Rotationsspin

Rotationsspin is a term used in physics to denote the interaction between rotational motion and the intrinsic angular momentum, or spin, of particles and macroscopic systems. It is most often discussed in relation to spin-rotation coupling, the influence of a rotating reference frame on the dynamics of spin.

In quantum mechanics, the effect can be described by a Hamiltonian term of the form H = -Ω · S, where Ω is the angular velocity of the rotation and S is the spin operator. This leads to a precession of spins described by dS/dt = Ω × S. In nonrelativistic and relativistic contexts, this coupling is called spin-rotation coupling and is sometimes attributed to the work of Mashhoon. The phenomenon connects with broader issues of how noninertial motion affects quantum degrees of freedom.

Applications and observations of Rotationsspin occur in atomic, molecular, and optical physics, neutron interferometry, and spintronics. In rotating bodies, spin-rotation coupling can influence resonance frequencies in precision spectroscopy and affect how spin polarization evolves in magnetic sensors and gyroscopes. Related ideas include the Barnett effect, where rotation induces magnetization, and the Einstein–de Haas effect, where angular momentum exchanges occur between spin and lattice. Collectively, these ideas form a family of rotation–spin phenomena relevant to metrology, fundamental tests of quantum mechanics, and spin-based technologies.

Terminology: Rotationsspin is not universally used in English-language literature; it may appear in German-language discussions or as a descriptive label for spin-rotation phenomena. The term complements, but does not replace, the more established phrase spin-rotation coupling and the related concepts of spin dynamics in rotating frames.