Induced Quantized Spin Current in Vacuum
Chong-Sun Chu (Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan and Center for Theory and Computation, National Tsing-Hua University, Hsinchu 30013, Taiwan); Chun-Hei Leung (Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan and Center for Theory and Computation, National Tsing-Hua University, Hsinchu 30013, Taiwan)
We uncover a fundamental effect of the QED vacuum in an external electromagnetic (EM) field. We show that the quantized vacuum of electrons is spin polarized by the EM field and manifests as a vacuum spin current. An experiment is proposed to measure the spin torque exerted by the spin current by measuring the twisted angle of the director axis of a nematic liquid crystal.
