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arXiv · 0905.1480

Phase transitions and localizable entanglement in cluster-state spin chains with Ising couplings and local fields

Stein Olav Skrøvseth·Stephen D. Bartlett
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Abstract

We consider a one-dimensional spin chain for which the ground state is the cluster state, capable of functioning as a quantum computational wire when subjected to local adaptive measurements of individual qubits, and investigate the robustness of this property to local and coupled (Ising-type) perturbations. We investigate the ground state both by identifying suitable correlation functions as order parameters, as well as numerically using a variational method based on matrix product states. We find that the model retains an infinite localizable entanglement length for Ising and local fields up to a quantum phase transition, but that the resulting entangled state is not simply characterized by a Pauli correction based on the measurement results.

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Stein Olav Skrøvseth, Stephen D. Bartlett. 2009-08-13. Phase transitions and localizable entanglement in cluster-state spin chains with Ising couplings and local fields. https://doi.org/10.1103/physreva.80.022316

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