1,720,954 research outputs found
Entangled protocols and non-local games for testing quantum systems.
No full textThesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.Cataloged from PDF version of thesis.Includes bibliographical references (pages 177-184).The field of quantum computing investigates the extent to which one can design a quantum system that outperforms all known classical hardware at a certain task. But, to what extent can a human being, capable only (perhaps) of classical computation and of observing classical bit-string messages, verify that a quantum device in their possession is performing the task that they wish? This is a fundamental question about the nature of quantum mechanics, and the extent to which humans can harness it in a trustworthy manner. It is also a natural and important consideration when quantum devices may be used to perform sensitive cryptographic tasks which have no known efficient classical witness of correctness (Quantum Key Distribution, and Randomness Expansion are two examples of such tasks). It is remarkable that any quantum behavior at all can be tested by a verifier under such a constraint, without trusting any other quantum mechanical device in the process! But, intriguingly, when there are two or more quantum provers available in an interactive proof, there exist protocols to verify many interesting and useful quantum tasks in this setting. This thesis investigates multi-prover interactive proofs for verifying quantum behavior, and focuses on the stringent testing scenario in which the verifier in the interactive proof is completely classical as described above. It resolves the question of the maximum attainable expansion rate of a randomness expansion protocol by providing an adaptive randomness expansion protocol that achieves an arbitrary, or infinite rate of randomness expansion [29]. Secondly it presents a new rigidity result for the parallel repeated magic square game [24], which provides some improvements on previous rigidity results that play a pivotal role in existing interactive proofs for entangled provers, QKD, and randomness expansion results. This new rigidity result may be useful for improving such interactive proofs in the future. The second half of this thesis investigates the problem of bounding the role of quantum entanglement in non-local processes. This is important for understanding the upper limit on the power of multi-prover interactive proof systems with entangled provers. In particular it establishes that, assuming the Strong Kirchberg Conjecture, one can provide a doubly exponential upper bound on the class MIP* [25] (for comparison, the best known unconditional upper bound on MIP* is that its languages are recursively enumerable!). Finally this thesis presents a result which characterizes the type of entanglement that is useful in entanglement assisted quantum communication complexity by showing that any communication protocol using arbitrary shared entanglement can be simulated by a protocol using only EPR pairs for shared entanglement. Therefore all quantum communication protocols can be approximately simulated by a protocol using only the maximally entangled state as a shared resource.by Matthew Ryan Coudron.Ph. D
Trading isolation for certifiable randomness expansion
Get PDFThesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (page 41).A source of random bits is an important resource in modern cryptography, algorithms and statistics. Can one ever be sure that a "random" source is truly random, or in the case of cryptography, secure against potential adversaries or eavesdroppers? Recently the study of non-local properties of entanglement has produced an interesting new perspective on this question, which we will refer to broadly as Certifiable Randomness Expansion (CRE). CRE refers generally to a process by which a source of information-theoretically certified randomness can be constructed based only on two simple assumptions: the prior existence of a short random seed and the ability to ensure that two or more black-box devices do not communicate (i.e. are non-signaling). In this work we make progress on a conjecture of [Col09] which proposes a method for indefinite certifiable randomness expansion using a growing number of devices (we actually prove a slight modification of the original conjecture in which we use the CHSH game as a subroutine rather than the GHZ game as originally proposed). The proof requires a technique not used before in the study of randomness expansion, and inspired by the tools developed in [RUV12]. The result also establishes the existence of a protocol for constant factor CRE using a finite number of devices (here the constant factor can be much greater than 1). While much better expansion rates (polynomial, and even exponential) have been achieved with only two devices, our analysis requires techniques not used before in the study of randomness expansion, and represents progress towards a protocol which is provably secure against a quantum eavesdropper who knows the input to the protocol.by Matthew Ryan Coudron.S.M
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
