010We numerically investigated the sequences of initial data of thin spindle and thin ring in five-dimensional space-time in the context of the cosmic censorship conjecture. We modeled the matter in non-rotating homogeneous spheroidal or toroidal configurations ... More
Design and Analysis on a Cryogenic Current Amplifier with a Superconducting Microwave ResonatorAug 13 2015We propose a new type of cryogenic current amplifiers, in which low-frequency power spectrum of current can be measured through a measurement of microwave response of a superconducting resonant circuit shunted by a series array of Josephson junctions. ... More
Diagonalizability of Constraint Propagation MatricesSep 27 2002Dec 22 2002In order to obtain stable and accurate general relativistic simulations, re-formulations of the Einstein equations are necessary. In a series of our works, we have proposed using eigenvalue analysis of constraint propagation equations for evaluating violation ... More
Will hyperbolic formulations help numerical relativity? - Experiments using Ashtekar's connection variablesMar 09 2001In order to perform accurate and stable long-term numerical integration of the Einstein equations, several hyperbolic systems have been proposed. We here report our numerical comparisons between weakly hyperbolic, strongly hyperbolic, and symmetric hyperbolic ... More
The pi N -> pi pi N reaction around the N(1440) energyJan 19 2006May 17 2006We study the pi N -> pi pi N reaction around the N(1440) mass-shell energy. Considering the total cross sections and invariant mass distributions, we discuss the role of N(1440) and its decay processes. The calculation is performed by extending our previous ... More
Delta(1232) in piN -> pipiN reactionOct 20 2003Feb 05 2004The contribution of Delta(1232) to the piN -> pipiN reaction is examined by making use of the chiral reduction formula developed by Yamagishi and Zahed. The influence of the pi-Delta-Delta and rho-N-Delta interactions on this reaction, which has not been ... More
Excitation Spectrum in the Friedberg-Lee ModelJan 09 2001The excitation spectrum of the nucleon with the spin 1/2 is examined by using the Friedberg-Lee model containing the constituent quark and the scalar meson. An appropriate way of quantization for the non-linear meson field is employed by taking account ... More
Quasi-coherent state of pions in the nucleonJul 30 2003Making use of the quasi-coherent state developed by Eriksson et al., we can find a nucleon solution accompanied by the pion field with trivial topology. We compare our approach with other related works, and examine a coherent state description of pions ... More
Ikeda's conjecture on the period of the Duke-Imamoglu-Ikeda liftAug 25 2010Oct 15 2013Let k and n be positive even integers. For a cuspidal Hecke eigenform h in the Kohnen plus subspace of weight k-n/2+1/2 and level 4, let I(h) be the Duke-Imamoglu-Ikeda lift of h in the space of cusp forms of weight k for Sp(n,Z), and f the primitive ... More
Hyperbolic formulations and numerical relativity II: Asymptotically constrained systems of the Einstein equationsJul 16 2000Dec 13 2000We study asymptotically constrained systems for numerical integration of the Einstein equations, which are intended to be robust against perturbative errors for the free evolution of the initial data. First, we examine the previously proposed "$\lambda$-system", ... More
Advantages of modified ADM formulation: constraint propagation analysis of Baumgarte-Shapiro-Shibata-Nakamura systemApr 01 2002Oct 01 2002Several numerical relativity groups are using a modified ADM formulation for their simulations, which was developed by Nakamura et al (and widely cited as Baumgarte-Shapiro-Shibata-Nakamura system). This so-called BSSN formulation is shown to be more ... More
Constraint propagation in the family of ADM systemsMar 09 2001Mar 11 2001The current important issue in numerical relativity is to determine which formulation of the Einstein equations provides us with stable and accurate simulations. Based on our previous work on "asymptotically constrained" systems, we here present constraint ... More
Fate of Kaluza-Klein BubbleMar 08 2000We numerically study classical time evolutions of Kaluza-Klein bubble space-time which has negative energy after a decay of vacuum. As the zero energy Witten's bubble space-time, where the bubble expands infinitely, the subsequent evolutions of Brill ... More
Constructing hyperbolic systems in the Ashtekar formulation of general relativityJan 19 1999May 01 2000Hyperbolic formulations of the equations of motion are essential technique for proving the well-posedness of the Cauchy problem of a system, and are also helpful for implementing stable long time evolution in numerical applications. We, here, present ... More
Lorentzian dynamics in the Ashtekar gravityOct 14 1997We examine the advantages of the SO(3)-ADM (Ashtekar) formulation of general relativity, from the point of following the dynamics of the Lorentzian spacetime in direction of applying this into numerical relativity. We describe our strategy how to treat ... More
Formation of naked singularities in five-dimensional space-timeFeb 10 2011We numerically investigate the gravitational collapse of collisionless particles in spheroidal configurations both in four and five-dimensional (5D) space-time. We repeat the simulation performed by Shapiro and Teukolsky (1991) that announced an appearance ... More
Symmetric hyperbolic system in the Ashtekar formulationMar 24 1998Dec 05 1998We present a first-order symmetric hyperbolic system in the Ashtekar formulation of general relativity for vacuum spacetime. We add terms from constraint equations to the evolution equations with appropriate combinations, which is the same technique used ... More
Hyperbolic formulations and numerical relativity: Experiments using Ashtekar's connection variablesMay 01 2000Sep 06 2000In order to perform accurate and stable long-time numerical integration of the Einstein equation, several hyperbolic systems have been proposed. We here present numerical comparisons between weakly hyperbolic, strongly hyperbolic, and symmetric hyperbolic ... More
$N+1$ formalism in Einstein-Gauss-Bonnet gravityOct 10 2008Towards the investigation of the full dynamics in higher-dimensional and/or stringy gravitational model, we present the basic equations of the Einstein-Gauss-Bonnet gravity theory. We show $(N+1)$-dimensional version of the ADM decomposition including ... More
Wormholes in higher dimensional space-time: Exact solutions and their linear stability analysisSep 09 2013We derive the simplest traversable wormhole solutions in $n$-dimensional general relativity, assuming static and spherically symmetric spacetime with a ghost scalar field. This is the generalization of the Ellis solution (or the so-called Morris-Thorne's ... More
Coherent Pair State of Pion in Constituent Quark ModelNov 06 2001Nov 07 2001A coherent state of pions is introduced to the nonrelativistic quark model. The coherent pair approximation is employed for the pion field in order to maintain the spin-isospin symmetry. In this approximation the pion is localized in the momentum space, ... More
An alternative marginal likelihood estimator for phylogenetic modelsJan 13 2010Jun 20 2010Bayesian phylogenetic methods are generating noticeable enthusiasm in the field of molecular systematics. Many phylogenetic models are often at stake and different approaches are used to compare them within a Bayesian framework. The Bayes factor, defined ... More
A unit-level small area model with misclassified covariatesNov 09 2016Small area models are mixed effects regression models that link the small areas and borrow strength from similar domains. When the auxiliary variables used in the models are measured with error, small area estimators that ignore the measurement error ... More
Asymptotically constrained and real-valued system based on Ashtekar's variablesJun 16 1999Aug 23 1999We present a set of dynamical equations based on Ashtekar's extension of the Einstein equation. The system forces the space-time to evolve to the manifold that satisfies the constraint equations or the reality conditions or both as the attractor against ... More
Dynamical evolution of boson stars in Brans-Dicke theoryDec 15 1997May 07 1998We study the dynamics of a self-gravitating scalar field solitonic object (boson star) in the Jordan-Brans-Dicke (BD) theory of gravity. We show dynamical processes of this system such as (i) black hole formation of perturbed equilibrium configuration ... More
Koecher-Maass series of a certain half-integral weight modular form related to the Duke-Imamoglu-Ikeda liftSep 09 2013Let k and n be positive even integers. For a cuspidal Hecke eigenform h in the Kohnen plus space of weight k-n/2+1/2, let f be the corresponding primitive form of weight 2k-n for SL(2,Z) under the Shimura correspondence, and I(h) the Duke-Imamoglu-Ikeda ... More
Modified Hartree-Fock-Bogoliubov at finite temperatureMay 30 2003The modified HFB (MHFB) theory at finite temperature is derived, which conserves the unitarity relation of the particle-density matrix. This is achieved by constructing a modified quasiparticle-density matrix, where the fluctuation of the quasiparticle ... More
Pairing effect on the giant dipole resonance width at low temperatureSep 05 2003The width of the giant dipole resonance (GDR) at finite temperature T in Sn-120 is calculated within the Phonon Damping Model including the neutron thermal pairing gap determined from the modified BCS theory. It is shown that the effect of thermal pairing ... More
Fate of the first traversible wormhole: black-hole collapse or inflationary expansionMay 10 2002May 11 2002We study numerically the stability of Morris & Thorne's first traversible wormhole, shown previously by Ellis to be a solution for a massless ghost Klein-Gordon field. Our code uses a dual-null formulation for spherically symmetric space-time integration, ... More
Gravitational waves from merging intermediate-mass black holes : II Event rates at ground-based detectorsOct 29 2016Based on a dynamical formation model of a super-massive black-hole (SMBH), we estimate expected observational profile of gravitational wave at ground-based detectors, such as KAGRA or advanced LIGO/VIRGO. Focusing that the second generation of detectors ... More
On the test of the modified BCS at finite temperatureOct 03 2005Oct 06 2006The results and conclusions by Ponomarev and Vdovin [Phys. Rev. C {\bf 72}, 034309 (2005)] are inadequate to judge the applicability of the modified BCS because they were obtained either in the temperature region, where the use of zero-temperature single-particle ... More
Quasi-spherical approximation for rotating black holesAug 30 2000Dec 21 2000We numerically implement a quasi-spherical approximation scheme for computing gravitational waveforms for coalescing black holes, testing it against angular momentum by applying it to Kerr black holes. As error measures, we take the conformal strain and ... More
Can Gravitational Waves Prevent Inflation?May 18 1993To investigate the cosmic no hair conjecture, we analyze numerically 1-dimensional plane symmetrical inhomogeneities due to gravitational waves in vacuum spacetimes with a positive cosmological constant. Assuming periodic gravitational pulse waves initially, ... More
Generation of scalar-tensor gravity effects in equilibrium state boson starsAug 28 1997Dec 15 1997Boson stars in zero-, one-, and two-node equilibrium states are modeled numerically within the framework of Scalar-Tensor Gravity. The complex scalar field is taken to be both massive and self-interacting. Configurations are formed in the case of a linear ... More
Zariski-van Kampen method and transcendental lattices of certain singular K3 surfacesJun 20 2008Jun 05 2009We present a method of Zariski-van Kampen type for the calculation of the transcendental lattice of a complex projective surface. As an application, we calculate the transcendental lattices of complex singular K3 surfaces associated with an arithmetic ... More
Generality of Inflation in a Planar UniverseFeb 10 1994We study a generality of an inflationary scenario by integrating the Einstein equations numerically in a plane-symmetric spacetime. We consider the inhomogeneous spacetimes due to (i) localized gravitational waves with a positive cosmological constant ... More
Constraint Propagation of $C^2$-adjusted Formulation - Another Recipe for Robust ADM Evolution SystemMar 07 2011With a purpose of constructing a robust evolution system against numerical instability for integrating the Einstein equations, we propose a new formulation by adjusting the ADM evolution equations with constraints. We apply an adjusting method proposed ... More
Ground state spin 0$^+$ dominance of many-body systems with random interactions and related topicsMay 26 2004In this talk we shall show our recent results in understanding the spin$^{\rm parity}$ 0$^+$ ground state (0 g.s.) dominance of many-body systems. We propose a simple approach to predict the spin $I$ g.s. probabilities which does not require the diagonalization ... More
Nucleon resonances in the constituent quark model with chiral symmetryDec 11 1997The mass spectra of nucleon resonances with spin 1/2, 3/2, and 5/2 are systematically studied in the constituent quark model with meson-quark coupling, which is inspired by the spontaneous breaking of chiral symmetry of QCD. The meson-quark coupling gives ... More
Energy Centroids of Spin $I$ States by Random Two-body InteractionsDec 21 2004In this paper we study the behavior of energy centroids (denoted as $\bar{E_I}$) of spin $I$ states in the presence of random two-body interactions, for systems ranging from very simple systems (e.g. single-$j$ shell for very small $j$) to very complicated ... More
Many-body Systems Interacting via a Two-body Random Ensemble (I): Angular Momentum distribution in the ground statesJun 18 2002In this paper, we discuss the angular momentum distribution in the ground states of many-body systems interacting via a two-body random ensemble. Beginning with a few simple examples, a simple approach to predict P(I)'s, angular momenta I ground state ... More
A simple approach to the angular momentum distribution in the ground states of many-body systemsDec 26 2001We propose a simple approach to predict the angular momentum I ground state (I g.s.) probabilities of many-body systems that does not require the diagonalization of hamiltonians with random interactions. This method is found to be applicable to {\bf all} ... More
Kinetic Theory of dilute gases under nonequilibrium conditionsDec 01 2004The significance of the recent finding of the velocity distribution function of the steady-state Boltzmann equation under a steady heat current obtained by Kim and Haykawa (J. Phys. Soc. Jpn. {\bf 72}, 1904 (2003)) is discussed. Through the stability ... More
Angular momentum I ground state probabilities of boson systems interacting by random interactionsApr 14 2003In this paper we report our systematic calculations of angular momentum $I$ ground state probabilities ($P(I)$) of boson systems with spin $l$ in the presence of random two-body interactions. It is found that the P(0) dominance is usually not true for ... More
Gigantic directional asymmetry of luminescence in multiferroic CuB2O4Feb 25 2016We report direction dependent luminescence (DDL), i.e., the asymmetry in the luminescence intensity between the opposite directions of the emission, in multiferroic CuB2O4. Although it is well known that the optical constants can change with the reversal ... More
Chiral Symmetry and N*(1440) -> N pi pi DecayDec 09 2004The N*(1440) -> N pi pi decay is studied by making use of the chiral reduction formula. This formula suggests a scalar-isoscalar pion-baryon contact interaction which is absent in the recent study of Hern{\'a}ndez et al. The contact interaction is introduced ... More
Regularities of Many-body Systems Interacting by a Two-body Random EnsembleNov 14 2003Jul 30 2004The ground states of all even-even nuclei have angular momentum, $I$, equal to zero, I=0, and positive parity, $\pi=+$. This feature was believed to be a consequence of the attractive short-range interaction between nucleons. However, in the presence ... More
Many-body Systems Interacting via a Two-body Random Ensemble: average energy of each angular momentumJun 18 2002In this paper, we discuss the regularities of energy of each angular momentum $I$ averaged over all the states for a fixed angular momentum (denoted as $\bar{E}_I$'s) in many-body systems interacting via a two-body random ensemble. It is found that $\bar{E}_I$'s ... More
Delta-Hole Interaction in Nuclei and the Gamow-Teller Strength in ^90NbAug 16 2000The recently obtained experimental result for the quenching of the GT sum rule in the reaction ^90Zr(p,n)^90Nb is used to extract the value of the Landau-Migdal parameter g_{N\Delta}', taking into account also the effect of the finite range meson exchange ... More
Gravitational Waves in Brans-Dicke Theory : Analysis by Test Particles around a Kerr Black HoleJan 01 1997Analyzing test particles falling into a Kerr black hole, we study gravitational waves in Brans-Dicke theory of gravity. First we consider a test particle plunging with a constant azimuthal angle into a rotating black hole and calculate the waveform and ... More
Charged Brane-World Black HolesAug 22 2000Dec 07 2000We study charged brane-world black holes in the model of Randall and Sundrum in which our universe is viewed as a domain wall in asymptotically anti-de Sitter space. Such black holes can carry two types of ``charge'', one arising from the bulk Weyl tensor ... More
Dynamics of Topological Defects and InflationJun 28 1995Oct 23 1995We study the dynamics of topological defects in the context of ``topological inflation" proposed by Vilenkin and Linde independently. Analysing the time evolution of planar domain walls and of global monopoles, we find that the defects undergo inflationary ... More
Finding Principal Null Direction for Numerical RelativistsJun 02 1994We present a new method for finding principal null directions (PNDs). Because our method assumes as input the intrinsic metric and extrinsic curvature of a spacelike hypersurface, it should be particularly useful to numerical relativists. We illustrate ... More
Strong Linear Correlation Between Eigenvalues and Diagonal Matrix ElementsJan 14 2008We investigate eigenvalues of many-body systems interacting by two-body forces as well as those of random matrices. We find a strong linear correlation between eigenvalues and diagonal matrix elements if both of them are sorted from the smaller values ... More
Electric-dipole active two-magnon excitation in {\textit{ab}} spiral spin phase of a ferroelectric magnet Gd$_{\textbf{0.7}}$Tb$_{\textbf{0.3}}$MnO$_{\textbf 3}$Nov 25 2008A broad continuum-like spin excitation (1--10 meV) with a peak structure around 2.4 meV has been observed in the ferroelectric $ab$ spiral spin phase of Gd$_{0.7}$Tb$_{0.3}$MnO$_3$ by using terahertz (THz) time-domain spectroscopy. Based on a complete ... More
One-pion exchange current corrections for nuclear magnetic moments in relativistic mean field theoryJan 31 2010The one-pion exchange current corrections to isoscalar and isovector magnetic moments of double-closed shell nuclei plus and minus one nucleon with $A=15,17,39$ and 41 have been studied in the relativistic mean field (RMF) theory and compared with previous ... More
Ferroelectric polarization flop in a frustrated magnet MnWO$_4$ induced by magnetic fieldsJul 19 2006Sep 01 2006The relationship between magnetic order and ferroelectric properties has been investigated for MnWO$_4$ with long-wavelength magnetic structure. Spontaneous electric polarization is observed in an elliptical spiral spin phase. The magnetic-field dependence ... More
Serving Database Information Using a Flexible Server in a Three Tier ArchitectureJul 01 2003The D0 experiment at Fermilab relies on a central Oracle database for storing all detector calibration information. Access to this data is needed by hundreds of physics applications distributed worldwide. In order to meet the demands of these applications ... More
General pairing interactions and pair truncation approximations for fermions in a single-j shellMay 30 2003Jul 11 2003We investigate Hamiltonians with attractive interactions between pairs of fermions coupled to angular momentum J. We show that pairs with spin J are reasonable building blocks for the low-lying states. For systems with only a J = Jmax pairing interaction, ... More
Rotational states in deformed nuclei: An analytic approachJun 08 2011The consequences of the spontaneous breaking of rotational symmetry are investigated in a field theory model for deformed nuclei, based on simple separable interactions. The crucial role of the Ward-Takahashi identities to describe the rotational states ... More
Ferroelectric properties controlled by magnetic fields in DyMn2O5May 25 2004Cross-correlation between magnetic and dielectric properties has been attracting renewed interest because of the fundamental as well as technological importance of controlling the electric (magnetic) polarization by an external magnetic (electric) field. ... More
Lowest Eigenvalues of Random HamiltoniansJan 14 2008In this paper we present results of the lowest eigenvalues of random Hamiltonians for both fermion and boson systems. We show that an empirical formula of evaluating the lowest eigenvalues of random Hamiltonians in terms of energy centroids and widths ... More
Dynamical Test of Constituent Quark Models with $πN$ ReactionsAug 16 1999A dynamical approach is developed to predict the $\pi N$ scattering amplitudes starting with the constituent quark models. The first step is to apply a variational method to solve the three-quark bound state problem. The resulting wave functions are used ... More
The pseudo-spin symmetry in Zr and Sn isotopes from the proton drip line to the neutron drip lineAug 11 1998Based on the Relativistic continuum Hartree-Bogoliubov (RCHB) theory, the pseudo-spin approximation in exotic nuclei is investigated in Zr and Sn isotopes from the proton drip line to the neutron drip line. The quality of the pseudo-spin approximation ... More
Lowest eigenvalue of the nuclear shell model HamiltonianJul 14 2010In this paper we investigate regular patterns of matrix elements of the nuclear shell model Hamiltonian $H$, by sorting the diagonal matrix elements from the smaller to larger values. By using simple plots of non-zero matrix elements and lowest eigenvalues ... More
Residual proton-neutron interactions and the $N_{\rm p} N_{\rm n}$ schemeJul 14 2010We investigate the correlation between integrated proton-neutron interactions obtained by using the up-to-date experimental data of binding energies and the $N_{\rm p} N_{\rm n}$, the product of valence proton number and valence neutron number with respect ... More
Determination of Matter Surface Distribution of Neutron-rich NucleiNov 11 2002We demonstrate that the matter density distribution in the surface region is determined well by the use of the relatively low-intensity beams that become available at the upcoming radioactive beam facilities. Following the method used in the analyses ... More
Analytic approach to nuclear rotational states: The role of spin - A minimal model -Dec 25 2013Jan 29 2014We use a simple field theory model to investigate the role of the nucleon spin for the magnetic sum rules associated with the low-lying collective scissors mode in deformed nuclei. Various constraints from rotational symmetry are elucidated and discussed. ... More
Microscopic shell-model description of the exotic nucleus ^{16}CFeb 01 2006May 15 2007The structure of the neutron-rich carbon nucleus ^{16}C is described by introducing a new microscopic shell model of no-core type. The model space is composed of the 0s, 0p, 1s0d, and 1p0f shells. The effective interaction is microscopically derived from ... More
Spin-singlet superconductivity with a full gap in locally non-centrosymmetric SrPtAsApr 08 2014We report $^{195}$Pt-NMR and $^{75}$As-NQR measurements for the locally non-centrosymmetric superconductor SrPtAs where the As-Pt layer breaks inversion symmetry while globally the compound is centrosymmetric. The nuclear spin lattice relaxation rate ... More
Generic Rotation in a Collective SD Nucleon-Pair SubspaceJun 18 2002Low-lying collective states involving many nucleons interacting by a random ensemble of two-body interactions (TBRE) are investigated in a collective SD-pair subspace, with the collective pairs defined dynamically from the two-nucleon system. It is found ... More
New s-process path and its implication to 187Re-187Os nucleo-cosmochronometerMar 30 2005We study a new s-process path through an isomer of $^{186}$Re to improve a $^{187}$Re-$^{187}$Os nucleo-cosmochronometer. The nucleus $^{187}$Re is produced by this new path of $^{185}$Re(n,$\gamma$)$^{186}$Re$^m$(n,$\gamma$)$^{187}$Re. We measure a ratio ... More