The Experts below are selected from a list of 14127 Experts worldwide ranked by ideXlab platform

Nicolas J Cerf - One of the best experts on this subject based on the ideXlab platform.

  • Entropy generation in Gaussian quantum transformations: applying the Replica Method to continuous-variable quantum information theory
    npj Quantum Information, 2016
    Co-Authors: Christos N. Gagatsos, Georgios Kordas, Alexandros I Karanikas, Nicolas J Cerf
    Abstract:

    In spite of their simple description in terms of rotations or symplectic transformations in phase space, quadratic Hamiltonians such as those modelling the most common Gaussian operations on bosonic modes remain poorly understood in terms of entropy production. For instance, determining the quantum entropy generated by a Bogoliubov transformation is notably a hard problem, with generally no known analytical solution, while it is vital to the characterisation of quantum communication via bosonic channels. Here we overcome this difficulty by adapting the Replica Method, a tool borrowed from statistical physics and quantum field theory. We exhibit a first application of this Method to continuous-variable quantum information theory, where it enables accessing entropies in an optical parametric amplifier. As an illustration, we determine the entropy generated by amplifying a binary superposition of the vacuum and a Fock state, which yields a surprisingly simple, yet unknown analytical expression.Quantum communication: the Replica Method gets its dueAn improved Method for calculating the entropy of quantum information carriers may help solve hard problems in quantum communication theory. Continuous-variable quantum information theory uses Gaussian states, such as laser-generated coherent light pulses, to perform communication or cryptography tasks. While quantum Gaussian processes can often be analyzed with simple mathematical expressions involving the amplitude and phase quadratures of the field, calculating entropies is generally impractical—a situation that causes problems, for example, when evaluating the bit rate through photonic channels. Nicolas Cerf from the Université Libre de Bruxelles in Belgium and co-workers adapted for this purpose the ‘Replica’ Method, a trick developed by statistical physicists for the description of random media such as spin glasses. Applying this Method to the amplification of a single photon superposed with vacuum revealed a new way of calculating entropy with surprising outcomes.

  • Entropy generation in Gaussian quantum transformations: applying the Replica Method to continuous-variable quantum information theory
    npj Quantum Information, 2016
    Co-Authors: Christos N. Gagatsos, Georgios Kordas, Alexandros I Karanikas, Nicolas J Cerf
    Abstract:

    In spite of their simple description in terms of rotations or symplectic transformations in phase space, quadratic Hamiltonians such as those modelling the most common Gaussian operations on bosonic modes remain poorly understood in terms of entropy production. For instance, determining the quantum entropy generated by a Bogoliubov transformation is notably a hard problem, with generally no known analytical solution, while it is vital to the characterisation of quantum communication via bosonic channels. Here we overcome this difficulty by adapting the Replica Method, a tool borrowed from statistical physics and quantum field theory. We exhibit a first application of this Method to continuous-variable quantum information theory, where it enables accessing entropies in an optical parametric amplifier. As an illustration, we determine the entropy generated by amplifying a binary superposition of the vacuum and a Fock state, which yields a surprisingly simple, yet unknown analytical expression. An improved Method for calculating the entropy of quantum information carriers may help solve hard problems in quantum communication theory. Continuous-variable quantum information theory uses Gaussian states, such as laser-generated coherent light pulses, to perform communication or cryptography tasks. While quantum Gaussian processes can often be analyzed with simple mathematical expressions involving the amplitude and phase quadratures of the field, calculating entropies is generally impractical—a situation that causes problems, for example, when evaluating the bit rate through photonic channels. Nicolas Cerf from the Université Libre de Bruxelles in Belgium and co-workers adapted for this purpose the ‘Replica’ Method, a trick developed by statistical physicists for the description of random media such as spin glasses. Applying this Method to the amplification of a single photon superposed with vacuum revealed a new way of calculating entropy with surprising outcomes.

  • Entropy generation in Gaussian quantum transformations: applying the Replica Method to continuous-variable quantum information theory
    npj Quantum Information, 2016
    Co-Authors: Christos N. Gagatsos, Georgios Kordas, Alexandros I Karanikas, Nicolas J Cerf
    Abstract:

    In spite of their simple description in terms of rotations or symplectic transformations in phase space, quadratic Hamiltonians such as those modelling the most common Gaussian operations on bosonic modes remain poorly understood in terms of entropy production. For instance, determining the quantum entropy generated by a Bogoliubov transformation is notably a hard problem, with generally no known analytical solution, while it is vital to the characterisation of quantum communication via bosonic channels. Here we overcome this difficulty by adapting the Replica Method, a tool borrowed from statistical physics and quantum field theory. We exhibit a first application of this Method to continuous-variable quantum information theory, where it enables accessing entropies in an optical parametric amplifier. As an illustration, we determine the entropy generated by amplifying a binary superposition of the vacuum and a Fock state, which yields a surprisingly simple, yet unknown analytical expression. An improved Method for calculating the entropy of quantum information carriers may help solve hard problems in quantum communication theory. Continuous-variable quantum information theory uses Gaussian states, such as laser-generated coherent light pulses, to perform communication or cryptography tasks. While quantum Gaussian processes can often be analyzed with simple mathematical expressions involving the amplitude and phase quadratures of the field, calculating entropies is generally impractical—a situation that causes problems, for example, when evaluating the bit rate through photonic channels. Nicolas Cerf from the Universite Libre de Bruxelles in Belgium and co-workers adapted for this purpose the ‘Replica’ Method, a trick developed by statistical physicists for the description of random media such as spin glasses. Applying this Method to the amplification of a single photon superposed with vacuum revealed a new way of calculating entropy with surprising outcomes.

Jun Kawai - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of human skin irritation by carboxylic acids, alcohols, esters and aldehydes, with nitrocellulose-Replica Method and closed patch testing.
    Contact Dermatitis, 1996
    Co-Authors: Atsushi Sato, Kishiko Ohkoshi, Hidenobu Okumura, Noriyasu Ozawa, Yasushi Katsumura, K Obata, K. Ikeda, Jun Kawai, Hisashi Tatsumi
    Abstract:

    Closed patch testing and the nitrocellulose Replica Method are performed as useful clinical Methods for the evaluation of human skin irritation by cosmetics and topical medicaments. Comparison of the sensitivity between microscopic scoring by nitrocellulose-Replica Method and visual scoring by closed patch test in the detection of skin irritation, however, has not been well studied with statistical analysis. Here, we evaluated human skin irritation by carboxylic acids. Alcohols, esters and aldehydes, with different chain length (C8-C18), using both Methods. The results of closed patch testing showed that, although the score of skin irritation for carboxylic acids (C8, C12), alcohols (C8) and aldehydes (C8), tested at a concentration of 0.5 m-2.0 m. significantly increased with increasing concentration of the test compounds, ester compounds scarcely caused any irritation on the surface of the skin occluded. In addition, an increase of carbon chain length in the test compounds made it impossible to detect skin irritation. In contrast, the nitrocellulose-Replica Method could evaluate skin reactions against very weak irritants that gave no macroscopic alterations on the skin surface in the closed patch test. However, the scoring system is somewhat subjective and should be improved to make the analysis more objective.

  • Evaluation of skin irritancy of sodium lauryl sulphate: a comparative study between the Replica Method and visual evaluation.
    Contact dermatitis, 1992
    Co-Authors: Kehchi Kawai, Jun Kawai, Mikio Nakagawa, Kyozo Kawai
    Abstract:

    For 20 years, using the Replica Method, we have evaluated the skin irritancy of about 10,000 commercial products which come into contact with the skin. In this Method, test substances are usually applied on the flexor side of the upper arm for 24 h by semi-open patch test. Subsequently, skin Replicas are taken and skin irritancy is evaluated microscopically. In the semi-open patch test, test substances are not completely occluded as in the closed patch test. Thus, this Method is less invasive than the closed patch test Method to the tested subjects. In this study, we investigated the sensitivity of microscopic scoring (MS) of the Replica and visual scoring (VS) of the skin. Sodium lauryl sulphate (SLS) at 0.02%, 0.05%, and 0.2% was applied on 20 subjects' upper arms, using closed and semi-open Methods. In both the closed patch test and the semi-open patch test, the value of MS correlated with the concentration of SLS, while VS did not show such a clear correlation. In addition, we compared 2 clinical tests for skin irritancy which are commonly performed in Japan: VS of 48 h closed patch test reaction on the subjects' upper backs and MS of 24 h semi-open patch test reaction on the subjects' upper arms (Replica Method). MS on the upper arms resulted in a constant score, regardless of the location of application, while VS on the upper back produced results which differed widely depending on the location. Thus, the Replica Method is a useful clinical test for skin irritancy, because it is sensitive, reproducible and non-invasive.

Hisashi Tatsumi - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of human skin irritation by carboxylic acids, alcohols, esters and aldehydes, with nitrocellulose-Replica Method and closed patch testing.
    Contact Dermatitis, 1996
    Co-Authors: Atsushi Sato, Kishiko Ohkoshi, Hidenobu Okumura, Noriyasu Ozawa, Yasushi Katsumura, K Obata, K. Ikeda, Jun Kawai, Hisashi Tatsumi
    Abstract:

    Closed patch testing and the nitrocellulose Replica Method are performed as useful clinical Methods for the evaluation of human skin irritation by cosmetics and topical medicaments. Comparison of the sensitivity between microscopic scoring by nitrocellulose-Replica Method and visual scoring by closed patch test in the detection of skin irritation, however, has not been well studied with statistical analysis. Here, we evaluated human skin irritation by carboxylic acids. Alcohols, esters and aldehydes, with different chain length (C8-C18), using both Methods. The results of closed patch testing showed that, although the score of skin irritation for carboxylic acids (C8, C12), alcohols (C8) and aldehydes (C8), tested at a concentration of 0.5 m-2.0 m. significantly increased with increasing concentration of the test compounds, ester compounds scarcely caused any irritation on the surface of the skin occluded. In addition, an increase of carbon chain length in the test compounds made it impossible to detect skin irritation. In contrast, the nitrocellulose-Replica Method could evaluate skin reactions against very weak irritants that gave no macroscopic alterations on the skin surface in the closed patch test. However, the scoring system is somewhat subjective and should be improved to make the analysis more objective.

Kyozo Kawai - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of skin irritancy of sodium lauryl sulphate: a comparative study between the Replica Method and visual evaluation.
    Contact dermatitis, 1992
    Co-Authors: Kehchi Kawai, Jun Kawai, Mikio Nakagawa, Kyozo Kawai
    Abstract:

    For 20 years, using the Replica Method, we have evaluated the skin irritancy of about 10,000 commercial products which come into contact with the skin. In this Method, test substances are usually applied on the flexor side of the upper arm for 24 h by semi-open patch test. Subsequently, skin Replicas are taken and skin irritancy is evaluated microscopically. In the semi-open patch test, test substances are not completely occluded as in the closed patch test. Thus, this Method is less invasive than the closed patch test Method to the tested subjects. In this study, we investigated the sensitivity of microscopic scoring (MS) of the Replica and visual scoring (VS) of the skin. Sodium lauryl sulphate (SLS) at 0.02%, 0.05%, and 0.2% was applied on 20 subjects' upper arms, using closed and semi-open Methods. In both the closed patch test and the semi-open patch test, the value of MS correlated with the concentration of SLS, while VS did not show such a clear correlation. In addition, we compared 2 clinical tests for skin irritancy which are commonly performed in Japan: VS of 48 h closed patch test reaction on the subjects' upper backs and MS of 24 h semi-open patch test reaction on the subjects' upper arms (Replica Method). MS on the upper arms resulted in a constant score, regardless of the location of application, while VS on the upper back produced results which differed widely depending on the location. Thus, the Replica Method is a useful clinical test for skin irritancy, because it is sensitive, reproducible and non-invasive.

Christos N. Gagatsos - One of the best experts on this subject based on the ideXlab platform.

  • Entropy generation in Gaussian quantum transformations: applying the Replica Method to continuous-variable quantum information theory
    npj Quantum Information, 2016
    Co-Authors: Christos N. Gagatsos, Georgios Kordas, Alexandros I Karanikas, Nicolas J Cerf
    Abstract:

    In spite of their simple description in terms of rotations or symplectic transformations in phase space, quadratic Hamiltonians such as those modelling the most common Gaussian operations on bosonic modes remain poorly understood in terms of entropy production. For instance, determining the quantum entropy generated by a Bogoliubov transformation is notably a hard problem, with generally no known analytical solution, while it is vital to the characterisation of quantum communication via bosonic channels. Here we overcome this difficulty by adapting the Replica Method, a tool borrowed from statistical physics and quantum field theory. We exhibit a first application of this Method to continuous-variable quantum information theory, where it enables accessing entropies in an optical parametric amplifier. As an illustration, we determine the entropy generated by amplifying a binary superposition of the vacuum and a Fock state, which yields a surprisingly simple, yet unknown analytical expression.Quantum communication: the Replica Method gets its dueAn improved Method for calculating the entropy of quantum information carriers may help solve hard problems in quantum communication theory. Continuous-variable quantum information theory uses Gaussian states, such as laser-generated coherent light pulses, to perform communication or cryptography tasks. While quantum Gaussian processes can often be analyzed with simple mathematical expressions involving the amplitude and phase quadratures of the field, calculating entropies is generally impractical—a situation that causes problems, for example, when evaluating the bit rate through photonic channels. Nicolas Cerf from the Université Libre de Bruxelles in Belgium and co-workers adapted for this purpose the ‘Replica’ Method, a trick developed by statistical physicists for the description of random media such as spin glasses. Applying this Method to the amplification of a single photon superposed with vacuum revealed a new way of calculating entropy with surprising outcomes.

  • Entropy generation in Gaussian quantum transformations: applying the Replica Method to continuous-variable quantum information theory
    npj Quantum Information, 2016
    Co-Authors: Christos N. Gagatsos, Georgios Kordas, Alexandros I Karanikas, Nicolas J Cerf
    Abstract:

    In spite of their simple description in terms of rotations or symplectic transformations in phase space, quadratic Hamiltonians such as those modelling the most common Gaussian operations on bosonic modes remain poorly understood in terms of entropy production. For instance, determining the quantum entropy generated by a Bogoliubov transformation is notably a hard problem, with generally no known analytical solution, while it is vital to the characterisation of quantum communication via bosonic channels. Here we overcome this difficulty by adapting the Replica Method, a tool borrowed from statistical physics and quantum field theory. We exhibit a first application of this Method to continuous-variable quantum information theory, where it enables accessing entropies in an optical parametric amplifier. As an illustration, we determine the entropy generated by amplifying a binary superposition of the vacuum and a Fock state, which yields a surprisingly simple, yet unknown analytical expression. An improved Method for calculating the entropy of quantum information carriers may help solve hard problems in quantum communication theory. Continuous-variable quantum information theory uses Gaussian states, such as laser-generated coherent light pulses, to perform communication or cryptography tasks. While quantum Gaussian processes can often be analyzed with simple mathematical expressions involving the amplitude and phase quadratures of the field, calculating entropies is generally impractical—a situation that causes problems, for example, when evaluating the bit rate through photonic channels. Nicolas Cerf from the Université Libre de Bruxelles in Belgium and co-workers adapted for this purpose the ‘Replica’ Method, a trick developed by statistical physicists for the description of random media such as spin glasses. Applying this Method to the amplification of a single photon superposed with vacuum revealed a new way of calculating entropy with surprising outcomes.

  • Entropy generation in Gaussian quantum transformations: applying the Replica Method to continuous-variable quantum information theory
    npj Quantum Information, 2016
    Co-Authors: Christos N. Gagatsos, Georgios Kordas, Alexandros I Karanikas, Nicolas J Cerf
    Abstract:

    In spite of their simple description in terms of rotations or symplectic transformations in phase space, quadratic Hamiltonians such as those modelling the most common Gaussian operations on bosonic modes remain poorly understood in terms of entropy production. For instance, determining the quantum entropy generated by a Bogoliubov transformation is notably a hard problem, with generally no known analytical solution, while it is vital to the characterisation of quantum communication via bosonic channels. Here we overcome this difficulty by adapting the Replica Method, a tool borrowed from statistical physics and quantum field theory. We exhibit a first application of this Method to continuous-variable quantum information theory, where it enables accessing entropies in an optical parametric amplifier. As an illustration, we determine the entropy generated by amplifying a binary superposition of the vacuum and a Fock state, which yields a surprisingly simple, yet unknown analytical expression. An improved Method for calculating the entropy of quantum information carriers may help solve hard problems in quantum communication theory. Continuous-variable quantum information theory uses Gaussian states, such as laser-generated coherent light pulses, to perform communication or cryptography tasks. While quantum Gaussian processes can often be analyzed with simple mathematical expressions involving the amplitude and phase quadratures of the field, calculating entropies is generally impractical—a situation that causes problems, for example, when evaluating the bit rate through photonic channels. Nicolas Cerf from the Universite Libre de Bruxelles in Belgium and co-workers adapted for this purpose the ‘Replica’ Method, a trick developed by statistical physicists for the description of random media such as spin glasses. Applying this Method to the amplification of a single photon superposed with vacuum revealed a new way of calculating entropy with surprising outcomes.