Spin-axion coupling

Understand

We establish a new covariant phenomenological model, which describes an influence of pseudoscalar (axion) field on spins of test massive particles.

• The model includes general relativistic equations of particle motion and spin evolution in background pseudoscalar (axion), electromagnetic and gravitational fields.
• It describes both the direct spin-axion coupling of the gradient type and indirect spin-axion interaction mediated by electromagnetic fields.
• Special attention is paid to the direct spin-axion coupling caused by the gradient of the pseudoscalar (axion) field.