Elementary optical gate for expanding an entanglement web

We introduce an elementary optical gate for expanding polarization entangled W states, in which every pair of photons are entangled alike. The gate is composed of a pair of 50:50 beamsplitters and ancillary photons in the two-photon Fock state. By seeding one of the photons in an $n$-photon W state into this gate, we obtain an $(n+2)$-photon W state after post-selection. This gate gives a better efficiency and a simpler implementation than previous proposals for $\rm W$-state preparation.

[1]  Masato Koashi,et al.  Pulse-mode quantum projection synthesis: Effects of mode mismatch on optical state truncation and preparation , 2002 .

[2]  W. Dür.  Multipartite entanglement that is robust against disposal of particles , 2001 .

[3]  A. Zeilinger,et al.  Local Conversion of Greenberger-Horne-Zeilinger States to Approximate W States , 2005 .

[4]  Charles H. Bennett,et al.  Teleporting an unknown quantum state via dual classical and Einstein-Podolsky-Rosen channels. , 1993, Physical review letters.

[5]  J. Cirac,et al.  Three qubits can be entangled in two inequivalent ways , 2000, quant-ph/0005115.

[6]  G. Tóth,et al.  Experimental observation of four-photon entangled Dicke state with high fidelity. , 2006, Physical review letters.

[7]  Yongmin Li,et al.  New high-efficiency source of a three-photon w state and its full characterization using quantum state tomography , 2005, International Quantum Electronics Conference, 2005..

[8]  X. Zou,et al.  Generation of an entangled four-photon W state , 2002, quant-ph/0202090.

[9]  M. Koashi,et al.  Polarization-entangled W state using parametric down-conversion , 2002, quant-ph/0208162.

[10]  Realization of symmetric sharing of entanglement in semiconductor microcrystallites coupled by a cavity field , 2002, quant-ph/0212150.

[11]  Kiel T. Williams,et al.  Extreme quantum entanglement in a superposition of macroscopically distinct states. , 1990, Physical review letters.

[12]  Ekert,et al.  Quantum cryptography based on Bell's theorem. , 1991, Physical review letters.

[13]  Akihisa Tomita,et al.  Creation of a polarization W state using optical fibre multiports , 2005 .

[14]  H. Weinfurter,et al.  Observation of three-photon Greenberger-Horne-Zeilinger entanglement , 1998, quant-ph/9810035.

[15]  Yongmin Li,et al.  Four-photon W state using two-crystal geometry parametric down-conversion , 2004 .

[16]  Masato Koashi,et al.  Quantum-scissors device for optical state truncation: A proposal for practical realization , 2001 .

[17]  Christian Kurtsiefer,et al.  Experimental realization of a three-qubit entangled W state. , 2004, Physical review letters.

[18]  Slovakia,et al.  Entangled webs: Tight bound for symmetric sharing of entanglement , 2000, quant-ph/0007086.

[19]  John Rarity,et al.  THREE-PARTICLE ENTANGLEMENT FROM ENTANGLED PHOTON PAIRS AND A WEAK COHERENT STATE , 1999 .

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

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

[22]  Christian Kurtsiefer,et al.  Three-photon W-state , 2003 .

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

[24]  Philip Walther,et al.  Heralded generation of multiphoton entanglement , 2007, 0804.2384.

[25]  A. Zeilinger,et al.  Full characterization of a three-photon Greenberger-Horne-Zeilinger state using quantum state tomography. , 2004, Physical review letters.

[26]  Yuan Liang Lim,et al.  Multiphoton entanglement through a Bell-multiport beam splitter (8 pages) , 2005 .

[27]  Timothy F. Havel,et al.  Quantum erasers and probing classifications of entanglement via nuclear magnetic resonance , 2002 .

[28]  M. Koashi,et al.  Concentration and purification scheme for two partially entangled photon pairs , 2001, quant-ph/0101042.

[29]  Thierry Paul,et al.  Quantum computation and quantum information , 2007, Mathematical Structures in Computer Science.