title: Identifying phases of quantum many-body systems that are universal for quantum computation.
abstract: Quantum computation can proceed solely through single-qubit measurements on an appropriate quantum state, such as the ground state of an interacting many-body system. We investigate a simple spin-lattice system based on the cluster-state model, and by using nonlocal correlation functions that quantify the fidelity of quantum gates performed between distant qubits, we demonstrate that it possesses a quantum (zero-temperature) phase transition between a disordered phase and an ordered "cluster phase" in which it is possible to perform a universal set of quantum gates.
authors: School of Physical Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
authors: Andrew C
authors: AC
authors: Doherty
authors: Stephen D
authors: SD
authors: Bartlett