We introduce an elementary optical gate for expanding polarization entangled $W$ states in which every pair of photons is 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 postselection. This gate gives a better efficiency and a simpler implementation than previous proposals for $W$ -state preparation.We introduce an elementary optical gate for expanding polarization entangled $W$ states in which every pair of photons is 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 postselection. This gate gives a better efficiency and a simpler implementation than previous proposals for $W$-state preparation.

arXiv:0803.1897Physical Review AMar 25, 200890 citations

Demonstration of Local Expansion Toward Large-Scale Entangled Webs

Toshiyuki Tashima, Tsuyoshi Kitano, Şahin Kaya Özdemir +3 more

We demonstrate an optical gate that increases the size of polarization-based W states by accessing only one of the qubits. Using this gate, we have generated three-photon and four-photon W states with fidelities 0.836 ± 0.042 and 0.784 ± 0.028, respectively. We also confirmed the existence of pairwise entanglement in every pair of qubits, including the one that was left untouched by the gate. The gate is applicable to any size of W states and hence is a universal tool for expanding entanglement.We demonstrate an optical gate that increases the size of polarization-based W states by accessing only one of the qubits. Using this gate, we have generated three-photon and four-photon W states with fidelities 0.836 ± 0.042 and 0.784 ± 0.028, respectively. We also confirmed the existence of pairwise entanglement in every pair of qubits, including the one that was left untouched by the gate. The gate is applicable to any size of W states and hence is a universal tool for expanding entanglement.

arXiv:1009.3086Physical Review LettersNov 17, 201053 citations

Optical parity gate and a wide range of entangled states generation

Qing Lin

Science China Physics Mechanics and AstronomyOct 24, 20149 citations

Quantum information experiments with optical CNOT gates

Geoff J. Pryde, Jeremy L. O’Brien, NK Langrford +5 more

Sep 20, 20040 citations

We introduce an elementary optical gate for expanding polarization entangled

W

states in which every pair of photons is 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 postselection. This gate gives a better efficiency and a simpler implementation than previous proposals for

W

-state preparation.