Ordinary photons do have spin, they have a notion of helicity so they spin around their direction on motion.

Ordinary photons do have spin, they have a notion of helicity so they spin around their direction on motion.

普通光子确实有自旋，它们有螺旋性的概念，所以它们在运动时绕着自己的方向旋转。

-- Roger Penrose 罗杰·彭罗斯