Spin Decoherence in a Gravitational Field
  We discuss a mechanism of spin decoherence in gravitation within the framework of general relativity. The spin state of a particle moving in a gravitational field is shown to decohere due to the curvature of spacetime. As an example, we analyze a particle going around a static spherically-symmetric object. 
Hiroaki Terashima, Masahito Ueda