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Protocoles de chiffrement quantiques de plusieurs parties en environnements réalistes / Quantum cryptographic primitives in realistic conditionsPappa, Anna 10 July 2014 (has links)
Cette thèse se situe à l’interface entre la théorie quantique et les expériences, en mettant l’accent sur les protocoles pratiques qui peuvent être mises en place en utilisant la technologie présente. Notre objectif est de contribuer à la construction d’un cadre général pour la conception et la mise en oeuvre de schémas de chiffrement quantiques qui permettront d’améliorer la sécurité des futurs réseaux de télécommunication. En outre, cette thèse veut avancer la recherche pertinente sur la physique quantique et l’informatique, en améliorant notre compréhension du phénomène d’intrication. Les corrélations des états intriqués ne peuvent pas être reproduites par des moyens classiques, ce qui permet d’effectuer des tâches (par exemple la téléportation et le codage super-dense) qui sont autrement impossibles. Il est donc d’une importance majeure d’être capables de vérifier si un état quantique est intriqué. Dans cette thèse, nous montrons comment vérifier efficacement si une source physique peut créer des états intriqués multipartites et les partager avec de nombreuses parties, dont certains sont malhonnêtes et collaborent avec la source. Ce protocole pourrait s’avérer essentiel pour tout type de calcul quantique entre les parties méfiantes et pourrait aussi faciliter la délégation sécurisée des tâches de calcul aux serveurs quantiques puissants qui ne sont pas fiables. Finalement, nous étudions le lien entre la théorie des jeux et la non-localité quantique, dans le cadre de jeux bayésiens. Nous examinons comment l’intrication partagé aide les joueurs gagner un jeu avec une probabilité plus élevée que les ressources classiques pourraient atteindre. / This thesis stands at the interface between quantum theory and experiments, focusing on practical protocols that can be implemented using present-day technology. Our goal is to build a general framework for the design and implementation of quantum cryptographic schemes that will improve the safety of future telecommunication networks. In addition, this thesis aims to advance research on quantum physics and computer science, by improving our understanding of entanglement. The correlations of entangled states can not be reproduced by conventional means, allowing to perform tasks (eg teleportation and superdense coding) that are otherwise impossible. It is therefore of major importance to be able to check whether a quantum state is entangled. In this thesis, we show how to efficiently check whether a physical source can create multi-party entangled states and share them with many parties, some of which are dishonest and work with the source. This protocol could prove essential for quantum computation between suspicious parties and could also facilitate the secure delegation of tasks to powerful untrusted quantum servers. Finally, we study the link between game theory and quantum non-locality, in the context of Bayesian games. We examine how the shared entanglement helps players win a game with a higher probability than the conventional resources could achieve.
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Análise teórica do jogo da Batalha dos Sexos e uma proposta experimental via Ressonância Magnética Nuclear / Theoretical analysis of the Battle of the Sexes game and an experimental proposal by Nuclear Magnetic ResonanceLeal, Adriane Consuelo da Silva 19 February 2018 (has links)
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Adriane C silva Leal.pdf: 12455813 bytes, checksum: 4943d9492ef5280324df4aba4d508c4e (MD5) / Made available in DSpace on 2018-03-13T19:32:04Z (GMT). No. of bitstreams: 2
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Previous issue date: 2018-02-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O principal objetivo deste trabalho é estudar o jogo da Batalha dos Sexos na versão quântica, para dois jogadores Alice e Bob. Uma análise teórica é fundamentada aplicando o protocolo elaborado por Eisert et al., no qual se aplicam propriedades advindas de emaranhamento de estratégias. Nesse sentido, é possível demonstrar que o emaranhamento otimizou os equilíbrios do jogo para Alice e Bob. Para o caso em que os jogadores escolhem o perfil de operadores de estratégias quânticas UA ^ UB 8 ou UA ; 38 ; ^ UB 0; 3 8 , o dilema pode ser resolvido. Por meio dos resultados teóricos uma proposta de implementação experimental do jogo na condição
de máximo emaranhamento foi sugerida via a técnica de Ressonância Magnética Nuclear. / The main objective of this work is to study the game of the Battle of the Sexes in the quantum version, for two players Alice and Bob. A theoretical analysis is substantiated applying the protocol elaborated by Eisert et al., in which apply properties oficial entangled strategies. In this sense, it is possible to demonstrate that the entanglement optimized the equilibria of the game. For the case where the players choose the profile of quantum strategies operators ( ^ UA 0;
8 ; ^ UB 0; 8 ) or ( ^ UA 0; 3 8 ; ^ UB 0; 3 8 ) the dilemma can be solved. By means of the theoretical results a proposal of experimental implementation of the game in the condition of maximum entanglement is purposed by Nuclear Magnetic Resonance technique.
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Kvantová teorie mezinárodních vztahů: Modelování strategické interakce pomocí kvantové teorie prevděpodobnosti / Quantum Theory of International Relations: Modeling Strategic Interaction with Quantum Probability TheoryTesař, Jakub January 2018 (has links)
Recent results from cognitive psychology suggest that human behavior can be, in some situations, better described by laws known from physical quantum theory. This work responds to this development and seeks to answer the question of how quantum models of cognition and decision-making can contribute to our understanding of the social world. We introduce the approaches to the application of quantum theory in social sciences - quantum consciousness, quantum reasoning and quantum metaphor and further develop the second, in the context of strategic interaction in game theory. We show that the quantum model corresponds to both the psychological intuition and many empirically known anomalies such as the order effect, disjunction effect, or context effect. In this work, we derive a specific model of strategic interaction between two players, and we test it in the experimental Prisoner's Dilemma game. The model is based on the rational choice theory, which is nevertheless re-defined when it is shown how the strategic choice is changed if the quantum probability (C*-algebra) is used as the underlying theory instead of classical probability (σ-algebra). The results obtained support the quantum model and showed a different representation of the game among various groups of players. The quantum model of...
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