Entanglement generation in the Unruh effect
  The master equation describing the completely positive time evolution of a uniformly accelerated two-level system in weak interaction with a scalar field in the Minkowski vacuum is derived and explicitly solved. It encodes the well known Unruh effect, leading to a purely thermal equilibrium state. This asymptotic state turns out to be entangled when the uniformly accelerating system is composed by two, independent two-level atoms. 
F. Benatti and R. Floreanini