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/0204073 · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Photon counting schemes and performance of non-deterministic nonlinear gates in linear optics

Stephen D. Bartlett, Eleni Diamanti, Barry C. Sanders, Y. Yamamoto

Published Dec 1, 2002• 12 citations
arXivHTMLPDF

Abstract

The performance of nondeterministic nonlinear gates in linear optics relies on the photon counting scheme being employed and the efficiencies of the detectors in such schemes. We assess the performance of the nonlinear sign gate, which is a critical component of linear optical quantum computing, for two standard photon counting methods: the double detector array and the visible light photon counter. Our analysis shows that the double detector array is insufficient to provide the photon counting capability for effective nondeterministic nonlinear transformations, and we determine the gate fidelity for both photon counting methods as a function of detector efficiencies.

DOI
10.1117/12.451332

Related papers

Nondeterministic Logic Gates in Optical Quantum Computing

Federico M. Spedalieri, Jonathan P. Dowling, Hwang Lee

Federico M. Spedalieri, Jonathan P. Dowling, and Hwang Lee Abstract We present a detailed description of nondeterministic quantum logic gates: the crucial component of linear optical quantum computing. We use the qubits that are encoded in the polarization degrees of freedom, as opposed to the original dual-rail encoding. Employing the polarization-encoding scheme, we can avoid the undetected errors due to the inefficiency of the photodetectors and, therefore, achieve high gate fidelity, independent of the quantum efficiency of the detectors. Furthermore, we show that such a high-fidelity gate operation can be performed with no need of number-resolving detectors.

Chapman & Hall/CRC eBooks•Sep 19, 2007•0 citations

Nondeterministic gates for photonic single-rail quantum logic

Austin P. Lund, Timothy C. Ralph

We discuss techniques for producing, manipulating, and measuring qubits encoded optically as vacuum- and single-photon states. We show that a universal set of nondeterministic gates can be constructed using linear optics and photon counting. We investigate the efficacy of a test gate given realistic detector efficiencies.

arXiv:quant-ph/0205044•Physical Review A•Sep 16, 2002•60 citations

Quantum computation with continuous variables: requirement of nonlinearity for photon counting

Stephen D. Bartlett, Barry C. Sanders

Summary form only given. We show that universal continuous-variable (CV) quantum computation can be obtained using linear optics (phase-space displacements and squeezing), homodyne measurement with classical feed-forward, and a realization of the photon counting projective value measurements (PVM). We describe the PVM for current (ideal) photodetectors, and demonstrate that such detectors cannot be used to implement the photon counting PVM with linear optics alone. Specifically, proposals to implement photon counting using arrays of beamsplitters to distribute the photons across several modes is insufficient for universal CV quantum computation. The photon counting PVM carries with it an implicit nonlinearity, and we discuss how it can be implemented in a CV system using a Kerr interaction (or another nonlinear Hamiltonian) and homodyne measurement. The resource requirements of this measurement scheme compared with using linear optics and current photodetectors are outlined.

Quantum Electronics and Laser Science Conference•Jun 25, 2003•0 citations

Optical implementation of quantum computers

John Rarity, Harald Weinfurter

Optical quantum computation was limited to a few photon applications such as quantum cryptography and partial teleportation until 2001. Then the possibility of performing arbitrary logic conditional on certain detection outcomes was introduced by Knill, Laflamme and Milburn ( Nature 2001 409 46). Simple circuits consisting of single photon sources, entangled pair sources, linear optical elements and high efficiency photon counting detectors can be used to develop probabilistic two-photon logic gates. Initially such gates show a low probability of success but can approach the success rate of deterministic (non-linear) logic at the cost of added complexity. These developments have led to the emergence of a novel field of research aimed at improving the efficiency of linear logic and developing the efficient sources and detectors for its implementation. This topical issue of Journal of Optics B: Quantum and Semiclassical Optics is devoted to recent advances in this field. Key to all linear optics gates is the interference effect between separate photons that have no previous history. In this issue we include the first experiment to show such an effect (Rarity et al ), on which many later experiments are based. These interference effects can then be used to entangle separate pairs of particles into higher order entangled states (Zou et al 2005 J. Opt. B: Quantum Semiclass. Opt. 7 119–121) and also to establish entanglement between matter qubits (Kok et al ). Quantum dot single photon sources suitable for linear optics quantum logic are discussed in the paper by Unitt et al while a waveguide source of pair photons is presented by Ducci et al . The difficulties in scaling linear optics quantum computing arise from the low success probabilities of the gates. Introducing a small amount of non-linearity could allow unit efficiency gates to be designed (Munro et al ) while large non-linearities generated by the collective effects in EIT could be used to implement a wide variety of quantum logic functions (Petrosyan). The development of algorithms suitable for optical implementation is addressed by Ellinas et al . Key contributors to this issue are collaborating in the project IST:38864 RAMBOQ which has a primary goal of developing linear optics computation tools and techniques.

Journal of Optics B Quantum and Semiclassical Optics•Jun 30, 2005•0 citations

On Photonic Implementation of Quantum Computers

Svetomir Simonović

The first section of the work investigates light modes as a means of implementing optical qubits and qudits. The modes considered are polarization mode, path mode, transverse spatial mode, frequency mode, temporal bin-mode and temporal mode. Subsequently, mathematical model of linear optical elements like beam splitters (BS) and phase shifters are deduced and their capability of representing any single qubit optical gate is exposed. Finally Knill, Laflamme and Milburn (KLM) method of using linear optical elements to promote nonlinear operations based on nonlinear (nondeterministic) sign-flip gate (NS) is explained, and designs of two qubits conditional sign flip gate (c-z1/16) and CNOT gate, both based on KLM method, are demonstrated. So, universal set of quantum gates based on linear optics is possible.

Advanced Technologies & Materials•Dec 2, 2023•0 citations

Efficient linear optics quantum computation

Gerard J Milburn, Timothy C. Ralph, Andrew G. White +2 more

Two qubit gates for photons are generally thought to require exotic materials with huge optical nonlinearities. We show here that, if we accept two qubit gates that only work conditionally, single photon sources, passive linear optics and particle detectors are sufficient for implementing reliable quantum algorithms. The conditional nature of the gates requires feed-forward from the detectors to the optical elements. Without feed forward, non-deterministic quantum computation is possible. We discuss one proposed single photon source based on the surface acoustic wave guiding of single electrons.

Quantum Information and Computation•Dec 1, 2001•14 citations
The performance of nondeterministic nonlinear gates in linear optics relies on the photon counting scheme being employed and the efficiencies of the detectors in such schemes. We assess the performance of the nonlinear sign gate, which is a critical component of linear optical quantum computing, for two standard photon counting methods: the double detector array and the visible light photon counter. Our analysis shows that the double detector array is insufficient to provide the photon counting capability for effective nondeterministic nonlinear transformations, and we determine the gate fidelity for both photon counting methods as a function of detector efficiencies.
Federico M. Spedalieri, Jonathan P. Dowling, and Hwang Lee Abstract We present a detailed description of nondeterministic quantum logic gates: the crucial component of linear optical quantum computing. We use the qubits that are encoded in the polarization degrees of freedom, as opposed to the original dual-rail encoding. Employing the polarization-encoding scheme, we can avoid the undetected errors due to the inefficiency of the photodetectors and, therefore, achieve high gate fidelity, independent of the quantum efficiency of the detectors. Furthermore, we show that such a high-fidelity gate operation can be performed with no need of number-resolving detectors.
Summary form only given. We show that universal continuous-variable (CV) quantum computation can be obtained using linear optics (phase-space displacements and squeezing), homodyne measurement with classical feed-forward, and a realization of the photon counting projective value measurements (PVM). We describe the PVM for current (ideal) photodetectors, and demonstrate that such detectors cannot be used to implement the photon counting PVM with linear optics alone. Specifically, proposals to implement photon counting using arrays of beamsplitters to distribute the photons across several modes is insufficient for universal CV quantum computation. The photon counting PVM carries with it an implicit nonlinearity, and we discuss how it can be implemented in a CV system using a Kerr interaction (or another nonlinear Hamiltonian) and homodyne measurement. The resource requirements of this measurement scheme compared with using linear optics and current photodetectors are outlined.
Optical quantum computation was limited to a few photon applications such as quantum cryptography and partial teleportation until 2001. Then the possibility of performing arbitrary logic conditional on certain detection outcomes was introduced by Knill, Laflamme and Milburn ( Nature 2001 409 46). Simple circuits consisting of single photon sources, entangled pair sources, linear optical elements and high efficiency photon counting detectors can be used to develop probabilistic two-photon logic gates. Initially such gates show a low probability of success but can approach the success rate of deterministic (non-linear) logic at the cost of added complexity. These developments have led to the emergence of a novel field of research aimed at improving the efficiency of linear logic and developing the efficient sources and detectors for its implementation. This topical issue of Journal of Optics B: Quantum and Semiclassical Optics is devoted to recent advances in this field. Key to all linear optics gates is the interference effect between separate photons that have no previous history. In this issue we include the first experiment to show such an effect (Rarity et al ), on which many later experiments are based. These interference effects can then be used to entangle separate pairs of particles into higher order entangled states (Zou et al 2005 J. Opt. B: Quantum Semiclass. Opt. 7 119–121) and also to establish entanglement between matter qubits (Kok et al ). Quantum dot single photon sources suitable for linear optics quantum logic are discussed in the paper by Unitt et al while a waveguide source of pair photons is presented by Ducci et al . The difficulties in scaling linear optics quantum computing arise from the low success probabilities of the gates. Introducing a small amount of non-linearity could allow unit efficiency gates to be designed (Munro et al ) while large non-linearities generated by the collective effects in EIT could be used to implement a wide variety of quantum logic functions (Petrosyan). The development of algorithms suitable for optical implementation is addressed by Ellinas et al . Key contributors to this issue are collaborating in the project IST:38864 RAMBOQ which has a primary goal of developing linear optics computation tools and techniques.
The first section of the work investigates light modes as a means of implementing optical qubits and qudits. The modes considered are polarization mode, path mode, transverse spatial mode, frequency mode, temporal bin-mode and temporal mode. Subsequently, mathematical model of linear optical elements like beam splitters (BS) and phase shifters are deduced and their capability of representing any single qubit optical gate is exposed. Finally Knill, Laflamme and Milburn (KLM) method of using linear optical elements to promote nonlinear operations based on nonlinear (nondeterministic) sign-flip gate (NS) is explained, and designs of two qubits conditional sign flip gate (c-z1/16) and CNOT gate, both based on KLM method, are demonstrated. So, universal set of quantum gates based on linear optics is possible.
Two qubit gates for photons are generally thought to require exotic materials with huge optical nonlinearities. We show here that, if we accept two qubit gates that only work conditionally, single photon sources, passive linear optics and particle detectors are sufficient for implementing reliable quantum algorithms. The conditional nature of the gates requires feed-forward from the detectors to the optical elements. Without feed forward, non-deterministic quantum computation is possible. We discuss one proposed single photon source based on the surface acoustic wave guiding of single electrons.