著者

岡崎 敏雄

出版者

筑波大学大学院博士課程文芸・言語研究科応用言語学コース

雑誌

筑波応用言語学研究 (ISSN:13424823)

巻号頁・発行日

no.19, pp.1-14, 2012-12-20

著者

東向観音寺史料調査団

出版者

東京大学大学院人文社会系研究科・文学部日本史学研究室

雑誌

東京大学日本史学研究室紀要

巻号頁・発行日

vol.9, pp.33-88, 2005-03-26

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史料目録・調査報告

著者

SUZUKI Shugo OHTA Hidehisa

出版者

The Physical Society of Japan

雑誌

Journal of the Physical Society of Japan (ISSN:00319015)

巻号頁・発行日

vol.79, no.07, pp.074703, 2010-06-25

被引用文献数

3 3

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We study the orbital, spin, and total magnetic moments in uranium monochalcogenides, UX where X=S, Se, and Te, using the fully relativistic full-potential calculations based on the spin density functional theory. In particular, the orbital magnetic moments are calculated with the Dirac current. We employ two methods which adopt distinctly different basis sets; one is the fully relativistic full-potential linear-combination-of-atomic-orbitals (FFLCAO) method and the other is the fully relativistic full-potential mixed-basis (FFMB) method. Showing that the orbital magnetic moments calculated using the FFLCAO method and those calculated using the FFMB method agree very well with each other, we demonstrate that, in contrast to the conventional method, the method with the Dirac current enables us to calculate the orbital magnetic moments even if the basis set includes basis functions with no definite angular momenta, e.g., the plane waves in the FFMB method. Furthermore, it is found that the orbital magnetic moments obtained in this work are larger by nearly 0.4 µB than those obtained using the conventional method. This is crucial because the resultant differences in the total magnetic moments are about 30%. We compare the results of this work with those of previous theoretical and experimental studies.

著者

Arai Hideyuki Kudo Hiroshi Tomita Shigeo Ishii Satoshi

出版者

The Physical Society of Japan

雑誌

Journal of the Physical Society of Japan (ISSN:00319015)

巻号頁・発行日

vol.78, no.10, pp.104301, 2009-10

被引用文献数

5

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We have specified the mechanism of suppressed electron emission from surfaces bombarded by fast cluster ions. From key information obtained from a comparison of the electron emissions for insulator KCl and conductor graphite, we concluded that the suppression is predominantly caused by the disturbance of the electron transport by the electric potential generated by moving cluster atoms. The possible shift from suppressed emission to enhanced emission of electrons as cluster speed increases is also discussed in relation to that in the case of cluster stopping power.

著者

Suzuki Shugo Li Ming-Fang Ariizumi Toshihiro

出版者

The Physical Society of Japan

雑誌

Journal of the Physical Society of Japan (ISSN:00319015)

巻号頁・発行日

vol.77, no.7, pp.074703, 2008-07

被引用文献数

7 5

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We study the structural, electronic, magnetic, optical, and magneto-optical properties of NpN in detail using the fully relativistic full-potential calculations based on the density functional theory within the local spin density approximation. We successfully reproduce the positive sign of the electric field gradient (EFG) at Np nuclei. The positive EFG is in striking contrast to the negative EFG in a Np3+ free ion, indicating the importance of the interplay between spin–orbit coupling and covalent bonding in NpN. Also, the calculated band structure shows large splittings induced by spin polarization and spin–orbit coupling, suggesting that both effects are indispensable for understanding the electronic properties of this material. This results in a large Kerr rotation angle of about 2°, which is comparable to those of uranium calcogenides.

著者

Li Ming-Fang Ariizumi Toshihiro Suzuki Shugo

出版者

The Physical Society of Japan

雑誌

Journal of the Physical Society of Japan (ISSN:00319015)

巻号頁・発行日

vol.76, no.5, pp.054702, 2007-04

被引用文献数

10

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We study the magneto-optical Kerr effect using fully relativistic calculations. Spin–orbit coupling is dealt with exactly solving the Dirac equation directly and the matrix elements of the Dirac matrices α are used in a fully relativistic expression of the Kubo formula for the optical conductivity derived with a relativistic sum rule. We also perform approximate calculations of the optical conductivity to examine the accuracy of a partly relativistic expression in which the matrix elements of the momentum operator p are used instead. As an example, we carry out calculations for bcc Fe and fcc Ni using the fully relativistic full-potential linear-combination-of-atomic-orbitals method. It is found that the partly relativistic treatment is good for the diagonal optical conductivity while it is not very good for the off-diagonal optical conductivity, the Kerr rotation angle, and the Kerr ellipticity. The results of the present study are compared to those of experimental and other theoretical studies.

著者

Suzuki Shugo Hirosawa Jin Nakao Kenji

出版者

The Physical Society of Japan

雑誌

Journal of the Physical Society of Japan (ISSN:00319015)

巻号頁・発行日

vol.75, no.8, pp.084709, 2006-08

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We study low-energy excitations in the Mott–Jahn–Teller insulator A4C60 theoretically, where A is alkali metal. A model which takes account of both the electron–electron and electron–phonon interactions is employed and the low-energy excitations are calculated by using the Tamm–Dancoff approximation. It is found that the lowest excitation corresponds to the creation of the spin-singlet Frenkel excitons at about 0.3 eV and the next lowest excitation corresponds to the creation of the spin-triplet Frenkel excitons at about 0.6 eV. It is also found that the excitations of a pair of a free electron and a free hole lie over 0.8 eV. A remarkable point is that the spin-singlet Frenkel excitons are lower in energy than the spin-triplet Frenkel excitons in A4C60 in contrast to usual insulators.

著者

Umeda T Ohno H Kanaya K

出版者

IOP Publishing Ltd

雑誌

Journal of physics. G, Nuclear and particle physics (ISSN:09543899)

巻号頁・発行日

vol.35, no.10, pp.104157, 2008-10

被引用文献数

1 1

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Dissociation temperatures of J/ψ, ψ' and χc states play key roles in the sequential J/ψ suppression scenario for high-energy heavy-ion collisions. We report on a study of charmonium dissociation temperatures in quenched lattice QCD. On anisotropic lattices, we first subtract the effects of the constant mode in finite temperature meson correlators, which have led to unphysical results in previous studies. We then extract ground and first exited state masses by diagonalizing correlation functions among different source and sink operators. To distinguish bound states from scattering states, we first compare the charmonium mass spectra under different spatial boundary conditions, and examine the shape and the volume dependence of their Bethe–Salpeter wavefunctions. From these studies, we found, so far, no sign of scattering states up to about 2.3Tc.

著者

Ohno H Umeda T Kanaya K WHOT-QCD Collaboration

出版者

IOP Publishing Ltd

雑誌

Journal of physics. G, Nuclear and particle physics (ISSN:09543899)

巻号頁・発行日

vol.36, no.6, pp.064027, 2009

被引用文献数

4

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Dissociation of charmonia in hot QCD is studied on a quenched anisotropic lattice using standard plaquette gauge action and O(a) improved Wilson fermion action. Simulations are carried out at temperatures in the range 0.88 TC to 2.3 TC. We calculate effective masses and Bethe–Salpeter wavefunctions for the ground state (1S, 1P) and some excited states (2S, 2P) with variational analysis. To distinguish between bound states and scattering states, we apply two methods: first, we compare effective masses for charmonium correlation functions under different spatial boundary conditions. Because the scattering states are sensitive to the boundary conditions, finite volume effects are expected when a charmonium dissociates. Second, we study if the wavefunctions show a sign of scattering states which will be characterized by a broad wavefunction. We find no clear evidence of dissociation for the charmonium states up to 2.3 TC so far.

著者

薬袋 秀樹

出版者

全日本社会教育連合会

雑誌

社会教育 (ISSN:13425323)

巻号頁・発行日

vol.64, no.2, pp.8-12, 2009-02

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特集 知識基盤社会における図書館の在り方を探る--公立図書館はどのようにして人々の生活を豊かにするのか

著者

Klemm Richard A Kadowaki Kazuo

出版者

IOP Publishing

雑誌

Journal of physics. Condensed matter (ISSN:09538984)

巻号頁・発行日

vol.22, no.37, pp.375701, 2010-08

被引用文献数

74 36

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The angular dependence of the radiation-zone output power and electric polarization of stimulated terahertz amplified radiation (STAR) emitted from a dc voltage applied across cylindrical and rectangular stacks of intrinsic Josephson junctions is calculated. The boundary conditions are obtained from Love's equivalence principles. During coherent emission, a spatially uniform ac Josephson current density in the stack acts as a surface electric current density antenna source, leading to a harmonic radiation frequency spectrum, as in experiment, but absent in all cavity models of cylindrical mesas. Spatial fluctuations of the ac Josephson current allow its fundamental mode to lock onto the lowest finite energy cylindrical cavity mode, causing it to resonate, leading to a non-uniform magnetic surface current density radiation source, and a non-trivial combined fundamental frequency output power with linear polarization for general radiation directions, which may be fully or partially coherent. The higher ac Josephson harmonics do not excite other cylindrical cavity modes. For rectangular mesas, the lowest energy modes are empirically not excited, but the non-uniform ac Josephson current can excite the harmonic sequence of modes with spatial variation across the rectangular widths, leading to combined radiation outputs both for the fundamental and the higher harmonics, which combinations also may be either fully or partially coherent. The superconducting substrate is modeled as a perfect magnetic conductor, greatly reducing the STAR emitter power and modifying its angular dependence, especially parallel to the substrate. Based upon this substrate model, existing Bi2Sr2CaCu2O8 + δ crystals atop perfect electric conductors could have STAR emitter power in excess of 5 mW, acceptable for many device applications.

著者

Oh Junepyo Kondo Takahiro Hatake Daigo Honma Yujiro Arakawa Keitaro Machida Takahiro Nakamura Junji

出版者

IOP Publishing

雑誌

Journal of physics. Condensed matter (ISSN:09538984)

巻号頁・発行日

vol.22, no.30, pp.304008, 2010-07-13

被引用文献数

8 6

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The effect of the local electronic modification of the graphite surface on the gas–graphite interaction has been investigated by the molecular beam scattering technique. The angular intensity distributions of He and Ar beams scattered from pristine and defect induced graphite surfaces have been measured at various surface temperatures. From the He scattering results, the cross-section for the He diffuse scattering per defect is estimated as being as much as 113 nm2. The origin of the extremely large cross-section is ascribed to the modulated electronic states of graphite around the defect based on the STM measurements, which is due to the local breaking of the π conjugated system of graphite. From the Ar scattering results, the effective mass of the graphite surface for the Ar collision has been estimated as M = 114 u, based on the analysis with the hard cube model. The new component appears in the scattering distribution of Ar for the defect induced graphite surface. The component has a larger peak position angle than that for the pristine graphite surface, indicating that the normal component of the translational energy of the Ar atom was greatly lost by the collision at the electronically modified area of graphite.

著者

Terada Yasuhiko Yoshida Shoji Takeuchi Osamu Shigekawa Hidemi

出版者

IOP Publishing

雑誌

Journal of physics. Condensed matter (ISSN:09538984)

巻号頁・発行日

vol.22, no.26, pp.264008, 2010-07

被引用文献数

32 25

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The development of time-resolved scanning tunnelling microscopy (STM), in particular, attempts to combine STM with ultrafast laser technology, is reviewed with emphasis on observed physical quantities and spatiotemporal resolution. Ultrashort optical pulse technology has allowed us to observe transient phenomena in the femtosecond range, which, however, has the drawback of a relatively low spatial resolution due to the electromagnetic wavelength used. In contrast, STM and its related techniques, although the time resolution is limited by the circuit bandwidth (~100 kHz), enable us to observe structures at the atomic level in real space. Our purpose has been to combine these two techniques to achieve a new technology that satisfies the requirements for exploring the ultrafast transient dynamics of the local quantum functions in organized small structures, which will advance the pursuit of future nanoscale scientific research in terms of the ultimate temporal and spatial resolutions.

著者

Hagiwara Yohsuke Tateno Masaru

出版者

IOP Publishing

雑誌

Journal of physics. Condensed matter (ISSN:09538984)

巻号頁・発行日

vol.21, no.24, pp.245103, 2009-05

被引用文献数

3 2

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Stacking involving aromatic rings has a significant contribution to the structural stability of biological macromolecules. However, conventional calculations such as density functional theory (DFT) and molecular mechanics (MM) fail to estimate such stabilization energies, most of which are fundamentally derived from van der Waals interactions. For the accurate description, higher level ab initio calculations, such as CCSD(T), should be employed; however, their computational costs are huge. MM calculations provide better estimation of the interactions of the aromatic rings than DFT, but not sufficient. In this report, we propose a novel scheme to calculate the interaction energy at an accuracy compatible to CCSD(T) with the computational costs comparable to MM calculations. In our scheme, the electron density of the aromatic rings is represented by Gaussian-type functions, and the parameters involved in the functions are determined by an optimization scheme to reproduce the CCSD(T) results. Here, we employ model structures involving tryptophan and tyrosine rings, and successfully obtain the optimal parameter set. By using this type of representation of the stacking proposed, the computational time to calculate the interaction energy is dramatically reduced by 10−10-fold, compared with CCSD(T).

著者

Lushnikov S G Fedoseev A I Gvasaliya S N Ko J-H Kojima Seiji

出版者

IOP Publishing

雑誌

Journal of physics. Condensed matter (ISSN:09538984)

巻号頁・発行日

vol.19, no.49, pp.496206, 2007-11

被引用文献数

7 6

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The behavior of longitudinal acoustic (LA) and transverse acoustic (TA) phonons in a cubic relaxor PbMg1/3Ta2/3O3 (PMT) ferroelectric has been investigated by Brillouin light scattering. Analysis of the temperature dependences of phonon velocity in the temperature range from 50 to 870 K has revealed anomalies in the vicinity of the Burns temperature (TB≈570 K) for LA phonons and a wide frequency-dependent minimum of the velocities of LA and TA phonons in the same temperature region as the dielectric response anomaly. Using experimental data, temperature dependences of the C11 and C44 elastic constants have been calculated. The elastic constants have been found to be frequency-independent in the gigahertz range. The results obtained are discussed in the framework of modern ideas on the crystalline lattice dynamics of relaxor ferroelectrics.

著者

Okada Susumu Nakada Kyoko Kawai Takazumi

出版者

IOP Publishing

雑誌

Journal of physics. Condensed matter (ISSN:09538984)

巻号頁・発行日

vol.19, no.36, pp.365231, 2007-09

被引用文献数

1

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We study the electronic structure and energetics of carbon nanotubes with topological line defects consisting of fused pentagons and octagon rings by means of first-principles calculation in density functional theory and tight-binding molecular dynamics simulations. The tubes with the topological line defects are found to exhibit magnetic ordering where polarized electron spins are localized around the topological defect and ferromagnetically aligned along the defect. Our analyses of the electronic energy band and spin density distributions reveal that this ferromagnetic spin ordering is associated with the edge states that are inherent in the graphite ribbon with zigzag edges. The tight-binding molecular dynamics simulations show that the nanotubes with the topological line defects are thermally stable up to temperature of 3000 K and disrupted over 4000 K.

著者

Onoda Masashige Kikuchi Yuji

出版者

IOP Publishing

雑誌

Journal of physics. Condensed matter (ISSN:09538984)

巻号頁・発行日

vol.19, no.34, pp.346206, 2007-08

被引用文献数

5

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A new type of the triangular lattice system HxCoO2 (x ≈ 0.3)is synthesized through a chemical extraction of Na from Na0.3CoO2 withH2SO4. The structure is modelled by two oxygen layers with a prismaticoxygen environment and a symmetric linear H−O bond on the basis of the xraypowder diffraction and magic-angle spinning NMR analyses. Measurementsof the electrical resistivity, thermoelectric power and magnetic susceptibilitysuggest a weakly correlated metallic state with the enhancement of effective mass.The transport anomalies, accompanied with the rapid decrease of thermoelectricpower, are observed at about 10 K.

著者

Hatsugai Yasuhiro

出版者

IOP Publishing

雑誌

Journal of physics. Condensed matter (ISSN:09538984)

巻号頁・発行日

vol.19, pp.145209, 2007-04

被引用文献数

32 13

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Recently, by using quantized Berry phases, a prescription for a local characterization of gapped topological insulators has been given (Hatsugai 2006 Preprint cond-mat/0603230). It requires that the ground state is gapped and is invariant under some anti-unitary operation. A spin liquid which is realized as a unique ground state of the Heisenberg spin system with frustrations is a typical target system, since pairwise exchange couplings are always time-reversal invariants even with frustrations.As for a generic Heisenberg model with a finite excitation gap, we locally modify the Hamiltonian by a continuous SU(2) twist only at a specific link and define the Berry connection by the derivative. Then the Berry phase evaluated by the entire many-spin wavefunction is used to define the local topological order parameter at the link. We numerically apply this scheme for several spin liquids and show its physical validity. For example, it implies that the Haldane phase of the S = 1 chains is characterized by uniform π quantized Berry phases.

著者

Konno Hidetoshi Watanabe Fumitoshi

出版者

American Institute of Physics

雑誌

Journal of Mathematical Physics (ISSN:00222488)

巻号頁・発行日

vol.48, no.10, pp.103303, 2007-10

被引用文献数

14 6

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Maximum likelihood estimator (MLE) for a generalized Cauchy process (GCP) is studied with the aid of the method of information geometry in statistics. Our GCP is described by the Langevin equation with multiplicative and additive noises. The exact expressions of MLEs are given for the two cases that the two types of noises are uncorrelated and mutually correlated. It is shown that the MLEs for these two GCPs are free from divergence even in the parameter region wherein the ordinary moments diverge. The MLE relations can be regarded as a generalized fluctuation-dissipation theorem for the present Langevin equation. Availability of them and of some other higher order statistics is demonstrated theoretically and numerically.

著者

Galstian Anahit Kinoshita Tamotu Yagdjian Karen

出版者

American Institute of Physics

雑誌

Journal of mathematical physics (ISSN:00222488)

巻号頁・発行日

vol.51, no.5, pp.052501, 2010-05

被引用文献数

20 5

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We consider the wave propagating in the Einstein and de Sitter space-time. The covariant d’Alembert’s operator in the Einstein and de Sitter space-time belongs to the family of the non-Fuchsian partial differential operators. We introduce the initial value problem for this equation and give the explicit representation formulas for the solutions. We also show the Lp−Lq estimates for solutions.