When do Frustration-free Spin Chains Become Entangled?

          @misc{ scivideos_PIRSA:12040112,
            doi = {10.48660/12040112},
            url = {https://pirsa.org/12040112},
            author = {Bravyi, Sergey},
            keywords = {},
            language = {en},
            title = {When do Frustration-free Spin Chains Become Entangled?},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2012},
            month = {apr},
            note = {PIRSA:12040112 see, \url{https://scivideos.org/pirsa/12040112}}
          }