Einstein--de Haas fluctuation of a nanoparticle in spin polarized gases

Abstract: We theoretically study angular momentum (AM) transfer from a spin-polarized dilute gas into an nanoparitcle (NP) tightly trapped in optical tweezers. We formulate a microscopic model based on the spin tunneling Hamiltonian method and derive a macroscopic stochastic differential equation (SDE) which governs the AM-transfer-induced rotational motion of the NP. It is shown that the AM transfer rate at the NP surface can be extracted via the inference of the SDE. This work will open the door to the manipulation of nano-spintronic systems in gaseous environments.