Analysis of Charge-spin-orbital Fluctuations by Ab Initio Calculation and Random Phase Approximation: Application to Non-coplanar Antiferromagnet Cd2Os2O7

We present a systematic analysis on the basis of ab initio calculations and many-body perturbation theory for clarifying the dominant fluctuation in complex charge-spin-orbital coupled systems. For a tight-binding multiband model obtained from the maximally-localized Wannier function analysis of the band structure by the local density approximation, we take into account electron correlations at the level of random phase approximation. To identify the dominant fluctuation, we carry out the eigenmode analysis of the generalized susceptibility that includes all the multiple degrees of freedom: charge, spin, and orbital. We apply this method to the paramagnetic metallic phase of a pyrochlore oxide Cd$_2$Os$_2$O$_7$, which shows a metal-insulator transition accompanied by a peculiar noncoplanar antiferromagnetic order of all-in all-out type. We find that the corresponding spin fluctuation is dominantly enhanced by the on-site Coulomb repulsions in the presence of strong spin-orbit coupling and trigonal crystal field splitting. Our results indicate that the combined method offers an effective tool for the systematic analysis of potential instabilities in strongly correlated electron materials.Comment: 8 pages, 4 figure

Charge-spin-orbital fluctuations in mixed valence spinels: Comparative study of AlV2O4{\mathrm{AlV}}_{2}{\mathrm{O}}_{4} and LiV2O4{\mathrm{LiV}}_{2}{\mathrm{O}}_{4}

Mixed valence spinels provide a fertile playground for the interplay between charge, spin, and orbital degrees of freedom in strongly correlated electrons on a geometrically frustrated lattice. Among them, AlV2O4 and LiV2O4 exhibit contrasting and puzzling behavior: self-organization of seven-site clusters and heavy fermion behavior. We theoretically perform a comparative study of charge-spin-orbital fluctuations in these two compounds, on the basis of the multiband Hubbard models constructed by using the maximally localized Wannier functions obtained from the ab initio band calculations. Performing the eigenmode analysis of the generalized susceptibility, we find that, in AlV2O4, the relevant fluctuation appears in the charge sector in σ-bonding type orbitals. In contrast, in LiV2O4, optical-type spin fluctuations in the a1g orbital are enhanced at an incommensurate wave number at low temperature. Implications from the comparative study are discussed for the contrasting behavior, including the metal-insulator transition under pressure in LiV2O4

ギョルイ コッカク ヒョウホン オ モチイタ リカ キョウイク ノ レイ - アゴ ノ ホネ ノ ヘンカ オ カンサツ シテ サカナ ト ワタシタチト ノ カンケイ オ サグロウ -

The fish transparent specimens were applied to a study of the evolution through the observation of jaw arches of the cartilaginous and bony fishes, and its effectiveness was investigated by the pre- and post- intervention questionnaire. The research examined 48 participants in the four learning interventions, the age ranging from 13 to 76 with a mean of 29.9 years old（ n=47, because one articipant did not describe the age）and the sex ratio being 27 females and 21 males. The program was composed of the followings: how to use the microscope; the basic knowledge of bones such as the kinds of bone, how to make specimens for bone observation, history and methods to make transparent specimens; main observation 1, jaw arches of cartilaginous and bony fi shes; and main observation 2, relationships between fi sh jaws and our auditory ossicles, known as the Theory of Reichert. The participants were significantly more concerned about the evolution of fish jaws to our auditory ossicles after the intervention, indicating that the transparent specimens and observation objects related to the Theory of Reichert would be suitable for the study of evolution. The picturesque transparent specimens attracting the participants would be a good resource of science education.透明骨格二重染色標本が、理科教育、とくに進化の理解を深めるための教材として有効かどうかを、事前と事後のアンケートにもとづいて調査した。対象としたのは、4 つのイベントに参加した13歳から76歳の男性21名、女性27名、計48名である。プログラムは、顕微鏡の使い方と透明標本の基礎知識（骨の種類、骨格を観察するための方法、透明標本の作製方法と歴史）、および二つからなる主題の観察（サメの顎と魚の顎、および私たちとの関係［ライヘルト説］）の順に進めた。アンケートによって、ほぼ全員が、透明標本を観察することによって魚類の顎の骨格と私たちの中耳骨との関係であるライヘルト説を理解したことが判明した。さらに自由記述では、進化自体の驚きや魚と私たちの系統関係、さらには透明標本の美しさに興味津々であることがうかがえた。河野博: 東京海洋大学学術研究院海洋環境学部門植原望: 東京海洋大学魚類学研究

HiGate (High Grade Anti-Tamper Equipment) Prototype and Application to e-Discovery

These days, most data is digitized and processed in various ways by computers. In the past, computer owners were free to process data as desired and to observe the inputted data as well as the interim results. However, the unrestricted processing of data and accessing of interim results even by computer users is associated with an increasing number of adverse events. These adverse events often occur when sensitive data such as personal or confidential business information must be handled by two or more parties, such as in the case of e-Discovery, used in legal proceedings, or epidemiologic studies. To solve this problem, providers encrypt data, and the owner of the computer performs decoding in the memory for encrypted data. The computer owner can be limited to performing only certain processing of data and to observing only the final results. As an implementation that uses existing technology to realize this solution, the processing of data contained in a smart card was considered, but such an implementation would not be practical due to issues related to computer capacity and processing speed. Accordingly, the authors present the concept of PC-based High Grade AntiTamper Equipment (HiGATE), which allows data to be handled without revealing the data content to administrators or users. To verify this concept, an eDiscovery application on a prototype was executed and the results are reported here