Quantum computational renormalization in the Haldane phase

Phys Rev Lett. 2010 Sep 10;105(11):110502. doi: 10.1103/PhysRevLett.105.110502. Epub 2010 Sep 10.

Abstract

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.