1,720,974 research outputs found
Quantum dynamics in sine-square deformed conformal field theory: Quench from uniform to nonuniform conformal field theory
No full textIn this work, motivated by the sine-square deformation (SSD) for (1+1)-dimensional quantum critical systems, we study the nonequilibrium quantum dynamics of a conformal field theory (CFT) with SSD, which was recently proposed to have a continuous energy spectrum and continuous Virasoro algebra. In particular, we study the time evolution of entanglement entropy after a quantum quench from a uniform CFT, which is defined on a finite space of length L, to a sine-square deformed CFT. We find that there is a crossover time t^{*} that divides the entanglement evolution into two interesting regions. For t≪t^{*}, the entanglement entropy does not evolve in time; for t≫t^{*}, the entanglement entropy grows as S_{A}(t)≃c/3logt, which is independent of the lengths of the subsystem and the total system. This logt growth with no revival indicates that a sine-square deformed CFT effectively has an infinite length, in agreement with previous studies based on energy spectrum analysis. Furthermore, we study the quench dynamics for a CFT with Möbius deformation, which interpolates between a uniform CFT and a sine-square deformed CFT. The entanglement entropy oscillates in time with period L_{eff}=Lcosh(2θ), with θ=0 corresponding to the uniform case and θ→∞ corresponding to the SSD limit. Our field theory calculation is confirmed by a numerical study on a (1+1)-dimensional critical fermion chain
Entanglement entropy for (3+1)-dimensional topological order with excitations
Get PDFExcitations in (3+1)-dimensional [(3+1)D] topologically ordered phases have very rich structures. (3+1)D topological phases support both pointlike and stringlike excitations, and in particular the loop (closed string) excitations may admit knotted and linked structures. In this work, we ask the following question: How do different types of topological excitations contribute to the entanglement entropy or, alternatively, can we use the entanglement entropy to detect the structure of excitations, and further obtain the information of the underlying topological order? We are mainly interested in (3+1)D topological order that can be realized in Dijkgraaf-Witten (DW) gauge theories, which are labeled by a finite group G and its group 4-cocycle ω∈H⁴[G;U(1)] up to group automorphisms. We find that each topological excitation contributes a universal constant ln d[subscript i] to the entanglement entropy, where d[subscript i] is the quantum dimension that depends on both the structure of the excitation and the data (G,ω). The entanglement entropy of the excitations of the linked/unlinked topology can capture different information of the DW theory (G,ω). In particular, the entanglement entropy introduced by Hopf-link loop excitations can distinguish certain group 4-cocycles ω from the others.Gordon and Betty Moore Foundation (Grant GBMF4303
Aspects of quantum entanglement in critical and topologically ordered systems
Get PDFQuantum entanglement plays an important role in characterizing the property of many-body systems and quantum field theories. In this thesis, we study the quantum entanglement in (1+1)-dimensional critical systems and (2+1)-dimensional topologically ordered phases. For (1+1)-d critical systems, we mainly study the non-equilibrium property of quantum entanglement, by focusing on three interesting cases: (i) the time evolution of entanglement hamiltonian during thermalization of a subsystem after a global quantum quench; (ii) time evolution of entanglement entropy after an inhomogeneous quantum quench; (iii) entanglement negativity evolution after a local quantum quench. For (2+1)-d topologically ordered phases, we use edge theory approach to study the topological entanglement entropy, mutual information and entnanglement negativity of Chern-Simons theories, which are further confirmed based on the surgey approach. In addition, we study the entanglement renormalization of topological insulators, and investigate the geometric and topological properties in the bulk of entanglement renormalization.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-08-01The student, Xueda Wen, accepted the attached license on 2017-07-06 at 09:15.The student, Xueda Wen, submitted this Dissertation for approval on 2017-07-06 at 09:26.This Dissertation was approved for publication on 2017-07-06 at 16:51.DSpace SAF Submission Ingestion Package generated from Vireo submission #11323 on 2017-09-29 at 10:46:45Made available in DSpace on 2017-09-29T17:45:11Z (GMT). No. of bitstreams: 2
WEN-DISSERTATION-2017.pdf: 5037080 bytes, checksum: fe2685b7147f09a2b7128e9a0e8ffe3f (MD5)
LICENSE.txt: 4206 bytes, checksum: 9714397c87d4bb64962d51deb912518d (MD5)
Previous issue date: 2017-07-06Embargo set by: Colleen Fallaw for item 103441
Lift date: 2019-09-29T17:48:06Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 103441
Lift date: 2020-03-02T19:56:41Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 103441
Lift date: 2020-03-02T19:59:52Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 103441
Lift date: 2020-03-02T20:02:46Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 103441 on 2020-03-03T10:15:39Z
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
- …
