1210.2360 (Isaac H. Kim)

Perturbative analysis of topological entanglement entropy from
conditional independence    [PDF]

Isaac H. Kim

We use structure of conditionally independent states to analyze the stability of topological entanglement entropy. For ground state of quantum double or Levin-Wen model, we obtain a bound on the first order perturbation of topological entanglement entropy in terms of energy gap and subsystem size. The bound decreases superpolynomially with the size of the subsystem, provided the energy gap is nonzero. We also study finite temperature stability of stabilizer models, for which we prove a stronger statement than strong subadditivity of entropy. Using this statement and assuming i) finite correlation length ii) small conditional mutual information of certain configurations, first order perturbation against arbitrary local perturbation can be bounded. We discuss technical obstacles in generalizing these results.

View original: http://arxiv.org/abs/1210.2360