论文标题
带有自旋的动力学理论：从巨大到无质量的费米子
Kinetic theory with spin: From massive to massless fermions
论文作者
论文摘要
我们发现，最近开发的动力学理论具有旋转，用于巨大和无质量的费米子。通过引入参考框矢量，我们将偶极矩张量分解为电和磁偶极矩。我们表明，Wigner函数的轴向矢量成分包含横向磁性偶极矩的贡献，该偶极矩构成了横向自由度的自由度（DOF），并在无质量极限下平稳消失。结果，描述四个用于大规模费米的DOF的动力学方程变得顺利地变为手性动力学方程，描述了两个DOF在无质量极限中。我们还通过使用高斯波数据包明确计算，确认了Wigner函数的小质量行为。
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.
