Corpus ID: 231924756

Stability of the bulk gap for frustration-free topologically ordered quantum lattice systems

  title={Stability of the bulk gap for frustration-free topologically ordered quantum lattice systems},
  author={B. Nachtergaele and Robert Sims and Amanda Young},
We prove that uniformly small short-range perturbations do not close the bulk gap above the ground state of frustration-free quantum spin systems that satisfy a standard local topological quantum order condition. In contrast with earlier results, we do not require a positive lower bound for finite-system Hamiltonians uniform in the system size. To obtain this result, we adapt the Bravyi-Hastings-Michalakis strategy to the GNS representation of the infinite-system ground state. 
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