  We show that the asymptotic state of a quantum system composed of two atoms
in circular motion in vacuum can be entangled when the angular velocity and the
radius of the orbit are appropriate. The asymptotic entanglement as a result of
centripetal acceleration is initial-state independent and can be viewed as a
manifestation of the circular version of the Unruh effect. Based on this
phenomenon, we propose an optomechanical setup to detect the circular Unruh
effect with the state-of-the-art technologies.
