著者
Saigusa Tetsu Tero Atsushi Nakagaki Toshiyuki Kuramoto Yoshiki
出版者
American Physical Society
雑誌
Physical Review Letters (ISSN:00319007)
巻号頁・発行日
vol.100, no.1, pp.018101, 2008-01-11
被引用文献数
137 130

When plasmodia of the true slime mold Physarum were exposed to unfavorable conditions presented as three consecutive pulses at constant intervals, they reduced their locomotive speed in response to each episode. When the plasmodia were subsequently subjected to favorable conditions, they spontaneously reduced their locomotive speed at the time when the next unfavorable episode would have occurred. This implied the anticipation of impending environmental change. We explored the mechanisms underlying these types of behavior from a dynamical systems perspective.
著者
Hattori T. Ihara Y. Nakai Y. Ishida K. Tada Y. Fujimoto S. Kawakami N. Osaki E. Deguchi K. Sato N. Satoh I.
出版者
American Physical Society
雑誌
Physical Review Letters (ISSN:00319007)
巻号頁・発行日
vol.108, no.6, 2012-02
被引用文献数
71

磁石でありながら超伝導にもなる物質の超伝導発現の新しい仕組みを解明 -磁石が生み出す超伝導-. 京都大学プレスリリース. 2012-02-07.
著者
Ozawa Misaki Kuroiwa Takeshi Ikeda Atsushi Miyazaki Kunimasa
出版者
American Physical Society
雑誌
Physical review letters (ISSN:00319007)
巻号頁・発行日
vol.109, no.20, pp.205701, 2012-11
被引用文献数
28 6

Recent studies show that volume fractions φJ at the jamming transition of frictionless hard spheres and disks are not uniquely determined but exist over a continuous range. Motivated by this observation, we numerically investigate the dependence of φJ on the initial configurations of the parent fluid equilibrated at a volume fraction φeq, before compressing to generate a jammed packing. We find that φJ remains constant when φeq is small but sharply increases as φeq exceeds the dynamic transition point which the mode-coupling theory predicts. We carefully analyze configurational properties of both jammed packings and parent fluids and find that, while all jammed packings remain isostatic, the increase of φJ is accompanied with subtle but distinct changes of local orders, a static length scale, and an exponent of the finite-size scaling. These results are consistent with the scenario of the random first-order transition theory of the glass transition.
著者
Sasaki Misao Suyama Teruaki Tanaka Takahiro Yokoyama Shuichiro
出版者
American Physical Society
雑誌
Physical Review Letters (ISSN:00319007)
巻号頁・発行日
vol.117, no.6, 2016-08-02
被引用文献数
112

初検出された重力波の起源は原始ブラックホール? : 宇宙の始まりに迫る新理論. 京都大学プレスリリース. 2016-08-09.
著者
Kuroda Noritaka Sakai Masamichi Nishina Yuichiro Tanaka Masatoshi Kurita Susumu クロダ ノリタカ サカイ マサミチ ニシナ ユウイチロウ タナカ マサトシ クリタ ススム 黒田 規敬 酒井 政道 仁科 雄一郎 田中 正俊 栗田 進
出版者
The American Physical Society
雑誌
Physical Review Letters (ISSN:00319007)
巻号頁・発行日
vol.58, no.20, pp.2122-2125, 1987-05-18
被引用文献数
3 86

A midgap absorption band is observed in the quasi one-dimensional semiconductor [Pt(en)2]-[Pt(en)2Cl2](ClO4)4 under hydrostatic pressures at room temperature, where en is ethylenediamine. The transition is allowed only for the polarization parallel to the -Cl-PtII-Cl-PtIV- chain. The peak position remains near the middle of the Peierls gap at any pressure up to 2.2 GPa. The intensity increases exponentially with the peak shift. The gap states responsible for this band are attributed to soliton excitations corresponding to kinks of the charge-density wave.顕著な一次元物性を示すことで注目を集めている擬一次元白金錯体[Pt(en)2][Pt(en)2Cl2](ClO4)4の結晶について光吸収スペクトルを静水圧下で測定した結果、パイエルスギャップのほぼ中間に対応する近赤外波長位置に、加圧と共に成長する一つの吸収帯が発見された。パイエルスギャップ自体は移動積分の増大のために圧力によって減少するが、新しい吸収帯も低エネルギー側にシフトし、かつシフト量はパイエルスギャップの減少分のほぼ二分の一に等しい。この結果に基づいて、新しい吸収帯は擬一次元結合上に生成した電子ソリトンによるものとの解釈を提案し、静水圧という手段で物理的に制御できた初めてのソリトンであることを論述した。
著者
Sasa Shin-Ichi Yokokura Yuki
出版者
American Physical Society
雑誌
Physical review letters (ISSN:10797114)
巻号頁・発行日
vol.116, no.14, 2016-04-08
被引用文献数
5

乱雑さを決める時間の対称性を発見-100年前の物理と数学の融合が築くミクロとマクロの架け橋-. 京都大学プレスリリース. 2016-05-24.
著者
Okada Susumu Oshiyama Atsushi
出版者
American Physical Society
雑誌
Physical review letters (ISSN:00319007)
巻号頁・発行日
vol.87, no.14, pp.146803, 2001-09
被引用文献数
260

We report first-principles total-energy electronic-structure calculations in the density-functional theory performed for hexagonally bonded honeycomb sheets consisting of B, N, and C atoms. We find that the ground state of BNC sheets with particular stoichiometry is ferromagnetic. Detailed analyses of energy bands and spin densities unequivocally reveal the nature of the ferromagnetic ordering, leading to an argument that the BNC sheet is a manifestation of the flat-band ferromagnetism.
著者
Hosokawa S. Inui M. Kajihara Y. Matsuda K. Ichitsubo T. Pilgrim W. -C. Sinn H. Gonzalez L. E. Gonzalez D. J. Tsutsui S. Baron A. Q. R.
出版者
American Physical Society
雑誌
PHYSICAL REVIEW LETTERS (ISSN:00319007)
巻号頁・発行日
vol.102, no.10, 2009-03
被引用文献数
66

The transverse acoustic excitation modes were detected by inelastic x-ray scattering in liquid Ga in the Q range above 9  nm-1 although liquid Ga is mostly described by a hard-sphere liquid. An ab initio molecular dynamics simulation clearly supports this finding. From the detailed analysis for the S(Q, ω) spectra with a good statistic quality, the lifetime of 0.5 ps and the propagating length of 0.4–0.5 nm can be estimated for the transverse acoustic phonon modes, which may correspond to the lifetime and size of cages formed instantaneously in liquid Ga.
著者
Yanagita Tatsuo Kaneko Kunihiko
出版者
American Physical Society
雑誌
PHYSICAL REVIEW LETTERS (ISSN:01433857)
巻号頁・発行日
vol.78, no.22, pp.4297-4300, 1997-06-02
被引用文献数
14

A phenomenological model for cloud dynamics is proposed, which consists of the successive operations of the physical processes: buoyancy, diffusion, viscosity, adiabatic expansion, fall of a droplet by gravity, descent flow dragged by the falling droplet, and advection. Through extensive simulations, the phases corresponding to stratus, cumulus, stratocumulus, and cumulonimbus are found by changing the ground temperature and the moisture of the air. They are characterized by order parameters such as the cluster number, perimeter-to-area ratio of a cloud, and Kolmogorov-Sinai entropy. Though our model is simple and constructive, it may shed some light on the true nature of clouds.
著者
Takatsu H. Onoda S. Kittaka S. Kasahara A. Kono Y. Sakakibara T. Kato Y. Fåk B. Ollivier J. Lynn J. W. Taniguchi T. Wakita M. Kadowaki H.
出版者
American Physical Society
雑誌
Physical Review Letters (ISSN:00319007)
巻号頁・発行日
vol.116, no.21, 2016-05-26
被引用文献数
12

スピン液体の近くの「隠れた秩序」. 京都大学プレスリリース. 2016-05-27.
著者
Dushenko S. Ago H. Kawahara K. Tsuda T. Kuwabata S. Takenobu T. Shinjo T. Ando Y. Shiraishi M.
出版者
American Physical Society
雑誌
Physical Review Letters (ISSN:10797114)
巻号頁・発行日
vol.116, no.16, 2016-04-21
被引用文献数
26

次世代スピントロニクス材料であるグラフェンにおいてスピンを電圧に変換する新しい機能を発見. 京都大学プレスリリース. 2016-05-18.
著者
Suzuki K. Barbiellini B. Orikasa Y. Go N. Sakurai H. Kaprzyk S. Itou M. Yamamoto K. Uchimoto Y. Wang Yung Jui Hafiz H. Bansil A. Sakurai Y.
出版者
American Physical Society
雑誌
Physical Review Letters (ISSN:00319007)
巻号頁・発行日
vol.114, no.8, 2015-02-25
被引用文献数
14

リチウムイオン二次電池の電池電極反応に寄与する電子軌道の解明 -マンガン酸リチウム系正電極材料設計に新たな指針-.京都大学プレスリリース. 2015-02-05.
著者
Takatsu Hiroshi Ishikawa Jun J. Yonezawa Shingo Yoshino Harukazu Shishidou Tatsuya Oguchi Tamio Murata Keizo Maeno Yoshiteru
出版者
American Physical Society
雑誌
Physical Review Letters (ISSN:00319007)
巻号頁・発行日
vol.111, no.5, 2013-08
被引用文献数
39

単純な金属を磁気センサーに応用できる新メカニズムの発見. 京都大学プレスリリース. 2013-07-31.
著者
Tomimoto S. Matsubara M. Ogasawara T. Okamoto H. Kimura T. Tokura Y.
出版者
American Physical Society
雑誌
Physical review letters (ISSN:00319007)
巻号頁・発行日
vol.98, no.1, pp.017402, 2007-01
被引用文献数
12

Optical manipulation of the magnetic anisotropy is demonstrated for bilayered manganites, La2-2xSr1+2xMn2O7, by means of femtosecond Kerr-rotation measurements. Upon the photoexcitation on the x=0.32 crystal, the magnetization exhibits the precessional motion for about 1 ns, revealing the directional change of the magnetocrystalline anisotropy from the c axis to the ab plane. This change of the anisotropy induces the nonthermal decrease of the c-axis magnetization component for about 1 ns.
著者
Tomimoto S. Nansei H. Saito S. Suemoto T. Takeda J. Kurita S.
出版者
American Physical Society
雑誌
Physical review letters (ISSN:00319007)
巻号頁・発行日
vol.81, no.2, pp.417-420, 1998-07
被引用文献数
50 58

Self-trapped-exciton (STE) luminescence of quasi-one-dimensional halogen-bridged platinum complex [Pt(en)2] [Pt(en)2Cl2] (ClO4)4 is investigated by femtosecond time-resolved luminescence spectroscopy. In the high energy tail of the luminescence band, a fast rise and decay are seen, whereas around the luminescence peak energy a slow rise of about 500 fs is observed. This rise becomes faster at the low energy side of the band. These results are consistently explained by the cooling of prethermalized STEs, following the rapid self-trapping which is estimated to occur within 140 fs.
著者
Yanagi Kazuhiro Moriya Rieko Cuong Nguyen Thanh Otani Minoru Okada Susumu
出版者
American Physical Society
雑誌
Physical review letters (ISSN:00319007)
巻号頁・発行日
vol.110, no.8, pp.086801, 2013-02
被引用文献数
12 1

We report clear experimental evidence for the charge manipulation of molecules encapsulated inside single-wall carbon nanotubes (SWCNTs) using electrochemical doping techniques. We encapsulated β-carotene (Car) inside SWCNTs and clarified electrochemical doping characteristics of their Raman spectra. C=C streching modes of encapsulated Car and a G band of SWCNTs showed clearly different doping behaviors as the electrochemical potentials were shifted. Electron extraction from encapsulated Car was clearly achieved. However, electrochemical characteristics of Car inside SWCNTs and doping mechanisms elucidated by calculations based on density-functional theory indicate the difficulty of charge manipulation of molecules inside SWCNTs due to the presence of strong on-site Coulomb repulsion energy at the molecules.
著者
Yonezawa Shingo Kajikawa Tomohiro Maeno Yoshiteru
出版者
American Physical Society
雑誌
Physical Review Letters (ISSN:00319007)
巻号頁・発行日
vol.110, no.7, 2013-02
被引用文献数
48

ルテニウム酸化物における超伝導の一次相転移の発見 -超伝導と磁場の未知の相互作用メカニズムの存在を示唆-. 京都大学プレスリリース. 2013-02-15.
著者
Okada Susumu Shiraishi Kenji Oshiyama Atsushi
出版者
American Physical Society
雑誌
Physical review letters (ISSN:00319007)
巻号頁・発行日
vol.90, no.2, pp.026803, 2003-01
被引用文献数
26 21

Based on total-energy electronic-structure calculations within the density-functional theory, we find that a high spin state is realized for an ultimate dangling bond unit on an otherwise hydrogen-covered Si(111) surface. We further propose a systematic method of constructing nanometer-scale dangling bond networks that exhibit the ferrimagnetic spin ordering. The interplay between the electron-electron interaction and the surface reconstruction is elucidated.
著者
Boero Mauro Parrinello Michele Terakura Kiyoyuki Ikeshoji Tamio Liew Chee Chin
出版者
American Physical Society
雑誌
Physical review letters (ISSN:00319007)
巻号頁・発行日
vol.90, no.22, pp.226403, 2003-06
被引用文献数
106 118

A first principles study of a hydrated electron in water at ordinary and supercritical conditions is presented. In the first case, the electron cleaves a cavity in the hydrogen bond network in which six H2O molecules form the solvation shell. The electron distribution assumes an ellipsoidal shape, and the agreement of the computed and the experimental optical absorption seems to support this picture. At supercritical conditions, instead, the H-bond network is not continuous and allows us to predict that the electron localizes in preexisting cavities in a more isotropic way. Four water molecules form the solvation shell but the localization time shortens significantly.
著者
Sato T. Matsui H. Takahashi T. Ding H. Yang H.-B. Wang S.-C. Fujii T. Watanabe T. Matsuda A. Terashima T. Kadowaki K.
出版者
American Physical Society
雑誌
Physical review letters (ISSN:00319007)
巻号頁・発行日
vol.91, no.15, pp.157003, 2003-10
被引用文献数
83 110

We report a systematic high-resolution angle-resolved photoemission spectroscopy on high-Tc superconductors Bi2Sr2Can-1CunO2n+4 (n=1–3) to study the origin of many-body interactions responsible for superconductivity. For n=2 and 3, a sudden change in the energy dispersion, so called “kink”, becomes pronounced on approaching (π,0) in the superconducting state, while a kink appears only around the nodal direction in the normal state. For n=1, the kink shows no significant temperature dependence even across Tc. This could suggest that the coupling of electrons with Q=(π,π) magnetic mode is dominant in the superconducting state for multilayered cuprates, while the interactions at the normal state and that of single-layered cuprates have a different origin.