著者

TAKATSUKA Tatsuyuki TAMAGAKI Ryozo

出版者

一般社団法人日本物理学会

雑誌

Progress of theoretical physics. Supplement (ISSN:03759687)

巻号頁・発行日

no.112, pp.27-65, 1993-06-20

被引用文献数

110

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Nucleon superfluids which are realized in neutron star interior and symmetric nuclear matter are studied with use of realistic nuclear forces, in the density domain from the subnuclear region to about 3ρ_0(ρ_0 being the nuclear density). It is shown that characteristic aspects of nuclear forces manifest themselves in the appearance of several kinds of nucleon superfluids, which strongly depends on the density ρ. In this chapter emphasis is put on the pairing correlations where strong noncentral (tensor and spin-orbit) forces play important roles. A theoretical framework applicable to the nonzero angular-momentum pairing including the coupling due to tensor force is given by extending the usual BCS-Bogoliubov theory for the ^<1>S_0 pairing (the zero angular-momentum one). This formulation has been applied to the ^<3>P_2+^<3>F_2 pairing in neutron matter (the dominant component of neutron stars) and the ^<3>S_1+^<3>D_1 pairing in symmetric nuclear matter. In the former case, although spin-orbit force mainly contributes to the ^<3>P_2 attraction, the tensor coupling with the ^<3>F_2 component assists to realize the ^<3>P_2 superfluid. In the latter case, the tensor coupling to the ^<3>D_1 component plays a vital role to realize the ^<3>S_1 superfluid with a large energy gap. Results of the energy gaps calculated for such nonzero angular-momentum pairings, as well as those for the ^<1>S_0 pairing, are shown. We have found the realization of the following nucleon superfluids; the neutron ^<3>P_2 superfluid and the proton ^<1>S_0 one in the fluid core of neutron stars at ρsime(0.7~3)ρ_0, the neutron ^<1>S_0 superfluid in the inner crust of neutron stars at ρsime(10^<-3>~0.5)ρ_0, and the ^<3>S_1 superfluid in symmetric nuclear matter at a wide range of ρ incliding ρ_0, contrary to the ^<1>S_0 one realized at ρIsim ρ_0/2. The properties of these superfluids and their implications are also discussed.

著者

SOTANI Hajime

出版者

Publication Office, Progress of Theoretical Physics

雑誌

Progress of theoretical physics. Supplement (ISSN:03759687)

巻号頁・発行日

no.196, pp.471-475, 2012-10-22

参考文献数

10

被引用文献数

1

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We show that the shear modes in the neutron star crust are quite sensitive to the existence of nonuniform nuclear structures, the so-called "pasta". Due to the existence of pasta phase, the frequencies of shear modes are reduced, where the dependence of fundamental frequency is different from that of overtones. Since the torsional shear frequencies depend strongly on the structure of pasta phase, through the observations of stellar oscillations, one can probe the pasta structure in the crust, although that is quite difficult via the other observations. Additionally, considering the effect of pasta phase, we show the possibility to explain the all observed frequencies in the SGR 1806-20 with using only crust torsional shear modes.

著者

Michel Francis Ohkubo Shigeo Reidemeister Guy

出版者

Published for the Research Institute for Fundamental Physics by Physical Society of Japan

雑誌

Progress of theoretical physics. Supplement (ISSN:03759687)

巻号頁・発行日

vol.132, pp.7-72, 1999-03-26

参考文献数

224

被引用文献数

101

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We review the merits of the local potential approach in the description of elastic alphaparticle scattering and of alpha-cluster structure in medium-weight nuclei. We recall how optical model analyses of elastic scattering angular distributions, displaying an anomalous large angle enhancement, yielded unique optical potentials, whose real part is determined with good accuracy up to small internucleus distances, and we investigate their properties; we then analyze the general compatibility of these potentials with the microscopic requirements resulting from the constraints due to antisymmetrization, in the case of a system which was thoroughly investigated from a microscopic point of view, and whose spectroscopy is well agreed upon, that is, the ^<20>Ne=α+^<16>O system. The local potential approach is then applied to the ^<44>Ti=α+^<40>Ca system-which is the analogue of ^<20>Ne in the fp-shell-whose α-cluster spectroscopy remained unclear for a long time and for which microscopic calculations led to contradictory interpretations; not only does this simple model give a nice account of the energy location and intraband electromagnetic transition probabilities for the members of the ^<44>Ti ground state band, but it predicts the existence of excited alpha-cluster bands, which were subsequently identified experimentally in alpha-transfer experiments. The same approach is applied to the ^<40>Ca=α+^<36>Ar system, where similar predictions have recently been confirmed experimentally, and to other systems close to the sd-shell closure region. Finally the persistence of alpha-cluster structure in medium-weight and heavy nuclei is discussed within the local potential approach.

著者

Hawley John F. De Villiers Jean-Pierre

出版者

Published for the Yukawa Institute for Theoretical Physics and the Physical Society of Japan

雑誌

Progress of theoretical physics. Supplement (ISSN:03759687)

巻号頁・発行日

no.155, pp.132-139, 2004-11-15

参考文献数

21

被引用文献数

4

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Observations are providing increasingly detailed quantitative information about the accretion flows that power such high energy systems as X-ray binaries and active galactic nuclei. Analytic models of such systems must rely on assumptions such as regular flow geometry and a simple, parameterized stress. Global numerical simulations offer a way to investigate the basic physical dynamics of accretion flows without these assumptions. For black hole accretion studies one solves the equations of general relativistic magnetohydro-dynamics. Magnetic fields are of fundamental importance to the structure and evolution of accretion disks because magnetic turbulence is the source of the anomalous stress that drives accretion. We have developed a three-dimensional general relativistic magnetohydrodynamic simulation code to evolve time-dependent accretion systems self-consistently. Recent global simulations of black hole accretion disks suggest that the generic structure of the accretion flow is usefully divided into five regimes : the main disk, the inner disk, the corona, the evacuated funnel, and the funnel wall jet. The properties of each of these regions are summarized.

著者

Mizuno Tsunefumi Miyawaki Ryohei Ebisawa Ken KUBOTA Aya MIYAMOTO Masao WINTER Lisa UEDA Yoshihiro ISOBE Naoki MAKISHIMA Kazuo

出版者

Published for the Yukawa Institute for Theoretical Physics and the Physical Society of Japan

雑誌

Progress of theoretical physics. Supplement (ISSN:03759687)

巻号頁・発行日

no.169, pp.229-233, 2007-12-19

参考文献数

24

被引用文献数

1

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We report about the Suzaku observation of two ultraluminous X-ray sources (ULXs), X-1 and X-2, in NGC1313, together with their spectra by XMM-Newton. During the observation, both showed intensity-correlated spectral changes. The brighter source, X-1, exhibited the highest luminosity (~3×10^<40>erg s^<-1>) ever recorded from this source. Its spectral variation is ascribed to a strong power-law like component with a mild high energy curvature, while about 10% of the flux is carried by a stable soft component modeled by a cool disk emission. These properties suggest that the source was in the "very high" state, wherein the disk emission is strongly Comptonized and the optically-thick disk is truncated at a large radii or cooled off. The spectrum of X-2 is best represented, in its fainter phase, by a multicolor disk model with the innermost disk temperature of 1.2-1.3keV, and becomes flatter as the source gets brighter. Hence X-2 is interpreted to be in a slim disk state. These results suggest that the two ULXs host black holes of a few tens to a few hundreds solar masses.

著者

Toki Hiroshi

出版者

Published for the Yukawa Institute for Theoretical Physics and the Physical Society of Japan

雑誌

Progress of theoretical physics. Supplement (ISSN:03759687)

巻号頁・発行日

no.168, pp.602-609, 2007

参考文献数

9

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We study the role of pion for the structure of finite nuclei. We take the chiral sigma model, where the pions are the Nambu-Goldstone bosons of chiral symmetry breaking. We then take the finite pion mean field in the relativistic mean field approximation. We study first the nuclei in the range of A=36 to A=64 with equal number of neutrons and protons. We find that the magic number gap at N = Z = 28 appears due to the finite pion mean field effect. The pion provides a large spin-orbit splitting effect due to a mechanism totally different from the ordinary spin-orbit term of the relativistic origin. On the other hand, we are not able to shift the magic number appearing at A=36 instead of A=40, which is now a motivation to work out the parity and charge projection. The standard projection technique provides an integro-differential equation for the Dirac equation. As an example, we work out ^4He in the relativistic chiral mean field model. We find good properties for the ground state energy and the size and the pion energy contribution. The form factor also comes out to be quite satisfactory. We then switch to the non-relativistic method to describe the large tensor correlations in terms of the tensor optimized shell model (TOSM). We describe ^4He and ^9Li in TOSM where the tensor force is treated fully by taking enough configuration space. We show important consequenses of the tensor correlations caused by the tensor interaction due to the Pauli blocking effect on the phase shifts of neutron scattering from ^4He and the halo structure of ^<11>Li.

著者

Yamanaka Yoshiya

出版者

一般社団法人日本物理学会

雑誌

Progress of theoretical physics. Supplement (ISSN:03759687)

巻号頁・発行日

no.111, pp.417-431, 1993-04-10

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A model with spontaneous breakdown of symmetry in quantum field theory is studied in the framework of the Parisi-Wu stochastic quantization (SQ). Looking at the conventional treatment of the model in the canonical and the path-integral quantizations including the problems of many inequivalent Hilbert spaces and measures, we explicitly construct the SQ formulation for the model in the conventional treatment of quantum field theory. The real power of SQ is found in extending quantum field theory beyond the existing frameworks; SQ easily avoids the problems imposed by choices of Hilbert space or measure. We demonstrate it by introducing c-numbers depending on the fictitious time into the starting formal Langevin equations for the model. This new formulation in SQ thus obtained is mathematically well-defined, leading to a definite calculational scheme. The result from this shows that the masses and number of excitation modes change from those in the conventional treatment.

著者

Suetani Hiromichi Iba Yukito Aihara Kazuyuki

出版者

Published for the Yukawa Institute for Theoretical Physics and the Physical Society of Japan

雑誌

Progress of theoretical physics. Supplement (ISSN:03759687)

巻号頁・発行日

no.161, pp.340-343, 2006-04-20

参考文献数

11

被引用文献数

1

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An approach based on the kernel methods for capturing the nonlinear interdependence between two signals is introduced. It is demonstrated that the proposed approach is useful for characterizing generalized synchronization with a successful simple example. An attempt to choose an optimal kernel parameter based on cross validation is also discussed.

著者

Maeda Yoshitomo Ebara Masatoshi Fujimoto Ryuichi HAYASHI Takayuki INOUE Hirohiko ISHISAKI Yoshitaka MORI Hideyuki OKADA Shunsaku SUZUKI Kensuke UCHIYAMA Yasunobu SERLEMITSOS Peter J. SOONG Yang CHAN Kai-Wing OKAJIMA Takashi LEHAN John P. ITOH Kei ITOH Akiharu YOKOYAMA Yushi ITOH Yumi NAKAMURA Ryoko ISHIDA Manabu HAYAKAWA Akira INOUE Chiaki OKUMA Satoshi KUBOTA Ren SUZUKI Masaki OSAWA Takeyuki YAMASHITA Koujun KUNIEDA Hideyo TAWARA Yuzuru OGASAKA Yasushi FURUZAWA Akihiro TAMURA Keisuke SHIBATA Ryo HABA Yoshito NAITOU Masataka MISAKI Kazutami IIZUKA Ryo

出版者

一般社団法人日本物理学会

雑誌

Progress of theoretical physics. Supplement (ISSN:03759687)

巻号頁・発行日

no.169, pp.322-325, 2007-12-19

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We present the in-flight performance of the X-ray telescopes (XRTs) onboard Suzaku. The imaging capability is significantly improved over the ASCA XRT, which had half-power diameters of 3'.6, to 1'.8-2'.3 for all four XRT-I modules. Contemporaneous fits of a power law to all the XIS spectra of the Crab Nebula taken at the two standard observing positions (XIS/HXD-default positions) gives a flux consistent with that obtained by Toor & Seward (1974) to within〜2%. The pre-collimator on the top of each XRT module successfully reduces the intensity of the stray light from the 20' and 50'-off directions down to the level of pre-flight expectations. We also present the thermal wobbling of the satellite. The wobbling causes the alignment error between the XRT-XIS system and the attitude and orbit control system. The wobbling of the alignment is as large as〜1arcmin. In the currently processed data, the absolute coordinate also has systematic uncertainty of up to〜1arcmin.

著者

Tomiya Mitsuyoshi Sakamoto Shoichi Inoue Hiroyuki YOSHINAGA Naotaka

出版者

一般社団法人日本物理学会

雑誌

Progress of theoretical physics. Supplement (ISSN:03759687)

巻号頁・発行日

no.157, pp.156-159, 2005-04-30

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We numerically study quantum mechanics of one-dimensional (1D) time-independent system whose energy level statistics obeys the Gaussian orthogonal ensemble. 1D conservative systems are known to be integrable. However, at least numerically, it is also shown that we can construct the potential for the Schrodinger equation that reproduces a finite number of given energy levels of chaotic regime, e.g., the random matrix theory. In this work a potential is constructed numerically by the standard gradient method. The more energy levels of chaotic regime we take, the more complicated and finer the ripples of the potential become. Then the potential has fractal structure at high energy limit and its fractal dimension is determined to be d=1.7.