Experimental oneway quantum computing
Abstract
Standard quantum computation is based on sequences of unitary quantum logic gates that process qubits. The oneway quantum computer proposed by Raussendorf and Briegel is entirely different. It has changed our understanding of the requirements for quantum computation and more generally how we think about quantum physics. This new model requires qubits to be initialized in a highly entangled cluster state. From this point, the quantum computation proceeds by a sequence of singlequbit measurements with classical feedforward of their outcomes. Because of the essential role of measurement, a oneway quantum computer is irreversible. In the oneway quantum computer, the order and choices of measurements determine the algorithm computed. We have experimentally realized fourqubit cluster states encoded into the polarization state of four photons. We characterize the quantum state fully by implementing experimental fourqubit quantum state tomography. Using this cluster state, we demonstrate the feasibility of oneway quantum computing through a universal set of one and twoqubit operations. Finally, our implementation of Grover's search algorithm demonstrates that oneway quantum computation is ideally suited for such tasks.
 Publication:

Nature
 Pub Date:
 March 2005
 DOI:
 10.1038/nature03347
 arXiv:
 arXiv:quantph/0503126
 Bibcode:
 2005Natur.434..169W
 Keywords:

 Quantum Physics
 EPrint:
 36 pages, 6 figures, 2 tables