Linear optical Fredkin gate based on partial-SWAP gate

Abstract

We propose a scheme for linear optical quantum Fredkin gate based on the combination of recently experimentally demonstrated linear optical partial SWAP gate and controlled-Z gates. Both heralded gate and simplified postselected gate operating in the coincidence basis are designed. The suggested setups have a simple structure and require stabilization of only a single Mach-Zehnder interferometer. A proof-of-principle experimental demonstration of the postselected Fredkin gate appears to be feasible and within the reach of current technology.

Fusing multipleWstates simultaneously with a Fredkin gate

“…The main difficulty in implementing the present setup with state-of-the-art photonic technology is the Fredkin gate. However, there are already proposals for the realization of the Fredkin gate using linear optical elements [36][37][38]. Here, it is important to note that due to the probabilistic nature of these linear optics gates, the overall cost in terms of photon number and time may be different from the resource cost analyzed in our work.…”

Highly efficient optical Fredkin gate with weak nonlinearities and classical information feed-forward

“…Recently, a scheme [10] for quantum Fredkin gate based on quantum Zeno effect in a bimodal cavity has been suggested. So far, there have been several linear optics schemes [26][27][28] to implement the quantum Fredkin gates. The optical Fredkin gate is also proposed by using the CKN [11,29].…”

“…In the protocol for [11], the photon from only the appointed output port of the last beam splitter (BS) is selected to construct the Fredkin gate, which enables it with the total success probability near 1/8. The heralded Fredkin gate in [26][27][28] has a rather complex structure and requires six or eight ancillary photons. The post-selected Fredkin gate, which requires only a single pair of ancillary photons in a maximally entangled state, succeeds with the probability 1/162 in [27] and 1/192 in [28].…”

“…The heralded Fredkin gate in [26][27][28] has a rather complex structure and requires six or eight ancillary photons. The post-selected Fredkin gate, which requires only a single pair of ancillary photons in a maximally entangled state, succeeds with the probability 1/162 in [27] and 1/192 in [28]. The other post-selected Fredkin gate proposed by Gong et al [28] do not need ancillary photons and has a success probability of 1/64 by using the photon-triplet source.…”

One-step implementation of the genuine Fredkin gate in high-Q coupled three-cavity arrays

“…Since the first quantum optical Fredkin gate was proposed in theory by Milburn [20], the physical realization of Fredkin gate has flourished in the field of linear optics in recent years. Fiurášek suggested a heralded Fredkin gate that used ancilla photons, interference, and single-photon detection to emulate the the cross-Kerr nonlinearity [21], then the author put forward an alternative scheme for linear optical quantum Fredkin gate based on the combination of recently experimentally demonstrated linear optical partial-SWAP gate and controlled-Z gates [22]. Gong et al presented two methods for a linear optical quantum Fredkin gate with only linear optics and single photons [23].…”