Cluster-state quantum computing enhanced by high-fidelity generalized measurements.
We introduce and implement a technique to extend the quantum computational power of cluster states by replacing some projective measurements with generalized quantum measurements (POVMs). As an experimental demonstration we fully realize an arbitrary three-qubit cluster computation by implementing a tunable linear-optical POVM, as well as fast active feedforward, on a two-qubit photonic cluster state. Over 206 different computations, the average output fidelity is 0.9832+/-0.0002; furthermore the error contribution from our POVM device and feedforward is only of O(10(-3)), less than some recent thresholds for fault-tolerant cluster computing.
Biggerstaff
D N
DN
Institute for Quantum Computing and Department of Physics & Astronomy, University of Waterloo, Waterloo, Canada, N2L 3G1.
Kaltenbaek
R
R
Hamel
D R
DR
Weihs
G
G
Rudolph
T
T
Resch
K J
KJ