Entanglement, subsystem particle numbers and topology in free fermion systems.

  title={Entanglement, subsystem particle numbers and topology in free fermion systems.},
  author={Yujie Zhang and Li Sheng and Rui Shen and Rui Wang and Ding-yu Xing},
  journal={Journal of physics. Condensed matter : an Institute of Physics journal},
  volume={26 10},
  • Y. Zhang, L. Sheng, +2 authors D. Xing
  • Published 3 November 2011
  • Physics, Medicine
  • Journal of physics. Condensed matter : an Institute of Physics journal
We study the relationship between bipartite entanglement, subsystem particle number and topology in a half-filled free fermion system. It is proposed that the spin-projected particle numbers can distinguish the quantum spin Hall state from other states, and can be used to establish a new topological index for the system. Furthermore, we apply the new topological invariant to a disordered system and show that a topological phase transition occurs when the disorder strength is increased beyond a… 
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