Entanglement extracted from vacuum into accelerated Unruh-DeWitt detectors and energy conservation

Understand

We consider a pair of two-level Unruh-DeWitt detectors accelerated uniformly in the Minkowski vacuum of a massless neutral scalar field, and analyze, within the perturbation theory, the entanglement extracted from the vacuum into the Unruh-DeWitt detectors when the switching of the detectors are performed adiabatically enough at the asymptotic past and future.

• We consider the cases where the detectors are accelerated parallelly, anti-parallelly, and in differently orientated directions.
• We show that entanglement is extracted if they are accelerated anti-parallelly and the ratios of the excitation energy to the magnitude of the acceleration coincide between the two detectors.
• On the other hand, we find the detectors are not entangled when the detectors are accelerated parallelly or in orientated directions.