Random bipartite entanglement from W and W-like states

          @misc{ pirsa_PIRSA:06090015,
            doi = {10.48660/06090015},
            url = {https://pirsa.org/06090015},
            author = {Lo, Hoi-Kwong},
            keywords = {Quantum Information},
            language = {en},
            title = {Random bipartite entanglement from W and W-like states },
            publisher = {Perimeter Institute},
            year = {2006},
            month = {sep},
            note = {PIRSA:06090015 see, \url{https://pirsa.org}}
          }
          

Abstract

We describe a protocol for distilling maximally entangled bipartite states between random pairs of parties (``random entanglement'') from those sharing a tripartite W state, and show that this may be done at a higher rate than distillation of bipartite entanglement between specified pairs of parties (``specified entanglement''). Specifically, the optimal distillation rate for specified entanglement for the W has been previously shown to be the asymptotic entanglement of assistance of 0.92 EPR pairs per W, while our protocol can distill 1 EPR pair per W between random pairs of parties, which we conjecture to be optimal. We further extend this to a more general class of W-like states and show by increasing the number of parties in the protocol that there exist states with fixed lower-bounded distillable random entanglement for arbitrarily small specified entanglement. [Work done in collaboration with Benjamin Fortescue. Preprint available at http://arxiv.org/abs/quant-ph/0607126 ]