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Esperto revisore per conto della Commissione Europea DG for Communications Networks, Content and Technology (contract number CT-EX2002B071944-102) del progetto Simulators and Interfaces with Quantum Systems (grant agreement ICT-FP7-600645-SIQS)
No full textPeriod covered by the report: Period No. 2, from 1/5/2014 to 30/4/2015
Place of review meeting: None – remote review
Date of review: August 201
Asymptotic Properties of Quantum Markov Processess
Get PDFHlavním cílem této práce je důkladné prozkoumání asymptotických vlastností konečnědimenzionálních stopu nezvětšujících homogenních kvantových Markovovských procesů (obou používaných tříd, diskrétních kvantových Markovovský́ch řetízků a spojitý́ch kvantový́ch Markovovských dynamických semigrup) jak ve Schrodingerově, tak v Heisenbergově obrazu.The thesis gives a thorough description of the asymptotic properties of finite dimensional trace-nonincreasing homogenous quantum Markov processes. It provides a fundamental theorem specifying the structure of the asymptotic space (so-called attractor space) and it uncovers a rich set of transformations between attractors in Schrödinger and Heisenberg picture. Furthermore, based on algebraic properties of attractor spaces, it gives a characterization of all asymptotic and stationary states as well the characterization of all asymptotic trajectories in a Gibbs-like form. This result enables formulation of the Jaynes principle for all trace-preserving quantum Markov processes, derived from the underlying dynamics of the system
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
Conditions for the existence of positive operator valued measures
No full textSufficient and necessary conditions are presented for the existence of (N;M)-positive operator valued measures ((N;M)-POVMs) valid for arbitrary-dimensional quantum systems. Firstly, a sufficient condition for the existence of (N;M)-POVMs is presented. It yields a simple relation determining an upper bound on the continuous parameter of an arbitrary (N;M)-POVM, below which all its POVM elements are guaranteed to be positive semidefinite. Secondly, for arbitrary optimal (N;M)-POVMs conditions on their existence are derived, which exhibit a close connection to the existence of sets of (M - 1)N isospectral, traceless, orthonormal, hermitian operators with particular common spectra. The specific form of the two possible types of spectra depends on whether M is smaller than the dimension of the quantum system under consideration or not. For the special case of M = 2 and dimensions, which are powers of two, these sets of operators always exist and can be expressed in terms of the Clifford algebra of tensor products of Pauli operators.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
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