To date, only Newtonian gravitational forces have been experimentally tested in quantum systems. Interesting new effects are expected when relativistic corrections are taken into account, including a coupling of center of mass to internal degrees of freedom for complex quantum systems leading, for instance, to de-coherence in gravitational fields. Here, I will focus on the ambiguities in the definition of relativistic center of mass coordinates in this context, and discuss how external forces affect its coupling to the internal dynamics.
Host: Caslav Brukner