Universal grammar assumes the existence of an innate structure common to all human languages. As with secret keys shared by two parties in cryptography, the innateness of language may be related to the continuity of language that both parties share. In other words, discrete language alone cannot construct continuous semantics, which therefore implies the innateness of continuity as proposed in universal grammar. This is also seen in the unique capacity to communicate quantum information, which contains continuity, using discrete language. On the other hand, ever since the development of quantum theory, its probabilistic nature during the measurement process has been debated, particularly by using the phenomenon of entanglement and nonlocality. Since a number of practical applications of quantum theory have been introduced more recently, various techniques of manipulating entanglement have been examined. In particular, it has been noted that for a given chain of non-maximal correlations, there exists a class of coefficients such that entanglement swapping yields the optimal result, namely the weakest link in the chain. A numerical comparison between the general coefficients and the optimal non-maximal states in the case of four and five 2-level entanglement is also provided.
Universal grammar assumes the existence of an innate structure common to all human languages. As with secret keys shared by two parties in cryptography, the innateness of language may be related to the continuity of language that both parties share. In other words, discrete language alone cannot construct continuous semantics, which therefore implies the innateness of continuity as proposed in universal grammar. This is also seen in the unique capacity to communicate quantum information, which contains continuity, using discrete language. On the other hand, ever since the development of quantum theory, its probabilistic nature during the measurement process has been debated, particularly by using the phenomenon of entanglement and nonlocality. Since a number of practical applications of quantum theory have been introduced more recently, various techniques of manipulating entanglement have been examined. In particular, it has been noted that for a given chain of non-maximal correlations, there exists a class of coefficients such that entanglement swapping yields the optimal result, namely the weakest link in the chain. A numerical comparison between the general coefficients and the optimal non-maximal states in the case of four and five 2-level entanglement is also provided.
In recent years, examining the information processing aspects of nature has received significant attention. In particular, entanglement has been shown to exhibit what is arguably the most distinctive and unique aspect of quantum information science. In this note, a numerical method is applied to the Bell inequalities for examining the range of nonlocality when imperfect measurements are performed at each end. A two-qubit direct protocol is also examined such that, unlike the Bell-type inequalities, the approach is not as stable as the indirect one against measurement errors in yielding the nonlocality. On the other hand, since many applications of quantum technology involve a particular type of entanglement, it is important to have a technique to manipulate correlations. In this paper, five chained 2-level entanglements are also examined with swapping protocols applied at each joint. It is numerically shown that there exists a class of states that approximate the optimal result, i.e., the weakest link.
Ce memoire examine le rôle des fonctions à sens unique en cryptographie quantique. À cette fin, elle se penche sur les générateurs d’états quantiques pseudaléatoires, un concept récemment introduit par Ji, Liu et Song, qui sont analogues aux générateurs pseudaléatoires. Des travaux récents ont montré que ces générateurs peuvent être construits à partir de toute fonction à sens unique (sécurisée quantiquement) et peuvent être utilisés pour créer diverses primitives cryptographiques quantiques, telles que l’engagement de bit quantique, le chiffrement quantique à clé symétrique et les codes d’authentification de messages quantiques. Cela implique que, tout comme en cryptographie classique, les fonctions à sens unique constituent une condition suffisante pour réaliser la cryptographie quantique.Bien qu’elles soient suffisantes, elles ne sont peut-être pas strictement nécessaires. Des travaux novateurs, présentés par Kretschmer, ont montré qu’il existe certains mondes relativisés dans lesquels des générateurs d’états quantiques pseudaléatoires existent alors même que les fonctions à sens unique n’existent pas. Cela suggère que les générateurs d’états quantiques pseudaléatoires pourraient reposer sur des hypothèses plus faibles. Ainsi, même si la cryptographie classique s’avérait impossible, la cryptographie quantique ne le serait peut-être pas. Ce memoire présente un résumé complet de ces résultats, en mettant l’accent sur la clarté et la lisibilité, et discute des perspectives de recherche prometteuses
The subjectivity seen in quantum theory has been the topic of major debate ever since the theory was first introduced about a century ago. The idea of treating the subject and the object independently has been difficult to accept in the science community; however, the subjective limit of knowledge has been discussed in philosophy for centuries. On the other hand, one of the important outcomes of recent studies of quantum theory is developing useful and practical applications from often controversial and philosophical debates such as the simultaneous existence of multiple states or superluminal influencing, which appears to violate the locality imposed by relativity. Establishing a long-distance correlation may be effective in a number of applications in quantum information technology. In this paper, an entanglement swapping scheme for three 2-level states is examined using numerical methods. In particular, it is studied that there is a class of non-maximal states that approximate the optimal outcome, namely, the weakest link.
La mécanique quantique est sans aucun doute la théorie la mieux vérifiée qui n’a jamais existée. En se retournant vers le passé, nous constatons qu’un siècle de théorie quantique a non seulement changé la perception que nous avons de l’univers dans lequel nous vivons mais aussi est responsable de plusieurs concepts technologiques qui ont le potentiel de révolutionner notre monde. La présente dissertation a pour but de mettre en avance ces potentiels, tant dans le domaine théorique qu’expérimental. Plus précisément, dans un premier temps, nous étudierons des protocoles de communication quantique et démontrerons que ces protocoles offrent des avantages de sécurité qui n’ont pas d’égaux en communication classique. Dans un deuxième temps nous étudierons trois problèmes spécifiques en clonage quantique ou chaque solution apportée pourrait, à sa façon, être exploitée dans un problème de communication quantique. Nous débuterons par décrire de façon théorique le premier protocole de communication quantique qui a pour but la distribution d’une clé secrète entre deux parties éloignées. Ce chapitre nous permettra d’introduire plusieurs concepts et outils théoriques qui seront nécessaires dans les chapitres successifs. Le chapitre suivant servira aussi d’introduction, mais cette fois-ci penché plutôt vers le côté expériemental. Nous présenterons une élégante technique qui nous permettra d’implémenter des protocoles de communication quantique de façon simple. Nous décrirons ensuite des expériences originales de communication quantique basées sur cette technique. Plus précisément, nous introduirons le concept de filtration d’erreur et utiliserons cette technique afin d’implémenter une distribution de clé quantique bruyante qui ne pourrait pas être sécurisé sans cette technique. Nous démontrerons ensuite des expériences implémentant le tirage au sort quantique et d’identification quantique. Dans un deuxième temps nous étudierons des problèmes de clonage quantique basé sur le formalisme introduit dans le chapitre d’introduction. Puisqu’il ne sera pas toujours possible de prouver l’optimalité de nos solutions, nous introduirons une technique numérique qui nous permettra de mettre en valeur nos résultats.
One of the important concepts in logical studies is the self-reference, which often leads to semantic inconsistencies. In order to resolve this problem, the cyclical time process of self-reference is discussed in terms of computing machines. This approach provides an interconnection between matter and mind that may help to solve one of the important physics predicaments, namely, the cosmological constant problem. On the other hand, entanglement is often considered a natural phenomenon that is clearly distinguishable from classical theory. Moreover, entanglement has been shown to be an essential part of recent developments in quantum computing and quantum cryptography. In this paper, the entanglement swapping protocol is applied to four 2-level non-maximal states, and a new non-trivial class of non-maximal states that approximate the weakest link is examined numerically.
Nowadays, no one should doubt that quantum entanglement is (at least, one of) the \ncharacteristic traits of quantum mechanics. Furthermore, quantum information science \nis strongly influenced by the advantages provided by quantum entanglement, as the \nlatter can be regarded as a genuine resource for an efficient (better-than-classical) \nprocessing of information in certain computational tasks. The very basic notion of \ncorrelation is fundamental for the conceptualization of the physical communicational \nproblem and, as a consequence, for the notion of information itself. Thus, the question \nabout the nature of quantum information is close (and unavoidably linked) to the \nquestion about the nature of quantum correlations.