1,720,981 research outputs found
Quantum message exchange based on entanglement and Bell-state measurements
No full textWe propose a scheme by which two parties can secretly and simultaneously exchange messages. The scheme requires the two parties to share entanglement and both to perform Bell-state measurements. Only two out of the four Bell states are required to be distinguished in the Bell-state measurements, and thus the scheme is experimentally feasible using only linear optical means. Generalizations of the scheme to high-dimensional systems and to multipartite entanglement are considered. We show also that the proposed scheme works even if the two parties do not possess shared reference frames. (c) 2005 Elsevier B.V. All rights reserved.This research was supported by a Grant from the Korea Science and Engineering Foundation (KOSEF) through Korea–China International Cooperative Research Program and from the Ministry of Science and Technology (MOST) of Korea
Effect of Gas Composition on TiN Thin-Film Fabrication in N2/H2/Ar/TiCl4 Inductively Coupled Plasma-Enhanced Chemical Vapor Deposition System
No full textTiN films were deposited in a N-2/H-2/Ar/TiCl4 rf inductively coupled plasma and the effect of gas composition on the properties of the TiN films were analyzed through investigation of the plasmas with a Langmuir single probe and a mass spectrometer. The quality of TiN films depended critically on the concentration of H and N radicals. H., had the effect of removing Cl from the TiCl4 and reducing N radicals in the plasma although the plasma density and electron temperature were not significantly affected. Accordingly, high-quality TiN films with low Cl content and good electric proper-ties were obtained with 10 similar to 20% of H-2. With the addition of Ar, the plasma density increased and the dissociation of the precursors was enhanced; as a result, the production of N and H radicals was enhanced and the quality of TiN films was improved.The consortium of semiconductor advanced research(COSAR) as project No. 00-B6-C0-00-09-00-01
Robustness of multiparty nonlocality to local decoherence
No full text©2006 The American Physical Society
URL: http://link.aps.org/abstract/PRA/v74/e062112
doi:10.1103/PhysRevA.74.062112
PACS: 03.65.Ud, 03.65.YzWe investigate the robustness of multiparty nonlocality under local decoherence, acting independently and equally on each subsystem. To be specific, we consider an N-qubit Greenberger-Horne-Zeilinger (GHZ) state under a depolarization, dephasing, or dissipation channel, and examine nonlocality by testing violation of the Mermin-Klyshko inequality, which is one of Bell's inequalities for multiqubit systems. The results show that the robustness of nonlocality increases with the number of qubits, and that the nonlocality of an N-qubit GHZ state with even N is extremely persistent against dephasing.The authors thank Jinhyoung Lee for helpful discussions. S.S.J. and J.W.K. appreciate the financial support from the Korea Ministry of Information and Communication. H.W.L. was supported by the Ministry of Science and Technology (MOST) of Korea through the Leading Basic S&T Research Projects
First-principles study of the switching mechanism of [2]catenane molecular electronic devices
No full textWe present a first-principles study of the coherent charge transport properties of bistable [2]catenane molecular monolayers sandwiched between Au(111) electrodes. We find that conduction channels around the Fermi level are dominated by the two highest occupied molecular orbital levels from tetrathiafulvalene (TTF) and dioxynaphthalene (DNP) and the two lowest unoccupied molecular orbital levels from tetracationic cyclophane (CBPQT(4+)), and the OFF to ON switching results from the energetic shifts of these orbitals as CBPQT(4+) moves from TTF to DNP. We show that the superposition principle can be adopted for predicting the function of the composite device
C-axis orientation of AIN films prepared by ECR PECVD
No full textAIN films were deposited on silicon substrates at low temperatures (300-500 degrees C) by electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR PECVD) using trimethylaluminum, N-2 and H-2 gases. The degree of c-axis orientation, crystallinity, functional groups and chemical composition of the films were investigated for various deposition conditions. The degree of c-axis orientation depends on the substrate surface condition and it improves with increasing substrate temperature as well as with increasing microwave power. A c-axis oriented (sigma = 4.3 degrees) AlN film was prepared at 500 degrees C. The importance of the system design which allows the precursor to be dissociated efficiently by the ECR plasma is discussed.The authors acknowledge the support of Samsung Electro-Mechanics Co., Ltd
Possible performance improvement in [2]catenane molecular electronic switches
No full textMechanically interlocked bistable supramolecular complexes are promising candidates of molecular electronics. Applying a multiscale computational approach, here we study the coherent charge transport properties of catenane monolayers sandwiched between Cu(111) electrodes. We demonstrate the robust nature of electrical switching behavior with respect to the variations in the monolayer packing density and the type of electrodes, as well as the thermal fluctuations of the molecules. We propose that the asymmetry of molecule-electrode barriers can be utilized to improve the switching ratio.(c) 2006 American Institute of Physics
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Charge Transport through Polyene Self-Assembled Monolayers from Multiscale Computer Simulations
No full textWe combine first-principles density-functional theory with matrix Green's function calculations to predict the structures and charge transport characteristics of self-assembled monolayers (SAMs) of four classes of systems in contact with Au(111) electrodes: conjugated polyene chains (n = 4, 8, 12, 16, and 30) thiolated at one or both ends and saturated alkane chains (n = 4, 8, 12, and 16) thiolated at one or both ends. For the polyene SAMs, we find no decay in the current as a function of chain length and conclude that these 1-3 nm long polyene SAMs act as metallic wires. We also find that the polyene-monothiolate leads to a contact resistance only 2.8 times higher than that for the polyene-dithiolate chains, indicating that the device conductance is dominated by the properties of the molecular connector with less importance in having a second molecule-electrode contact. For the alkane SAMs, we observe the normal exponential decay in the current as a function of the chain length with a decay constant of beta(n) = 0.82 for the alkane-monothiolate and 0.88 for the alkane-dithiolate. We find that the contact resistance for the alkane-monothiolate is 12.5 times higher than that for the alkane-dithiolate chains, reflecting the extra resistance due to the weak contact on the nonthiolated end. These contrasting charge transport characteristics of alkane and polyene SAMs and their contact dependence are explained in terms of the atomic projected density of states
Variations on the Author
Full text link“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
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