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/0206198 · Physical Review A

Suitability versus fidelity for rating single-photon guns

G. Hockney, Pieter Kok, Jonathan P. Dowling

Published Mar 18, 2003• 10 citations
arXivHTMLPDF

Abstract

The creation of specified quantum states is important for most, if not all, applications in quantum computation and communication. The quality of the state preparation is therefore an essential ingredient in any assessment of a quantum-state gun. We show that the fidelity, under the standard definitions, is not sufficient to assess quantum sources, and we propose a measure of suitability that necessarily depends on the application for the source. We consider the performance of single-photon guns in the context of quantum key distribution (QKD) and linear optical quantum computation. Single-photon sources for QKD need radically different properties than sources for quantum computing. Furthermore, the suitability for single-photon guns is discussed explicitly in terms of experimentally accessible criteria.

DOI
10.1103/physreva.67.032306

Related papers

Suitability vs. fidelity: Toward better measures of goodness for single-photon guns

G. Hockney, Pieter Kok, Jonathan P. Dowling

We propose a new measure, suitability, to assess the performance of single-photon guns in the context of specific applications. In particular, we demonstrate the requirements for applications to quantum key distribution (QKD) are quite different, and less stringent, than those for linear optical quantum computing.

Frontiers in Optics•Jan 1, 2003•0 citations

Certification of linear optical quantum state preparation

Riko Schadow, Naomi Spier, Stefan N. van den Hoven +6 more

Certification is important to guarantee the correct functioning of quantum devices. A key certification task is verifying that a device has produced a desired output state. In this work, we study this task in the context of photonic platforms, where single photons are propagated through linear optical interferometers to create large, entangled resource states for metrology, communication, quantum advantage demonstrations and for so-called linear optical quantum computing (LOQC). This setting derives its computational power from the indistinguishability of the photons, i.e., their relative overlap. Therefore, standard fidelity witnesses developed for distinguishable particles (including qubits) do not apply directly, because they merely certify the closeness to some fixed target state. We introduce a measure of fidelity suitable for this setting and show several different ways to witness it, based on earlier proposals for measuring genuine multi-photon indistinguishability. We argue that a witness based upon the discrete Fourier transform is an optimal choice. We experimentally implement this witness and certify the fidelity of several multi-photon states.

quant-pharXiv:2602.12269•Feb 13, 2026•0 citations

Single-photon sources–an introduction

Stefan Scheel

This review surveys the physical principles and recent developments in manufacturing single-photon sources. Special emphasis is placed on important potential applications such as linear optical quantum computing (LOQC), quantum key distribution (QKD) and quantum metrology that drive the development of these sources of single photons. We discuss the quantum-mechanical properties of light prepared in a quantum state of definite photon number and compare it with coherent light that shows a Poissonian distribution of photon numbers. We examine how the single-photon fidelity directly influences the ability to transmit secure quantum bits over a predefined distance. The theoretical description of modified spontaneous decay, the main principle behind single-photon generation, provides the background for many experimental implementations such as those using microresonators or pillar microcavities. The main alternative way to generate single photons using postselection of entangled photon pairs from parametric down-conversion, will be discussed. We concentrate on describing the underlying physical principles and we will point out limitations and open problems associated with single-photon production.

Journal of Modern Optics•Jan 20, 2009•96 citations

Characterization of the nonclassical nature of conditionally prepared single photons

Alfred B. U’Ren, Christine Silberhorn, Jonathan L. Ball +2 more

A reliable single photon source is a prerequisite for linear optical quantum computation and for secure quantum key distribution. A criterion yielding a conclusive test of the single photon character of a given source, attainable with realistic detectors, is therefore highly desirable. In the context of heralded single photon sources, such a criterion should be sensitive to the effects of higher photon number contributions, and to vacuum introduced through optical losses, which tend to degrade source performance. In this Rapid Communication we present, theoretically and experimentally, a criterion meeting the above requirements.

arXiv:quant-ph/0412184•Physical Review A•Aug 25, 2005•60 citations

Criteria for single photon sources with variable nonclassicality threshold

Lukáš Lachman, Radim Filip

Abstract Single photon sources are necessary for optical quantum technology. The nonclassicality of emitted single photons manifests itself in diverse experiments and applications. The applications already require different nonclassical aspects of single photons, however, a suitable hierarchy of criteria is missing. We propose variable experimental tests, based on adjustable linear optical networks and single photon detectors, giving a hierarchy of such nonclassicality criteria. The hierarchy goes beyond Hanbury–Brown–Twiss test of photon antibunching and allows us to compare faithfully quality and performance of single photon sources via their nonclassical properties.

arXiv:1908.02578•New Journal of Physics•Jul 25, 2019•8 citations

Study of the Influence of Electromagnetic Scattering on the Spontaneous Emission of a Solid-State Single-Photon Emitter

Shaikh Arhama Gufran

From secure communication to blazingly fast computation, quantum technologies promise arevolutionary horizon with transformative potential across many areas. Single photon sources,essential to utilizing the special qualities of quantum mechanics, are at the core of many ofthese developments. Because single photons are discrete quanta of light, they provide quantum systems withunmatched precision and control, opening up new possibilities for security and sensitivity inapplications like quantum cryptography, quantum key distribution, and quantum sensing.These sources are fundamental components of quantum computing, in which complicatedcomputations can be completed tenfold more quickly than with traditional computers thanks toqubits contained in single photons. To fully realize the promise of quantum technologies andtheir widespread application, single-photon source development and optimization mustcontinue. In the field of quantum technologies, increasing the spontaneous emission rate of a singlephoton source is important for multiple reasons. First of all, a higher emission rate results in amore effective production of single photons, which is necessary for applications like quantumkey distribution (QKD) that demand a high photon flux. A greater emission rate in QKDincreases the overall security and efficiency of quantum communication systems byguaranteeing a quicker and more dependable interchange of quantum information. All things considered, increasing the spontaneous emission rate of a single photon source iscritical to realizing the full promise of quantum technologies, facilitating quicker and moreeffective quantum computing, sensing, integrated photonics, and communication, and openingthe door for revolutionary developments across a range of industries. This thesis explores the impact of electromagnetic scattering on solid-state single photonemitters' spontaneous emission behavior. By applying sophisticated computational approachesand conducting a comprehensive literature analysis, the study seeks to confirm and reproduceprevious findings, expanding and solidifying our knowledge of basic principles andcomputational strategies in this field. Two different scatterer geometries, a sphere, and a cylinder, activated by a point dipoleapproximation that is frequently employed in quantum optics simulations are the subject of thiswork. The main goal is to thoroughly evaluate and validate previously published results, not topresent new physics, but to guarantee the stability and dependability of computational modelsin the study of interactions between light and matter.

•Jul 28, 2026•0 citations
The creation of specified quantum states is important for most, if not all, applications in quantum computation and communication. The quality of the state preparation is therefore an essential ingredient in any assessment of a quantum-state gun. We show that the fidelity, under the standard definitions, is not sufficient to assess quantum sources, and we propose a measure of suitability that necessarily depends on the application for the source. We consider the performance of single-photon guns in the context of quantum key distribution (QKD) and linear optical quantum computation. Single-photon sources for QKD need radically different properties than sources for quantum computing. Furthermore, the suitability for single-photon guns is discussed explicitly in terms of experimentally accessible criteria.
Certification is important to guarantee the correct functioning of quantum devices. A key certification task is verifying that a device has produced a desired output state. In this work, we study this task in the context of photonic platforms, where single photons are propagated through linear optical interferometers to create large, entangled resource states for metrology, communication, quantum advantage demonstrations and for so-called linear optical quantum computing (LOQC). This setting derives its computational power from the indistinguishability of the photons, i.e., their relative overlap. Therefore, standard fidelity witnesses developed for distinguishable particles (including qubits) do not apply directly, because they merely certify the closeness to some fixed target state. We introduce a measure of fidelity suitable for this setting and show several different ways to witness it, based on earlier proposals for measuring genuine multi-photon indistinguishability. We argue that a witness based upon the discrete Fourier transform is an optimal choice. We experimentally implement this witness and certify the fidelity of several multi-photon states.
This review surveys the physical principles and recent developments in manufacturing single-photon sources. Special emphasis is placed on important potential applications such as linear optical quantum computing (LOQC), quantum key distribution (QKD) and quantum metrology that drive the development of these sources of single photons. We discuss the quantum-mechanical properties of light prepared in a quantum state of definite photon number and compare it with coherent light that shows a Poissonian distribution of photon numbers. We examine how the single-photon fidelity directly influences the ability to transmit secure quantum bits over a predefined distance. The theoretical description of modified spontaneous decay, the main principle behind single-photon generation, provides the background for many experimental implementations such as those using microresonators or pillar microcavities. The main alternative way to generate single photons using postselection of entangled photon pairs from parametric down-conversion, will be discussed. We concentrate on describing the underlying physical principles and we will point out limitations and open problems associated with single-photon production.
A reliable single photon source is a prerequisite for linear optical quantum computation and for secure quantum key distribution. A criterion yielding a conclusive test of the single photon character of a given source, attainable with realistic detectors, is therefore highly desirable. In the context of heralded single photon sources, such a criterion should be sensitive to the effects of higher photon number contributions, and to vacuum introduced through optical losses, which tend to degrade source performance. In this Rapid Communication we present, theoretically and experimentally, a criterion meeting the above requirements.
Abstract Single photon sources are necessary for optical quantum technology. The nonclassicality of emitted single photons manifests itself in diverse experiments and applications. The applications already require different nonclassical aspects of single photons, however, a suitable hierarchy of criteria is missing. We propose variable experimental tests, based on adjustable linear optical networks and single photon detectors, giving a hierarchy of such nonclassicality criteria. The hierarchy goes beyond Hanbury–Brown–Twiss test of photon antibunching and allows us to compare faithfully quality and performance of single photon sources via their nonclassical properties.
From secure communication to blazingly fast computation, quantum technologies promise arevolutionary horizon with transformative potential across many areas. Single photon sources,essential to utilizing the special qualities of quantum mechanics, are at the core of many ofthese developments. Because single photons are discrete quanta of light, they provide quantum systems withunmatched precision and control, opening up new possibilities for security and sensitivity inapplications like quantum cryptography, quantum key distribution, and quantum sensing.These sources are fundamental components of quantum computing, in which complicatedcomputations can be completed tenfold more quickly than with traditional computers thanks toqubits contained in single photons. To fully realize the promise of quantum technologies andtheir widespread application, single-photon source development and optimization mustcontinue. In the field of quantum technologies, increasing the spontaneous emission rate of a singlephoton source is important for multiple reasons. First of all, a higher emission rate results in amore effective production of single photons, which is necessary for applications like quantumkey distribution (QKD) that demand a high photon flux. A greater emission rate in QKDincreases the overall security and efficiency of quantum communication systems byguaranteeing a quicker and more dependable interchange of quantum information. All things considered, increasing the spontaneous emission rate of a single photon source iscritical to realizing the full promise of quantum technologies, facilitating quicker and moreeffective quantum computing, sensing, integrated photonics, and communication, and openingthe door for revolutionary developments across a range of industries. This thesis explores the impact of electromagnetic scattering on solid-state single photonemitters' spontaneous emission behavior. By applying sophisticated computational approachesand conducting a comprehensive literature analysis, the study seeks to confirm and reproduceprevious findings, expanding and solidifying our knowledge of basic principles andcomputational strategies in this field. Two different scatterer geometries, a sphere, and a cylinder, activated by a point dipoleapproximation that is frequently employed in quantum optics simulations are the subject of thiswork. The main goal is to thoroughly evaluate and validate previously published results, not topresent new physics, but to guarantee the stability and dependability of computational modelsin the study of interactions between light and matter.