studies the physics of the manybody system of including atomic nuclei, microclusters and quantum information theory.












The scope of activities of Mathematics and Physics Group spans all aspects of research and education in the fields of mathematical sciences. Our current researches in the field of mathematics are devoted to various subjects and problems arising in both pure and applied mathematics: nonassociative algebras, neural networks, unimodality problems, algebraic combinatorics, spherical functions, homotopy theory, and arithmetic theory.
In the fields of physics, theoretical research is performed in manybody theories, nuclear physics, quantum gravity and quantum mechanics of constrain system. There has been also a project to develop educational textbooks and software for mechanics, electromagnetism and quantum mechanics. The research areas assigned to each coresearcher are as follows:
Prof. H. Sagawa
studies the physics of the manybody system of including atomic nuclei, microclusters and quantum information theory.
Prof. A. Fujitsu
studies the numerical superstring and quantum gravity.
Prof. M. Honma
researches the microscopic structures and dynamics of the nuclei by the algebraic methods and geometrical models performing the quantitative analysis by the largescale numeric calculations.
Prof. K. Shimizu
advances the traditional quantum theory and creates the geometrical theory of quantum gravity.
Prof. M. Yamagami
studies the physics of atomic nuclei under the extreme condition based on the density functional theory.
Prof. N. Kamiya
studies the theory of nonassociative algebras and a structure theory of algebras from triple systems.
Prof. T. Watanabe
generalizes the unimodality problems of 1dimensional infinitely divisible distributions to multidimensional cases in the use of analytical methods.
Prof. K. Asai
researches combinatorial identities for generalized Young tableaux, and also, several generating functions arising from algebraic combinatorics.
Prof. T. Maeda
studies arithmetic of elliptic curves and modular forms and their applications.
Prof. S. Watanabe
studies geometrical interpretations of generating functions for spherical functions on homogeneous spaces.
Prof. H. Kihara
studies homotopy theory and its applications to various areas of mathematics.
N. Kamiya. On Lie algebras and triple systems. Koninklijke VLaamse Academie Van Belgie (Belgie Acad. Math.2010), page 10, Aug. 2010.
In this paper, we consider several different construction of B 3type Lie algebras from several triple systems and the correspondence with extended Dynkin diagrams associated with such triple systems
Kamiya and Shibukawa. Dynamical YangBaxter maps associated with homogeneous systems. JGLTA, pages 112, Jan 2011.
We construct dynamical YangBaxter maps, generalizations of set theorical solutions to the quantum YangBaxter equation, by means of homogeneous systems
Kamiya, Mondoc, and Okubo. On Lie and Jordan structures associated with (α, β)FreudenthalKantor triple systems. Mitt.Math.Ges.Hamburg, 29:115, Oct. 2010.
In this paper, we discuss the construction of δ Lie triple systems and associated Jordan triple systems structure,in particular,we study Lie super algebras.
Hiroshi Kihara and Nobuyuki Oda. Homotopical presentations and calculations of algebraic K0groups for rings of continuous functions. Publications of the Research Institute for Mathematical Sciences, page in press, 2011,.
Let K0(CF(X)) = K0 CF(X) be the K0group of the ring CF(X) of Fvalued continuous functions on a topological space X, where F is the field of real or complex numbers or the quaternion algebra. It is known that the functor K0 CF is representable on the category of compact Hausdorff spaces. It is a homotopy functor which is notrepresentable on the category of topological spaces. Making use of the compactlybounded homotopy set, which is a variant of the homotopy set, the functor K0 CF has a homotopical presentation by the product of the ring of integers Z and the infinite Grassmannian G1(F). This presentation makes it possible to calculate the groups K0(CF(X)) explicitly for some infinite dimensional complexes X by use of the results of H. Miller on Sullivan conjecture
B. Cheal, E. Mané, J. Billowes, M. L. Bissell, K. Blaum, B. A. Brown, F. C. Charlwood, K. T. Flanagan amd D. H. Forest, C. Geppert, M. Honma, A. Jokinen, M. Kowalska, A. Krieger, J. Krämer, I. D. Moore, R. Neugart, G. Neyens, W. Nërtershäuser, M. Schug, H. H. Stroke, P. Vingerhoets, D. T. Yordanov, and M. Z'aková. Nuclear Spins and Moments of Ga Isotopes Reveal Sudden Structural Changes between N=40 and N=50. Phys. Rev. Lett., 104:252502/15, 2010.
Collinear laser spectroscopy was performed on Ga (Z=31) isotopes at ISOLDE, CERN. A gasfilled linear Paul trap (ISCOOL) was used to extend measurements towards very neutronrich isotopes (N=3650). A ground state (g.s.) spin I=1/2 is measured for ^{73}Ga, being near degenerate with a 3/2measured for ^{73}Ga, being near degenerate with a 3/2^{−} isomer (75eV < E_{ex} < 1keV). The ^{79}Ga g.s., with I=3/2, is dominated by protons in the pif_{5/2} orbital and in ^{81}Ga the 5/2the 5/2^{−} level becomes the g.s. The data are compared to shellmodel calculations level becomes the g.s. The data are compared to shellmodel calculations in the f_{5/2pg9/2} model space, calling for further theoretical developments and new experiments.
Noritaka Shimizu, Yutaka Utsuno, Takahiro Mizusaki, Takaharu Otsuka, Takashi Abe, and Michio Honma. Novel extrapolation method in the Monte Carlo shell model. Phys. Rev. C, 82:061305(R)/14, 2010.
We propose an extrapolation method utilizing energy variance in the Monte Carlo shell model to estimate the energy eigenvalue and observables accurately. We derive a formula for the energy variance with deformed Slater determinants, which enables us to calculate the energy variance efficiently. The feasibility of the method is demonstrated for the full pfshell calculation of ^{56}Ni, and the applicability of the method to a system beyond the current limit of exact diagonalization is shown for the pf + g_{9/2}shell calculation of ^{64}Ge.
K. Moschner, K.H. Speidel, J. Leske, C. Bauer, C. Bernards, L. Bettermann, M. Honma, T. Mëller, P. MaierKomor, and D. Mücher. New measurement of the ^{68}Zn(4_{1}^{+}) g factor combined with a reanalysis of previous data. Phys. Rev. C, 82:014301/17, 2010.
We have remeasured and have redetermined the g factor for the 4_{1}^{+} state in ^{68}Zn following inconsistencies between earlier measurements and a recent result. We have reanalyzed several former measurements by applying an alternative analysis procedure, which allows for determining the precession effect separately for each gamma detector implying less uncertainties in the background subtraction for the relevant spectra. In addition, all measured gfactor and B(E2) data for the first 2+ and 4+ states in all stable evenA Zn isotopes and the radioactive ^{62}Zn, are compared with new largescale shell model calculations based on the most advanced effective interaction in the fpgshell model space.
K. T. Flanagan, P. Vingerhoets, M. L. Bissell, K. Blaum, B. A. Brown, B. Cheal, M. De Rydt, D. H. Forest, Ch. Geppert, M. Honma, M. Kowalska, J. Krämer, A. Krieger a nd E. Mané, R. Neugart, G. Neyens, W. Nërtershäuser, M. Schug, H. H. Stroke, and D. T. Yordanov. Experimental determination of an Iss = 2determination of an I<μ = 2− ground state in 72,^{74}Cu. Phys. Rev. C, ground state in 72;^{74}Cu. Phys. Rev. C, 82:041302(R)/15, 2010.
This article reports on the groundstate spin and moments measured in ^{72,74}Cu using collinear laser spectroscopy at the CERN OnLine Isotope Mass Separator (ISOLDE) facility. From the measured hyperfine coefficients, the nuclear observables μ(^{72}Cu)=−1.3472(10)μ_{N}, μ(^{74}Cu)=−1.068(3)μ_{N}, Q(^{72}Cu)=+8(2)efm^{2}, Q(^{74}Cu)=+26(3)efm^{2}, I(^{72}Cu)=2, and I(^{74}Cu)=2 have been determined. Through a comparison of the measured magnetic moments with different models, the negative moment reveals a strong μf_{5/2} ⊕ νg_{9/2} component in the groundstate wave function. Consequently, a negative parity has been assigned to the ground states of ^{72,74}Cu. Largescale shellmodel calculations illustrate the strong sensitivity of the nuclear moments to configuration mixing and to the effective interaction employed.
Takahiro Mizusaki, Kazunari Kaneko, Michio Honma, and Tetsuya Sakurai. Filter diagonalization of shellmodel calculations. Phys. Rev. C, 82:024310/110, 2010.
We present a method of filter diagonalization for shellmodel calculations. This method is based on the Sakurai and Sugiura (SS) method, but extended with the help of the shifted complex orthogonal conjugate gradient (COCG) method. A salient feature of this method is that it can calculate eigenvalues and eigenstates in a given energy interval. We show that this method can be an alternative to the Lanczos method for calculating ground and excited states, as well as spectral strength functions. With an application to the Mscheme shellmodel calculations we demonstrate that several inherent problems in the widely used Lanczos method can be removed or reduced.
F.C. Charlwood, J. Billowes, P. Campbell, B. Cheal, T. Eronen, D.H. Forest, S. Fritzsche, M. Honma, A. Jokinen, I.D. Moore, H. Penttilä, R. Powis, A. Saastamoinen, G. Tungate, and J. Äystë. Ground state properties of manganese isotopes across the N=28 shell closure. Phy. Lett. B, 690:346351, 2010.
The first optical study of the N=28 shell closure in manganese is reported. Meansquare charge radii and quadrupole moments, obtained for ground and isomeric states in 50states in ^{50−56}Mn, are extracted using new calculations of atomic factors. The ^{56}Mn, are extracted using new calculations of atomic factors. The charge radii show a well defined shell closure at the magic number. The behaviour of the charge radii is strikingly different to that of the neutron separation energies where no shell effect can be observed. The nuclear parameters can be successfully described by large scale shell model calculations using the GXPF1A interaction.
A. Gade, T. Baugher, D. Bazin, B. A. Brown, C. M. Campbell, T. Glasmacher, G. F. Grinyer, M. Honma, S. McDaniel, R. Meharchand, T. Otsuka a nd A. Ratkiewicz, J. A. Tostevin, K. A. Walsh, and D. Weisshaar. Collectivity at N=50: ^{82}Ge and ^{84}Se. Phys. Rev. C, 81:064326/17, 2010.
The neutronrich N=50 isotones ^{82}Ge and ^{84}Se were investigated using intermediateenergy Coulomb excitation on a ^{197}Au target and inelastic scattering on 9Be. As typical for intermediateenergy Coulomb excitation with projectile energies exceeding 70 MeV/nucleon, only the first 2^{+} states were excited in ^{82}Ge and ^{84}Se. However, in the inelastic scattering on a 9Be target, a strong population of the first 4^{+} state was observed for ^{84}Se, while there is no indication of a similarly strong excitation of the corresponding state in the neighboring eveneven isotone ^{82}Ge. The results are discussed in the framework of systematics and shellmodel calculations using three different effective interactions.
K. Hagino, H. Sagawa, and P. Schuck. Cooper Pair Sizes in 11Li and in superfluid nuclei: a puzzlein superfluid nuclei: a puzzle? J. Phys. G, 37:064040/pp. 1−7, 2010. J. Phys. G, 37:064040/pp. 17, 2010.
It has been recognised that two neutrons take a spatially compact configuration around the nuclear surface in finite nuclei. This is referred to as dineutron correlation, and the pairing has been considered to play an important role. Here we discuss open questions concerning pairing properties in light exotic nuclei as w ell as in mediumheavy neutronrich nuclei, from a viewpoint of dineutron correlation.
LiGang Cao, H. Sagawa, and G. Colë. Effects of the Tensor Correlations on Lowlying Collective States in Finite Nuclei. Phys. Rev. C, 83:034324/pp. 16, 2011.
We present a systematic analysis of the effects induced by tensor correlations on lowlying collective states of magic nuclei, by using the fully selfconsistent Random Phase Approximation (RPA) model with Skyrme interactions. The role of the tensor correlations is analyzed in detail in the case of quadrupole (2^{+}) and octupole (3^{−}) lowlying collective states in ^{208}Pb. The example of magnetic dipole states ) lowlying collective states in ^{208}Pb. The example of magnetic dipole states (1^{+}) is also discussed.
LiGang Cao, G. Colë, and H. Sagawa. Spin and SpinIsospin instabilities and Landau parameters of Skyrme interactions with tensor terms. Phys. Rev. C, 81:044302/pp.17, 2010.
The Landau parameters of Skyrme interactions in the spin and spinisospin channels are studied by using various Skyrme effective interactions with and without tensor correlations. The role of the tensor terms is examined on the stability conditions of the spin and spinisospin modes in nuclear matter above saturation densities. We point out that the spin and/or the spinisospin instabilities are realized in the nuclear matter at the critical density of about 2 times more than the saturation density for all the adopted parameter sets. The critical density is shown very much depending not only on the choice of the Skyrme parameter set, but also on the inclusion of the tensor terms.
Y. Urata, K. Hagino, and H. Sagawa. Ground state properties and Coulomb dissociation of the deformed halo nucleus 31Ne. Phys. Rev. C, 83:04303(R)/pp. 15, 2011.
The recently observed large cross sections for the Coulomb dissociation of 31Ne nucleus indicate that this nucleus takes a halo structure in the ground state. We analyse these experimental data using the particlerotor model, that takes into account the rotational excitation of the core nucleus ^{30}Ne. We show that the experimental data can be well reproduced when the quadrupole deformation parameter of ^{30}Ne is around
P. F. Bortignon, G. Colë, and H. Sagawa. Nuclear singleparticle states: dynamical shell model and energy density functional methods. J. Phys. G, 37:064013/pp. 16, 2010.
We will discuss different approaches to the problem of reproducing the observed features of nuclear singleparticle (s.p.) spectra. In particular, we will analyze the dominant energy peaks, and the singleparticle strength fragmentation, using the example of neutron states in 208Pb. Our main emphasis is the interpretation of that fragmentation as due to particlevibration coupling (PVC). We will compare with recent Energy Density Functional (EDF) approaches, and try to present a critical perspective.
C.L. Bai, H.Q. Zhang, X.Z. Zhang, F.R.Xu, H. Sagawa, and G. Colë. Effect of the Tensor Force on ChargeExchange SpinDependent Excitations of ^{208}Pb. Phys. Rev. Lett, 105:072501/pp.14, 2010.
The chargeexchange spindipole (SD) excitations of ^{208}Pb are studied by using a fully selfconsistent Skyrme HartreeFock plus Random Phase Approximation (HF+RPA) formalism which includes the tensor interaction. It is found, for the first time, that the tensor correlations have a unique, multipoledependent effect on the SD excitations, that is, they produce softening of 1on the SD excitations, that is, they produce softening of 1^{−} states, but hardening states, but hardening of 0^{−} and 2^{−} states. This paves the way to a clear assessment of the strength of the tensor terms. We compare our results with a recent measurement, showing that our choice of tensor terms improves the agreement with experiment. The robustness of our results is supported by the analytic form of the tensor matrix elements.
E. Khan, J. Margueron, G. Colë, K. Hagino, and H. Sagawa. Effect of pairing correlations on incompressibility and symmetry energy in nuclear matter and finite nuclei. Phys. Rev. C, 82:024322/pp. 18, 2010.
The role of superfluidity in the incompressibility and in the symmetry energy is studied in nuclear matter and finite nuclei. Several pairing interactions are used: surface, mixed and isovector dependent. Pairing has a small effect on the nuclear matter incompressibility at saturation density, but the effects are significant at lower densities. The pairing effect on the centroid energy of the isoscalar Giant Monopole Resonance (GMR) is also evaluated for Pb and Sn isotopes by using a microscopic constrainedHFB approach, and found to change at most by 10 % the nucleus incompressibility K_{A}. It is shown by using the Local Density Approximation (LDA) that most of the pairing effect on the GMR centroid come from the lowdensity nuclear surface.
G. Colë, P. F. Bortignon, and H. Sagawa. Effect of particlevibration coupling on the singleparticle states: a consitent study within the Skyrme framework. Phys. Rev. C, 82:064307/pp. 18, 2010.
We discuss calculations of the singleparticle states in magic nuclei, performed within the particlevibration coupling (PVC) approach by using consistently the Skyrme effective interaction. The vibrations are calculated within fully selfconsistent RPA and the whole interaction is also used in the PVC vertex. Our main emphasis is therefore the discussion of our results in comparison with those in which some approximation is made. The perspectives for improving current Density Functional Theory (DFT) calculations are also addressed.
K. Hagino T. Oishi and H. Sagawa. Diproton correlation in a protonrich Borromean nucleus ^{17}Ne. Phys. Rev. C, 82:024315, pp. 15, 2010.
We carry out threebodymodel calculations for a protonrich Borromean nucleus ^{17}Ne by assuming a ^{15}O + p + p structure. To this end, we use a density dependent contact interaction between the valence protons, explicitly treating also the Coulomb interaction. We find that the twoparticle density distribution for ^{17}Ne is similar to that for 16C, which has two valence neutrons outside the N = 8 core. That is, the two protons take a spatially compact configuration, while the Coulomb repulsion plays a minor role. This indicates that there is a strong diproton correlation in the ground state of the ^{17}Ne nucleus. We also show that the Coulomb interaction reduces the expectation value of the protonproton interaction by about
P. Mëller, A. J. Sierk, R. Bengtsson, H. Sagawa, and T. Ichikawa. Nuclear Shape Isomers. Atomic Data and Nuclear Data Tables, in press:in press, 2010.
Nuclear Shape Isomers are systematically discussed by using Finite range liquid drop model (FRLDM).
K. Hagino, A. Vitturi, F. PérezBernal, and H. Sagawa. Twoneutron halo nuclei in one dimension: dineutron correlation and breakup reaction. J. of Phys G, 38:015105/pp. 115,, 2011.
We propose a simple schematic model for twoneutron halo nuclei. In this model, the two valence neutrons move in a onedimensional mean field, interacting with each other via a densitydependent contact interaction. We first investigate the ground state properties, and demonstrate that the dineutron correlation can be realized with this simple model due to the admixture of even and oddparity singleparticle states. We then solve the timedependent twoparticle Schrëdinger equation under the influence of a timedependent onebody external field, in order to discuss the effect of dineutron correlation on nuclear breakup processes. The time evolution of twoparticle density shows that the dineutron correlation enhances the total breakup probability, especially for the twoneutron breakup process, in which both the valence neutrons are promoted to continuum scattering states. We find that the interaction between the two particles definitely favours a spatial correlation of the two outgoing particles, which are mainly em itted in the same direction.
T. Watanabe and K. Yamamuro. Local subexponentiality and selfdecomposability. J. Theoretical Probability, 23(4):10391067, 2010,.
The class of the exponential tilts of convolution equivalent distributions is determined. As a corollary, the local subexponentiality of onesided infinitely divisible distributions is characterized. It is applied to the subexponentiality of the densities of a selfdecomposable distribution and its Lévy measure. Bondesson's conjecture on the density of the Lévy measure of a lognormal distribution is solved as an example. Results of Denisov et al. on the distributions of random sums are extended to the twosided case. Finally, the local subexponentiality of the distribution of the supremum of a random walk is characterized.
T. Watanabe and K. Yamamuro. Limsup behaviors of multidimensional selfsimilar processes with independent increments. ALEA Lat. Am. J. Probab. Math. Stat, 7:79116, 2010,.
Laws of the iterated logarithm of limsup type are studied for multidimensional selfsimilar processes X(t) with independent increments having exponent H. A necessary and sufficient condition for the normalization is obtained. In the case where the normalization does not exist, a criterion to classify the limit 0 or infinity is given. Moreover, various limsup type laws with identification of the positive limit are explicitly presented in several propositions and examples.
H. Nakada and M. Yamagami. Coulombic effect and renormalization in nuclear pairing. Phys. Rev. C, 83:031302(R) [4pages], 2011.
We investigate effects of the Coulomb force on the nuclear pairing properties by performing the Gogny HartreeFockBogolyubov calculations for the N = 20, 28, 50, 82 and 126 nuclei. The Coulomb force reduces the proton pair energy and the evenodd mass difference by about 25%, except for nuclei at and around the proton shell or subshell closure. We then propose a renormalization scheme via a reduction factor γ_{p} for the proton pairing channel. It is found that a single value of γ_{p}(= 0:90) well takes account of the Coulombic effect, for nuclei covering wide range of the mass number and the neutron excess including the nuclei around the shell or subshell closure.
M.Yamagami, Y.R.Shimizu, and T.Nakatsukasa. Global fitting of pairing density functional. RIKEN Accel. Prog. Rep., 43:58, 2010.
We have developed a density functional for the global description of pairing correlations by focusing on the neutronexcess dependence. The accurate pairing density functional (pairDF) is indispensable for predicting pairingsensitive properties (for example, lowenergy dynamics) in reaction networks of rprocess nucleosynthesis and nuclear reactors, predicting the superfluidity in neutronstar matter. We demonstrated that the pairDF should include the isovector density (ae1 = aen demonstrated that the pairDF should include the isovector density (ρ_{1} = ρ_{n} − ρ_{p}), since the standard pairDF with only isoscalar density (ρ_{1} = ρ_{n} + ρ_{p}) terms fails to reproduce the αdependence (α = (N − Z)/A) of the pairing correlations.
M. Yamagami, Y. R. Shimizu, and T. Nakatsukasa. Pairing correlations and effective masses in nuclei with large neutron excess. Mod. Phys. Lett. A, pages 19231926, 2010.
We propose a local energy density functional for global description of pairing correlations by focusing on the neutron excess dependence. gaps and effective mass parameters as a function of neutron excess. This effect can be taken into account to the density functional by the isovector density dependence in the particleparticle channel.
P. Vingerhoets, K. T. Flanagan, M. Avgoulea, J. Billowes, M. L. Bissell, K. Blaum, B. A. Brown, B. Cheal, M. De Rydt, D. H. Forest, Ch. Geppert, M. Honma, M. Kowalska, J. Krämer, A. Krieger, E. Mané, R. Neugart, G. Neyens, W. Nërtershäuser, T. Otsuka, M. Schug, H. H. Stroke, G. Tungate, and D. T. Yordanov. Nuclear spins, magnetic moments, and quadrupole moments of Cu isotopes from N=28 to N=46: Probes for core polarization effects. volume 82, pages 064311/112, 2010.
Measurements of the groundstate nuclear spins and magnetic and quadrupole moments of the copper isotopes from ^{61}Cu up to ^{75}Cu are reported. The experiments were performed at the CERN online isotope mass separator (ISOLDE) facility, using the technique of collinear laser spectroscopy. The trend in the magnetic moments between the N=28 and N=50 shell closures is reasonably reproduced by largescale shellmodel calculations starting from a ^{56}Ni core. The quadrupole moments reveal a strong polarization of the underlying Ni core when the neutron shell is opened, which is, however, strongly reduced at N=40 due to the parity change between the pf and g orbits. No enhanced core polarization is seen beyond N=40. Deviations between measured and calculated moments are attributed to the softness of the ^{56}Ni core and weakening of the Z=28 and N=28 shell gaps.
XianRong Zhou and H. Sagawa. Effect of tensor interaction on heavy and superheavy nuclei. In Proc. of Int. Conference Niigata2010, pages pp.18091814, 2010.
The effect of tensor interaction is discussed on the deformation and the shell structure of heavy and superheavy nuclei within the deformed Skyrme HartreeFock+BCS model. The importance of the tensor correlations is shown for the single particle spectra of protons in ^{249}Bk. The large shell gaps of superheavy nuclei are found at Z=114 and Z=120 for protons and N=184 for neutrons with the spherical shape irrespective of the tensor correlations. It is also shown that Z=114 and N=164 shell gaps are more pronounced by the tensor correlations in the case of SLy5+T interaction.
K. Hagino, H. Sagawa, and T. Oishi. Dineutron correlation in the ground state and E1 excitations of Borromean nuclei. In Proc. of Int. Conference Niigata2010, pages pp.18421845, 2010.
Using a threebody model with densitydependent contact interaction, we discuss the role of dineutron correlation in the ground state properties as well as in the dipole excitation of typical weaklybound Borromean nuclei, ^{11}Li and ^{6}He. We show that, while both the nuclei manifest themselves similar strong dineutron correlations to each other in the ground state, the energy distributions for the two emitted neutrons from the dipole excitation are considerably different. We also discuss briefly the diproton correlation in a protonrich Borromean nucleus, ^{17}Ne.
Takao Maeda, Shinya Matsufuji, and Takafumi Hayashi. A Novel Class of ZeroCorrelation Zone Array Sets. In Proceedings of Annual Conference of JSIAM 2010, pages 2140. The Japan Society for Industrial and Applied Mathematics, September 2010.
A method by which a zero correlation zone array set is generated, is proposed. A perfect sequence of 1dim (mainly ternary sequence)is used.(in Japanese)
Takafumi Hayashi, Takao Maeda, and Satoshi Okawa. A Novel ZeroCorrelation Zone Sequence Set with Sequence subsets. In Abstracts of ISCITS 2010,International Symposium on Communications and Information Technologies, page 29. IEEE, IEEE, November 2010.
The present paper intloduces a new approach to the construction of a sequence set with a zerocorrelation zone. The proposed sequences can be constructed from a pair of Hadamard matriccs of the orders n_{0} and n_{1}. The constructed sequence set consists of n_{0}n_{1} ternary sequences, each of length n_{0}^{m+1}(n_{1} + 2) for a non negative integer m: The sequence member size of the proposed sequence set is equal to n_{1}(n_{1} + 2) times that of the theoretical upper bound of the member size of a sequence set with a zerocorrelation zone. The proposed sequence set consists of n_{0} subsets, with each of member size being n_{1}: The correlation function of the sequences of a pair of different subsets, so called intersubset correlation function, has a zerocorrealtion zone that is almost twice the width of the correlation function of the sequences of the same subset (intrasubset correlation function). This wider intersubset zerocorrelation contributes to the performance improvement of applications of the proposed sequence set. The proposed sequence sets have a zerocorrelation zone for both periodic and aperiodic corlelation functions.
Takao Maeda, Shigeru Kanemoto, and Takafumi Hayashi. A Novel Class of Binary ZeroCorrelation Zone Sequence Sets. In Proceedeings of TENCON 2010,IEEE Region 10 Conference, pages 708711. IEEE, IEEE, November 2010.
The present paper introduces the construction of binary sequences having a zerocorrelation zone. The crosscorrelation function and the sidelobe of the autocorrelation function of the proposed sequence set is zero for the phase shifts within the zerocorrelation zone. The proposed zerocorrelation zone sequence set can be generated from an arbitrary Hadamard matrix of order n. The proposed zerocorrelation zone sequence set consists of two sub groups. The intergroup crosscorrelation function has much wider than the innergroup crosscorrelation function. When the proposed sequence set is applied to the synthetic aperture ultrasonic imaging, this wide intergroup zerocorrelation zone enables better image than usual method. The proposed sequence set is suitable for realtime synthetic aperture ultrasonic imaging.
Takao Maeda and Takafumi Hayashi. Parameterization of Perfect Sequences. In Proceedeings of TENCON 2010, IEEE Region 10 Conference, pages 13071312. IEEE, IEEE, November 2010.
A ZCZ (Zero Correlation Zone) sequence set plays an important role in the research of CDMA, ultrasonic imaging, position control and so on. It's a set of perfect sequences which has a property about crosscorrelation. We treat the set of perfect sequences as a zero set of quadratic equations and try to simplify these equations. We prove `Decomposition Theorem' of perfect sequences and the theorem convert the problem of the structures of perfect sequences into the problem of the structures of quasiperfect sequences which we named. Parameterizing of perfect sequences of easy case and quasiperfect sequences lead us to the parameterization of perfect sequences of arbitrary length.
Kazuto Asai. The group generated by gamma functions [kasai01:2010] Kazuto Asai. The group generated by gamma functions Γ(ax + 1), and its sungroup of the elements converging to constants. preprint, 2010.
M. Honma, T. Otsuka, T. Mizusaki, and M. HjorthJensen. Recent Progress in ShellModel Calculations for pfgshell Nuclei. In A. Ozawa and Editor W. Lu, editors, AIP Conference Proceedings Volume 1235 (NUCLEAR PHYSICS TRENDS: 7th JapanChina Joint Nuclear Physics Symposium, Tsukuba (Japan), 913 November 2009), pages 384390, 2010.
Takao Maeda, Shigeru Kanemoto, and Takafumi Hayashi. Application of Zero Correlation Sequence Set to Ultrasonic Imaging. In IEICE Technical Report US2010(201006), pages 3740. IEICE, June 2010.
The present paper introduces the construction of binary sequences having a zerocorrelation zone. The crosscorrelation function and the sidelobe of the autocorrelation function of the proposed sequence set is zero for the phase shifts within the zerocorrelation zone. The proposed zerocorrelation zone sequence set can be generated from an arbitrary Hadamard matrix of order n. The proposed zerocorrelation zone sequence set consists of two sub groups. The intergroup crosscorrelation function has much wider than the innergroup crosscorrelation function. When the proposed sequence set is applied to the synthetic aperture ultrasonic imaging, this wide intergroup zerocorrelation zone enables better image than usual method. The proposed sequence set is suitable for realtime synthetic aperture ultrasonic imaging.
H. Sagawa and N. Yoshida. Fundamentals of Quantum Informations. World Scientific, 2011.
H. Sagawa and K. Shimizu. Quantum Mechanics (Second Edition). SpringerJapan, 2011.
H. Sagawa and M. Honma. Electromagnetism (Second Edition). Springer Japan, 2010.
H. Sagawa and M. Honma. Mechanics (Second Edition). Springer Japan, 2010.
H. Sagawa. Ministry of Education Scientific Research Fund C2, 20082011.
S. Watanabe, 20102011.
Reviewer: Mathematical Reviews published by the American Mathematical Society
Takahiro Nemoto. Graduation Thesis: Ising model on random surface, University of Aizu, 2010.
Thesis Adviser: A. Fujitsu
Fumiya Kouno. Graduation Thesis: Programming for physics learning, University of Aizu, 2010.
Thesis Adviser: A. Fujitsu
Tomohiro Nishimura. Graduation Thesis: A Computer Simulation of Kepler Motion in the Solar Wind, School of Computer Science and Engineering, March 2011.
Thesis Adviser: M. Honma
Yuji Ohara. Graduation Thesis: The theory of relativity and GPS, School of Computer Science and Engineering, March 2011.
Thesis Adviser: H. Sagawa
Takefumi Ogata. Graduation Thesis: The effect of general relativistic theory on GPS, School of Computer Science and Engineering, March 2011.
Thesis Adviser: H. Sagawa
Rune Okabe. Graduation Thesis: Time dilation in Global positioning system cansed by General relativity, School of Computer Science and Engineering, March 2011.
Thesis Adviser: H. Sagawa
Tomohide Osikiri. Graduation Thesis:Big bang and age of the universe, School of Computer Science and Engineering, March 2011.
Thesis Adviser: H. Sagawa
Tomohide Yukawa. Graduation Thesis: Quasar and Accretion disk, School of Computer Science and Engineering, March 2011.
Thesis Adviser: H. Sagawa
Takuya Kojima. Graduation thesis, School of Computer Science and Engineering, March 2011.
Thesis Adviser: S. Watanabe
Erika Suzuki. Graduation thesis, School of Computer Science and Engineering, March 2011.
Thesis Adviser: S. Watanabe
Wataru Kumamoto. Graduation thesis, The University of Aizu, 2011.
Thesis Adviser: S. Watanabe
Genki Sato. Graduation thesis, School of Computer Science and Engineering, M 2011.
Thesis Adviser: S. Watanabe
Kazuya Ikeda. Graduation thesis, School of Computer Science and Engineering, March 2011.
Thesis Adviser: S. Watanabe
Kensuke Iseki. Graduation thesis, School of Computer Science and Engineering, March 2011.
Thesis Adviser: S. Watanabe
Akira Murakoshi. Master thesis, Graduate School of Computer Science and Engineering, March 2011.
Thesis Adviser: S. Watanabe
Hiroshi Kihara. Introduction to Homotopical Algebra I, II, and III, March 2011,.
Consecutive lectures in the symposium '(Non)commutative algebra and topology' (at Shinshu University)