Multiphoton entanglement is an important resource for linear optics quantum computing. Here we show that a wide range of highly entangled multiphoton states, including $W$ -states, can be prepared by interfering single photons inside a Bell multiport beam splitter and using postselection. A successful state preparation is indicated by the collection of one photon per output port. An advantage of the Bell multiport beam splitter is that it redirects the photons without changing their inner degrees of freedom. The described setup can therefore be used to generate polarization, time-bin, and frequency multiphoton entanglement, even when using only a single photon source.Multiphoton entanglement is an important resource for linear optics quantum computing. Here we show that a wide range of highly entangled multiphoton states, including $W$-states, can be prepared by interfering single photons inside a Bell multiport beam splitter and using postselection. A successful state preparation is indicated by the collection of one photon per output port. An advantage of the Bell multiport beam splitter is that it redirects the photons without changing their inner degrees of freedom. The described setup can therefore be used to generate polarization, time-bin, and frequency multiphoton entanglement, even when using only a single photon source.

arXiv:quant-ph/0406047Physical Review AJun 13, 200565 citations

Single Photon on a Beam Splitter

Ray LaPierre

Undergraduate texts in physicsJan 1, 20221 citation

Creation of maximally entangled photon-number states using optical fiber multiports

Geoff J. Pryde, Andrew G. White

We theoretically demonstrate a method for producing the maximally path-entangled state $(1/\sqrt{2})(|N,0〉+\mathrm{exp}[\mathrm{iN}\ensuremath{\varphi}]|0,N〉)$ using intensity-symmetric multiport beam splitters, single photon inputs, and either photon-counting postselection or conditional measurement. The use of postselection enables successful implementation with non-unit efficiency detectors. We also demonstrate how to make the same state more conveniently by replacing one of the single photon inputs by a coherent state.We theoretically demonstrate a method for producing the maximally path-entangled state $(1/\sqrt{2})(|N,0〉+\mathrm{exp}[\mathrm{iN}\ensuremath{\varphi}]|0,N〉)$ using intensity-symmetric multiport beam splitters, single photon inputs, and either photon-counting postselection or conditional measurement. The use of postselection enables successful implementation with non-unit efficiency detectors. We also demonstrate how to make the same state more conveniently by replacing one of the single photon inputs by a coherent state.

arXiv:quant-ph/0304135Physical Review ANov 21, 200391 citations

Simulation of quantum gates by postselection of interference experiments in multi-port beam-splitter (BS) configurations

Y. Ben-Aryeh

Using multiport beam-splitter (BS) configurations eight input operators a(0),a(1),a(2) a(3),a(4) a(5),a(6), a(7) are mixed by 12 BS's to produce the output operators b(0), b(1), b(2), b(3), b(4), b(5), b(6), b(7). A single photon entering into, or exiting from, one port of a BS is considered as the |0> state while that in the second port of the BS is considered as the |1> state. Two single photons are inserted into two of the BS's simulating two input qubit-states by operators a(0), a(1),a(2), a(3) . In order to simulate the two-qubit gates we exclude by postselection all the cases in which one or two photons exit through output ports b(4), b(5), b(6), b(7) so that only 25% of the experiments are taken into account. The method simulates explicitly the CNOT and SWAP gates but similar methods can be used for other gates.Using multiport beam-splitter (BS) configurations eight input operators a(0),a(1),a(2) a(3),a(4) a(5),a(6), a(7) are mixed by 12 BS's to produce the output operators b(0), b(1), b(2), b(3), b(4), b(5), b(6), b(7). A single photon entering into, or exiting from, one port of a BS is considered as the |0> state while that in the second port of the BS is considered as the |1> state. Two single photons are inserted into two of the BS's simulating two input qubit-states by operators a(0), a(1),a(2), a(3) . In order to simulate the two-qubit gates we exclude by postselection all the cases in which one or two photons exit through output ports b(4), b(5), b(6), b(7) so that only 25% of the experiments are taken into account. The method simulates explicitly the CNOT and SWAP gates but similar methods can be used for other gates.

arXiv:0909.3970Sep 22, 20090 citations

Multiphoton entanglement is an important resource for linear optics quantum computing. Here we show that a wide range of highly entangled multiphoton states, including

W

-states, can be prepared by interfering single photons inside a Bell multiport beam splitter and using postselection. A successful state preparation is indicated by the collection of one photon per output port. An advantage of the Bell multiport beam splitter is that it redirects the photons without changing their inner degrees of freedom. The described setup can therefore be used to generate polarization, time-bin, and frequency multiphoton entanglement, even when using only a single photon source.