4.4. young scientist initiative c€¦ · “theory of orbital frustration and its quantum...

4. Research Report in 2010 Fiscal Year: 4.4. Young Scientist Initiative C

Tohoku University GCOE program "Weaving Science Web beyond Particle-Matter Hierarchy"

4.4. Young Scientist Initiative C

The GCOE supported the research expense as “Young Scientist Initiative C” for the doctoral

course students of the department of Physics, Astronomy, Mathematics and Philosophy in 2010. The

GCOE“Young Scientist Initiative C” was given to the 20 students who were also adopted as

Research Fellowship for Young scientists by JSPS (Japan Society for the Promotion of Science). The

student names and their research titles are as listed below. Then, their research reports are the

following. There were 30 publications, 126 presentations, and 3 awards by the 20 students

1. Tosiyuki Arakane (Physics, D3)

“The fine electronic structure of the layered NaxCoO2 superconductor studied by low-energy

high-resolution photoemission spectroscopy”.

2. Joji Nasu (Physics, D3)

“Theory of Orbital Frustration and Its Quantum Phenomena”

3. Azusa Gando-Terashima (Physics, D2)

“Neutrino-less double beta decay experiment with KamLAND”

4. Yasuhiro Takemoto (Physics, D2)

“Wideband real-time observation of solar neutrinos with dead-time free electronics”

5. Kenji Hosomi (Physics, D2)

“Study of modification of baryons in nuclear medium through hypernuclear gamma-ray

spectroscopy experiments at J-PARC”

6. Yasuyuki Horii (Physics, D3)

“Measurement of the CP-violating angle phi3 at Belle”

7. Yutaro Sato (Physics, D1)

“Study of B-pi tagging method at the Y(5S) resonance for the measurement of phi1”

8. Akari Takayama (Physics, D1)

“Development of ultrahigh-resolution spin-resolved photoemission spectrometer and study of

surface states of magnetic thin films”

9. Takeshi Yamamoto (Physics, D1)

“Study of Λ magnetic moment by hypernuclear γ-ray spectroscopy”

10. Shigeki Inoue (Astronomy, D3)

“A solution for dark matter cusp/core problem of dwarf galaxies”

11. Tomohiro Okamura (Astronomy, D1)

“Observational and theoretical cosmology based on the weak gravitational lensing”

12. Norisuke Ioku (Mathematics, D3)



“The regularity theory of nonlinear elliptic and parabolic partial differential equations”

13. Toshiaki Omori (Mathematics, D3)

“Study on bubbling phenomena for harmonic maps”

14. Shin Kikuta (Mathematics, D2)

“Measure hyperbolicity and positivity of canonical bundle”

15. Takayuki Kihara (Mathematics, D2)

“Study of effectively closed degree structures by using effective randomness and computational

learning”

16. Hirotake Kurihara (Mathematics, D2)

“A construction of spherical designs using the method of discrete geometric analysis”

17. Ryo Takada (Mathematics, D2)

“Harmonic analytic approach to the partial differential equations arising in fluid mechanics”

18. Erika Ushikoshi (Mathematics, D1)

“Hadamard variational formula for the Green matrix of the Stokes equations”

19. Touhei Fujishima (Mathematics, D1)

“Blow-up problem for nonlinear diffusion equations and the profile of the solution”

20. Haruka Hikasa (Philosophy, D3)

“Study on Decision-making Process from the Perspective of 〈Person〉in Clinical Ethics”



No.1

Name Toshiyuki Arakane

Department Physics

Position D3, JSPS Research Fellow

Research Title The fine electronic structure of the layered NaxCoO2

superconductor studied by low-energy high-resolution

photoemission spectroscopy.

I. Summary of Research

I have studied the electronic structure of cobalt oxide NaxCoO2 by high-resolution angle-resolved

photoemission spectroscopy (ARPES). The cobalt oxides are regarded an excellent candidate of

high thermo-electric materials which do not contain rare metals or poisonous elements. Moreover,

the discovery of superconductivity in hydrated compounds also attracted significant attention, since

its superconducting properties are highly unusual. In order to elucidate the origin of unusual

physical properties, I have studied the electronic states of cobalt oxides. In the following, I list my

main research results.

1. Origin of high thermo-power in cobalt oxides

I have studied fine electronic states in the vicinity of the Fermi level of cobalt oxide NaxCoO2

in a wide doping range, by the newly-developed high-resolution ARPES spectrometer and

the synchrotron facility in Wisconsin and Tsukuba. I have revealed that the high

thermo-power of this material originates in the peculiar electronic states of Co3d orbital

showing an unusual band dispersion around the Brillouin-zone center. Based on the present

result, I proposed the basic electronic-structure design to achieve higher thermo-power.

2. Mechanism of superconductivity in hydrated cobalt oxides

I have studied the fine electronic states in the vicinity of the Fermi level of hydrated cobalt

oxide NaxCoO2・1.4H2O by high-resolution ARPES. I found that the Co3d a1g Fermi

surface which has been predicted by the band structure calculation is completely absent in

the experiment, demonstrating the single-band nature of the superconductivity. I have thus

concluded that the superconductivity is mediated by phonons which strongly couples to the

Co3d electronic states near the Fermi level.

II. Publications

1. “Evidence for the transition of Fermi surface topology in highly-doped NaxCoO2”, T.

Arakane, T. Sato, T. Takahashi, T. Fujii, and A. Asamitsu, Physical Review B, 81, 115132,

(2010).



2. “Direct evidence for cage conduction band in superconducting cement 12CaO・7Al2O3 by

low-energy high-resolution photoemission spectroscopy”, S. Souma, T. Arakane, T. Sato, T.

Takahashi, S.-W. Kim, S. Matsuishi, and H. Hosono, Journal of the Physical Society of Japan,

79, 103704, (2010). 3. “Three-dimensional electronic structure in highly-doped NaxCoO2 studied by angle-resolved

photoemission spectroscopy”, T. Arakane, T. Sato, T. Takahashi, T. Fujii, and A. Asamitsu, J. Phys. Chem. Solids (in press)

III. Presentations

1. “Three dimensional electronic structure in highly-doped NaxCoO2”, T. Arakane, T. Sato, T.

Takahashi, T. Fujii, and A. Asamitsu, The 9th International Conference on Spectroscopies in

Novel Superconductors, May 2010, Shanghai, China.

IV. Prizes (Awards)

1. Physics Department Award, “Angle-resolved photoemission study of layered cobalt oxides”,

Tohoku University, February, 21, 2011

No. 2

Name Joji Nasu

Department Physics


Research Title Theory of Orbital Frustration and Its Quantum Phenomena


1. Orbital degree of freedom is one of the recent attractive themes in transition-metal oxides. In

contrast to the spin degree of freedom, the orbital interaction explicitly depends on the bond

direction, and a certain kind of frustration exists. In the geometrical frustrated lattice,

cooperating and competing effects between the orbital frustration and the geometrical

frustration provide new features in the static and dynamical properties of orbital. The present

purpose is to study the intrinsic orbital frustration effect in a geometrical frustrated lattice.

We introduce the spin-less Hubbard-type model with the doubly degenerate dyz and dzx

orbitals in the checkerboard lattice. The effective Hamiltonian for the strong correlation limit

is derived. We have the Jz Siz Sjz type Ising interaction for the nearest-neighbor bonds and

the Jx Six Sjx type Ising one for the next nearest-neighbor bonds. Here S is the orbital



pseudo-spin operator. In the mean-field approximation, there is a macroscopic number of

degeneracy at the frustration point Jx/Jz=2. In the classical Monte-Carlo simulation, we have

a staggered orbital order and the reentrant phase-boundary. In the analyses by the spin-wave

approximation and the exact diagonalization method, a large damping of the high-energy

orbital dynamics due to the frustration is observed.

2. The ring-exchange (RE) interaction in a Mott insulator with doubly degenerate eg orbitals is

studied. The Hamiltonian for the RE interaction is derived by a perturbational calculation. A

remarkably weak RE interaction destroys the orbital order caused by the order-by-fluctuation

mechanism in the nearest-neighbor exchange–interaction model. A magnetic octupole

moment with long range order, i.e., complex orbital wave functions, appears. Competition

between octupole and quadrupole interactions strongly suppresses the ordered moments.

II. Publications

1. “Ring-exchange interaction in doubly degenerate orbital system”, J. Nasu, and S. Ishihara: J.

Phys. Soc. Jpn., 80, 033704 (2011)

III. Presentations

1. “Order and Dynamics in Frustrated Orbital System”, J. Nasu, and S. Ishihara, Bussei Kagaku

Ryouiki Odan Kenkyukai, (November 2010, Tokyo, Japan)

2. “Study of Orbital Degenerate System in Frustrated Checkerboard Lattice”, J. Nasu, and S.

Ishihara: 2011 American Physical Society, March Meeting, L18.00013, Dallas, Texas, March,

2011

3. “Phase Transition and Dynamics of Orbital Model on Checkerboard Lattice”, J. Nasu, and S.

Ishihara, Physical Society of Japan, (March 2011, Niigata, Japan)

4. “Mott Transition in Correlated Electron System with Anisotropic Orbital Degree of

Freedom”, J. Nasu, and S. Ishihara, Physical Society of Japan, (September 2010, Osaka,

Japan)

IV. Prizes (Awards)

1. Prize of Physics department chairman (Tohoku University, February 2011)



No.3

Name Azusa Gando-Terashima

Department Physics


Research Title Neutrino-less double beta decay experiment with KamLAND


The Kamioka Liquid scintillator Anti-Neutrino Detector (KamLAND) is low energy neutrino

detector with 1,000 tons of highly purified liquid scintillator (LS) located on the former Kamiokande

experiment site in Japan. Next target of this experiment is to search the neutrinoless double beta

decay with 400kg of 90% enriched 136Xe nuclei in order to understand the nature of neutrinos

(Dirac/Majorana), its effective mass via its half-life and neutrino mass hierarchy. The 1st phase of

this experiment (KamLAND-Zen) will start on early summer in 2011 to verify the KKDC claim and

search the degenerated hierarchy.

To start the experiment, we develop the mini balloon, container of new Xe loaded LS (Xe loaded

LS development was done and its various parameter are measured precisely). To hold 400 kg of Xe

in the LS, suspend in KamLAND and keep its performance, real scale balloon’s radius is about 1.6m,

neck part is 7m, thickness is only 25 micrometer and extremely clean. The performance estimation

of mini-balloon was done at 8m depth of 1/4 cylindrical pool between 22 Dec. 2010 and 19 Jan.

2011. Many kinds of test items were checked, for example, mini balloon folding, connection of

support flange (real one), support string, un-slipping knot of string, load cell (real one) and so on. We

established how install the balloon and how handle it including personnel distribution by this test.

Layer test with different density water was also done for exchanging light LS with heavier Xe loaded

LS at real installation. Pressurize test for checking safety of balloon, energy calibration tool, how to

remove the mini balloon in case of emergency are also considered. For the real installation, we

continue discussing and decision of the method and way of those and another things.

II. Publications

1. “Constraints on θ13 from A Three-Flavor Oscillation Analysis of Reactor Antineutrinos at

KamLAND”, A. Gando et. al. (the KamLAND collaboration), Physical Review D, 83,

052002 (2011)

III. Presentations

1. “Anti-neutrino search from GRB with KamLAND”, A. Gando, KamLAND international

collaboration meeting (Sep. 3 - 6, 2010, Felix Meritis & Nikhef, Amsterdam, the



Netherlands)

2. “Towards a double beta decay experiment with KamLAND”, A. Gando, 11th International

Workshop on Next generation Nucleon Decay and Neutrino Detectors (NNN10), (Dec. 13-16,

2010, Toyama International Conference Center, Toyama, Japan)

3. “116CdWO4+KamLAND”, A. Gando, Workshop on double beta decay, (Dec. 17-18, 2010,

Montana Resort, Iwanuma, Japan)

4. “Towards a double beta decay experiment with KamLAND”, A. Gando, The 3rd International

GCOE symposium on “Weaving Science Web beyond Particle-Matter Hierarchy” (Feb.

17-19, 2011, Tohoku University, Sendai, Japan)

5. “Search for anti-neutrinos from gamma ray burst with KamLAND”, A. Gando, KamLAND

international collaboration meeting (Mar. 22-24, 2011, Toyama International Conference

Center, Toyama, Japan)

6. “Double beta decay experiment with KamLAND (13) -Present status-”, A. Gando, Japan

Physical Society 2011 Spring Meeting (Mar. 25-28, Niigata University, Niigata, Japan)

No.4

Name Yasuhiro Takemoto

Department Physics

Position DC2, JSPS Research Fellow

Research Title Wideband real-time observation of solar neutrinos with dead-time

free electronics


1. Dead-time free DAQ with dead-time free electronics has been started with accomplishing

fundamental software. Energy threshold varies from ~ 350 to ~ 600 keV and data size from ~

300 to ~ 500 GB/day. The major malfunction against dead-time free DAQ was fixed, and a

few to be fixed.

2. One of major background events against solar neutrinos’ observation, 85Kr will be taken with

a newly developed trigger logic.

II. Publications

1. “Constrains on θ13 from a three-flavor oscillation analysis of reactor antineutrinos at

KamLAND”, The KamLAND Collaboration, Physical Review D, 83, 0520002, (2011)



III. Presentations

1. “7Be solar neutrino analysis”, “MoGURA hardware and DAQ status”,

Takemoto Yasuhiro, KamLAND collaboration meeting, (Sep. 03-06, 2011, Amsterdam,

Holland)

2. “Dead-time free DAQ with MoGURA and its contribution to KamLAND experiment”,

Takemoto Yasuhiro, The 3rd International GCOE symposium on “Weaving Science Web

beyond Particle-Matter Hierarchy”, (Feb. 17-19, 2011, Tohoku University, Sendai, Japan)

3. “KamLAND experiment and contribution of dead-time free DAQ”, Takemoto Yasuhiro, 17th

ICEPP Symposium, (Feb. 20-23, 2011, Nagano)

No.5

Name Kenji Hosomi

Department Physics


Research Title Study of modification of baryons in nuclear medium through

hypernuclear gamma-ray spectroscopy experiments at J-PARC


1. For a hypernuclear gamma-ray spectroscopy experiment at J-PARC K1.8 beam line, a new

Ge detector array (Hyperball-J) is under construction. Hyperball-J consist of 32 Ge detectors

that are equipped with pulse-tube refrigerators and of PWO background suppressors

surrounding the each Ge detector. PWO detectors was developed and produced. A new heat

insulator made of SiO2 aero gel was used. PWO crystals were cooled down to about -5

degree of Celsius. As a result of cooling, we obtained 1.6 times more photoelectrons than we

did at root temperature (~20 degree of Celsius).

2. PWO detectors and Ge detectors were mounted on Hyperball-J frame in order to measure the

performance of background suppression. The result was consistent with GEANT4

simulation.

3. The status of Hyperball-J construction and motivations of hypernuclear gamma-ray

spectroscopy experiment at J-PARC were reported and discussed at JPS Spring Meeting.

II. Publications



III. Presentations

1. “Development of a readout system for Ge detectors of Hyperball-J”, K. Hosomi, Workshop

for detectors and readout systems in nuclear-hadron experiments, (June 4, Japan Atomic

Energy Agency, Tokai, Japan)

2. “Status report of K1.8 beamline (ll)”, K. Hosomi, Japan-Korea Meeting on Nuclear and

Particle Physics at J-PARC Hadron Hall, (Nov. 29-30, 2011, Seoul National University,

Seoul, Korea)

3. “Gamma-ray spectroscopy of 19F-lambda”, K. Hosomi, The 3rd International GCOE

symposium on “Weaving Science Web beyond Particle-Matter Hierarchy”, (Feb. 18-19,

2011, Tohoku University, Sendai, Japan)

4. “Study of hypernuclei by using the Hyperball detector”, K. Hosomi, The 4th symposium of

Good Practice for Graduate School of Science, (Feb. 22, 2011, Tohoku University, Sendai,

Japan)

5. “Gamma-ray spectroscopy of light hypernuclei at J-PARC K1.8 beam line”, K. Hosomi,

Japan Physical Society 2011 Spring Meeting, (Mar. 25-28, 2011, Niigata University, Niigata,

Japan)

No.6

Name Yasuyuki Horii

Department Physics

Position D3

Research Title Measurement of the CP-violating angle phi3 at Belle


1. Introduce new method of the discrimination between the B decays and the continuum

backgrounds from e+e- qq (q = u, d, s, c) based on modified Super Fox-Wolfram moments,

decay angles, positions of vertices, etc. The variables are combined by using a neural

network provided by the NeuroBayes package.

2. Obtain the first evidence of the suppressed decay chain B- DK- followed by D K+π-,

where D indicates a D0 meson or its antimeson. The significance of the signal yield is 4.1σ,

which is obtained by including systematic uncertainties. 3. Measure the ratio RDK of the suppressed decay rate to the favored decay rate obtained in the



chain B- DK-, D K-π+ and the asymmetry ADK between the charge conjugate decays of the

suppressed mode as RDK = [1.63+0.44-0.41(stat)+0.07

-0.13(syst)] x 10-2 and ADK =

-0.39+0.26-0.28(stat)+0.04

-0.03(syst). 4. Extract the CP-violating angle phi3 to be phi3 = 89°+13°

-16°, which is consistent with an

expectation from the Cabibbo-Kobayashi-Maskawa model: 67.2°±3.9°. II. Publications

1. “Belle time-integrated φ3 (γ) measurements”, Y. Horii (Belle Collaboration), Proceedings of

the 6th International Workshop on the CKM Unitarity Triangle,

arXiv:1101.0878v1 (will appear in eConf)

III. Presentations

1. “Belle time-integrated phi3 (gamma) measurements”, Y. Horii, CKM2010, the 6th

International Workshop on the CKM Unitarity Triangle, (Sep. 6-10, 2010, University of

Warwick, Coventry, UK)

2. “Study of the decay B D(*)K for the measurement of the CP-violating angle phi3”, Y.

Horii, K. Trabelsi, H. Yamamoto, and the Belle collaboration, Japan Physical Society 2010

Fall Meeting, (Sep. 11-14, 2010, Kyushu Institute of Technology, Kitakyushu, Japan)

3. “First Evidence of the Suppressed B Meson Decay B- DK-, D K+pi-”, Y. Horii, The 3rd

International GCOE symposium on “Weaving Science Web beyond Particle-Matter

Hierarchy”, (Feb. 17-19, 2011, Tohoku University, Sendai, Japan)

4. “Status and Physics Prospects of the SuperKEKB Project”, Y. Horii (Belle II Collaboration),

La Thuile 2011, Les Rencontres de Physique de la Vallee d’Aoste, (Feb. 27-Mar. 5, 2011, La

Thuile, Aosta Valley, Italy)

No.7

Name Yutaro Sato

Department Physics


Research Title Study of B-pi tagging method at the Y(5S) resonance for the

measurement of phi1




1. We aim to measure CP-violation parameter sin2phi1 using new flavor tagging method. In our

analysis, signal modes is Y (5S) BBpi(pi) and an initial flavor of neutral B meson is tagged

by charge of a pion. Selection criteria were optimized by the Montecarlo data of general

Y(5S) decay and real data of Y(4S). The results were reported at B workshop at Atami. The

measurement accuracy of sin2phi1 was estimated by the Montecarlo data of general Y(5S)

decay. The results were reported at the 2nd International GCOE symposium on “Weaving

Science Web beyond Particle-Matter Hierarchy @ Tohoku University. and Japan Physical

Society 2011 Spring Meeting at Niigata University.

2. We belong to SOI pixel group and develop a pixel detector. We submitted papers about

performance study and radiation tolerance test of prototype readout ASIC separately to

Nuclear Instruments and Method in Physics Research Section A, and then accepted.

II. Publications

1. “Radiation test on FD-SOI readout ASIC of pair-monitor for ILC”, Y. Sato, et al., Nucl. Instr.

And Meth. A(2011), doi:10.1016/j.nima.2010.12.149

2. “SOI Readout ASIC of Pair-monitor for International Linear Collider”, Y. Sato, et al., Nucl.

Instr. And Meth. A(2011), doi:10.1016/j.nima.2011.02.063

III. Presentations

1. “The development of the readout ASIC for the pair-monitor with SOI technology ~irradiation

test~”, Yutaro Sato, FCAL collaboration meeting(Apr., 12-13, 2010, Cracow, Poland)

2. “Development of Readout ASIC for Pair-monitor ~Radiation Test~”, Yutaro Sato, ILC

summer camp with accelerator and physics(Aug. 9-12, 2010, Shiroishi, Miyagi, Japan)

3. “Radiation test on FD-SOI Readout ASIC of Pair-monitor for ILC”, Sato Y., International

Workshop on Semiconductor Pixel Detectors for Particles and Imaging (Sep. 6-10, 2010,

Grindelwald, Switzerland)

4. “Measurement of CP-violation parameter sin2phi1 in Y(5S) decay”, Yutaro Sato, B physics

workshop (Oct.12-15, 2010, Atami, Shizuoka, Japan)

5. “Study of B-pi tagging method at the Y(5S) resonance for the measurement of CP-violation

parameter sin2phi1”, Yutaro Sato, The 2nd International GCOE symposium on “Weaving

Science Web beyond Particle-Matter Hierarchy”, (Feb. 17-19, 2011, Tohoku University,

Sendai, Japan)

6. “Study of B-pi tagging method at the Y(5S) resonance for the measurement of phi1”, Yutaro

Sato, Japan Physical Society 2011 Spring Meeting (Mar. 25-28, 2011, Niigata University,

Niigata, Japan)



No.8

Name Akari Takayama

Department Physics


Research Title Development of ultrahigh-resolution spin-resolved photoemission

spectrometer and study of surface states of magnetic thin films.


We have developed an ultrahigh-resolution spin-resolved photoemission spectrometer with a

highly efficient mini Mott detector and an intense xenon plasma discharge lamp. For

three-dimensional observation of spin-polarization, we attached an electron deflector which

transports the electron from analyzer to mini Mott detector with bending electron trajectory by 90

degree. The spectrometer achieves the energy resolutions of 0.9 and 8 meV for non-spin-resolved

and spin-resolved modes, respectively. The energy resolution of 8 meV in spin-resolving mode is

1-2 order higher than that of the conventional spin-resolved ARPES, and even the highest among the

currently available spectrometer. We published this result in Rev. Sci. Instrum.

By using the developed spectrometer, we have studied the spin texture of surface states of bismuth

(Bi) caused by strong spin-orbit coupling. For the sake of high accuracy and reliability in

spin-resolved ARPES experiment, we have fabricated single crystalline ultrathin Bi film on Si(111)

substrate. Sample quality was checked by low energy electron diffraction. In the spin-integrated

ARPES measurement, we have determined the band structure in the vicinity of the Fermi level and

the accurate shape of Fermi surface of Bi(111) surface. In the spin-resolved ARPES measurement,

we have determined in-plane and out-of-plane spin polarization with directly specifying the

momentum location pre-determined by simultaneous spin-integrated ARPES. By mapping out the

spin polarization at various momentum point in Brillouin zone, we found striking deviation of spin

texture of spin-split surface state on Bi(111) from what expected in the simple Rashba picture that

electron spin is polarized parallel to the plane and perpendicular to electron momentum vector from

Gamma point. We published this result in Phys. Rev. Lett. and reported these results at The 3rd

International GCOE symposium and Japan Physical Society Meeting.

II. Publications

1. “Ultrahigh-resolution spin-resolved photoemission spectrometer with a mini Mott detector”,

S. Souma, A. Takayama, K. Sugawara, T. Sato, and T. Takahashi, Rev. Soc. Instrum.

81,095101, (2010).

2. “Giant out-of-plane spin component and the asymmetry of spin-polarization in surface



Rashba state of Bismuth thin film”, A. Takayama, T. Sato, S. Souma and T. Takahashi, Phys. Rev.

Lett., in press.

III. Presentations

1. “Anomalous Rashba effect of Bi(111) surface studied by high-resolution spin-resolved ARPES”, A.

Takayama, The 3rd International GCOE symposium on “Weaving Science Web beyond

Particle-Matter Hierarchy”, (Feb. 17-19, 2011, Tohoku University, Sendai, Japan)

2. “Spin-resolved electronic structure of Bi(111) surface”, A. Takayama, K. Kosaka, K. Sugawara,

S. Souma, T. Sato, and T. Takahashi, Japan Physical Society 2010 Autumn Meeting (September 23-26,

Osaka prefecture University, Osaka, Japan)

3. “Anomalous Rashba effect of Bi(111) surface studied by high-resolution spin-resolved ARPES”, A.

Takayama, S. Souma, T. Sato, and T. Takahashi, Japan Physical Society 2011 Spring

Meeting (March 25-28, Niigata University, Niigata, Japan)

No.9

Name Takeshi Yamamoto

Department Physics


Research Title Study of Λ magnetic moment by hypernuclear γ-ray spectroscopy


1. We have developed Ge detector and PWO background suppressor for Hyperball-J( will be

used in hypernuclear γ-ray spectroscopy experiment: J-PARC E13) and checked performance

of them.

2. We have developed a Hyperball-J control system. We have checked whole Hyperball-J

system with one detector unit mounted to frame. This setup is almost same as system in E13

experiment. We checked that our system is working well.

3. We checked performance of detector unit mounted to the frame. Measured energy resolution

of Ge detector was 3.5 KeV (FWHM) at 1 MeV. Peak-to-total ratio was 0.33 after

suppression. (0.19 before suppression)

II. Publications



III. Presentations

1. “E13 experiment and status of Hyperball-J”, T. O. Yamamoto, Japan-Korea Meeting on

Nuclear and Particle Physics at J-PARC Hadron Hall (November 29-30, 2010, Seoul national

University, Seoul, Korea)

2. “Hypernuclear gamma-ray spectroscopy system: Hyperball-J (3)”, T. O. Yamamoto, Japan

Physical Society 2010 Autumn Meeting (September 11-14, 2010, Kyushu Institute of

Technology, Kitakyushu, Japan)

3. “E13 Day-1 experiment and status of Hyperball-J”, T. O. Yamamoto, Strangeness nuclear

physics 2010 meeting (December 2-4, 2010, KEK, Tsukuba, Japan)

4. “Hypernuclear γ-ray spectroscopy system: Hyperball-J”, T. O. Yamamoto, The 2nd

International GCOE symposium on “Weaving Science Web beyond Particle-Matter

Hierarchy”, (Feb. 18-19, 2011, Tohoku University, Sendai, Japan)

No.10

Name Shigeki Inoue

Department Astronomy


Research Title A solution for dark matter cusp/core problem of dwarf galaxies


1. “Why does a constant density structure suppress dynamical friction?”. I investigated a

possible mechanism to suppress dynamical friction on a heavy particle in a cored density

profile by means of N–body simulation.

2. “Galactic disk and bulge formation from clump clusters/chain galaxies”, I have investigated

formation of galactic bulge and disk in a clump cluster: infant primitive disk galaxy in the

high-z universe.

II. Publications

III. Presentations

1. “Why does a constant density structure suppress dynamical friction?”, S. Inoue, the 4th

Japn-Korea Young Astronomers Meeting 2010, (August 25-27, 2010, Miura, Kanagawa,

Japan)



2. “Galactic disk and bulge formation from clump clusters/chain galaxies”, S. Inoue, the 23rd

RIRONKON Symposium (December 20-22, 2010, Kyoto University, Kyoto, Japan)

3. “Galactic disk and bulge formation from clump clusters/chain galaxies”, S. Inoue, CfCA

Users' Meeting 2010 (January 11-12, 2011, Notional Astronomical Observatory, Tokyo,

Japan)

4. “Galactic disk and bulge formation from clump clusters”, S. Inoue, First star and first galaxy

workshop (January 26-28, 2011, Ehime University, Ehime, Japan)

5. “Galactic disk and bulge formation from clump clusters”, S. Inoue, East Asia Young

Astronomers Meeting 2011 (February 13-18, 2011, Jeju island, Korea)

6. “Galactic disk and bulge formation from clump clusters/chain galaxies”, S. Inoue, Spring

Society Meeting 2011 of the Astronomical Society of Japan (March 16-19, 2011, Tsukuba

University, Ibaragi, Japan)

No.11

Name Tomohiro Okamura

Department Astronomy


Research Title Observational and theoretical cosmology based on the weak

gravitational lensing


1. To evaluate the nonlinear growth of the cosmological large-scale structure accurately, we

improve the cosmological perturbation theory via the Lagrangian picture.

2. Comparing our model with N-body simulation in detail, we find excellent agreements and

confirm the superiority of our model.

II. Publications

III. Presentations

1. “Resuming cosmological perturbations via the Lagrangian picture: Two-loop result in real

space”, T. Okamura, The 3rd International GCOE symposium on “Weaving Science Web

beyond Particle-Matter Hierarchy”, (February 17-19, 2011, Tohoku University, Sendai,

Japan)



2. “Resuming cosmological perturbations via the Lagrangian picture: Current status of two-loop

results”, T. Okamura, Observational Astronomy, February 16, 2011, Tohoku University,

Sendai, Japan

3. “Impact of magnification effect on the constraining the primordial non-gaussianity through

the galaxy clustering”, T. Okamura, T. Namikawa, T. Futamase, Japan Astronomical Society

2010 Autumn Meeting (September 20-24, Kanazawa University, Ishikawa, Japan)

No.12

Name Norisuke Ioku

Department Mathematics

Position D3, JSPS Research fellow

Research Title The regularity theory of nonlinear elliptic and parabolic partial

differential equations


1. We considered a regularity estimate for a solution of the inhomogeneous initial boundary

value problem for heat equations in 2 dimensional bounded domain with integrable external

force. Introducing the oscillation type space which is related to BMO space, we showed the

boundedness of the oscillation of a solution with the sharp constant. We also obtained the

sharp integrablity estimate proved by Brezis-Merle as a corollary of the oscillation type

estimate.

2. We considered the Cauchy problem for heat equations with exponential nonlinearity and

obtained that there exists a time global solution in some Orlicz space under the smallness

assumption on the initial data.

II. Publications

1. “Brezis-Merle type inequality for a heat equation in two dimensions”, N. Ioku, Adv.

Differential Equations, to appear.

2. “The Cauchy problem for heat equations with exponential nonlinearity”, N. Ioku, Journal of

Differential Equations, to appear.

3. “Some space-time integrability estimates of the solution for heat equations in two

dimensions”, N. Ioku, revised.

4. “The global existence for semilinear heat equations with some exponential nonlinear term”,



N. Ioku, The Reports of the 32th Evolution Equations Seminar for Young mathematicians,

193--201, (2010)

III. Presentations

1. “Some space-time integrability estimates of the solution for heat equations in two

dimensions”, The 8th AIMS Conference, Dresden University of Technology, Dresden,

Germany, May.2010.

2. “Exponential integrability estimates to a solution of the heat equation in 2-dimension and its

application”, Spectrum seminar, Gakushuin Univ., Tokyo Jun. 2010.

3. “The existence of time global solutions for the semilinear equation with exponential

nonlinearity”, The 32th Evolution Equations Seminar for Young mathematicians, Aug. 2010.

4. “Some oscillation type estimate for the solution of the heat equation in two dimensions”, The

method of real analysis for some nonlinear problems, Tohoku Univ., Sendai, Aug. 2010.

5. “The existence of time global solutions for the semilinear equation with exponential

nonlinearity”, PDE seminar at Hamamatsu, Shizuoka Univ., Hamamatsu, Sep. 2010.

6. “Global soluvability of the semilinear heat equation with exponential nonlinearity”, Autumn

Meetings 2010, Mathematical Society of Japan, Tokyo institute of technology, Tokyo, Sep.

2010.

7. “The global solution for the semilinear heat equation related to the critical Sobolev

embeddings”, Kagurazaka seminar, Tokyo Univ. Science, Tokyo, Nov. 2010.

8. “Global soluvability of the semilinear heat equation in some Orlicz space”, PDE and

Mathematical Analysis for Young mathematicians, Kyushu University, Fukuoka, Feb. 2010,

IV. Prizes (Awards)

1. Aoba society for the promotion of Science Prize for the study on “Regularity theory of

exponential type for elliptic and parabolic partial differential equations in Orlicz spaces”,

Aoba society for the promotion of Science (Mar. 2011).

No.13

Name Toshiaki Omori


Research Title Study on bubbling phenomena for harmonic maps




1. I studied bubbling phenomena for a sequence of ε-exponentially harmonic maps from

Riemann surfaces with bounded energy. Then the singular set of such a sequence was found

to be finite. As a corollary, it was proven that an energy minimizing harmonic map from a

compact Riemann surface exists provided that the two dimensional homotopy class of the

target manifold vanishes.

2. I also investigated bubbling phenomena for such a sequence as in 1 in the case that the

dimension of the domain is grater than 2. It was proven that for any δ>0 there exists a closed

subset of the domain with locally finite Hausdorff (m-2+δ)-dimensional measure outside

which such a sequence subconverges to a harmonic map.

3. I also studied bubbling phenomena for a sequence of ε-exponentially Yang-Mills connections

in higher dimensional case. Then a result similar to 2 was obtained. That is to say, it was

proven that for any δ>0 there exists a closed subset of the domain with locally finite

Hausdorff (m-4+δ)-dimensional measure outside which such a sequence subconverges, under

a suitable gauge, to a Yang-Mills connection.

II. Publications

1. “On Eells-Sampson’s existence theorem for harmonic maps via exponentially harmonic

maps”, T. Omori, Nagoya Math. J. 201, 133—146 (2011).

2. “A new approach to the existence of harmonic maps”, T. Omori, Oberwolfach Report No. 21,

1313—1313 (2010).

3. “Existence theorem for harmonic maps via exponentially harmonic maps”, T. Omori, RIMS

kokyuroku 1720, 28—36 (2010)

4. “A new approach to the existence of harmonic maps”, to appear in RIMS kokyuroku.

III. Presentations

1. “A new approach to the existence of harmonic maps” (poster session), T. Omori, Progress in

Surface Theory (May 6, 2010, Mathematisches Forschungsinstitut Oberwolfach,

Oberwolfach, Germany).

2. “Existence theorem for harmonic maps via exponentially harmonic maps”, T. Omori,

Geometry seminar (May 11, 2010, Nagoya University, Nagoya, Japan).

3. “Existence theorem for harmonic maps via exponentially harmonic maps”, T. Omori, RIMS

Workshop: “The progress and view of Harmonic Map Theory” (June 2, 2010, Research

Institute for Mathematical Science, Kyoto, Japan).

4. “A new approach to the existence of harmonic maps”, T. Omori, RIMS Workshop:



“Geometric Aspect of Partial Differential Equations and Conservation Laws” (June 11, 2010,

Research Institute for Mathematical Science, Kyoto, Japan).

5. “Some existence theorems for harmonic maps via exponentially harmonic maps”, T. Omori,

OCAMI Differential Geometry Seminar (July 7, 2010, Osaka City University, Osaka, Japan).

6. “Compactification of moduli space of harmonic maps from surfaces”, T. Omori, OCAMI

Differential Geometry Seminar, Special Lecture (July 8, 2010, Osaka City University, Osaka,

Japan).

7. “On C^{2,ε}-regularity for a solution to the Monge-Ampere equation”, T. Omori,

Monge-Ampere Equations and Complex Geometry (August, 12, 2010, Tambara Institute of

Mathematical Sciences The University of Tokyo, Tambara, Japan).

8. “Bubbling phenomena for a sequence of exponentially harmonic maps – towards an

existence theorem for harmonic maps in higher dimensions – ”, T. Omori, 9th Kanazawa

series, “Differential Equations on Manifolds” (November 12, 2010, Ishikawa City College,

Kanazawa, Japan).

9. “Towards an existence theorem for harmonic maps in higher dimensions”, T. Omori,

Differential Topology Seminar (November 12, 2010, Kyoto University, Kyoto, Japan).

10. “On exponentially harmonic maps and Yang-Mills connections”, T. Omori, Geometry

Seminar (January 11, 2011, Tohoku University, Sendai, Japan).

11. “On exponentially Yang-Mills connections”, T. Omori, Awaji Island Geometry Workshop

2011 (February 12, 2011, Keino-matsubara-sou, Awaji Island, Japan).

12. “An approach to the existence of harmonic maps and Yang-Mills connections”, T. Omori,

The 3rd International GCOE symposium on “Weaving Science Web beyond Particle-Matter

Hierarchy”, (Feb. 17, 2011, Tohoku University, Sendai, Japan).

13. “Towards an existence of Yan-Mills connections in higher dimensions”, T. Omori, General

Relativity and Mathematics (March 4, 2011, Kinosaki Dai-Kaigi-Kan, Kinosaki, Japan).

No.14

Name Shin Kikuta



Research Title Measure hyperbolicity and positivity of canonical bundle




We try to clarify explicit relations between the measure hyperbolicities and the positivities of the

canonical bundle over a complex manifold. For this purpose, our method is simply to investigate the

curvatures of the pseudo-volume forms defining the measure hyperbolicities. Especially, we treat the

Caratheodory measure hyperbolic case much more so far.

The concept of the Caratheodory measure hyperbolicity appears naturally when the Schwarz

lemma is generalized to higher dimensional cases if it is regarded as a volume decreasing property.

And it is defined by certain positivity condition of some intrinsic measure called Caratheodory

measure.

By its definition, it seems very likely that the measure hyperbolicity leads to the positivity of the

canonical bundle. In fact, in the last fiscal year, we have as an explicit inequality that the volume of

the canonical bundle of a compact complex manifold is bounded from below by the total volume

with respect to the Caratheodory measure over its universal cover. It is proved by investigating the

curvature of the Caratheodory measure. Namely the inequality helps us to figure out more easily and

in more detail the fact that the Caratheodory measure hyperbolicity leads to a positivity called big of

the canonical bundle.

In this fiscal year, we consider a “restricted” version to a subvariety of the inequality. The word

“restricted” means that we take into account only extendable objects on the subvariety to the ambient

space. The restricted version of the volume of the canonical bundle is already known, and is called

the restricted volume. It has been well-investigated and is applied to the extension theorem and so on.

So we similarly define a restricted version of the Caratheodory pseudo-volume form (we call it the

restricted Caratheodory measure, but Eisenman essentially considered it before) and find out some

properties of this. And by the same way as above, we obtain an analogous inequality to the above

one over a compact complex manifold between these two “restricted” concepts. Here in fact we

suppose that the subvariety is not contained in an analytic subset called the augmented base locus of

the canonical bundle. It is the exactly generalized “restricted” version that we required. Moreover we

show by constructing a counterexample using blow-ups that the assumption on the subvariety cannot

be removed.

II. Publications

1. “Carathéodory measure hyperbolicity and positivity of canonical bundles”, S.Kikuta, Proc.

Amer. Math. Soc. 139, 1411-1420, (2011)

III. Presentations

1. “On the curvatures of the pseudo-volume forms defining measure hyperbolicities”, S. Kikuta,

Differential Geometry and Topology seminar (April 12, 2010, Keio University, Yokohama ,



Japan)

2. “C^{2,ε}-estimates for Monge-Ampere equation”, S. Kikuta, Monge-Ampere Equation and

Complex Geometry (August 12, 2010, Tambara Institute of Mathematical Sciences,

University of Tokyo, Gunma, Japan)

3. “On the curvature of Caratheodory pseudo-volume form”, S. Kikuta, 45th Summer Seminar

on Function Theory, (August 29, 2010, Hills Sunpia Yamagata, Yamagata, Japan)

4. “On the curvature of Caratheodory pseudo-volume form”, S. Kikuta, MSJ Autumn Meeting

2010, Complex Analysis section (September 23, 2010, Nagoya University, Nagoya, Japan)

5. “On the curvature of Caratheodory pseudo-volume form”, S. Kikuta, MSJ Autumn Meeting

2010, Geometry section (September 23, 2010, Nagoya University, Nagoya, Japan)

6. “Restricted Caratheodory pseudo-volume form”, S. Kikuta, Geometry seminar (November 2,


7. “Curvatures of Caratheodory pseudo-volume form and its applications”, S. Kikuta, 53th

Symposium on Function Theory (November 22, 2010, Neijyo University, Nagoya, Japan)

8. “Restricted Caratheodory pseudo-volume form and restricted volume of canonical bundle”, S.

Kikuta, Matsue Differential Geometry Workshop 2010 (December 10, 2010, Shimane

University, Matsue, Japan)

9. “Restricted Caratheodory measure and restricted volume of canonical bundle”, S. Kikuta,

The 3rd International GCOE symposium on “Weaving Science Web beyond Particle-Matter

Hierarchy’’ (February 18, 2011, Tohoku University, Sendai, Japan)

10. “On the restricted Caratheodory pseudo-volume form”, S. Kikuta, MSJ Spring Meeting 2011,

Complex Analysis section (March 23, 2011, Waseda University, Tokyo, Japan)

No.15

Name Takayuki Kihara



Research Title Study of effectively closed degree structures by using effective

randomness and computational learning


1. Recent exciting progress in Computable Analysis naturally raises the question about

computability of connected subsets of Euclidean space. Le Roux and Ziegler asked whether



every simply connected compact nonempty planar effectively closed set always contains a

computable point. We solved this problem negatively.

2. As mentioned in Penrose’s book “Emperor’s New Mind”, the Mandelbrot set is an example

of a simply connected compact planar effectively closed set, and Penrose conjectured that the

Mandelbrot set is not computable as a closed set. Our next question is which topological

property determines which computability property. We showed that not every contractible

and locally contractible planar effectively closed set is almost computable.

3. We found that a certain method to prove some theorems on tree-immunity gives rise to a kind

of “disjunction” under the limit-BHK interpretation of Limit Computable Mathematics

(abbreviated LCM), a kind of constructive mathematics based on Learning Theory. This

allows us to define various disjunctions as operations on the power set of Baire space. We

found that these disjunctive operators turn out to be useful for analyzing the Medvedev lattice

of effectively closed subsets of Cantor space. By using our disjunctions, we introduced some

operations on effectively closed subsets of Cantor space, as "analogies of the Turing jump

and the hyperjump". Then, we showed that every nonzero Tex Medvedev degree has the

anti-cupping property.

II. Publications

1. “Incomputability of simply connected planar continua”, submitted.

2. “Computability theory of continua”, to appear in Proof theoretical study of the structure of

logic and computation, RIMS Kokyuroku (proceedings).

3. “Medvedev and Muchnik degrees of 01Π classes with incomplete c.e. filters”, Programs,

Proofs, Processes, Local Proceedings of Sixth Conference on Computability in Europe, CiE

2010, Extended Abstracts, pp. 225--234, (2010). III. Presentations

1. “Medvedev and Muchnik degrees of 01Π classes with incomplete c.e. filters”,

Computability in Europe 2010 on “Programs, Proofs, Processes” (June 30-July 4, 2010,

University of Azores, Ponta Delgada (Azores), Portugal).

2. “Incomputability phenomena of 01Π continua in 2R ”, RIMS workshop on ”Formal

Systems and Computability Theory”, (Sep 13-17, 2010, Kyoto University, Kyoto, Japan).

3. “ 01Π closed sets and their generators”, Mathematical Society of Japan Autumn meeting

2010, (Sep 22-25, 2010, Nagoya University, Nagoya, Japan).

4. “When a dendroid is written on a paper by lightface”, Young logicians' gathering, (November

19-21, 2010, Aichi Prefectural Youth House, Aichi, Japan).



5. “Global and local noncomputability of simply connected zero sets”, The 3rd GCOE

International Symposium on “weaving science web beyond particle-matter hierarchy”,

(February 17-19, 2011, Tohoku University, Sendai, Japan).

6. “Degrees of difficulty of disjunctions”, Workshop on proof theory and computability theory

2011, (February 21-23, 2011, Iwanumaya, Sendai, Japan).

7. “Computability and incomputability of simply connected spaces”, Mathematical Society of

Japan Spring meeting 2011, (Mar 20-23, 2011, Waseda University, Tokyo, Japan).

.

No.16

Name Hirotake Kurihara



Research Title A construction of spherical designs using the method of discrete

geometric analysis


The theory of designs is originally started from a combinatorial study of some collections of

subsets of finite sets which are called block designs. In 1977, Delsarte, Goethals and Seidel gave the

definition of designs in spheres in Euclidean spaces. Here, a finite subset of a sphere is called a

spherical design if the averaging over the subset is equals to the averaging over the sphere for any

function on the sphere in a specific class. The concept of designs appears in our life, for instance in

meteorology, and the theory is also related to several mathematical areas. In this year, I got the

following results:

1. Most of ‘good’ configuration of finite points in spheres are obtained from embeddings of

symmetric association schemes. Thus, embeddings of association schemes are interesting. A

finite set in a Euclidean space is called an s-distance set if there are s kinds of distances of

two distinct elements in the set. In 1977, Larman-Rogers-Seidel proved that a certain ratio

related to distances of a two-distance set (Larman-Rogers-Seidel's ratio) must be an integer if

the cardinality of the two-distance set is large enough. A symmetric association scheme of

class d is naturally embedded as a spherical s-distance set with s<d in a sphere. In 2005, E.

Bannai and E. Bannai proved that when a symmetric association scheme of class two is

embedded as a two-distance set, Larman-Rogers-Seidel's ratio of this two-distance set

appears in the character table of this association scheme. In 2009, H. Nozaki extended



Larman-Rogers-Seidel's theorem to the case of any s-distance set and gave the ratios

corresponding to the case of two-distance sets. I and H. Nozaki firstly generalized

Bannai-Bannai's theorem with the generalized ratios of an s-distance set. Namely, if an

association scheme is Q-polynomial, then the ratios appear in the character table of the

association scheme. We also proved the converse, and gave a new characterization of

Q-polynomial association schemes.

2. First, I explain the excess theorem for connected regular graphs. Let G=(V,E) is a connected

regular graph with d+1 distinct eigenvalues. For x in V, let k_d (x) be the excess (number of

vertices at distance d) of x. Then the average of the excess is bounded above by a specific

number, which is determined by the `predistance polynomials' of G, and equality is attained if

and only if G is a distance-regular graph. By using this theorem, we can check the distance

regularity of a graph whose spectrum coincides with the spectrum of a distance-regular graph.

To obtain a dual theorem, I define s-distance sets which are the dual concept of connected

regular graphs, and give the excess theorem for s-distance sets. Namely we can check

whether an s-distance set has the Q-polynomial property or not.

II. Publications

1. “An equivalent condition of the $Q$-polynomial property on the spherical embedding of

symmetric association schemes”, H. Kurihara, H. Nozaki, submit to J. Comb. Theory Ser. A,

arXiv: [1007.0473]

2. “Character tables of association schemes based on attenuated spaces”, H. Kurihara, submit to

Annals of Combinatorics, arXiv: [1101.3455]

III. Presentations

1. “A new equivalent condition of the Q-polynomial property on the spherical embedding of

symmetric association schemes”, H. Kurihara, Combinatrics seminar (May. 8, Nishijin plaza,

Fukuoka, Japan)

2. “On distance sets and designs on compact symmetric spaces”, H. Kurihara, Geometry

seminar (Jul. 6, Tohoku University, Sendai, Japan)

3. “An equivalent condition of the Q-polynomial property on the spherical embedding of

symmetric association schemes”, H. Kurihara, International Conference on Algebraic and

Geometric Combinatorics 2010 (Jul. 13, Concorde Hotel, Kyongju, Korea)

4. “Designs on compact symmetric spaces”, H. Kurihara, The 57th Geometry symposium (Aug.

7, Kobe University, Kobe, Japan)

5. “On codes and designs on compact symmetric spaces”, H. Kurihara, The conference



‘Differential equalities on manifolds’ (Nov. 11, Ishikawa city college, Kanazawa, Japan)

6. “Character tables of association schemes based on attenuated spaces”, H.Kurihara, Workshop

on Algebraic Combinatorics in Hebei (Nov. 28, Hebei Normal University，Hebei, China)

7. “The excess theorem for s-distance sets”, H. Kurihara, Combinatorics seminar (Dec. 2,

Tohoku University, Sendai, Japan)

8. “On the character tables of association schemes based on attenuated spaces”, H. Kurihara,

Workshop on the cojoint applied mathematics – Discrete system & analysis system -

(Dec.16-18, 2010, Ryukoku University, Shiga, Japan)

9. “On the excess theorem for s-distance sets”, H. Kurihara, Japan-Korea Mini-Workshop on

Algebra and Combinatorics 2011 (Jan. 26, Tohoku University, Sendai, Japan)

10. (Poster) " On the excess theorem for polynomial spaces”, H. Kurihara, The 3rd International

GCOE symposium on “Weaving Science Web beyond Particle-Matter Hierarchy”, (Feb. 18,


11. “On the excess theorem for polynomial spaces”, H. Kurihara, Mathematic colloquium (Feb.

23, 2011, Kanazawa University, Kanazawa, Japan)

12. “The excess theorem for s-distance sets and spherical designs”, H. Kurihara,

Mini workshop ‘Algebraic combinatorics’ (Mar. 5, 2011, Hokkaido University, Sapporo,

Japan)

13. “On the character tables of association schemes based on attenuated spaces”, H. Kurihara,

Annual meeting of Mathematical Society of Japan (Mar. 20-23, 2011, Waseda University,

Tokyo, Japan)

No.17

Name Ryo Takada



Research Title Harmonic analytic approach to the partial differential equations

arising in fluid mechanics


1. We consider the commutator estimates of the Kato-Ponce type in the Besov spaces and the

Triebel-Lizorkin spaces related to the nonlinearity of the Euler equations, describing the

motion of perfect incompressible fluids. We investigate the relation between the optimal



bound of the commutator estimates and the solvability of the Euler equations. In particular,

we show that these commutator estimates break down in the Besov spaces and the

Triebel-Lizorkin spaces with the critical differential order and various integrability and

interpolation exponents.

2. We consider the Cauchy problem of the Euler equations in the whole space with

non-decaying initial velocity in the framework of the critical Besov space. It is proved that if

the initial velocity is real analytic then the solution is also real analytic in spatial variables.

Furthermore, a new estimate for the size of the radius of convergence of Taylor’s expansion

is established. The key of the proof is to derive the suitable estimates for the higher order

derivatives of the bilinear terms of the Euler equations. It is also shown the propagation

property of the almost periodicity in spatial variables.

II. Publications

1. “Counterexamples of commutator estimates in the Besov and the Triebel-Lizorkin spaces

related to the Euler equations”, Ryo Takada, SIAM J. Math. Anal. 42, 2473—2483, (2010)

2. “On the analyticity and the almost periodicity of the solution to the Euler equations with

non-decaying initial velocity”, Okihiro Sawada and Ryo Takada, J. Funct. Anal. 260,

2148—2162, (2011)

III. Presentations

1. “Counterexamples of commutator estimates in the Besov and the Triebel-Lizorkin spaces

related to the Euler equations”, Ryo Takada, International Research Training Group 1529

Seminar, (June 1, 2010, Darmstadt University of Technology, Darmstadt, Germany)

2. “On the commutator estimates in the Besov and the Triebel-Lizorkin spaces related to the

Euler equations”, Ryo Takada, Klausurtagung IRTG 1529 (June 28-30, 2010,

inrich-Fabri-Institut, Blaubeuren, Germany)

3. “On the commutator estimates in the Besov and the Triebel-Lizorkin spaces related to the

Euler equations”, Ryo Takada, Harmonic Analysis for Nonlinear Problem (August 27, 2010,


4. “On the analyticity of the solution to the Euler equations with non-decaying initial velocity”,

Ryo Takada, the Applied Mathematics Seminar (December 2, 2010, Tohoku University,

Sendai, Japan)

5. “Propagation of the analyticity for the solution to the Euler equations with non-decaying

initial velocity”, Ryo Takada, Mini-workshop Applications of nonlinear partial differential

equations (February 14-15, 2011, RIMS Kyoto University, Kyoto, Japan)



6. “Propagation of the analyticity for the solution to the Euler equations with non-decaying

initial velocity”, Ryo Takada, Nonlinear Wave and Dispersive Equations (February 14-16,

2011, Kyoto University, Kyoto, Japan)

7. “Propagation of real analyticity for the Euler equations”, Ryo Takada, The 3rd GCOE

International Symposium on “Weaving Science Web beyond Particle-Matter Hierarchy”

(February 17-19, 2011, Tohoku University, Sendai, Japan)

8. “Propagation of the real analyticity and the almost periodicity for the solution to the Euler

equations with spatially non-decaying initial velocity”, Ryo Takada, Mathematical Society of

Japan 2011 Spring Meeting (March 20-23, 2011, Waseda University, Tokyo, Japan)

No.18

Name Erika Ushikoshi



Research Title Hadamard variational formula for the Green matrix of the Stokes

equations


We consider the stationary Stokes equations governing the motion of incompressible viscous fluid.

Our purpose is to prove the Hadamard variational formula for the Green matrix associated with the

Stokes equations. Hadamard variational formula represents the variation of the Green function under

a certain perturbation of its domain. We construct its formula for the Stokes equations for any

dimension.

II. Publications

III. Presentations

1. “Hadamard variational formula for the Green matrix of the Stokes equations”, Erika

Ushikoshi, The 12th RIMS Workshop on “Mathematical Analysis in Fluid and Gas

Dynamics”, (Jul. 7-9, 2010, Rims, Kyoto University, Kyoto, Japan)


Ushikoshi, The 32th evolutional equation seminar for young researcher, (Aug. 28-31, 2010,

Shizuoka, Japan)




Ushikoshi, Autumn meeting of the Mathematical society of Japan, (Sep. 22-25, 2010,

Nagoya University, Japan)


Ushikoshi, Workshop on the fundamental equations in fluid mechanics for young researcher,

(Jun. 6-7, 2011, Nagoya University, Japan)


Ushikoshi, Mini-workshop on Application of nonlinier partial differential equations, (Feb.

14-15, 2011, Kyoto University, Japan)


Ushikoshi, Northeastern Symposium on Mathematical Analysis, (Feb. 21-22, 2011, Tohoku

University, Sendai, Japan)


Ushikoshi, The 3rd International GCOE symposium on “Weaving Science Web beyond

Particle-Matter Hierarchy”, (Feb. 18-19, 2011, Tohoku University, Sendai, Japan)

No.19

Name Yohei Fujishima



Research Title Blow-up problem for nonlinear diffusion equations and the profile

of the solution


We study the location of the blow-up set for a semilinear heat equation. In general, because of

the complexity between the diffusive term and the nonlinear term, it seems to be difficult to

characterize the location of the blow-up set from the given data such as the initial function, the shape

of the domain, the boundary data, and so on. So we focus on the diffusive coefficient, and break the

balance between the diffusive term and the nonlinear term by letting the diffusive coefficient be

sufficiently small or be sufficiently large. Then we proved the following results:

1. We consider the location of the blow-up set for a semilinear heat equation with small

diffusion. If the diffusive constant is sufficiently small, then we conjecture that the solution is

approximated by the solution of ordinary differential equation, and that the solution blows up



only near the set of the maximum points of the initial function. We show that this conjecture

is true under some assumptions on the blow-up rate estimates. Furthermore we show that the

effect of the short time behavior for the heat equation appears in the study of the location of

the blow-up set. In particular, we prove that, if the initial function has several maximum

points, then the location of the blow-up set is determined by the mean curvature of the graph

of the initial function at its maximum points.

2. We consider the location of the blow-up set for a semilinear parabolic equation with large

diffusion on the whole space whose spatial dimension is larger than or equals to 3. If the

initial function tends to some positive constant, then the solution blow-up in finite time. We

show that, if the diffusive constant is sufficiently large, then the location of the blow-up set is

determined by the large time behavior of the set of the maximum points of the solution of the

heat equation. More precisely, we prove that the solution blows up only near the center of the

mass of the initial function under suitable assumptions.

II. Publications

1. “Blow-up set for a semilinear heat equation with small diffusion”, Y. Fujishima and K.

Ishige, J. Differential Equations, 249, 1056-1077, (2010).

2. “Blow-up for a semilinear parabolic equation with large diffusion on {¥bf R}^N”, Y.

Fujishima and K. Ishige, J. Differential Equations 250, 1056-1077, (2011).

III. Presentations

1. “Blow-up set for a semilinear heat equation and pointedness of the initial data”, Y. Fujishima,

Differential equation seminar, (June 7, 2010, Nagoya University, Nagoya, Japan)


Mathematical analysis seminar (June 18, 2011, Hiroshima University, Higashi-hiroshima,

Japan)


4th Euro-Japanese workshop on blow-up, (September 6-10, 2010, Lorentz Center, Leiden,

Netherlands)


Analysis seminar, (September 17, 2010, University of Florence, Florence, Italy)


Analysis seminar, (October 22, 2010, Ehime University, Matsuyama, Japan)

6. “The problem of the spread of communication on the net space”, Y. Fujishima, Study group

workshop, (October 25-29, 2010, The University of Tokyo, Tokyo, Japan)




Morioka applied mathematical mini workshop, (November 6-7, 2010, Iwate University,

Morioka, Japan)


3rd Sendai workshop on elliptic and parabolic differential equations, (December 3-4, 2010,



3rd GCOE International symposium on ‘’Weaving Science Web beyond Particle-Matter

Hierarchy’’, (February 17-19, 2011, Tohoku University, Sendai, Japan)


12th Northeastern symposium on mathematical analysis, (February 21-22, 2011, Tohoku

University, Sendai, Japan)


2nd Japan-Taiwan joint workshop for graduate students in applied mathematics, (February

25-26, 2011, Meiji University, Kawasaki, Japan)

12. “Blow-up set for a semilinear heat equation and pointedness of the initial data”, Y. Fujishima

and K. Ishige, Mathematical society of Japan 2011 Spring meeting (March 20-23, 2011,

Waseda University, Tokyo, Japan)

No.20

Name Haruka Hikasa

Department Philosophy


Research Title Study on Decision-making Process from the Perspective of

〈Person〉in Clinical Ethics


1. This research explores the issue focusing on decision-making process for end-of-life care in

clinical ethics.

2. The principle of respect for autonomy of the individual is emphasized in Bioethics. Yet, in

the case of doubtfully autonomous or non-autonomous patients the principle of bioethics may

not be granted or even be absent.

3. In these cases, difficult problems may arise concerning patient’s best interests if the patient’s



advance decision-making conflicts with the patient’s contemporaneous interests.

4. I suggest a new method of surrogate decision-making in order to make decisions on behalf of

individuals incompetent to seek decisions on their own.

5. For balancing components of patient’s best interests, surrogate decision-makers take the

patient’s advance derectives（precedent autonomy, perspectives）and present benefits (values,

preferences, experiential interests) into consideration in order to make decisions on behalf of

formerly competent patients.

6. In evaluating the result of medical interventions for incompetent patients, surrogate

decision-makers must attempt to ascertain the patient’s present point of view,

biographical-life, and biological-life.

7. Furthermore, to determine patient’s best interests, we should consider the underlying ethical

concepts --for example the difference between “natural dying process” and “artificial dying

process”--

II. Publications

1. “How should we think about decision making for end-of-life care”, H. Hikasa, Tohoku

University Rinsyo-siseigaku-kenkyukai, (2010)

III. Presentations

1. “Advance Decision-making for End-of-life -- How should we think about living will? ”, H.

Hikasa, Meeting on talking about end-of-life care, (Jun. 13, 2010, Sensai-fukkou-kinenkan,

Sendai, Japan)

2. “Over the Validity of Advance Directives and Patient’s Best Interests”, H. Hikasa, Clinical

death-life-studies and ethics (Jun. 24, 2010, Tokyo University, Tokyo, Japan)

3. “How should we think about living will ? -- Over the advance decision-making and best

interests”, H. Hikasa, Seminar on care and end-of-life, (Feb. 19, 2011, Tohoku-tabunka-

academy, Sendai, Japan)

4.4. young scientist initiative c€¦ · “theory of orbital frustration and its quantum...

Documents