4.4. Young Scientist Initiative C

4. Research Report in 2009 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 16 doctoral

course students in the department of Physics, Astronomy, Mathematics and Philosophy in 2009.

They 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.

1. Koji Isiwata(Physics, D3)

Study of Cold Dark Matter in Supersymmetric model

2. Daisuke Kawama (Physics, D3)

Establishment of lambda hypernuclear spectroscopic experiment via electromagnetic

interaction

3. Kosuke Nakayama (Physics, D3)

Construction of low-energy ultrahigh-resolution photoemission spectrometer and study of

the fine electronic structure in high-Tc superconductors

4. Koutaro Shiratori (Physics, D3)

Research of ΛN interaction via hypernuclear γ-ray spectroscopy experiment at J-PARC

5. Takafumi Hatano (Physics, D3)

Photo voltage induced by circulary polarized light

6. Tosiyuki Arakane (Physics, D2)

Low-energy Angle-resolved photoemission study of the superconductivity in hydrated

NaxCoO2

7. Kenji Hosomi (Physics, D2)

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

spectroscopy experiments at J-PARC

8. Yasuyuki Horii (Physics, D2)

Measurement of the CP-violating angle phi3 at Belle

9. Yuji Matsumoto (Physics, D2)

Study of electron state in highly correlated f electron system via de Haas – fan Alphen effect

10. Yohei Kawakami (Physics, D1)

Ultrafast photo-induced phase transitions in highly correlated organic conductors and metal

complexes

11. Yuji Chinone (Astronomy, D2)

A Test of Inflation models with “QUIET” experiment



12. Masashi Mizuno (Mathematics, D3)

Analysis of the regularity for moving interfaces with the theory of partial differential

equations

13. Tadakatsu Sawada (Mathematics, D2)

Study of algebraic varieties via vector bundles

14. Asuka Takatsu (Mathematics, D2)

Deformation of Riemannian metrics via optimal transportation - reinterpretation of Ricci

flow on surfaces -

15. Hirotake Kurihara (Mathematics, D1)

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

16. Ryo Takada (Mathematics, D1)

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



No.1

Name Koji Ishiwata

Department Physics

Position D3, JSPS Research Fellow

Research Title Study of Cold Dark Matter in Supersymmetric model

I. Summary of Research in 2009 fiscal year

1. In recent years, the observations of cosmic rays have been very active and published new

data with higher accuracy ever before. Among them, cosmic-ray positron observed by

PAMELA satellite reported high-energy anomalous flux, which could not be explained by

standard astrophysical phenomena. Since then, the observed positron flux is called

“PAMELA anomaly”. Motivated by the PAMELA anomaly, I searched for the origin of

the anomalous flux in particle physical point of view. In this attempt, my collaborators

and I focused on dark matter, which account for 23 % of the total energy density of the

universe. If we suppose that parts of the existing dark matter decay, the products from the

decay can be a source of cosmic ray. In supersymmetric model, which is one of the

promising models beyond the standard model of particle physics, lightest superparticle is a

viable candidate for dark matter. Furthermore, one can consider decaying dark matter

scenario under small violation of R-parity. In 2008 fiscal year, we performed the

simulation of various cosmic rays from decaying dark matter. Then, we found that

PAMELA anomaly can be well explained when mass of dark matter is larger than nearly

200 GeV and its lifetime is of the order of 1026 sec. Also we found that the simulated

positron flux is consistent with data observed by Fermi LAT. Furthermore, we simulated

cosmic antiproton and gamma ray fluxes. Then, it was shown that those cosmic rays are

consistent with the present observation.

II. Publications

1. “Cosmic Gamma-ray from Inverse Compton Process in Unstable Dark Matter Scenario”,

Koji Ishiwata, Shigeki Matsumoto, Takeo Moroi, Phys.Lett.B, 679, 1-5 (2009)

III. Presentations

1. "Cosmic Gamma-ray from Inverse Compton Process in Unstable Dark Matter Scenario”,

Koji Ishiwata, The VII workshop on Science with the New Generation of High Energy

Gamma-ray Experiments (SciNeGHE 2009), (October 7-9, 2009, Assisi, Italy)

2. "Cosmic Gamma-ray from Inverse Compton Process in Unstable Dark Matter Scenario ",



Koji Ishiwata, Japan Physical Society 2009 Autumn Meeting (September 10-13, Konan

University, Kobe, Japan)



N0. 2

Name Daisuke Kawama

Department Physics


Research Title Establishment of lambda hypernuclear spectroscopic

experiment via electromagnetic interaction


1. We carried out JLab E05-115 experiment from August to November 2009 and took

high-quality data for hypernuclear spectroscopy.

2. Data analysis is now in progress. Especially calibration of energy scale which is our the

greatest challenge is being carried out using 3D magnetic field calculation of finite element

method.

3. I make a presentation of our analysis status in JPS 2010 Spring Meeting in March.

II. Publications

1. “The third generation (e,e’K+) Λ hypernuclear spectroscopy at JLab.”,

D. Kawama et al. Nuclear Phyoscs Review, 26, 88, (2009)

2. “Experimental design and simulation for the third generation (e,e’K+) hypernuclear

spectroscopy at JLab”,

D. Kawama et al. Proceedings of the Sendai international symposium, 1, 394, (2009)

III. Presentations

1. "The third generation Λ hypernuclear spectroscopy via the (e,e’K+) reaction at Jefferson

Lab”,

D. Kawama, 2009 APS April Meeting, (May 2-5, 2009, Denver, US)

2. "The third generation Lambda hypernuclear spectroscopic experiment via the (e,e’K+)

reaction at JLab-HallC",

D. Kawama, Japan Physical Society 2010 Spring Meeting (March 20-23, Okayama

University, Okayama, Japan)



No.3

Name Kosuke Nakayama

Department Physics

Position D3, JSPS Research Fellow (DC1)

Research Title Construction of low-energy ultrahigh-resolution photoemission

spectrometer and study of the fine electronic structure in

high-Tc superconductors


1. By developing a method to replace Al filters, which play an important role for achieving

ultrahigh vacuum of angle-resolved photoemission spectroscopy systems, we have

successfully used a glove box filled with Ar gas to prevent oxidation of Al and thus

enhance the transparency of Al filters up to ~20%, which is high enough to perform

measurements with high statistics and high-energy resolution. We have also applied this

method to the preparation of samples that are reactive in air.

2. By using the developed system, we have determined the comprehensive momentum and

temperature dependencies of the superconducting gap and the pseudogap on high-Tc

cuprate superconductor Bi2Sr2CuO6 to elucidate the origin of the pseudogap. We have

found that the pseudogap smoothly evolves from the superconducting gap across Tc. We

also revealed that the characteristic temperature of the pseudogap scales with the

superconducting gap size irrespective of the momentum location. These experimental

results point to the pairing origin of the observed pseudogap.

3. We have directly observed Fermi surfaces, band dispersions, and the superconducting gap

of iron-chalcogenide superconductor Fe(Te,Se) for the first time. We observed a hole- and

an electron-like Fermi surfaces at the Brillouin zone center and corner, respectively, which

are nearly nested by the Q~(p, p) wave vector. While the experimentally determined Fermi

surface topology is distinctly different from that of the parent antiferromagnetic phase, we

found that it is qualitatively similar to that of iron-arsenide superconductors. We also

observed an isotropic superconducting gap along the hole-like Fermi surface with the gap

size D of 4 meV (2D/kBTc~7), demonstrating the strong coupling nature of the

superconductivity. These results suggest that the coupling to Q~(p, p) antiferromagnetic

fluctuations plays important role for the emergence of superconductivity.

II. Publications

1. “Evolution of a Pairing-Induced Pseudogap from the Superconducting Gap of



(Bi,Pb)2Sr2CuO6”,

K. Nakayama et al., Phys. Rev. Lett., 102, 227006, (2009).

2. “Doping dependence of the gap anisotropy of the high-temperature YBa2Cu3O7-d

superconductor”,

K. Nakayama et al., Phys. Rev. B, 79, 140503(R), (2009).

3. “Xenon-plasma-light ultrahigh-resolution ARPES study of low-energy single-particle excitation

gap in (Bi,Pb)2Sr2CuO6”,

K. Nakayama et al., Physica C, in press.

4. “Band Structure and Fermi Surface of an Extremely Overdoped Iron-Based Superconductor

KFe2As2”,

T. Sato, K. Nakayama et al., Phys. Rev. Lett., 103, 047002, (2009).

5. “Observation of Dirac Cone Electronic Dispersion in BaFe2As2”,

P. Richard, K. Nakayama et al., Phys. Rev. Lett., in press.

6. “Fermi surface nesting induced strong pairing in iron-based superconductors”,

K. Terashima, Y. Sekiba, J. H. Bowen, K. Nakayama et al., Proc. Natl. Acad. Sci. USA, 106, 7330,

(2009).

7. “Pseudogap of charge-density-wave compound SmNiC2 studied by high-resolution

photoemission spectroscopy”,

T. Sato, S. Souma, K. Nakayama et al., J. Phys. Soc. Jpn., in press.

8. “Angle-resolved photoemission study of heavily electron-doped BaFe2-xCoxAs2”,

Y. Sekiba, T. Sato, K. Nakayama et al., Physica C, in press.

9. “High-resolution ARPES study of electron-doped Fe-based superconductor BaFe1.85Co0.15As2”

T. Kawahara, K. Terashima, Y. Sekiba, J. H. Bowen, K. Nakayama et al., , Physica C, in press.

III. Presentations

1. "Fermi surface and band structure of FeTe1-xSex studied by high-resolution ARPES”,

K. Nakayama, Japan Physical Society 2009 Autumn Meeting (September 25-28, 2009,

Kumamoto University, Kumamoto, Japan)

2. "Observation of a Dirac cone dispersion in BaFe2As2",

K. Nakayama, Japan Physical Society 2009 Autumn Meeting (September 25-28, 2009,

Kumamoto University, Kumamoto, Japan)

3. "Low-energy angle-resolved photoemission spectroscopy of Fe-based high-Tc

superconductor Ba1-xKxFe2As2",

K. Nakayama, UVSOR Workshop on Low Energy Photoemission Spectroscopy 2009,

(October 3-4, 2009, Okazaki Conference center, Okazaki, Japan)



4. "Pairing Origin of a Small Pseudogap in Bi2Sr2CuO6 Studied by Ultrahigh-Resolution

Angle-Resolved Photoemission Spectroscopy",

K. Nakayama, 9th International Conference on Materials and Mechanisms of

Superconductivity and High Temperature Superconductors, (September 7-12, 2009, Keio Plaza

Hotel Tokyo, Tokyo, Japan)

5. "Universal Electronic Structure for Superconductivity in Iron Arsenides and

Chalcogenides",

K. Nakayama, 9th International Conference on Materials and Mechanisms of

Superconductivity and High Temperature Superconductors, (September 7-12, 2009, Keio Plaza

Hotel Tokyo, Tokyo, Japan)

6. "Fermi surface and superconducting gap of FeTe1-xSex superconductor studied by

high-resolution ARPES",

K. Nakayama, American Physical Society March Meeting 2010, (March 15-19, 2010,

Oregon Convention Center, Portland, USA)

7. "High-resolution ARPES study of (Sr2VO3)FeAs",

K. Nakayama, Japan Physical Society 2010 Spring Meeting (March 20-23, 2010, Okayama




No.4

Name Kotraro Shirotori

Department Physics

Position DC3, JSPS Research Fellow

Research Title Research of ΛN interaction via hypernuclear γ-ray

spectroscopy experiment at J-PARC


1. Research purpose

For the first hypernuclear γ-ray spectroscopy experiment at the J-PARC K1.8 beam line

(J-PARC E13), several light hypernuclei are planned to be studied. Hypernuclei of interest

have been chosen from the past experimental results.

The level structure and the mass spectrum of 4ΛHe compared with that of 4ΛHe

measured in out dated experiments give the information on charge symmetry breaking of

the ΛN interaction. From γ-ray yield, the cross sections of the spin-flip 4ΛHe (1+) and

non-spin-flip 4ΛHe (0+) states for several K- beam momenta will also be measured to study

the spin-flip/non-spin-flip property of hypernuclear production in the (K-, π-) reaction. This

experiment is very important to understand the charge symmetry breaking of the ΛN

interaction.

2. Research activities

Exited states of Λ hypernuclei are produced via the (K－, π－) reaction at the incident

Kaon beam momentum of 1.5 GeV/c. Kaon beams and scattered pions are identified and

momentum-analyzed by using the K1.8 beam line spectrometer and the modified SKS

(Superconducting Kaon Spectrometer), SksMinus, respectively. γ-rays from the

hypernuclei are measured by the Ge detector array, Hyperball-J, placed around the target.

Through the coincidence measurement between these spectrometer systems and

Hyperball-J, γ rays from produced hypernuclei are identified.

SksMinus consists of several detectors which are drift chambers for the momentum

analysis, and timing counters, Cherenkov counters for the particle identification and several

background veto counters. The parts of Detectors which compose SksMinus were used for

the commissioning experiment using the SKS magnet. In this year, we have constructed the

SKS spectrometer and beam line spectrometer system at J-PARC K1.8 beam line. The

commissioning has been successfully finished by using J-PARC first beam (October 2009-

February 2010).



For the performance of Drift chambers, 99.9% of particle detection efficiency and

position resolution of 200µm (rms) are achieved. The time resolution of timing counters

is less than 200ps (rms). The particle detection efficiency of Cherenkov counter is 99.9%.

We confirmed the expected performance of detectors of SksMinus

For the analysis of experimental data, we made the new code based on the previously

using programs for the KEK experiments. The program works well and we confirmed the

performance of it.

The commissioning data for the calibration of the SKS system was successfully taken by

the p(π－, K+)Σ－と p(π-, p) π－ reaction. The momentum resolution of the SKS system is

achieved to be 3 MeV/c, which is enough for the hypernuclear γ-ray spectroscopy

experiment.

We successfully finished the commissioning of the SKS spectrometer system. It is very

important result for many hypernuclear and hadronic experiments which will be performed

at the J-PARC K1.8 beam line.

II. Publications

1. " The gamma-ray spectroscopy of light hypernuclei at J-PARC (E13)",

K. Shirotori, T. Tamura, M. Ukai, T. Koike, K. Miwa for the Hyperball-J corroboration,

Proceeding of the Sendai international symposium: Strangeness in Nuclear and Hadronic

systems (SENDAI08), page 408-409, (2009)

III. Presentations

1. "Hypernuclear gamma-ray spectroscopy detector system at J-PARC :

Hyperball-J", K. Shirotori, T. Tamura, M. Ukai, T. Koike, K. Miwa, for the Hyperball-J

corroboration, Hypernuclear and Strange Particle (HYP2009), (September 14-18, 2009,

Tokai, Japan)

2. "Commissioning of the J-PARC K1.8 beam line and the SKS spectrometer 3 -SKS-",

K. Shirotori, T. Tamura, T. Takahashi, K. Miwa for the K1.8 experimental group, Japan

Physical Society 2010 Spring Meeting (March 20-23, Okayama University, Okayama,

Japan)



No.5

Name Takafumi Hatano

Department Physics


Research Title Photo voltage induced by circulary polarized light


Artificial periodic structure whose scale is comparable to incident wavelength is called

photonic crystals. We discovered that when circulary polarized light is obliquely incident on 2D

metallic photonic crystal slabs, electrical voltage was induced perpendicular direction against

incident plane. We called it Transverse Photo-Induced Voltage (TPIV). It is quite unique

phenomenon for two reasons as follows. First, the sign of TPIV signal is reversed by changing

the sense of incident circular polarization. Secondary, the direction of signal is perpendicular to

the direction of transfer of translational momentum of light. We discussed the origin of TPIV by

using of rectification terms of electromagnetic force for free electrons in artificial structure.

From symmetric discussion against incident plane, we concluded that the mathematical

expression of TPIV is

( ) .]Im[~ * dVV spy

cir

TPIV ∫ ±∇− EE

Here, Ep and Es are electric field distributions in artificial structure for p- and s- polarization

light incidence. This expression indicate that the correlation of s-mode and p-mode generate

TPIV signal.

II. Publications

1. "Transverse Photo Voltage Induced by Circulary Polarized Light"

Takafumi Hatano, Teruya Ishihara, Sergei. G. Tikhodeev, Nikolay. A. Gippius, Physical

Review Letters, 103, 103906 (2009).

III. Presentations

1. "Photo-induced voltage due to circulary polarized light"

Takafumi Hatano, Yosuke Kurami, Keisuke Otani, Naoshi Nishimura and Teruya

Ishihara,

Photonic and Electromagnetic Crystal Structure VIII (PECS VIII), Poster B-137, AU SYD

(2009).



No.6

Name Tohiyuki Arakane

Department Physics


Research Title Low-energy Angle-resolved photoemission study of the

superconductivity in hydrated NaxCoO2


1. We have performed high-resolution angle-resolved photoemission spectroscopy of

Na0.5CoO2 to elucidate the origin of two-step phase transition at Tc1= 88 K and Tc2= 53 K.

At well below Tc2, we find anisotropic energy-gap opening at everywhere in Brillouin zone.

This gap does not disappear at the metal-insulator transition temperature Tc2 but survives up

to Tc1. The remnant Fermi surface below Tc2 shows apparent deviation from the

normal-state Fermi surface above Tc1, suggesting a possible influence from the magnetic

ordering.

2. We have performed angle-resolved photoemission spectroscopy of NaxCoO2 (x = 0.65 and

0.77) to clarify the origin of antiferromagnetic (AF) transition. We determined electronic

structure along the out-of-plane direction by varying photon energy, and revealed that new

three-dimensional electron pocket appears at the G point in the AF sample (x = 0.77)

whereas it is absent in the non-AF counterpart (x = 0.65), providing first direct evidence for

the transition of Fermi surface topology as a function of band filling. Present result

strongly suggests that the emergence of the electron pocket is intimately related to the

various anomalies in the magnetic, transport, and thermodynamic properties of the Na-rich

cobaltates.

II. Publications

1. “Evidence for Transition of Fermi-Surface Topology in Highly Doped NaxCoO2”,

T. Arakane, T. Sato, T. Takahashi, T. Fujii and A. Asamitsu, Physical Review B (in

press).

2. “Reconstruction of the Fermi surface and the anisotropic excitation gap of Na0.5CoO2”,

T. Arakane, T. Sato, T. Sato, T. Fujii and A. Asamitsu, Physical Review B 80, 081101(R)

(2009).

3. “High-Resolution Photoemission Study of NaV2O4”,

T. Qian, K. Nakayama, Y. J. Sun, T. Arakane, T. Sato, T. Takahashi, K. Yamaura and E.

Takayama-Muromachi, J. Phys. Soc. Jpn. 78 (2009) 024709.



4. “Magnetic Phase Transition of CeSb Studied by Low-Energy Angle-Resolved

Photoemission Spectroscopy”,

A. Takayama, S. Souma, T. Sato, T. Arakane and T. Takahashi, J. Phys. Soc. Jpn.,78

(2009) 073702

III. Presentations

1. “Transition of Fermi surface topology in highly-doped NaxCoO2 studied by angle-resolved

photoemission spectroscopy.”

T. Arakane, T. Sato, T. Takahashi, T. Fujii, A. Asamitsu, American Physical Society 2010

MARCH Meeting”, (March 15-19, 2010, Oregon conventional center, Portland, U.S.A.)

2. “Three dimensional Fermi surface in highly-doped NaxCoO2 studied by Anrle-resolved

photoemission spectroscopy",

T. Arakane, T. Sato, T. Takahashi, T. Fujii, A. Asamitsu, Japan Physical Society 2010 Fall

Meeting (September 23-27, Kumamoto University, Kumamoto, Japan)

3. “Doping dependence of 3-D Fermi surface in highly-doped NaxCoO2 studied by

Anrle-resolved photoemission spectroscopy",

T. Arakane, T. Sato, T. Takahashi, T. Fujii, A. Asamitsu, Japan Physical Society 2010 Fall

Meeting (March 20-23, Okayama University, Okyama, Japan)

4. “High-resolution angle-resolved photoemission study of MxCoO2(M = Na, K, Rb)",

T. Arakane, T. Sato, T. Takahashi, T. Fujii, A. Asamitsu, SRC users meeting 2009

(October 23-24, SRC at Wisconscin University, Wisconscin, USA)



No.7

Name Kenji Hosomi

Department Physics


Research Titl Study of modification of baryons in nuclear medium through

hypernuclear gamma-ray spectroscopy experiments at J-PARC


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

new Ge detector array (Hyperball-J) is under construction. Hyperball-J consists of 32 Ge

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

surrounding the each Ge detector. Energy resolution of the detector is FWHM 3.1 keV for 1.33

MeV gamma rays. A cooling system of PWO crystal was developed and produced. PWO

crystals wrapped in Teflon and ESR film showed the best results in photon collection. Quality of

the 246 PWO crystals was found sufficient from an estimate obtained with 6 samples of each

crystal size. Difference in photon collection of each crystal size was measured and the result

was consistent with GEANT4 simulation.

A support frame of Hyperball-J has been constructed in parallel. The frame has 6 stages that

can move vertically up and down by 2 AC-motors for each stage. A control program that

synchronizes the 2 AC-motors was developed. We succeeded in driving all stages using this

control program.

II. Publications

III. Presentations

1. “Hypernuclear gamma-ray spectroscopy system: Hyperball-J (2)”, K. Hosomi, Japan

Physical Society 2010 Spring Meeting (March 20-23, Okayama University, Okayama,

Japan)



No.8

Name Yasuyuki Horii

Department Physics


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


1. The new particle-reconstruction algorithm is confirmed to provide ~30% increase of the

detection efficiency for the decay B－ � D* K－, which is one of most important modes for

measuring the CP-violating angle phi3. A study on the background from e+e－ � qq (q = u,

d, s, c) is performed for the effective background rejection.

2. The data acquisition system is prepared and the first laser-image is obtained for the

prototype of the SOI pixel detector for the upgrade of the Belle detector.

II. Publications

1. “Measurement of phi3 (gamma) at Belle”,

Y. Horii, Fundamental Interactions (Proceedings of the 23rd Lake Louise Winter Institute

2008), 249, (2009)

III. Presentations

1. "Development of the SOI pixel detector for Belle II”,

Y. Horii and the SOIPIX group, Japan Physical Society 2009 Autumn Meeting (September

10-13, Konan University, Kobe, Japan)



No.9

Name Yuji Matsumoto

Department Physics


Research Title Study of electron state in highly correlated f electron system via

de Haas – fan Alphen effect


We have performed the de Haas - Alphen effect measurements to study the delocalization of

the f electron at quantum phase transitions in CeRu2(Si1-xGex)2. We have found a Fermi

surface reconstruction at the first order transition between the ferromagnetic state and the

antiferromagnetic state, which can be attributed to the f electron delocalization. Mass

enhancement is observed both at the first order transition and at the quantum critical point.

II. Publications

1. “ DHvA effect study on the metamagnetic transitions in CexLa1−xRu2Si2”,

Y. Matsumoto, N. Kimura, T. Komatsubara, H. Aoki, M. Kimata, T. Terashima, S. Uji,

Journal of Physics: Conference Series, 150, 042006, (2009)

2. “4f-Derived Fermi Surfaces of CeRu2(Si1-xGex)2 near the Quantum Critical Point: Resonant

Soft-X-Ray ARPES Study”,

T. Okane, T. Ohkochi, Y. Takeda, S.-i. Fujimori, A. Yasui, Y. Saitoh, H. Yamagami, A.

Fujimori, Y. Matsumoto, M. Sugi, N. Kimura, T. Komatsubara H. Aoki Physical Review

Letters, 102, 216401, (2009)

3. “Anomalous behavior of the dHvA oscillations in CexLa1−xRu2Si2 “,


Journal of Physics: Conference Series, 200, 021115, (2010)

III. Presentations

1. " DHvA effect study of spin dependence of effective mass in CexLa1-xRu2Si2”,

Y. Matsumoto, M. Sugi, N. Kimura, T. Komatsubara, H. Aoki, M. Kimata, T. Terashima, S.

Uji, Japan Physical Society 2010 Autumn Meeting (September 25-28, Kumamoto

University, Kumamoto, Japan)

2. " f electron nature of CeRu2(Si1-xGex)2 - dHvA effect study under chemical pressure”,


Japan Physical Society 2010 Autumn Meeting (September 25-28, Kumamoto University,



Kumamoto, Japan)

3. " f electron nature of CeRu2(Si1-xGex)2 - dHvA effect study under chemical pressure II",

Y. Matsumoto, M. Sugi, N. Kimura, T. Komatsubara, H. Aoki, M. Kimata, T. Terashima, S.

Uji, Japan Physical Society 2010 Spring Meeting (March 20-23, Okayama University,

Okayama, Japan)

4. “ Anomalous behavior of the dHvA oscillations in CexLa1-xRu2Si2”


International conference on magnetism 2009 (July 25-31, Karlsruhe, Germany)

5. “Transition of f electron nature from localized to itinerant in CeRu2(Si1-xGex)2 －dHvA

effect study utilizing chemical pressure”,

Y. Matsumoto, N. Kimura, T. Komatsubara, H. Aoki, M. Kimata, T. Terashima, S. Uj

Emergence of Heavy Electrons and Their Ordering 2nd workshop (Aug.18-20, Hiroshima,

Japan)



No.10

Name Yohei Kawakami

Department Physics


Research Title Ultrafast photo-induced phase transitions in highly correlated

organic conductors and metal complexes


1. Optical modulation of the effective on-site Coulomb energy U on a dimer (Udimer) was

realized for achieving the Mott insulator-to-metal transition in

κ-(BEDT-TTF)2Cu[N(CN)2]Br, as investigated by IR pump-probe spectroscopy[1]. A

reduction of Udimer is optically induced by molecule displacement in the dimer under

intradimer excitation. The mechanism of this metallization differs greatly from the

photodoping-type mechanism reported previously[2, 3]. In contrast, a faster transition via

the photodoping mechanism is detected for interdimer excitation.

2. Few-optical-cycle near-IR pulse with a pulse

width of 12 fs was generated to measure early

dynamics of the photoinduced phase

transition. i) Broad (1.3 - 1.8 µm) spectrum,

as shown in Fig. 1(a), was obtained by using

degenerate optical parametric amplifier

(OPA). We have succeeded to construct a

two-stage type -I BBO OPA which provides

∼10 µJ intensive pulses. ii) Furthermore, the

IR broadband pulse was compressed into 12

fs FWHM by using deformable mirror (DM)

compressor [4].

Generated ultrashort pulses were characterized by frequency resolved optical gating

(FROG). Figs. 1(b) and 1(c) show the FROG trace indicating time-wavelength relation and

retrieved time profile of the 12 fs pulse, respectively. This few-optical cycle 12 fs pulse in

IR region is expected to be powerful tool for clarifying the initial process of photo-induced

phase transition in highly correlated organic conductors.

FIG. 1. (a) Spectrum of the 12 fs pulse. (b)

FROG trace. (c) Retrieved time profile of

the 12 fs pulse.

(b)

Wavelength (nm)

800

700

0-100 100 200Time (fs)

-40 0 400

0.5

1

Time (fs)

Intensity (arb. unit)

1200 1600 20000

0.5

1

Wavelength (nm)Intensity (arb. unit)

(a) (c)

(b)

Wavelength (nm)

800

700

0-100 100 200Time (fs)

(b)

Wavelength (nm)

800

700

0-100 100 200Time (fs)

-40 0 400

0.5

1

Time (fs)

Intensity (arb. unit)

1200 1600 20000

0.5

1

Wavelength (nm)Intensity (arb. unit)

(a) (c)



3. Ultrafast time resolved

spectroscopy using 12 fs near-IR

pulses was performed to clarify the

initial process of photo-induced

insulator-to-metal transition in

typical layered organic conductor

α-(BEDT-TTF)2I3 [3]. Figs. 2(a)

and 2(b) show the time evolutions

of photoinduced reflectivity change

(∆R/R) and their oscillating

components, respectively.

Considering the strong electron

intramolecular vibration (EMV)

coupling, these results indicate that the growth of metallic domain is driven by the interplay

between the electronic oscillation and the coherent intramolecular/ intermolecular

oscillations. That is the first observation of “dynamical EMVC” during the photoinduced

insulator-to-metal transition.

[1] Kawakami et al. Phys. Rev. Lett. 103, 066403 (2009).

[2] Iwai et al. Phys. Rev. Lett. 91, 057401 (2003).

[3] Iwai et al. Phys. Rev. Lett. 98, 097402 (2007).

[4] Brida et al. Opt. Lett. 33, 741 (2008).

II. Publications

1. “Optical Modulation of Effective On-Site Coulomb Energy for the Mott Transition in an

Organic Dimer Insulator”,

Y. Kawakami, S. Iwai, T. Fukatsu, M. Miura, N. Yoneyama, T. Sasaki and N. Kobayashi,

Physical Review Letters, 103, 066403 (2009).

2. “Photo-induced macroscopic oscillation between insulator and metal in layered organic

Mott insulator”,

Y. Kawakami, S. Iwai, N. Yoneyama, T. Sasaki, N. Kobayashi, Ultrafast Phenomena XVI,

176, (2009).(Proceeding)

III. Presentations

1. "Optical control of effective on-site Coulomb repulsion in organic dimer Mott insulator”,

FIG.2. (a) Time evolution of photoinduced

reflectivity change (∆R/R). (b) Oscillating

components. (c) Images of the electronic/

intramolecular/ intermolecular oscillations.

0 2 4 6 8

0

1

2

3

4

5

Time Delay (ps)

∆R/R

(x 102)

0 100 200 300-4

-2

0

2

4

∆R/R

(x 104)

Time Delay (fs)

t ~ 1800 cm-1 ν3 ~ 1500 cm-1

ν7 ~ 790 cm-1 250 cm-1

t ~ 1800 cm-1 ν3 ~ 1500 cm-1

ν7 ~ 790 cm-1 250 cm-1

(a)

(b)

(c)20K, E//b

Iex = 0.03mJ/cm2

t ~ 1800 cm-1 ν3~ 1500 cm-1

ν7 ~ 1800 cm-1 250 cm-1

0 2 4 6 8

0

1

2

3

4

5

Time Delay (ps)

∆R/R

(x 102)

0 100 200 300-4

-2

0

2

4

∆R/R

(x 104)

Time Delay (fs)

t ~ 1800 cm-1 ν3 ~ 1500 cm-1

ν7 ~ 790 cm-1 250 cm-1

t ~ 1800 cm-1 ν3 ~ 1500 cm-1

ν7 ~ 790 cm-1 250 cm-1

(a)

(b)

(c)20K, E//b

Iex = 0.03mJ/cm2

0 2 4 6 8

0

1

2

3

4

5

Time Delay (ps)

∆R/R

(x 102)

0 100 200 300-4

-2

0

2

4

∆R/R

(x 104)

Time Delay (fs)

t ~ 1800 cm-1 ν3 ~ 1500 cm-1

ν7 ~ 790 cm-1 250 cm-1

t ~ 1800 cm-1 ν3 ~ 1500 cm-1

ν7 ~ 790 cm-1 250 cm-1

(a)

(b)

(c)

0 2 4 6 8

0

1

2

3

4

5

Time Delay (ps)

∆R/R

(x 102)

0 100 200 300-4

-2

0

2

4

∆R/R

(x 104)

Time Delay (fs)

t ~ 1800 cm-1 ν3 ~ 1500 cm-1

ν7 ~ 790 cm-1 250 cm-1

t ~ 1800 cm-1 ν3 ~ 1500 cm-1

ν7 ~ 790 cm-1 250 cm-1

(a)

(b)

(c)20K, E//b

Iex = 0.03mJ/cm2

t ~ 1800 cm-1 ν3~ 1500 cm-1

ν7 ~ 1800 cm-1 250 cm-1

t ~ 1800 cm-1 ν3~ 1500 cm-1

ν7 ~ 1800 cm-1 250 cm-1



Y. Kawakami, S. Iwai, T. Fukatsu, M. Miura, N. Yoneyama, T. Sasaki, N. Kobayashi, The

8th International Symposium on Crystalline Organic Metals, Superconductors and

Ferromagnets, September 12-17, 2009, Hilton Niseko Village, Hokkaido, Japan

2. "Ultrafast dynamics of photoexcited state in MX-Ladder platinum complex",

M. Miura, T. Fukatsu, Y. Kawakami, S. Iwai, T. Sasaki, D. Kawakami, S, Takaishi, M.

Yamashita, Japan Physical Society 2009 Autumn Meeting, September 25-28, 2009,

Kumamoto University, Kumamoto, Japan

3. “Automatic compression system of ultrashort optical pulses using a deformable mirror”,

Y. Kawakami, The Japan Society of Applied Science PC Interface Technology Seminar,

March 4, 2010, Stanley Electric, R&D Center, Yokohama, Japan

4. "10 fs IR spectroscopy of photoinduced phase transition in 2-D organic conductor I",

T. Fukatsu, Y. Kawakami, H. Nakaya, H. Itoh, S. Iwai, N. Yoneyama, T. Sasaki, N.

Kobayashi, K. Yamamoto, K. Yakushi, Japan Physical Society 65th Annual Meeting,

March 20-23, 2010, Okayama University, Okayama, Japan

5. "10 fs IR spectroscopy of photoinduced phase transition in 2-D organic conductor II",

Y. Kawakami, T. Fukatsu, H. Nakaya, H. Itoh, S. Iwai, N. Yoneyama, T. Sasaki, N.

Kobayashi, K. Yamamoto, K. Yakushi, Japan Physical Society 65th Annual Meeting,

March 20-23, 2010, Okayama University, Okayama, Japan



No.11

Name Yuji Chinone

Department Astronomy


Research Title A Test of Inflation models with “QUIET” experiment


1. I have been to the University of Chicago and stayed at the the Kavli Institute for

Cosmological Physics (KICP) for about 2 months to research with the “QUIET”

collaborations. I analyzed the polarization data which I have observed in last summer on

Chajnantor Observatory in Chile. I studied the calibration analysis, which is the most

important analysis to obtain the physical information (in this case, temperature) from the

output of our detectors. And I also studied the Cosmic Microwave Background radiation

(CMB) analysis to get cosmological information, which I need to test inflation models,

from the time-order data (TOD). To get cosmological information from the TOD, I have to

make the CMB map and CMB power spectrum. At the same time, I have to estimate the

errors (statistic and systematic) to test the models more precisely.

II. Publications

III. Presentations

1. "CMB Polarization Data analysis of the QUIET experiment”,

Yuji Chinone, Osamu Tajima, Masaya Hasegawa, Masashi Hazumi, Takeo Higuchi and

QUIET collaborations, The 65th JPS Annual Meeting, (March 20-23, 2010, Okayama




No.12.

Name Masashi Mizuno

Department Mathematics

Position D3, JSPS Research fellow

Research Title Analysis of the regularity for moving interfaces with the theory

of partial differential equations


I study the Hölder continuity for solutions of some degenerate parabolic equation of porous

medium type with the external forces of divergence form. The regularity of solutions of the

degenerate parabolic equation is related to the regularity of moving interfaces since the level set

of solutions evolves in time. DiBenedetto and Friedman observed the Hölder continuity for

solutions of the porous medium equation with the external forces belonging to some Lebesgue

spaces however they did not give proof. I extend their results, namely we obtain Hölder

estimates of solutions of the degenerate parabolic equations of porous medium type with the

external forces belonging to the weak Lebesgue spaces, which are strictly larger than the

Lebesgue spaces. As an application of the Hölder estimates, I study the asymptotic stability for

the global decaying solution of the Keller-Segel system of degenerate type. We obtain the

algebraic convergence rate for the solution in the Lebesgue spaces for the case of critical

non-linearity. This result is joint work with Professor Takayoshi Ogawa.

II. Publications

1. (no peer review) “Regularity estimates for solutions of some degenerate parabolic

equation,”

Masashi Mizuno, Hokkaido University technical report series in mathematics, 142,

104-107, (2010).

2. (no peer review) “Hölder continuity for solutions of the nonlinear diffusion equation of

porous medium type”

Masashi Mizuno, the report collection from the 31st mathematical seminar of the evolution

equation for young researchers, 289-298, (2010).

III. Presentations

Talking in International Conferences

1. “Hölder continuity for some degenerate parabolic equation and its application,”

Masashi Mizuno, RIMS Workshop “Nonlinear evolution equations and mathematical



modeling” (Oct. 20-23, 2009, Kyoto University, Kyoto, Japan).

2. “Hölder estimates for solutions of some degenerate parabolic equation and its application,”

Masashi Mizuno, The 11th Northeastern symposium on mathematical analysis, (Feb. 22-23,

2010, Hokkaido University, Hokkaido, Japan).

Talking in Japanese Conferences

3. “Hölder continuity for solutions of the nonlinear diffusion equation of porous medium

type”

Masashi Mizuno, the 31st mathematical seminar of the evolution equation for young

researchers (Aug. 31-Sep. 3, 2009, National women’s education center, Saitama, Japan).

4. “Regularity estimates for solutions of some degenerate parabolic equation”

Masashi Mizuno, The 6th mathematics conference for young researchers, (Feb. 15-18,

2010, Hokkaido University, Hokkaido, Japan).

5. “The Hölder continuity and asymptotic stability for a solution of the Keller-Segel system of

degenerate type”

Takayoshi Ogawa, Masashi Mizuno, Spring meetings of the Mathematical Society of Japan

(Mar. 24-27, 2010, Keio University, Yokohama, Japan).

Talking in Japanese Seminars

6. “Hölder estimates and the asymptotic stability for solutions of some degenerate parabolic

equation”

Masashi Mizuno, Kagurazaka analysis seminar (Nov. 28, 2, Tokyo University of Science,

Tokyo, Japan).

7. “Hölder continuity for solutions of some degenerate parabolic equation and its application”

Masashi Mizuno, Kaiseki zemi (Dec. 10, 2009, Saitama University, Saitama, Japan).

8. “Hölder estimates for solutions of some degenerate parabolic equation”

Masashi Mizuno, Applied analysis seminar (Jan. 30, 2010, Kumamoto University,

Kumamoto, Japan).



No.13

Name Tadakazu SAWADA



Research Title Study of algebraic varieties via vector bundles


1. A vector bundle on a hypersurface is arithmetically Cohen-Macaulay if its intermediate

cohomologies vanish. On projective spaces, such bundles coincide with those which split

into a direct sum of line bundles, but this fails on hypersurfaces of higher degree in general.

We have studied when an arithmetically Cohen-Macaulay bundle splits. We have given an

inequality which gives a sufficient condition for splitting of arithmetically

Cohen-Macaulay bundles on general hypersurfaces. In the proof, the matrix factorization

introduced by Eisenbud plays an essential role. So we have tried to generalize it and apply

to the study of splitting of vector bundles. We have no results on this attempt yet.

2. We have studied equivariant vector bundles on toric varieties. In particular we have tried to

establish a numerical criterion for the ampleness of equivariant vector bundles. This subject

is in progress.

II. Publications

1. “A sufficient condition for splitting of arithmetically Cohen-Macaulay bundles on general

hypersurfaces”, accepted.

III. Presentations


hypersurfaces”,

Tadakazu SAWADA, Mathematical Society of Japan Autumn Meeting 2009, (September

24-27, 2009, Osaka University, Osaka, Japan)


hypersurfaces (poster presentation)”,

Tadakazu SAWADA, Algebraic Geometry Symposium in Kinosaki 2009, (October 26-30,

2009, Kinosaki, Japan)



No.14

Name Asuka Takatsu



Research Title Deformation of Riemannian metrics via optimal transportation

- reinterpretation of Ricci flow on surfaces -


My research is in the area of geometric analysis, mainly focuses on interactions between

differential geometry and partial differential equations. I investigated the geometry of the

Wasserstein space over a complete separable metric space. The Wasserstein space is a pair of a

space of Borel probability measures with finite second moment and a distance function derived

from the Monge-Kantorovich transport problem.

To understand better the geometric structure of the Wasserstein space, Yokota and I focused

on the cone structure. We showed that a complete separable space has a cone structure if and

only if its Wasserstein also has. In particular, the Wasserstein space over Euclidean space Rd

has a cone structure and it splits Rd isometrically but not Rd+1.

I also analyzed two inequalities associated with the porous medium equation on a basis of the

result by Otto that the gradient flow of the Tsallis entropy on the Wasserstein space over

Euclidean space is the porous medium equation. Moreover, I studied the space consisting of q

-Gaussian measures which maximize the Tsallis entropy under the mean and variance

constraints in terms of the inequalities. The approach closely follows the setting of the heat

equation which is the gradient flow of the Boltzmann entropy and Gaussian measures.

II. Publications

1. “On Wasserstein geometry of Gaussian measures”,

A. Takatsu, to appear in Advanced Studies in Pure Mathematics (proceedings the First

MSJ-SI, "Probabilistic Approach to Geometry")

2. “Wasserstein geometry of non-linear Fokker-Planck type equations”,

A. Takatsu, Surikaisekikenkyusho Kokyuroku, Variational problems and related topics

(Japanese) (2009), no.1671, 20-36.

III. Presentations

1. “Cone structure of L2-Wasserstein spaces”,

A. Takatsu and T. Yokota, Sendai Max Dehn Seminar, (April 30, 2009, Tohoku University,



Sendai, Japan)

2. “Entropy and Wasserstein spaces”,

A. Takatsu, Differential Topology Seminar at Kyoto University, (May 12, 2009, Kyoto

University, Kyoto, Japan)


A. Takatsu, Variational Problems and Related Topics, (June 8-10, 2009, Research Institute

for Mathematical Sciences, Kyoto, Japan)

4. “Cone structure of L2-Wasserstein spaces”,

A. Takatsu and T. Yokota, Seminar at Shimane University, (July 10, 2009, Shimane

University, Matsue, Japan)


A. Takatsu, The 56th Geometry Symposium, (August 28-31, 2009, Saga University, Saga,

Japan)

6. “Geometric Structure of Wasserstein spaces”,

A. Takatsu, Geometry Conference in Aso, (September 13-16, 2009, Kyukamura

Minami-Aso, Aso, Japan)


A. Takatsu, Mathematical Society of Japan, Semiannual Meeting, (September 24-27, 2009,

Osaka University, Toyonaka, Japan)

8. “Entropy and Wasserstein space”,

A. Takatsu, Mini-Workshop on Differential Geometry and Topology, (October 3, 2009,

Tohoku University, Sendai, Japan)

9. “Wasserstein geometry of non-linear Fokker-Planck equations”,

A. Takatsu, Mini-Workshop on the occasion Y.L.Xin’s visit, (October 7, 2009, Tohoku

University, Sendai, Japan)

10. “Wasserstein geometry of porous medium equations”,

A. Takatsu, Geometry Seminar at Tohoku University, (November 17, 2009, Tohoku

University, Sendai, Japan)

11. “Wasserstein geometry of porous medium equations”,

A. Takatsu, The 5th Probability and Geometry, (January 8-10, 2009, Kyoto University,

Kyoto, Japan)

12. “Wasserstein geometry of non-linear Fokker-Planck equations”,

A. Takatsu, The 5th Geometry Conference for Friendship of Japan and China, (January 29-

February 2, 2010, OIST Seaside House, Kunigami, Japan)

13. “Wasserstein geometry of porous medium equations”(poster),



A. Takatsu, Joint Symposium of Six-Departments in Graduate School of Science,

(February 16, 2010, Tohoku University, Sendai, Japan)

14. “Tsallis entropy and Wasserstein geometry”,

S. Ohta and A. Takatsu, OCAMI Meeting on Information Geometry and Related Fields

2010, (February 20-21, 2010, Osaka City University, Osaka, Japan)

15. “Geometry of Probability spaces”,

A. Takatsu, Aoba Society awards ceremony, (March 19, 2010, Tohoku University, Sendai,

Japan)



No.15

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.

On the other hand, the concept of standard realizations of crystal lattices was introduced by

Kotani and Sunada in 2001. This concept gives a mathematical formulation of crystals with

equilibrium configurations of the atoms. In this year we focus on relations between the design

theory and the concept of standard realizations of crystal lattices, and proved the following

results:

1. If all element of the building block have the same norm, then the building block carries a

configuration of spherical 3-design.

2. Each Building block obtained from association schemes consists of vectors which have the

same norm. Therefore the building block obtained from as association scheme carries a

configuration of spherical 3-design.

II. Publications

1. “H. Kurihara, Character tables of affine $m$-flat association schemes”, H. Kurihara, to

appear in Advances in Geometry

III. Presentations

1. "On spherical design and Association schemes”, H. Kurihara, Geometry seminar (June 16,

2009, Tohoku University, Sendai, Japan)

2. "Character tables of the generalized affine m-flat association schemes" (Poster session), H.

Kurihara, Summer school “Designs and Codes” (June 21, Hills-Sunpia Yamagata,



Yamagata, Japan)

3. "On character tables of association schemes based on attenuated spaces", H. Kurihara,

Japan-Korea Workshop on Algebra and Combinatorics (August 28, Kyushu University,

Fukuoka, Japan)

4. "The calculation of character tables of association schemes based on attenuated spaces", H.

Kurihara, Summer school of Combinatorics (September 2, Wakkanai Hokusei Gakuen

University, Wakkanai, Japan)

5. "A construction of spherical designs from association schemes using the theory of crystal

lattices", H. Kurihara, Mini-Workshop on Differential Geometry and Topology (October 3,

Tohoku University, Sendai, Japan)

6. "Spherical designs and crystal lattices", H. Kurihara, Matsue seminar (November 4,

Shimane University, Matsue, Japan)

7. "On designs in symmetric spaces", H. Kurihara, Differential Geometry Seminar (February

10, Osaka City University, Osaka, Japan)

8. "Crystal lattices and designs" (Poster session), H. Kurihara, 3rd Graduate School “GP”

Symposium (February 16, Tohoku University, Sendai, Japan)

9. "On spherical designs and crystal lattices", H. Kurihara, Mathematics Seminar (March 1,

University of Texas at Brownsville, Texas, USA)



No.16

Name Ryo Takada



Research Title Harmonic analytic approach to the partial differential

equations arising in fluid mechanics

I. I. I. I. Summary oSummary oSummary oSummary of Research in 2009f Research in 2009f Research in 2009f Research in 2009 fiscal yearfiscal yearfiscal yearfiscal year

1. We consider the problem whether there does exist a finite-time self-similar solution

of the backward type to the semilinear Keller–Segel system. In the case of

parabolic–elliptic type for n ≧ 3, we show that there is no such a solution with a

finite mass in the scaling invariant class. On the other hand, in the case of

parabolic–parabolic type for n ≧ 2, nonexistence of finite-time self-similar

solutions is proved in a larger class of a finite mass with some local bounds.

2. We consider the Kato-Ponce type commutator estimates in the Besov space Bsp,q(Rn

) and

the Triebel-Lizorkin space Fsp,q(Rn

) related to the Euler equations describing the motion of

perfect incompressible fluid. 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 fail in Bsp,q(Rn

) and Fsp,q(Rn) with the critical differential order s

= n/p+1 and various exponents p and q.

II. Publications

1. “Non-existence of finite-time self-similar solutions of the Keller-Segel system in the scaling

invariant class ”,

Hideo Kozono, Yoshie Sugiyama and Ryo Takada, Journal of Mathematical Analysis and

Applications, 365, 60–66 (2010).

III. Presentations

1. “Nonexistence of backward self-similar weak solutions to the Euler equations”,

Ryo Takada, Mathematical Analysis in Fluid and Gas Dynamics (July 8–10, 2009, RIMS

Kyoto University, Kyoto, Japan)

2. “Nonexistence of backward self-similar weak solutions to the Euler equations”,



Ryo Takada, Mathematical Society of Japan 2009 Autumn Meeting (September 24–27,

2009, Osaka University, Osaka, Japan)

3. “Counterexamples of commutator estimates in Besov and Triebel-Lizorkin spaces related

to the Euler equations”,

Ryo Takada, Partial Differential Equations and Mathematical Analysis for the Young

Scientists, (February 15–17, 2010, Fukuoka University, Fukuoka, Japan)



Ryo Takada, The 11th Northeastern Symposium on Mathematical Analysis (February

22–23, 2010, Hokkaido University, Sapporo, Japan)

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

related to the Euler equations”,

Ryo Takada, JSPS-DFG Japanese-German Graduate Externship “International Workshop

on Mathematical Fluid Dynamics” (March 8–16, 2010, Waseda University, Tokyo, Japan)



Ryo Takada, Mathematical Society of Japan 2010 Spring Meeting (, Japan)

Documents

4.4. Young Scientist Initiative C