Experimental entanglement of six photons in graph states

Graph states1,2,3—multipartite entangled states that can be represented by mathematical graphs—are important resources for quantum computation4, quantum error correction3, studies of multiparticle entanglement1 and fundamental tests of non-locality5,6,7 and decoherence8. Here, we demonstrate the experimental entanglement of six photons and engineering of multiqubit graph states9,10,11. We have created two important examples of graph states, a six-photon Greenberger–Horne–Zeilinger state5, the largest photonic Schrodinger cat so far, and a six-photon cluster state2, a state-of-the-art ‘one-way quantum computer’4. With small modifications, our method allows us, in principle, to create various further graph states, and therefore could open the way to experimental tests of, for example, quantum algorithms4,12 or loss- and fault-tolerant one-way quantum computation13,14.

[1]  G. Tóth,et al.  Entanglement detection in the stabilizer formalism , 2005, quant-ph/0501020.

[2]  Jian-Wei Pan,et al.  Experimental entanglement purification of arbitrary unknown states , 2003, Nature.

[3]  W Dür,et al.  Multiparticle entanglement purification for graph states. , 2003, Physical review letters.

[4]  O. Gühne,et al.  03 21 7 2 3 M ar 2 00 6 Scalable multi-particle entanglement of trapped ions , 2006 .

[5]  T. Rudolph,et al.  Resource-efficient linear optical quantum computation. , 2004, Physical review letters.

[6]  A. Shimony,et al.  Bell’s theorem without inequalities , 1990 .

[7]  R. B. Blakestad,et al.  Creation of a six-atom ‘Schrödinger cat’ state , 2005, Nature.

[8]  P. Knight,et al.  Multiparticle generalization of entanglement swapping , 1998 .

[9]  R. Cleve,et al.  HOW TO SHARE A QUANTUM SECRET , 1999, quant-ph/9901025.

[10]  Philip Walther,et al.  Experimental violation of a cluster state bell inequality. , 2005, Physical review letters.

[11]  G. Tóth,et al.  Bell inequalities for graph states. , 2004, Physical review letters.

[12]  G Weihs,et al.  Experimental demonstration of four-photon entanglement and high-fidelity teleportation. , 2001, Physical review letters.

[13]  H. Briegel,et al.  Persistent entanglement in arrays of interacting particles. , 2000, Physical review letters.

[14]  Terry Rudolph,et al.  Loss tolerance in one-way quantum computation via counterfactual error correction. , 2006, Physical review letters.

[15]  A. Zeilinger,et al.  Experimental one-way quantum computing , 2005, Nature.

[16]  L-M Duan,et al.  Efficient quantum computation with probabilistic quantum gates. , 2005, Physical review letters.

[17]  Bo Zhao,et al.  Experimental quantum teleportation of a two-qubit composite system , 2006, quant-ph/0609129.

[18]  H. Weinfurter,et al.  THREE-PARTICLE ENTANGLEMENTS FROM TWO ENTANGLED PAIRS , 1997 .

[19]  J. Eisert,et al.  Multiparty entanglement in graph states , 2003, quant-ph/0307130.

[20]  O. Gühne,et al.  Estimating entanglement measures in experiments. , 2006, Physical review letters.

[21]  W Dür,et al.  Stability of macroscopic entanglement under decoherence. , 2004, Physical review letters.

[22]  H. Briegel,et al.  Experimental demonstration of five-photon entanglement and open-destination teleportation , 2004, Nature.

[23]  Acknowledgements , 1992, Experimental Gerontology.

[24]  R Raussendorf,et al.  A one-way quantum computer. , 2001, Physical review letters.

[25]  Jeremy L O'Brien,et al.  Linear optical quantum computing , 2002 .

[26]  V. Scarani,et al.  Nonlocality of cluster states of qubits , 2004, quant-ph/0405119.

[27]  Géza Tóth,et al.  Experimental analysis of a four-qubit photon cluster state. , 2005, Physical review letters.

[28]  Christian Kurtsiefer,et al.  Experimental detection of multipartite entanglement using witness operators. , 2004, Physical review letters.

[29]  Michael A. Nielsen,et al.  Fault-tolerant quantum computation with cluster states , 2005 .

[30]  M. Kim,et al.  Hybrid cluster state proposal for a quantum game , 2005, quant-ph/0509066.

[31]  M. Nielsen,et al.  Noise thresholds for optical quantum computers. , 2005, Physical review letters.

[32]  Charles H. Bennett,et al.  Mixed-state entanglement and quantum error correction. , 1996, Physical review. A, Atomic, molecular, and optical physics.

[33]  M. Nielsen.  Optical quantum computation using cluster States. , 2004, Physical review letters.

[34]  Dirk Schlingemann,et al.  Quantum error-correcting codes associated with graphs , 2000, ArXiv.

[35]  L-M Duan,et al.  Scalable generation of graph-state entanglement through realistic linear optics. , 2006, Physical review letters.

[36]  Todd B. Pittman,et al.  Linear optical quantum computing , 2003 .

[37]  G. Tóth,et al.  Detecting genuine multipartite entanglement with two local measurements. , 2004, Physical review letters.

[38]  Shih,et al.  New high-intensity source of polarization-entangled photon pairs. , 1995, Physical review letters.