Distillation of multiple copies of Bell states
Yi-Xin Chen, Jinshuang Jin, Dong Yang · Physical Review A · 2003
It is impossible to discriminate four Bell states through local operations and classical communication, if only one copy is provided. To complete this task, two copies will suffice and be necessary. When $2n$ copies are provided, we show that the distillable entanglement is exactly $2n\ensuremath{-}2.$ Surprisingly, when $2n\ensuremath{-}1$ copies are provided, the distillable entanglement is also $2n\ensuremath{-}2.$