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Nakata, Koki; Zou, J.*; Klinovaja, J.*; Loss, D.*
Physical Review Research (Internet), 6(3), p.033207_1 - 033207_11, 2024/08
Terada, Noriki*; Khalyavin, D. D.*; Manuel, P.*; Asai, Shinichiro*; Masuda, Takatsugu*; Saito, Hiraku*; Nakajima, Taro*; Osakabe, Toyotaka
Physical Review B, 110(2), p.024406_1 - 024406_9, 2024/07
The frustrated antiferromagnet CuFeO exhibits pressure-induced complex magnetic phase transitions from the commensurate collinear (CM1) phase to several incommensurate noncollinear phases. To study the effect of high pressure on magnetic interactions, we performed neutron diffraction and inelastic neutron scattering experiments under high-pressure conditions. With increasing pressure, the CM1 ground state becomes less stable against application of a magnetic field even below the critical pressure ( 3 GPa), as proved by the significant reduction in the critical magnetic field from =7.5 T to 4.5 T at 2.1 GPa. Additionally, the energy gap in the spin-wave dispersion relation is reduced from 1.0 to 0.88 meV by the application of a pressure of = 2.1 GPa. Comparing the experimental results with spin-wave calculations revealed that the change in the spin-wave excitation can be explained by the reduction in either the uniaxial anisotropy term or the degree of separation in the nearest-neighbor exchange interactions.
Tamatsukuri, Hiromu; Murakami, Yoichi*; Saito, Noriko*; Ohashi, Naoki*; Tsutsui, Satoshi*
Physical Review B, 110(2), p.024301_1 - 024301_8, 2024/07
Yoshida, Kazuki; Chazono, Yoshiki*; Ogata, Kazuyuki*
Physical Review C, 110(1), p.014617_1 - 014617_9, 2024/07
Nakada, Hibiki*; Nakayama, Shinsuke; Yoshida, Kazuki; Watanabe, Yukinobu*; Ogata, Kazuyuki*
Physical Review C, 110(1), p.014616_1 - 014616_8, 2024/07
Previous studies have revealed the importance of introducing surface correction into a phenomenological model for inclusive and reactions, and these findings have contributed significantly to the improvement of nuclear data evaluation. However, the necessity for the surface correction in an inclusive reaction has hardly been investigated.The energy spectra and their radial distributions for the and reactions are calculated by the one-step semiclassical distorted wave model.The radial distribution of the energy spectra for the reaction is shifted toward the outer region of the nucleus compared to the reaction. Based on this finding, we consider a larger surface correction into a phenomenological model for the reaction than that for the reaction, and calculated values reproduce the experimental spectra well.The peripherality of the reaction is more prominent than that of the reaction. The stronger surface correction thus should be introduced for the reaction than for the reaction.
Fujii, Daisuke; Nakayama, Katsumasa*; Suzuki, Kei
Physical Review D, 110(1), p.014039_1 - 014039_15, 2024/07
The Casimir effect is known to be induced from photon fields confined by a small volume, and also its fermionic counterpart has been predicted in a wide range of quantum systems. Here, we investigate what types of Casimir effects can occur from quark fields in dense and thin quark matter. In particular, in the dual chiral density wave, which is a possible ground state of dense quark matter, we find that the Casimir energy oscillates as a function of the thickness of matter. This oscillating Casimir effect is regarded as an analog of that in Weyl semimetals and is attributed to the Weyl points in the momentum space of quark fields. In addition, we show that an oscillation is also induced from the quark Fermi sea, and the total Casimir energy is composed of multiple oscillations.
Liao, J.*; Huang, Z.*; Shangguan, Y.*; Zhang, B.*; Cheng, S.*; Xu, H.*; Kajimoto, Ryoichi; Kamazawa, Kazuya*; Bao, S.*; Wen, J.*
Physical Review B, 109(22), p.224411_1 - 224411_10, 2024/06
Elyasi, M.*; Yamamoto, Kei; Hioki, Tomosato*; Makiuchi, Takahiko*; Shimizu, Hiroki*; Saito, Eiji*; Bauer, G. E. W.*
Physical Review B, 109(18), p.L180402_1 - L180402_7, 2024/05
Matsumura, Takeshi*; Tabata, Chihiro; Kaneko, Koji; Nakao, Hironori*; Kakihana, Masashi*; Hedo, Masato*; Nakama, Takao*; Onuki, Yoshichika*
Physical Review B, 109(17), p.174437_1 - 174437_8, 2024/05
Iwamoto, Hiroki; Meigo, Shinichiro; Sugihara, Kenta*
Physical Review C, 109(5), p.054610_1 - 054610_12, 2024/05
Nuclide production cross sections are crucial in nuclear research, development, space exploration, and astrophysical investigations. Despite their importance, limited experimental data availability restricts the practicality of phenomenological approaches to comprehensive cross-section estimation. To address this, we propose a Gaussian process-based machine learning (ML) model capable of transferring knowledge from elements with abundant data to those with limited or no experimental data. Our ML model not only enables comprehensive cross-section estimations for various elements but also demonstrates predictive capabilities akin to physics models, even in regions with scarce training data.
Shizuma, Toshiyuki*; Omer, M.; Hajima, Ryoichi*; Koizumi, Mitsuo
Physical Review C, 109(5), p.054320_1 - 054320_8, 2024/05
Sakurai, Hirohisa*; Kurebayashi, Yutaka*; Suzuki, Soichiro*; Horiuchi, Kazuho*; Takahashi, Yui*; Doshita, Norihiro*; Kikuchi, Satoshi*; Tokanai, Fuyuki*; Iwata, Naoyoshi*; Tajima, Yasushi*; et al.
Physical Review D, 109(10), p.102005_1 - 102005_18, 2024/05
Secular variations of galactic cosmic rays (GCRs) are inseparably associated with the galactic activities and should reflect the environments of the local galactic magnetic field, interstellar clouds, and nearby supernova remnants. The high-energy muons produced in the atmosphere by high-energy GCRs can penetrate deep underground and generate radioisotopes in the rock. As long lived radionuclides such as Be and Al have been accumulating in these rocks, concentrations of Be and Al can be used to estimate the long-term variations in high-energy muon yields, corresponding to those in the high-energy GCRs over a few million years. This study measured the production cross sections for muon induced Be and Al by irradiating positive muons with the momentum of 160 GeV/c on the synthetic silica plates and the granite core at the COMPASS experiment line in CERN SPS. In addition, it the contributions of the direct muon spallation reaction and the nuclear reactions by muon-induced particles on the production of long lived radionuclides in the rocks were clarified.
Tabata, Chihiro; Kon, Fusako*; Ota, Kyugo*; Hibino, Ruo*; Matsumoto, Yuji*; Amitsuka, Hiroshi*; Nakao, Hironori*; Haga, Yoshinori; Kaneko, Koji
Physical Review B, 109(13), p.134403_1 - 134403_7, 2024/04
Okudaira, Takuya*; Nakabe, Rintaro*; Auton, C. J.*; Endo, Shunsuke; Fujioka, Hiroyuki*; Gudkov, V.*; Ide, Ikuo*; Ino, Takashi*; Ishikado, Motoyuki*; Kambara, Wataru*; et al.
Physical Review C, 109(4), p.044606_1 - 044606_9, 2024/04
Nakabe, Rintaro*; Auton, C. J.*; Endo, Shunsuke; Fujioka, Hiroyuki*; Gudkov, V.*; Hirota, Katsuya*; Ide, Ikuo*; Ino, Takashi*; Ishikado, Motoyuki*; Kambara, Wataru*; et al.
Physical Review C, 109(4), p.L041602_1 - L041602_4, 2024/04
Filipescu, D.*; Gheorghe, I.*; Goriely, S.*; Nishio, Katsuhisa; Utsunomiya, Hiroaki*; Suzaki, Fumi; Hirose, Kentaro; 10 of others*
Physical Review C, 109(4), p.044602_1 - 044602_23, 2024/04
Rapp, L.*; Matsuoka, Takeshi*; Firestein, K. L.*; Sagae, Daisuke*; Habara, Hideaki*; Mukai, Keiichiro*; Tanaka, Kazuo*; Gamaly, E. G.*; Kodama, Ryosuke*; Seto, Yusuke*; et al.
Physical Review Research (Internet), 6(2), p.023101_1 - 023101_18, 2024/04
It is generally known that irradiating a solid surface with a laser pulse of ultra-relativistic intensity generates a plasma on the surface, which in turn creates an ultrahigh pressure inside. In this study, the crystal structure analysis of high-pressure phases generated inside silicon single-crystals irradiated by this laser was performed using the diffraction system at the Stress and Imaging apparatus of BL22XU, which is a JAEA-BL. The results obtained confirm the existence of high-pressure phases that silicon is said to possess: body-centered, rhombohedral, hexagonal, and tetragonal phases in the interior. We can get the results that the crystal structure of silicon polymorphs of being include body-centered, rhombohedral, hexagonal-diamond, tetragonal exists. In the future, we will accumulate data and apply them to control the internal structure, strength, and functionality of materials.
Yamazaki, Takumi*; Hirai, Takamasa*; Yagi, Takashi*; Yamashita, Yuichiro*; Uchida, Kenichi*; Seki, Takeshi*; Takanashi, Koki
Physical Review Applied (Internet), 21(2), p.024039_1 - 024039_11, 2024/02
Times Cited Count:0 Percentile:0.00(Physics, Applied)Shiga, Motoyuki; Thomsen, B.; Kimizuka, Hajime*
Physical Review B, 109(5), p.054303_1 - 054303_12, 2024/02
Inelastic neutron scattering spectra of hydrogen in palladium were calculated considering nuclear quantum effects at finite temperatures. A computational method combining semiclassical molecular dynamics based on path integrals and machine learning potentials was used. The calculated spectra agree well with the experimental spectra with respect to the positions and intensities of the peaks corresponding to the fundamental and first harmonic of the vibrational excitation of hydrogen atoms. Comparison with classical molecular dynamics shows that nuclear quantum effects play an essential role in the inelastic neutron scattering spectra.
Park, P.*; Cho, W.*; Kim, C.*; An, Y.*; Avdeev, M.*; Iida, Kazuki*; Kajimoto, Ryoichi; Park, J.-G.*
Physical Review B, 109(6), p.L060403_1 - L060403_7, 2024/02