Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:quant-ph/0602220 · Physical Review A

Linear-optics quantum Toffoli and Fredkin gates

Jaromı́r Fiurášek

Published Jun 9, 2006• 106 citations
arXivHTMLPDF

Abstract

We design linear-optics multiqubit quantum logic gates. We assume the traditional encoding of a qubit onto the state of a single photon in two modes (e.g., spatial or polarization). We suggest schemes allowing direct probabilistic realization of the fundamental Toffoli and Fredkin gates without resorting to a sequence of single- and two-qubit gates. This yields more compact schemes and potentially reduces the number of ancilla photons. The proposed setups involve passive linear optics, sources of auxiliary single photons or maximally entangled pairs of photons, and single-photon detectors. In particular, we propose an interferometric implementation of the Toffoli gate in the coincidence basis, which does not require any ancilla photons and is experimentally feasible with current technology.

DOI
10.1103/physreva.73.062313

Related papers

Linear optical implementation of an ancilla-free quantum SWAP gate

Hong‐Fu Wang, Xiao‐Qiang Shao, Yongfang Zhao +2 more

We propose a simple linear optical scheme for directly implementing an ancilla-free two-qubit quantum SWAP gate with high success probability. The proposed setup consists of only simple linear optical elements and photon detectors without introducing additionally ancillary single photons or entangled photons sources. The scheme is feasible and within the reach of current experimental technology.

Physica Scripta•Jan 1, 2010•4 citations

Methods for a linear optical quantum Fredkin gate

Yan-Xiao Gong, Guang‐Can Guo, Timothy C. Ralph

We consider the realization of a quantum Fredkin gate with only linear optics and single photons. First we construct a heralded Fredkin gate using four heralded controlled-NOT (CNOT) gates. Then we simplify this method to a post-selected one utilizing only two CNOT gates. We also give a possible realization of this method which is feasible with current experimental technology. Another post-selected scheme requires time entanglement of the input photons but needs no ancillary photons.

arXiv:0804.0992•Physical Review A•Jul 2, 2008•57 citations

Enhancing the W State Fusion Process With a Toffoli Gate and a CNOT Gate via One-Way Quantum Computation and Linear Optics

Fırat Diker, Fatih Özaydin, Md Sadik Hassan Arik

Creation of large-scale W state quantum networks is a key step for realization of various quantum information tasks.Regarding the photonics technology, a simple optical setup was proposed for the fusion of two W states.Recently it was shown that via a single Fredkin gate, this basic so-called fusion setup can be enhanced.However the main problem was that the probability of success of realization of Fredkin gate with linear optics is too low.In this work, we show that the same enhancement can be made possible via one Tooli and one CNOT gate, instead of a Fredkin gate.Not only the probability of success of the combination of these two gates is much higher, than that of a single Fredkin gate via linear optics, but also there is another method for implementing our setup with current photonics technology, almost with a unity success probability: A hybrid circuit consisting of a Tooli gate which can be implemented via one-way quantum computation on a weighted graph state of 8 qubits with a unity success probability and a linear optical CNOT gate which has a success probability close to unity.Therefore the preparation of polarization based encoded multi particle entangled W states of arbitrary sizes becomes considerably more ecient.

Acta Physica Polonica A•Apr 1, 2015•15 citations

Experimental Implementation of Efficient Linear Optics Quantum Computation

Gerard J Milburn, Timothy C. Ralph, Andrew G. White

One of the earliest proposals for implementing quantum computation was based on encoding each qubit in two optical modes, each containing exactly one photon. However, it is extremely difficult to unitarily couple two optical modes containing few photons. In 2001, Knill, Laflamme, and Milburn (KLM) found a way to circumvent this restriction and implement efficient quantum computation using only passive linear optics, photodetectors, and single photon sources. This efficient linear optical quantum computing (LOQC) is distinct from other linear optical schemes that are not efficiently scalable. The technological requirements for even the simplest gates in the KLM proposal initially seemed out of reach. However, Ralph, White, Munro and Milburn soon showed that, in principle, demonstrations of key gates and techniques could be achieved with current technology. The objective of the research undertaken in this project was to produce, in three years, a prototype two-qubit gate for photons using the KLM linear optics quantum computation approach, and to develop a blue-print for a multiple qubit device that might be implemented over a longer time scale. A non-deterministic two-qubit gate was demonstrated that operates with high fidelity. A number of key tasks were demonstrated using this gate, and several theoretical investigations of short, medium, and longer term issues for the LOQC approach were successfully completed.

•Nov 25, 2004•0 citations

Linear optical scheme for direct implementation of a nondestructive N -qubit controlled phase gate

Xu‐Bo Zou, Ke Li, Guang‐Can Guo

We propose a linear optical scheme for direct realization of a nondestructive $N$-qubit controlled phase gate without resorting to a sequence of single- and two-qubit gates. The proposed setup involves linear optical elements, nonmaximally entangled pairs of photons, and multiphoton coincidence detection. To implement the scheme, physical qubits represented by the polarization states of single photons are probabilistically encoded into the two-photon states. Based on such encoding operation, a nondestructive $N$-qubit phase gate can be directly achieved by $N$-photon interference on an array of polarization beam splitters and $N$-photon coincidence detection.

Physical Review A•Oct 26, 2006•54 citations

Single-photon logic gates using minimal resources

Qing Lin, Bing He

We present a simple architecture for deterministic quantum circuits operating on single-photon qubits. Few resources are necessary to implement two elementary gates and can be recycled for computing with large numbers of qubits. The deterministic realization of some key multiqubit gates, such as the Fredkin and Toffoli gate, is greatly simplified in this approach.

arXiv:0909.0300•Physical Review A•Oct 15, 2009•127 citations
We design linear-optics multiqubit quantum logic gates. We assume the traditional encoding of a qubit onto the state of a single photon in two modes (e.g., spatial or polarization). We suggest schemes allowing direct probabilistic realization of the fundamental Toffoli and Fredkin gates without resorting to a sequence of single- and two-qubit gates. This yields more compact schemes and potentially reduces the number of ancilla photons. The proposed setups involve passive linear optics, sources of auxiliary single photons or maximally entangled pairs of photons, and single-photon detectors. In particular, we propose an interferometric implementation of the Toffoli gate in the coincidence basis, which does not require any ancilla photons and is experimentally feasible with current technology.
Creation of large-scale W state quantum networks is a key step for realization of various quantum information tasks.Regarding the photonics technology, a simple optical setup was proposed for the fusion of two W states.Recently it was shown that via a single Fredkin gate, this basic so-called fusion setup can be enhanced.However the main problem was that the probability of success of realization of Fredkin gate with linear optics is too low.In this work, we show that the same enhancement can be made possible via one Tooli and one CNOT gate, instead of a Fredkin gate.Not only the probability of success of the combination of these two gates is much higher, than that of a single Fredkin gate via linear optics, but also there is another method for implementing our setup with current photonics technology, almost with a unity success probability: A hybrid circuit consisting of a Tooli gate which can be implemented via one-way quantum computation on a weighted graph state of 8 qubits with a unity success probability and a linear optical CNOT gate which has a success probability close to unity.Therefore the preparation of polarization based encoded multi particle entangled W states of arbitrary sizes becomes considerably more ecient.
One of the earliest proposals for implementing quantum computation was based on encoding each qubit in two optical modes, each containing exactly one photon. However, it is extremely difficult to unitarily couple two optical modes containing few photons. In 2001, Knill, Laflamme, and Milburn (KLM) found a way to circumvent this restriction and implement efficient quantum computation using only passive linear optics, photodetectors, and single photon sources. This efficient linear optical quantum computing (LOQC) is distinct from other linear optical schemes that are not efficiently scalable. The technological requirements for even the simplest gates in the KLM proposal initially seemed out of reach. However, Ralph, White, Munro and Milburn soon showed that, in principle, demonstrations of key gates and techniques could be achieved with current technology. The objective of the research undertaken in this project was to produce, in three years, a prototype two-qubit gate for photons using the KLM linear optics quantum computation approach, and to develop a blue-print for a multiple qubit device that might be implemented over a longer time scale. A non-deterministic two-qubit gate was demonstrated that operates with high fidelity. A number of key tasks were demonstrated using this gate, and several theoretical investigations of short, medium, and longer term issues for the LOQC approach were successfully completed.
We propose a linear optical scheme for direct realization of a nondestructive NNN-qubit controlled phase gate without resorting to a sequence of single- and two-qubit gates. The proposed setup involves linear optical elements, nonmaximally entangled pairs of photons, and multiphoton coincidence detection. To implement the scheme, physical qubits represented by the polarization states of single photons are probabilistically encoded into the two-photon states. Based on such encoding operation, a nondestructive NNN-qubit phase gate can be directly achieved by NNN-photon interference on an array of polarization beam splitters and NNN-photon coincidence detection.