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Entanglement Generation by Fock-State Filtration

Physical Review Letters 2007年第20期98卷 203602-203602页

作者： K. J. Resch J. L. O’Brien T. J. Weinhold K. Sanaka B. P. Lanyon N. K. Langford A. G. White Department of Physics & Centre for Quantum Computer Technology University of Queensland Brisbane QLD 4072 Australia Department of Physics & Institute for Quantum Computing University of Waterloo Waterloo ON N2L 3G1 Canada H. H. Wills Physics Laboratory & Department of Electrical and Electronic Engineering University of Bristol Bristol BS8 1UB United Kingdom E. L. Ginzton Laboratory Stanford University Stanford California 94305 USA

We demonstrate a Fock-state filter which is capable of preferentially blocking single photons over photon pairs. The large conditional nonlinearities are based on higher-order quantum interference, using linear optics, an ancilla photon, and measurement. We demonstrate that the filter acts coherently by using it to convert unentangled photon pairs to a path-entangled state. We quantify the degree of entanglement by transforming the path information to polarization information; applying quantum state tomography we measure a tangle of T=(20±9)%.

关键词： .nonlinearities blocking nonclassical Quantum Interference photon pairs single photons ancilla quantum state tomography Fock-state filter tangle

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Time-Reversal and Super-Resolving Phase Measurements

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Physical Review Letters 2007年第22期98卷 223601-223601页

作者： K. J. Resch K. L. Pregnell R. Prevedel A. Gilchrist G. J. Pryde J. L. O’Brien A. G. White Department of Physics University of Queensland Brisbane QLD 4072 Australia Institute for Quantum Computing and Department of Physics & Astronomy University of Waterloo Waterloo ON N2L 3G1 Canada Centre for Quantum Computer Technology University of Queensland Brisbane QLD 4072 Australia Institute for Mathematical Sciences Imperial College London SW7 2PG Unied Kingdom Institute for Experimental Physics University of Vienna Vienna A-1090 Austria Centre for Quantum Dynamics & Centre for Quantum Computer Technology School of Biomolecular and Physical Sciences Griffith University Nathan Brisbane QLD 4111 Australia H. H. Wills Physics Laboratory & Department of Electrical and Electronic Engineering University of Bristol Bristol BS8 1UB United Kingdom

We demonstrate phase super-resolution in the absence of entangled states. The key insight is to use the inherent time-reversal symmetry of quantum mechanics: our theory shows that it is possible to measure, as opposed to prepare, entangled states. Our approach is robust, requiring only photons that exhibit classical interference: we experimentally demonstrate high-visibility phase super-resolution with three, four, and six photons using a standard laser and photon counters. Our six-photon experiment demonstrates the best phase super-resolution yet reported with high visibility and resolution.

关键词： .TIME-REVERSAL Centre for Quantum entangled states phase super-resolution high-visibility

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Demonstration of spectral-amplitude encoding/decoding for multimedia optical CDMA applications

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Journal of Optical Communications 2006年第2期27卷 121-124页

作者： Djordjevic, Ivan B. Geraghty, David F. Patil, Anita Chen, Chia Hung Kostuk, Raymond K. Vasic, Bane University of Arizona Department of Electrical and Computer Engineering Tucson AZ 85721 United States University of the West of England Faculty of Computing Engineering and Mathematical Sciences Bristol BS16 1QY United Kingdom

Wavelength-time encoding/decoding for optical CDMA systems is evaluated using NRZ modulation at 10 Gbit/s. Commercial available devices are used for implementation. Experimental results are presented for the channel b... 详细信息

关键词： Code division multiple access

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Residual stress distribution, intermolecular force, and frictional coefficient maps in diamond films: Processing-structure-mechanical property relationship

Residual stress distribution, intermolecular force, and fric...

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2006 MRS Fall Meeting

作者： Gupta, Sanju Williams, Oliver Patel, R.J. Bohannan, E. May, P.W. Electrical and Computer Engineering University of Missouri-Columbia 6th St. 303 EBW Columbia MO 65211-2300 United States Institute of Materials Research Diepenbeek BE-3590 Belgium Physics and Materials Science Department Missouri State University 901 S. National Ave. Springfield MO 65987 United States Department of Chemistry University of Missouri-Rolla Rolla MO 65409 United States School of Chemistry University of Bristol Bristol BS8 1TS United Kingdom

ISBN: (纸本)9781604234251

Carbon in its various forms, specifically nanocrystalline diamond, may become a key material for the manufacturing of micro- and nano-electromechanical (M/NEMS) devices in the 21st Century. In order to utilize effectively these materials for M/NEMS applications, understanding of their microscopic structure and physical properties (mechanical, in particular) become indispensable. The micro- and nanocrystalline diamond films were grown using hot-filament and microwave chemical vapor deposition techniques involving novel CH4 / [TMB for boron doping and H2S for sulfur incorporation] in high hydrogen dilution chemistry. To investigate residual stress distribution and intermolecular forces at the nanoscale, the films were characterized using Raman spectroscopy and atomic force microscopy in terms of topography, force curves and force volume imaging. Traditional force curve measures the force felt by the tip as it approaches and retracts from a point on the sample surface, while force volume is an array of force curves over an extended range of sample area. Moreover, detailed microscale structural studies are able to demonstrate that the carbon bonding configuration (sp2 versus sp3 hybridization) and surface chemical termination in both the un-doped and doped diamond have a strong effect on nanoscale intermolecular forces. The preliminary information in the force volume measurement was decoupled from topographic data to offer new insights into the materials' surface and mechanical properties of diamond films. These measurements are also complemented with scanning electron microscopy and X-ray diffraction to reveal their morphology and structure and frictional properties, albeit qualitative using lateral force microscopy mode. We present these comparative results and discuss their potential impact for electronic and electromechanical applications. © 2007 Materials Research Society.

关键词： Diamond films

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COST292 experimental framework for TRECVID 2006

COST292 experimental framework for TRECVID 2006

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TREC Video Retrieval Evaluation, TRECVID 2006

作者： Ćalić, J. Krämer, P. Naci, U. Vrochidis, S. Aksoy, S. Zhangk, Q. Benois-Pineau, J. Saracoglu, A. Doulaverakis, C. Jarina, R. Campbell, N. Mezaris, V. Kompatsiaris, I. Spyrou, E. Koumoulos, G. Avrithis, Y. Dalkilic, A. Alatan, A. Hanjalic, A. Izquierdo, E. Dept. of Computer Science University of Bristol 2.11 MVB Woodland Road Bristol BS8 1UB United Kingdom LaBRI University of Bordeaux 1 351 cours de la Libération F-33405 Talence France Delft University of Technology Mekelweg 4 2628CD Delft Netherlands Informatics and Telematics Institute Centre for Research and Technology Hellas Thermi-Panorama Road P.O. Box 361 57001 Thermi-Thessaloniki Greece Department of Computer Engineering Bilkent University Bilkent 06800 Ankara Turkey Department of Electronic Engineering Queen Mary University of London Mile End London E1 4NS United Kingdom Department Of Electrical and Electronics Engineering Middle East Technical University 06531 Ankara Turkey Image Video and Multimedia Laboratory National Technical University of Athens 9 Iroon Polytechniou Str 157 80 Athens Greece Department of Computer Engineering Hacettepe University Cankaya 06532 Ankara Turkey Department of Telecommunications University of Zilina Univerzitna 1 010 26 Zilina Slovakia

In this paper we give an overview of the four TRECVID tasks submitted by COST292, European network of institutions in the area of semantic multimodal analysis and retrieval of digital video media. Initially, we present shot boundary evaluation method based on results merged using a confidence measure. The two SB detectors user here are presented, one of the Technical University of Delft and one of the LaBRI, University of Bordeaux 1, followed by the description of the merging algorithm. The high-level feature extraction task comprises three separate systems. The first system, developed by the National Technical University of Athens (NTUA) utilises a set of MPEG-7 low-level descriptors and Latent Semantic Analysis to detect the features. The second system, developed by Bilkent University, uses a Bayesian classifier trained with a "bag of subregions" for each keyframe. The third system by the Middle East Technical University (METU) exploits textual information in the video using character recognition methodology. The system submitted to the search task is an interactive retrieval application developed by Queen Mary, University of London, University of Zilina and ITI from Thessaloniki, combining basic retrieval functionalities in various modalities (i.e. visual, audio, textual) with a user interface supporting the submission of queries using any combination of the available retrieval tools and the accumulation of relevant retrieval results over all queries submitted by a single user during a specified time interval. Finally, the rushes task submission comprises a video summarisation and browsing system specifically designed to intuitively and efficiently presents rushes material in video production environment. This system is a result of joint work of University of Bristol, Technical University of Delft and LaBRI, University of Bordeaux 1.

关键词： Semantics

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Comparative study of CA with phase shifters and GLFSRs

Comparative study of CA with phase shifters and GLFSRs

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IEEE International Test Conference, ITC 2005

作者： Chidambaram, S. Kagaris, D. Pradhan, D.K. Electrical and Computer Engineering Dept. Southern Illinois University Carbondale IL 62901 United States Department of Computer Science University of Bristol Bristol BS8 1UB United Kingdom

ISBN: (纸本)0780390393

In this paper, we investigate the use of Galois LFSRs (GLFSRs) as test pattern generators in BIST schemes that employ multiple scan chains. Current schemes use LFSRs or Cellular Automata (CA) with additional phase shifters to provide guaranteed minimum phase shifts between successive scan chains and also impose an upper bound on the number of taps for the XOR gate of each phase shifter. We compare CA with phase shifters (CAPSs) and GLFSRs without phase shifters in terms of the minimum inter-channel separation that they achieve and the overall XOR cost for each construction. Experimental results for different degrees show that GLFSRs are preferable in both hardware cost and fault coverage. © 2005 IEEE.

关键词： Automata theory

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Performance assessment of optical CDMA systems based on wavelength-time codes from balanced incomplete block designs

Performance assessment of optical CDMA systems based on wave...

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TELSIKS 2005 - 7th International Conference on Telecommunications in Moderm Satellite, Cable and Broadcasting Services

作者： Patil, Anita Djordjevic, Ivan B. Geraghty, David F. University of Arizona Department of Electrical and Computer Engineering Tucson AZ 85721 United States University of the West of England Faculty of Computing Engineering and Mathematical Sciences Bristol BS16 1QY United Kingdom

ISBN: (纸本)0780391640

A new family of unipolar wavelength-time codes with zero out-of-phase autocorrelation and maximum cross-correlation equal to one, based on balanced incomplete block design is proposed. The system performance is assessed in a realistic simulation environment taking into account multi-access interference, transmitter/receiver imperfections. © 2005 IEEE.

关键词： Code division multiple access

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Gallium nitride based ballistic electron acceleration negative- differential-conductivity diodes for potential THz applications

Gallium nitride based ballistic electron acceleration negati...

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63rd Device Research Conference, DRC'05

作者： Cha, Ho-Young Chen, Xiaodong Schaff, William J. Spencer, Michael G. Eastman, Lester F. Ridley, Brian K. Pomeroy, James Kuball, Martin School of Electrical and Computer Engineering Cornell Nanoscale Science and Technology Facility Cornell University Ithaca NY 14853 United States Department of Electronic Systems Engineering University of Essex Colchester CO4 3SQ United Kingdom Department of Physics University of Bristol Bristol BS8 1TL United Kingdom

ISBN: (纸本)0780390407

In order to achieve operation at Terahertz frequency, electronic devices are required to reach the highest possible transit velocity, even if this velocity is limited to a short distance. The concept of ballistic electrons in compound semiconductors was initially reported using GaAs [1]. However, limitations on bias voltage, transit distance, and operating temperature in that material have prohibited the development of practical devices. In contrast, electrons in GaN can be raised in energy over short times and lengths with electric fields beyond 1-2 MV/cm before their velocity falls to lower saturation values. In this work, progress in initial research on GaN based ballistic electron acceleration negative-differential-conductivity (BEAN) diodes for potential THz oscillator is reported along with their device concepts. A short drift distance N-I-N device, with high electric field, allows ballistic electron accelerations and drift. Electrons at low wave numbers, below 1 eV energy, have a positive electron effective mass, while those above 1 eV energy, at a higher wave number, have negative electron effective mass in the Γ-A direction. The design goal is to have more electrons with negative effective mass than electrons with positive effective mass. In order to get more electrons with the negative effective mass, electrons must be injected over a potential step, yielding an injected electron wave number that is substantial, with an electron injection energy step of 0.25 - 0.75 eV. N-I-N devices using an Al 0.2Ga0.8N/GaN heterojunction were designed with a 50 Å thick undoped AlGaN to allow a barrier, over which the electrons will be emitted. Those electrons passing over the top will have 0.38 eV injection energy and will be accelerated ballistically, reaching 8.5 × 10 7 cm/s peak velocity. If electrons have no longitudinal optical phonon launches, they will be turned around with negative velocity when they reach the ∼2.8 V limit of the conduction band (in this c-axis d

关键词： Diodes

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Joint ACE ground penetrating radar antenna test facility at the Technical University of Denmark

Joint ACE ground penetrating radar antenna test facility at ...

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2005 IEEE Antennas and Propagation Society International Symposium and USNC/URSI Meeting

作者： Lenler-Eriksen, H.-R. Meincke, P. Sarri, A. Chatelee, V. Nair, B. Craddock, I.J. Alli, G. Dauvignac, J.-Y. Huang, Y. Lymperopoulos, D. Nilavalan, R. Ørsted-DTU Build. 348 Technical University of Denmark DK-2800 Kgs. Lyngby Denmark IDS - Ingegneria Dei Sistemi S.p.A. Via Livornese 1019 56010 Pisa Italy 250 rue Albert Einstein 06560 Valbonne France Dept. of Electrical Engineering and Electronics University of Liverpool Brownlow Hill Liverpool L69 3GJ United Kingdom Dept. of Electrical and Electronic Engineering Merchant Venturers Building Woodland Road Bristol BS8 1UB United Kingdom Microwave and Fiber Optics Laboratory Institute of Communications and Computer Systems School of Electrical and Computer Engineering Iroon Polytexneiou St. Zografou Athens Attiki GR 15780 Greece

No abstract available

ISBN: (纸本)0780388836

No abstract available

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Fault analysis in four-wire distribution networks

Fault analysis in four-wire distribution networks

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作者： Ciric, R.M. Ochoa, L.F. Padilla-Feltrin, A. Nouri, H. Faculty of Computing Engineering and Mathematical Sciences School of Electrical and Computer Engineering University of the West of England Frenchay Campus Coldharbour Lane Bristol BS16 1QY United Kingdom Faculdade de Engenharia de Ilha Solteira UNESP - Universidade Estadual Paulista 'Julio de Mesquita Filho' Av. Brasil 56 CEP 15385-000 Ilha Solteira - SP Brazil

The neutral wire in most existing power flow and fault analysis software is usually merged into phase wires using Kron's reduction method. In some applications, such as fault analysis, fault location, power quality studies, safety analysis, loss analysis etc., knowledge of the neutral wire and ground currents and voltages could be of particular interest. A general short-circuit analysis algorithm for three-phase four-wire distribution networks, based on the hybrid compensation method, is presented. In this novel use of the technique, the neutral wire and assumed ground conductor are explicitly represented. A generalised fault analysis method is applied to the distribution network for conditions with and without embedded generation. Results obtained from several case studies on medium- and low-voltage test networks with unbalanced loads, for isolated and multi-grounded neutral scenarios, are presented and discussed. Simulation results show the effects of neutrals and system grounding on the operation of the distribution feeders. © IEE, 2005.

关键词： Electric power distribution

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