Crow's nest, Kangaroo Point House, Kangaroo Point, Brisbane

Deck and seating overlooking river.

Outdoor room, Kangaroo Point House, Kangaroo Point, Brisbane

Looking towards section of original house from outdoor room area. Hand-made spotted gum columns on edge of outdoor room on right.

Crow's nest, Kangaroo Point House, Kangaroo Point, Brisbane

Deck and seating overlooking river.

Battened roof to outdoor room, Kangaroo Point House, Kangaroo Point, Brisbane

Timber battened concave roof and supporting structure over outdoor room area.

Outdoor room, Kangaroo Point House, Kangaroo Point, Brisbane

Dining setting, sculptures, timber columns and curved roof in outdoor room

Crow's nest, Kangaroo Point House, Kangaroo Point, Brisbane

Structure to underside of deck and seating area.

Fault-tolerant quantum computation with cluster states

The one-way quantum computing model introduced by Raussendorf and Briegel [Phys. Rev. Lett. 86, 5188 (2001)] shows that it is possible to quantum compute using only a fixed entangled resource known as a cluster state, and adaptive single-qubit measurements. This model is the basis for several practical proposals for quantum computation, including a promising proposal for optical quantum computation based on cluster states [M. A. Nielsen, Phys. Rev. Lett. (to be published), quant-ph/0402005]. A significant open question is whether such proposals are scalable in the presence of physically realistic noise. In this paper we prove two threshold theorems which show that scalable fault-tolerant quantum computation may be achieved in implementations based on cluster states, provided the noise in the implementations is below some constant threshold value. Our first threshold theorem applies to a class of implementations in which entangling gates are applied deterministically, but with a small amount of noise. We expect this threshold to be applicable in a wide variety of physical systems. Our second threshold theorem is specifically adapted to proposals such as the optical cluster-state proposal, in which nondeterministic entangling gates are used. A critical technical component of our proofs is two powerful theorems which relate the properties of noisy unitary operations restricted to act on a subspace of state space to extensions of those operations acting on the entire state space. We expect these theorems to have a variety of applications in other areas of quantum-information science.

Timber cross-bracing, Mooloomba House, Point Lookout, North Stradbroke Island

Detail view of timber cross-bracing with polycarbonate sheeting behind as seen from upper level dining studio.

Mooloomba House, Point Lookout, North Stradbroke Island

North elevation, deck below and belvedere above, as seen from path to beach.

South elevation edge, Mooloomba House, Point Lookout, North Stradbroke Island

View along south elevation, stair to belvedere beyond and bedboxes above.

Entrance deck, Mooloomba House, Point Lookout, North Stradbroke Island

View past kitchen windows and roof overhang to entrance deck to the south-west.

View from Mooloomba House, Point Lookout, North Stradbroke Island

View of ocean and coastal vegetation

Timber cross-bracing, Mooloomba House, Point Lookout, North Stradbroke Island

Detail view of timber cross-bracing to dining studio, as seen from upper living area.

Timber cross-bracing, Mooloomba House, Point Lookout, North Stradbroke Island

Detail view of timber cross-bracing with polycarbonate sheeting behind as seen from upper level dining studio.

Upper circulation deck, Mooloomba House, Point Lookout, North Stradbroke Island

View along circulation deck to belvedere (deck) beyond.