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The layered van der Waals antiferromagnet MnBi2Te4 has been predicted to combine the band ordering of archetypical topological insulators such as Bi2Te3 with the magnetism of Mn, making this material a viable candidate for the realization of various magnetic topological states. We have systematically investigated the surface electronic structure of MnBi2Te4(0001) single crystals by use of spin- and angle-resolved photoelectron spectroscopy experiments. In line with theoretical predictions, the results reveal a surface state in the bulk band gap and they provide evidence for the influence of exchange interaction and spin-orbit coupling on the surface electronic structure., We acknowledge financial support from the DFG through SFB1170 ’Tocotronics’, SFB1143 ’Correlated Magnetism’, SPP 1666 ’Topological insulators’, ERA-Chemistry Programm (RU-776/15-1), and the Wurzburg-Dresden Cluster of ¨Excellence on Complexity and Topology in Quantum Matter – ct.qmat (EXC 2147, project-id 39085490). We also acknowledge the support by Spanish Ministerio de Economia y Competitividad (MINECO Grant No. FIS2016-75862-P), Academic D.I. Mendeleev Fund Program of Tomsk State University (Project No. 8.1.01.2018), the Saint Petersburg State University grant for scientic investigations (Grant No. 15.61.202.2015), and Russian Foundation for Basic Research (Grant No. 18-52-06009). S.M. acknowledges support by the Swiss National Science Foundation (Grant No. P300P2-171221). This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. We acknowledge Diamond Light Source for access to beamline I05 (proposals No. SI19278 and No. SI22468) that contributed to the results presented here. Parts of this research were carried out at PETRA III (DESY, Hamburg, Germany) under Proposal No. I-20180510. This work has been partly performed in the framework of the Nanoscience Foundry and Fine Analysis (NFFA-MIUR, Italy) facility. M.M.O. acknowledges support by the Diputacion Foral de Gipuzkoa ((SAREA 2018 - RED ´2018, project no. 2018-CIEN-000025-01).

Aspiring secondary school science teachers must experientially learn the way of using a telescope and teaching star watching through a stargazing session. As a part of experiential activities, a stargazing session to observe the moon and Saturn was organized for 5-year-old kindergarten children on October 27, 2017, by graduate and undergraduate students; the session was conducted on the roof of building C of the Faculty of Education, Hiroshima University. The preparation for the session was a good opportunity for the students to review the knowledge that they had learned in class. The students interviewed the children about the shape of moon and Saturn immediately after they observed the planets. The two kinds of telescope used in star observing and the order of the planets that the children watched did not have much effect on the visibility of the planets. The results of interviews on the shape of the Moon indicated that the children understood the rough shape of the moon; however, they could not make an accurate understanding of the difference of the shape on the right and left sides. Furthermore, a possible effect of visual information, such as drawings, on the form of stars was confirmed., 本研究の一部にJSPS科研費(JP26350235, JP17H00820) を使用した。

核燃料サイクル工学研究所では、「日本原子力研究開発機構核燃料サイクル工学研究所再処理施設保安規定、第IV編 環境監視」に基づき、再処理施設周辺の環境放射線モニタリングを実施している。本報告書は、2016年4月から2017年3月までの間に実施した環境モニタリングの結果、及び大気、海洋への放射性物質の放出に起因する周辺公衆の線量算出結果について、取りまとめたものであり、2011年3月に発生した東京電力福島第一原子力発電所事故の影響が多くの項目でみられた。なお、環境監視計画の概要、測定方法の概要、測定結果及びその経時変化、気象統計結果、放射性廃棄物の放出状況、東京電力福島第一原子力発電所事故の影響による平常の変動幅を外れた値の評価について付録として収録した。, Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2016 to March 2017. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Electric Power Company Holdings, Inc. in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and were exceeded the normal range of fluctuation in the monitoring, were evaluated.

Topological insulators (TIs) with an inverted bulk band and a strong spin-orbit coupling exhibit gapless topological surface states (TSSs) protected by time-reversal symmetry. Helical spin textures driven by spin-momentum locking offer the opportunity to generate spin-polarized currents and therefore TIs are expected to be used for future spintronic applications. For practical applications TIs are urgently required that are operable at room temperature due to a wide bulk band gap as well as a distinct topological surface state that is robust to atmospheric exposure. Here we show two distinguishable TSSs originating from different terminations on PbBi4Te4S3 by using spin- and angle-resolved photoemission spectroscopy. We find that one TSS is persistently observed, while the other becomes invisible upon intentional oxygen exposure. The result signifies the presence of a protected TSS buried under the topmost surface. Our finding paves the way for realizing a topological spintronics device under atmospheric conditions., This work was partly supported by the bilateral collaboration program between RFBR (Russia; No. 15-52-50017) and JSPS (Japan) and also by KAKENHI Grants No. 17H06138 and No. 18H03683. K.S. was financially supported by a Grant-in-Aid for JSPS Fellows (No. 16J03874). The study has also been supported by the Russian Science Foundation (Grant No. 17-12-01047) and RFBR (Grant No. 17-08-00955) for growing the single crystals and characterizing the samples. I.V.S. acknowledges financial support from the Russian Science Foundation (Grant No. 18-12-00169) for band structure calculations and the Ministry of Education and Science of the Russian Federation within governmental program Megagrants (State Task No. 3.9003.2017/9.10) for charge density calculations. This work has been partly performed in the framework of the nanoscience foundry and fine analysis (NFFA-MIUR Italy, Progetti Internazionali) facility. E.V.C. acknowledges financial support from the Saint Petersburg State University Project No. 15.61.202.2015 and the Spanish Ministry of Science and Innovation Grant No. FIS2016-75862-P.

The ongoing research in topologically protected electronic states is driven not only by the obvious interest from a fundamental perspective but is also fueled by the promising use of these non-trivial states in energy technologies such as the field of spintronics. It is therefore important to find new materials exhibiting these compelling topological features. InBi has been known for many decades as a semi-metal in which Spin-Orbit Coupling (SOC) plays an important role. As SOC is a key ingredient for topological states, one may expect InBi to exhibit non-trivial states. Here we present a thorough analysis of InBi, grown on InAs(111)-A surface, by both experimental Angular-Resolved PhotoEmission Spectroscopy (ARPES) measurements and by fully-relativistic ab-initio electronic band calculations. Our investigation suggests the existence of topologically non-trivial metallic surface states and emphasizes the fundamental role of Bi within these electronic states. Moreover, InBi appears to be a topological crystalline insulator whose Dirac cones at the (001) surface are pinned at high-symmetry points. Consequently, as they are also protected by time-reversal symmetry, they can survive even if the in-plane mirror symmetry is broken at the surface., Comment: 4 figures, 15 pages

核燃料サイクル工学研究所では、「日本原子力研究開発機構核燃料サイクル工学研究所再処理施設保安規定、第IV編 環境監視」に基づき、再処理施設周辺の環境放射線モニタリングを実施している。本報告書は、2015年4月から2016年3月までの間に実施した環境モニタリングの結果、及び大気、海洋への放射性物質の放出に起因する周辺公衆の線量算出結果について、取りまとめたものであり、2011年3月に発生した東京電力福島第一原子力発電所事故の影響が多くの項目でみられた。なお、環境監視計画の概要、測定方法の概要、測定結果及びその経時変化、気象統計結果、放射性廃棄物の放出状況、東京電力福島第一原子力発電所事故の影響による平常の変動幅を外れた値の評価について付録として収録した。, Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2015 to March 2016. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Electric Power Company Holdings, Inc. in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and were exceeded the normal range of fluctuation in the monitoring, were evaluated.

In this paper, we discuss the Tsallis relative entropy with negative parameters for positive semidefinite matrices. Moreover, we give a simple proof that the Karcher mean for positive semidefinite matrices is the unique positive semidefinite solution of the extended Karcher equation.

Tsallis relative operator entropy was firstly formulated by Fujii and Kamei as an operator version of Uhlmann's relative entropy. Afterwards, Yanagi, Kuriyama and Furuichi reformulated Tsallis relative operator entropy as an operator version of Tsallis relative entropy. In this paper, we define Tsallis relative operator entropy with negative parameters of (non-invertible) positive operators on a Hilbert space and show some properties.