Single-spin measurements on the ground state of an interacting spin lattice can be used to perform a quantum computation. We show how such measurements can mimic renormalization group transformations and remove the short-ranged variations of the state that can reduce the fidelity of a computation. This suggests that the quantum computational ability of a spin lattice could be a robust property of a quantum phase. We illustrate our idea with the ground state of a rotationally invariant spin-1 chain, which can serve as a quantum computational wire not only at the Affleck-Kennedy-Lieb-Tasaki point, but within the Haldane phase.
Stephen D. Bartlett, Gavin K. Brennen, Akimasa Miyake, and Joseph M. Renes, Phys. Rev. Lett. 105, 110502 (2010) [4 pages]. Copyright (2010) by the American Physical Society. The original article can be found at http://link.aps.org/doi/10.1103/PhysRevLett.105.110502.