liu.seSearch for publications in DiVA
Change search
Refine search result
1 - 10 of 10
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Fedorov, Aleksey
    et al.
    Russian Quantum Ctr, Russia; QRate, Russia; QApp, Russia.
    Gerhardt, Ilja
    Univ Stuttgart, Germany; Inst Quantum Sci and Technol, Germany; Max Planck Inst Solid State Res, Germany.
    Huang, Anqi
    Natl Univ Def Technol, Peoples R China; Natl Univ Def Technol, Peoples R China.
    Jogenfors, Jonathan
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Kurochkin, Yury
    Russian Quantum Ctr, Russia; QRate, Russia.
    Lamas-Linares, Antia
    Univ Texas Austin, TX 78712 USA.
    Larsson, Jan-Åke
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Leuchs, Gerd
    Max Planck Inst Sci Light, Germany; Univ Erlangen Nurnberg, Germany.
    Lydersen, Lars
    Kringsjavegen 3E, Norway.
    Makarov, Vadim
    Russian Quantum Ctr, Russia; Natl Univ Sci and Technol MISIS, Russia.
    Skaar, Johannes
    Univ Oslo, Norway.
    Comment on Inherent security of phase coding quantum key distribution systems against detector blinding attacks (vol 15, 095203, 2018)2019In: Laser Physics Letters, ISSN 1612-2011, E-ISSN 1612-202X, Vol. 16, no 1, article id 019401Article in journal (Other academic)
    Abstract [en]

    n/a

    The full text will be freely available from 2019-12-18 11:18
  • 2.
    Jogenfors, Jonathan
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, The Institute of Technology.
    A Classical-Light Attack on Energy-Time Entangled Quantum Key Distribution, and Countermeasures2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Quantum key distribution (QKD) is an application of quantum mechanics that allowstwo parties to communicate with perfect secrecy. Traditional QKD uses polarization of individual photons, but the development of energy-time entanglement could lead to QKD protocols robust against environmental effects. The security proofs of energy-time entangled QKD rely on a violation of the Bell inequality to certify the system as secure. This thesis shows that the Bell violation can be faked in energy-time entangled QKD protocols that involve a postselection step, such as Franson-based setups. Using pulsed and phase-modulated classical light, it is possible to circumvent the Bell test which allows for a local hidden-variable model to give the same predictions as the quantum-mechanical description. We show that this attack works experimentally and also how energy-time-entangled systems can be strengthened to avoid our attack.

    List of papers
    1. Energy-time entanglement, elements of reality, and local realism
    Open this publication in new window or tab >>Energy-time entanglement, elements of reality, and local realism
    2014 (English)In: Journal of Physics A: Mathematical and Theoretical, ISSN 1751-8113, E-ISSN 1751-8121, Vol. 47, no 42, p. 424032-Article in journal (Refereed) Published
    Abstract [en]

    The Franson interferometer, proposed in 1989 (Franson 1989 Phys. Rev. Lett. 62 2205-08), beautifully shows the counter-intuitive nature of light. The quantum description predicts sinusoidal interference for specific outcomes of the experiment, and these predictions can be verified in experiment. In the spirit of Einstein, Podolsky, and Rosen it is possible to ask if the quantum-mechanical description (of this setup) can be considered complete. This question will be answered in detail in this paper, by delineating the quite complicated relation between energy-time entanglement experiments and Einstein-Podolsky-Rosen (EPR) elements of reality. The mentioned sinusoidal interference pattern is the same as that giving a violation in the usual Bell experiment. Even so, depending on the precise requirements made on the local realist model, this can imply (a) no violation, (b) smaller violation than usual, or (c) full violation of the appropriate statistical bound. Alternatives include (a) using only the measurement outcomes as EPR elements of reality, (b) using the emission time as EPR element of reality, (c) using path realism, or (d) using a modified setup. This paper discusses the nature of these alternatives and how to choose between them. The subtleties of this discussion needs to be taken into account when designing and setting up experiments intended to test local realism. Furthermore, these considerations are also important for quantum communication, for example in Bell-inequality-based quantum cryptography, especially when aiming for device independence.

    Place, publisher, year, edition, pages
    IOP Publishing: Hybrid Open Access, 2014
    Keywords
    bell inequalities; energy-time entanglement; elements of reality
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-112643 (URN)10.1088/1751-8113/47/42/424032 (DOI)000344222200033 ()
    Available from: 2014-12-05 Created: 2014-12-05 Last updated: 2017-12-05
    2. Hacking the Bell test using classical light in energy-time entanglement–based quantum key distribution
    Open this publication in new window or tab >>Hacking the Bell test using classical light in energy-time entanglement–based quantum key distribution
    Show others...
    2015 (English)In: Science Advances, ISSN 2375-2548, Vol. 1, no 11, p. 1-7, article id e1500793Article in journal (Refereed) Published
    Abstract [en]

    Photonic systems based on energy-time entanglement have been proposed to test local realism using the Bell inequality. A violation of this inequality normally also certifies security of device-independent quantum key distribution (QKD) so that an attacker cannot eavesdrop or control the system. We show how this security test can be circumvented in energy-time entangled systems when using standard avalanche photodetectors, allowing an attacker to compromise the system without leaving a trace. We reach Bell values up to 3.63 at 97.6% faked detector efficiency using tailored pulses of classical light, which exceeds even the quantum prediction. This is the first demonstration of a violation-faking source that gives both tunable violation and high faked detector efficiency. The implications are severe: the standard Clauser-Horne-Shimony-Holt inequality cannot be used to show device-independent security for energy-time entanglement setups based on Franson’s configuration. However, device-independent security can be reestablished, and we conclude by listing a number of improved tests and experimental setups that would protect against all current and future attacks of this type.

    Place, publisher, year, edition, pages
    American Association for the Advancement of Science, 2015
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-114210 (URN)10.1126/sciadv.1500793 (DOI)000216604200020 ()
    Note

    At the time for thesis presentation publication was in status: Manuscript

    At the time for thesis presentation name of publication was: A Classical-Light Attack on Energy-Time Entangled Quantum Key Distribution, and Countermeasures

    Available from: 2015-02-13 Created: 2015-02-13 Last updated: 2018-03-09Bibliographically approved
  • 3.
    Jogenfors, Jonathan
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Breaking the Unbreakable: Exploiting Loopholes in Bell’s Theorem to Hack Quantum Cryptography2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis we study device-independent quantum key distribution based on energy-time entanglement. This is a method for cryptography that promises not only perfect secrecy, but also to be a practical method for quantum key distribution thanks to the reduced complexity when compared to other quantum key distribution protocols. However, there still exist a number of loopholes that must be understood and eliminated in order to rule out eavesdroppers. We study several relevant loopholes and show how they can be used to break the security of energy-time entangled systems. Attack strategies are reviewed as well as their countermeasures, and we show how full security can be re-established.

    Quantum key distribution is in part based on the profound no-cloning theorem, which prevents physical states to be copied at a microscopic level. This important property of quantum mechanics can be seen as Nature's own copy-protection, and can also be used to create a currency based on quantummechanics, i.e., quantum money. Here, the traditional copy-protection mechanisms of traditional coins and banknotes can be abandoned in favor of the laws of quantum physics. Previously, quantum money assumes a traditional hierarchy where a central, trusted bank controls the economy. We show how quantum money together with a blockchain allows for Quantum Bitcoin, a novel hybrid currency that promises fast transactions, extensive scalability, and full anonymity.

    List of papers
    1. Energy-time entanglement, elements of reality, and local realism
    Open this publication in new window or tab >>Energy-time entanglement, elements of reality, and local realism
    2014 (English)In: Journal of Physics A: Mathematical and Theoretical, ISSN 1751-8113, E-ISSN 1751-8121, Vol. 47, no 42, p. 424032-Article in journal (Refereed) Published
    Abstract [en]

    The Franson interferometer, proposed in 1989 (Franson 1989 Phys. Rev. Lett. 62 2205-08), beautifully shows the counter-intuitive nature of light. The quantum description predicts sinusoidal interference for specific outcomes of the experiment, and these predictions can be verified in experiment. In the spirit of Einstein, Podolsky, and Rosen it is possible to ask if the quantum-mechanical description (of this setup) can be considered complete. This question will be answered in detail in this paper, by delineating the quite complicated relation between energy-time entanglement experiments and Einstein-Podolsky-Rosen (EPR) elements of reality. The mentioned sinusoidal interference pattern is the same as that giving a violation in the usual Bell experiment. Even so, depending on the precise requirements made on the local realist model, this can imply (a) no violation, (b) smaller violation than usual, or (c) full violation of the appropriate statistical bound. Alternatives include (a) using only the measurement outcomes as EPR elements of reality, (b) using the emission time as EPR element of reality, (c) using path realism, or (d) using a modified setup. This paper discusses the nature of these alternatives and how to choose between them. The subtleties of this discussion needs to be taken into account when designing and setting up experiments intended to test local realism. Furthermore, these considerations are also important for quantum communication, for example in Bell-inequality-based quantum cryptography, especially when aiming for device independence.

    Place, publisher, year, edition, pages
    IOP Publishing: Hybrid Open Access, 2014
    Keywords
    bell inequalities; energy-time entanglement; elements of reality
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-112643 (URN)10.1088/1751-8113/47/42/424032 (DOI)000344222200033 ()
    Available from: 2014-12-05 Created: 2014-12-05 Last updated: 2017-12-05
    2. Hacking the Bell test using classical light in energy-time entanglement–based quantum key distribution
    Open this publication in new window or tab >>Hacking the Bell test using classical light in energy-time entanglement–based quantum key distribution
    Show others...
    2015 (English)In: Science Advances, ISSN 2375-2548, Vol. 1, no 11, p. 1-7, article id e1500793Article in journal (Refereed) Published
    Abstract [en]

    Photonic systems based on energy-time entanglement have been proposed to test local realism using the Bell inequality. A violation of this inequality normally also certifies security of device-independent quantum key distribution (QKD) so that an attacker cannot eavesdrop or control the system. We show how this security test can be circumvented in energy-time entangled systems when using standard avalanche photodetectors, allowing an attacker to compromise the system without leaving a trace. We reach Bell values up to 3.63 at 97.6% faked detector efficiency using tailored pulses of classical light, which exceeds even the quantum prediction. This is the first demonstration of a violation-faking source that gives both tunable violation and high faked detector efficiency. The implications are severe: the standard Clauser-Horne-Shimony-Holt inequality cannot be used to show device-independent security for energy-time entanglement setups based on Franson’s configuration. However, device-independent security can be reestablished, and we conclude by listing a number of improved tests and experimental setups that would protect against all current and future attacks of this type.

    Place, publisher, year, edition, pages
    American Association for the Advancement of Science, 2015
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-114210 (URN)10.1126/sciadv.1500793 (DOI)000216604200020 ()
    Note

    At the time for thesis presentation publication was in status: Manuscript

    At the time for thesis presentation name of publication was: A Classical-Light Attack on Energy-Time Entangled Quantum Key Distribution, and Countermeasures

    Available from: 2015-02-13 Created: 2015-02-13 Last updated: 2018-03-09Bibliographically approved
    3. Tight bounds for the Pearle-Braunstein-Caves chained inequality without the fair-coincidence assumption
    Open this publication in new window or tab >>Tight bounds for the Pearle-Braunstein-Caves chained inequality without the fair-coincidence assumption
    2017 (English)In: Physical Review A: covering atomic, molecular, and optical physics and quantum information, ISSN 2469-9926, E-ISSN 2469-9934, Vol. 96, no 2, article id 022102Article in journal (Refereed) Published
    Abstract [en]

    In any Bell test, loopholes can cause issues in the interpretation of the results, since an apparent violation of the inequality may not correspond to a violation of local realism. An important example is the coincidence-time loophole that arises when detector settings might influence the time when detection will occur. This effect can be observed in many experiments where measurement outcomes are to be compared between remote stations because the interpretation of an ostensible Bell violation strongly depends on the method used to decide coincidence. The coincidence-time loophole has previously been studied for the Clauser-Horne-Shimony-Holt and Clauser-Horne inequalities, but recent experiments have shown the need for a generalization. Here, we study the generalized chained inequality by Pearle, Braunstein, and Caves (PBC) with N amp;gt;= 2 settings per observer. This inequality has applications in, for instance, quantum key distribution where it has been used to reestablish security. In this paper we give the minimum coincidence probability for the PBC inequality for all N amp;gt;= 2 and show that this bound is tight for a violation free of the fair-coincidence assumption. Thus, if an experiment has a coincidence probability exceeding the critical value derived here, the coincidence-time loophole is eliminated.

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2017
    National Category
    Atom and Molecular Physics and Optics
    Identifiers
    urn:nbn:se:liu:diva-139910 (URN)10.1103/PhysRevA.96.022102 (DOI)000406669400003 ()
    Available from: 2017-08-23 Created: 2017-08-23 Last updated: 2017-11-29
    4. High-visibility time-bin entanglement for testing chained Bell inequalities
    Open this publication in new window or tab >>High-visibility time-bin entanglement for testing chained Bell inequalities
    Show others...
    2017 (English)In: Physical Review A, ISSN 2469-9926, Vol. 95, no 3, article id 032107Article in journal (Refereed) Published
    Abstract [en]

    The violation of Bells inequality requires a well-designed experiment to validate the result. In experiments using energy-time and time-bin entanglement, initially proposed by Franson in 1989, there is an intrinsic loophole due to the high postselection. To obtain a violation in this type of experiment, a chained Bell inequality must be used. However, the local realism bound requires a high visibility in excess of 94.63% in the time-bin entangled state. In this work, we show how such a high visibility can be reached in order to violate a chained Bell inequality with six, eight, and ten terms.

    Place, publisher, year, edition, pages
    AMER PHYSICAL SOC, 2017
    National Category
    Other Physics Topics
    Identifiers
    urn:nbn:se:liu:diva-136599 (URN)10.1103/PhysRevA.95.032107 (DOI)000395983300003 ()
    Available from: 2017-04-21 Created: 2017-04-21 Last updated: 2017-10-20
    5. Quantum Bitcoin: An Anonymous, Distributed, and Secure Currency Secured by the No-Cloning Theorem of Quantum Mechanics
    Open this publication in new window or tab >>Quantum Bitcoin: An Anonymous, Distributed, and Secure Currency Secured by the No-Cloning Theorem of Quantum Mechanics
    2019 (English)In: 2019 IEEE International Conference on Blockchain and Cryptocurrency (ICBC), 2019Conference paper, Published paper (Refereed)
    Abstract [en]

    The digital currency Bitcoin has had remarkable growth since it was first proposed in 2008. Its distributed nature allows currency transactions without a central authority by using cryptographic methods and a data structure called the blockchain. Imagine that you could run the Bitcoin protocol on a quantum computer. What advantages can be had over classical Bitcoin? This is the question we answer here by introducing Quantum Bitcoin which, among other features, has immediate local verification of transactions. This is a major improvement over classical Bitcoin since we no longer need the computationally-intensive and time-consuming method of recording all transactions in the blockchain. Quantum Bitcoin is the first distributed quantum currency, and this paper introduces the necessary tools including a novel two-stage quantum mining process. In addition, we have counterfeiting resistance, fully anonymous and free transactions, and a smaller footprint than classical Bitcoin.

    Keywords
    Quantum Bitcoin, Bitcoin, Quantum Computing
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:liu:diva-129217 (URN)10.1109/BLOC.2019.8751473 (DOI)978-1-7281-1328-9 (ISBN)978-1-7281-1329-6 (ISBN)
    Conference
    1st IEEE International Conference on Blockchain and Cryptocurrency (IEEE ICBC)
    Available from: 2016-06-13 Created: 2016-06-13 Last updated: 2019-11-05Bibliographically approved
    6. Comment on "Franson Interference Generated by a Two-Level System"
    Open this publication in new window or tab >>Comment on "Franson Interference Generated by a Two-Level System"
    2017 (English)Other (Other academic)
    Abstract [en]

    In a recent Letter [Phys. Rev. Lett. 118, 030501 (2017)], Peiris, Konthasinghe, and Muller report a Franson interferometry experiment using pairs of photons generated from a two-level semiconductor quantum dot. The authors report a visibility of 66% and claim that this visibility “goes beyond the classical limit of 50% and approaches the limit of violation of Bell’s inequalities (70.7%).” We explain why we do not agree with this last statement and how to fix the problem.

    Place, publisher, year, pages
    Ithaca, New York, USA: Cornell University Press, 2017. p. 1
    National Category
    Atom and Molecular Physics and Optics
    Identifiers
    urn:nbn:se:liu:diva-142073 (URN)
    Available from: 2017-10-20 Created: 2017-10-20 Last updated: 2019-08-15
  • 4.
    Jogenfors, Jonathan
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Quantum Bitcoin: An Anonymous, Distributed, and Secure Currency Secured by the No-Cloning Theorem of Quantum Mechanics2019In: 2019 IEEE International Conference on Blockchain and Cryptocurrency (ICBC), 2019Conference paper (Refereed)
    Abstract [en]

    The digital currency Bitcoin has had remarkable growth since it was first proposed in 2008. Its distributed nature allows currency transactions without a central authority by using cryptographic methods and a data structure called the blockchain. Imagine that you could run the Bitcoin protocol on a quantum computer. What advantages can be had over classical Bitcoin? This is the question we answer here by introducing Quantum Bitcoin which, among other features, has immediate local verification of transactions. This is a major improvement over classical Bitcoin since we no longer need the computationally-intensive and time-consuming method of recording all transactions in the blockchain. Quantum Bitcoin is the first distributed quantum currency, and this paper introduces the necessary tools including a novel two-stage quantum mining process. In addition, we have counterfeiting resistance, fully anonymous and free transactions, and a smaller footprint than classical Bitcoin.

  • 5.
    Jogenfors, Jonathan
    et al.
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Adán, Cabello
    Departamento de Física Aplicada II, Universidad de Sevilla, Sevilla, Spain.
    Larsson, Jan-Åke
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Comment on "Franson Interference Generated by a Two-Level System"2017Other (Other academic)
    Abstract [en]

    In a recent Letter [Phys. Rev. Lett. 118, 030501 (2017)], Peiris, Konthasinghe, and Muller report a Franson interferometry experiment using pairs of photons generated from a two-level semiconductor quantum dot. The authors report a visibility of 66% and claim that this visibility “goes beyond the classical limit of 50% and approaches the limit of violation of Bell’s inequalities (70.7%).” We explain why we do not agree with this last statement and how to fix the problem.

  • 6.
    Jogenfors, Jonathan
    et al.
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, The Institute of Technology.
    Elhassan, Ashraf M
    Physics Department, Stockholm University, Stockholm, Sweden.
    Ahrens, Johan
    Physics Department, Stockholm University, Stockholm, Sweden.
    Bourennane, Mohamed
    Physics Department, Stockholm University, Stockholm, Sweden.
    Larsson, Jan-Åke
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, The Institute of Technology.
    Hacking the Bell test using classical light in energy-time entanglement–based quantum key distribution2015In: Science Advances, ISSN 2375-2548, Vol. 1, no 11, p. 1-7, article id e1500793Article in journal (Refereed)
    Abstract [en]

    Photonic systems based on energy-time entanglement have been proposed to test local realism using the Bell inequality. A violation of this inequality normally also certifies security of device-independent quantum key distribution (QKD) so that an attacker cannot eavesdrop or control the system. We show how this security test can be circumvented in energy-time entangled systems when using standard avalanche photodetectors, allowing an attacker to compromise the system without leaving a trace. We reach Bell values up to 3.63 at 97.6% faked detector efficiency using tailored pulses of classical light, which exceeds even the quantum prediction. This is the first demonstration of a violation-faking source that gives both tunable violation and high faked detector efficiency. The implications are severe: the standard Clauser-Horne-Shimony-Holt inequality cannot be used to show device-independent security for energy-time entanglement setups based on Franson’s configuration. However, device-independent security can be reestablished, and we conclude by listing a number of improved tests and experimental setups that would protect against all current and future attacks of this type.

  • 7.
    Jogenfors, Jonathan
    et al.
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, The Institute of Technology.
    Larsson, Jan-Åke
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, The Institute of Technology.
    Energy-time entanglement, elements of reality, and local realism2014In: Journal of Physics A: Mathematical and Theoretical, ISSN 1751-8113, E-ISSN 1751-8121, Vol. 47, no 42, p. 424032-Article in journal (Refereed)
    Abstract [en]

    The Franson interferometer, proposed in 1989 (Franson 1989 Phys. Rev. Lett. 62 2205-08), beautifully shows the counter-intuitive nature of light. The quantum description predicts sinusoidal interference for specific outcomes of the experiment, and these predictions can be verified in experiment. In the spirit of Einstein, Podolsky, and Rosen it is possible to ask if the quantum-mechanical description (of this setup) can be considered complete. This question will be answered in detail in this paper, by delineating the quite complicated relation between energy-time entanglement experiments and Einstein-Podolsky-Rosen (EPR) elements of reality. The mentioned sinusoidal interference pattern is the same as that giving a violation in the usual Bell experiment. Even so, depending on the precise requirements made on the local realist model, this can imply (a) no violation, (b) smaller violation than usual, or (c) full violation of the appropriate statistical bound. Alternatives include (a) using only the measurement outcomes as EPR elements of reality, (b) using the emission time as EPR element of reality, (c) using path realism, or (d) using a modified setup. This paper discusses the nature of these alternatives and how to choose between them. The subtleties of this discussion needs to be taken into account when designing and setting up experiments intended to test local realism. Furthermore, these considerations are also important for quantum communication, for example in Bell-inequality-based quantum cryptography, especially when aiming for device independence.

  • 8.
    Jogenfors, Jonathan
    et al.
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Larsson, Jan-Åke
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Tight bounds for the Pearle-Braunstein-Caves chained inequality without the fair-coincidence assumption2017In: Physical Review A: covering atomic, molecular, and optical physics and quantum information, ISSN 2469-9926, E-ISSN 2469-9934, Vol. 96, no 2, article id 022102Article in journal (Refereed)
    Abstract [en]

    In any Bell test, loopholes can cause issues in the interpretation of the results, since an apparent violation of the inequality may not correspond to a violation of local realism. An important example is the coincidence-time loophole that arises when detector settings might influence the time when detection will occur. This effect can be observed in many experiments where measurement outcomes are to be compared between remote stations because the interpretation of an ostensible Bell violation strongly depends on the method used to decide coincidence. The coincidence-time loophole has previously been studied for the Clauser-Horne-Shimony-Holt and Clauser-Horne inequalities, but recent experiments have shown the need for a generalization. Here, we study the generalized chained inequality by Pearle, Braunstein, and Caves (PBC) with N amp;gt;= 2 settings per observer. This inequality has applications in, for instance, quantum key distribution where it has been used to reestablish security. In this paper we give the minimum coincidence probability for the PBC inequality for all N amp;gt;= 2 and show that this bound is tight for a violation free of the fair-coincidence assumption. Thus, if an experiment has a coincidence probability exceeding the critical value derived here, the coincidence-time loophole is eliminated.

  • 9.
    Lavesson, Nils
    et al.
    ABB Corporate Research, Västerås, Sweden.
    Jogenfors, Jonathan
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, The Institute of Technology.
    Widlund, Ola
    ABB Corporate Research, Västerås, Sweden.
    Modeling of streamers in transformer oil using OpenFOAM2014In: Compel, ISSN 0332-1649, Vol. 33, no 4, p. 1272-1281Article in journal (Refereed)
    Abstract [en]

    Purpose – A model for streamers based on charge transport has been developed by MIT and ABB. The purpose of this paper is to investigate the consequences of changing numerical method from the finite element method (FEM) to the finite volume method (FVM) for simulations using the streamer model. The new solver is also used to extend the simulations to 3D. Design/methodology/approach – The equations from the MIT-ABB streamer model are implemented in OpenFOAM which uses the FVM. Checks of the results are performed including verification of convergence. The solver is then applied to some of the key simulations from the FEM model and results presented. Findings – The results for second mode streamers are confirmed, whereas the results for third mode streamers differ significantly leading to questioning of one hypothesis proposed based on the FEM results. The 3D simulations give consistent results and show a way forward for future simulations. Originality/value – The FVM has not been applied to the model before and led to more confidence in second mode result and revising of third mode results. In addition the new simulation method makes it possible to extend the results to 3D.

  • 10.
    Tomasin, Marco
    et al.
    University of Padua, Italy; UOS Padova, Italy.
    Mantoan, Elia
    University of Padua, Italy; UOS Padova, Italy.
    Jogenfors, Jonathan
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Vallone, Giuseppe
    University of Padua, Italy; UOS Padova, Italy.
    Larsson, Jan-Åke
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, Faculty of Science & Engineering.
    Villoresi, Paolo
    University of Padua, Italy; UOS Padova, Italy.
    High-visibility time-bin entanglement for testing chained Bell inequalities2017In: Physical Review A, ISSN 2469-9926, Vol. 95, no 3, article id 032107Article in journal (Refereed)
    Abstract [en]

    The violation of Bells inequality requires a well-designed experiment to validate the result. In experiments using energy-time and time-bin entanglement, initially proposed by Franson in 1989, there is an intrinsic loophole due to the high postselection. To obtain a violation in this type of experiment, a chained Bell inequality must be used. However, the local realism bound requires a high visibility in excess of 94.63% in the time-bin entangled state. In this work, we show how such a high visibility can be reached in order to violate a chained Bell inequality with six, eight, and ten terms.

1 - 10 of 10
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf