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arXiv 2005.00204hep-phhep-thnucl-th
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自旋动力学理论:从大质量到无质量费米子

Kinetic theory with spin: From massive to massless fermions

Xin-Li Sheng, Qun Wang, Xu-Guang Huang

摘要:

我们发现最近发展的有质量和无质量费米子的自旋动力学理论是光滑连接的。通过引入参考系矢量,我们将偶极矩张量分解为电偶极矩和磁偶极矩。我们表明,维格纳函数的轴向矢量分量包含横向磁偶极矩占横向自旋自由度(DOF)的贡献,并顺利消失在无质量的限制。结果,描述有质量费米子四自由度的动力学方程在无质量极限下光滑地变为描述两自由度的手征动力学方程。我们还确认了小质量行为的维格纳函数的明确计算使用高斯波包。

英文摘要:

We find that the recently developed kinetic theories with spin for massive and massless fermions are smoothly connected. By introducing a reference-frame vector, we decompose the dipole-moment tensor into electric and magnetic dipole moments. We show that the axial-vector component of the Wigner function contains a contribution from the transverse magnetic dipole moment which accounts for the transverse spin degree of freedom (DOF) and vanishes smoothly in the massless limit. As a result, the kinetic equations, describing four DOF for massive fermions, becomes smoothly the chiral kinetic equations describing two DOF in the massless limit. We also confirm the small-mass behavior of the Wigner function by explicit calculation using a Gaussian wave packet.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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