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丸山 敏毅; 安武 伸俊*
Nuclear Physics Review, 41(3), p.806 - 810, 2024/09
We present a microscopic simulation of particles with time-dependent spins, where different interaction and density are considered. Ferromagnetism has been observed for the attractive spin-spin interaction, while antiferromagnetism and paramagnetism have been observed in different density region for the repulsive spin-spin interaction. The method developed here should be extended to include spin-color interaction into "color molecular dynamics".
安武 伸俊*; 丸山 敏毅
Nuclear Physics Review, 41(3), p.801 - 805, 2024/09
We present the current status of molecular dynamics, in which hadron and quark matter are described only within quark models. In our previous calculations, we solved the time evolution of internal degrees of freedom for color. In this article, we show the results simultaneously solved the internal degrees of freedom for spin as well. Unlike conventional methods, our approach also considers the flavor conversion between quarks and electrons during the calculations, which naturally achieves the beta equilibrium under the charge neutrality condition. Based on this latest formulation, the equation of state for dense matter is studied, replicating the saturation properties: symmetric energy, 
-parameter, incompressibility around nuclear density. The resultant mass-radius relations are also consistent with the observations such as the gravitational wave observations, and NICER. Our numerical results suggest that deconfined quark matter appears in the core of neutron stars via crossover. The key difference from previous molecular dynamics simulations is the spontaneous emergence of clustering of quarks or baryons on a local scale. These properties would never be observed in equations of state based on the other approaches. While our formulation does not yet fully include strangeness, we expect that our method has a possibility to show the direct evidence of the quark clustering models such as "the strangeon model" or "the sexaquark model".
Xia, C.-J.*; 丸山 敏毅; 安武 伸俊*; 巽 敏隆*; Zhang, Y.-X.*
Nuclear Physics Review, 41(3), p.818 - 827, 2024/09
Based on the relativistic mean field (RMF) model with Thomas-Fermi approximation, we investigate the elastic properties of neutron star matter. The elastic constants are estimated by introducing deformations on the nuclear pasta structures in 
-equilibrium, where various crystalline configurations are considered in a fully three-dimensional geometry without the Wigner-Seitz approximation. Two scenarios with different symmetry energy slope (=41.34 and 89.39 MeV) are examined, where the elastic constants can vary by ten times. By fitting to the numerical results, we improve the analytic formulae for the elastic properties of nuclear pasta by introducing damping factors.
川瀬 啓悟; 神門 正城; 早川 岳人; 大東 出; 近藤 修司; 本間 隆之; 亀島 敬; 小瀧 秀行; Chen, L.*; 福田 祐仁; et al.
Nuclear Physics Review, 26(Suppl.), p.94 - 99, 2009/07
SPring-8とKPSI-JAEAにおいて、それぞれMeV領域,sub-MeV領域の逆コンプトン散乱による光源を開発した。MeV光源は光励起型遠赤外レーザーと8GeV電子ビームとからなっている。sub-MeV光源はNd:YAGパルスレーザーとマイクロトロンで加速された150MeV電子ビームからなっている。どちらの光源も逆コンプトン光の発生に成功した。ここでは、これらの光源の特徴と今後の展望について発表する。
