Entanglement, subsystem particle numbers and topology in free fermion systems
Abstract
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 critical value. It is also shown that the subsystem particle number fluctuation displays behavior very similar to that of the entanglement entropy. This provides a lower-bound estimation for the entanglement entropy, which can be utilized to obtain an estimate of the entanglement entropy experimentally.
Keywords
Cite
@article{arxiv.1111.0791,
title = {Entanglement, subsystem particle numbers and topology in free fermion systems},
author = {Y. F. Zhang and L. Sheng and R. Shen and Rui Wang and D. Y. Xing},
journal= {arXiv preprint arXiv:1111.0791},
year = {2014}
}
Comments
14 pages, 6 figures