************************************ * QUANTUM OPTICS AND ATOM OPTICS * * IN AUSTRALASIA * * * * * * * * MONTHLY NEWSLETTER * * VOL IX, NO 11 * * * CONTENTS: * November 2001 * * * 0. EDITORIAL NOTE * ISSN 1325-6467 * Edited by: 1. ABSTRACTS * * Alexei Gilchrist 2. CONFERENCES * \ | / * Physics, University of Queensland, 3. WANTED TO BUY/SELL * \__|__/ * QLD 4072, Australia. 4. SITUATIONS VACANT * | * email: alexei@physics.uq.edu.au 5. MISC NEWS * | * phone: +61 7 3365 2422 * | * fax: +61 7 3365 1242 Available on WWW at: * * http://www.physics.uq.edu.au/qonews =============================================================================== 0. EDITORIAL NOTE =============================================================================== Boo! :-) After a recent slumber the QO&AO newsletter is awake again, though I'm expecting a few email addresses to bounce. If you know of anyone that would like to subscribe to the newsletter please ask them to send me a message. As usual, please send me any abstracts or notices you would like included. I'll endeavour to send out the newsletter early each month. If there are urgent notices they can be circulated immediately. Please note the early-bird registration deadline for ACOLS. Cheers, Alexei =============================================================================== 1. ABSTRACTS =============================================================================== Exploring Hilbert Space: accurate characterisation of quantum information A. G. White, D. F. V. James, W. J. Munro, P. G. Kwiat Submitted to Physical Review A, quant-ph/0108088 We report the creation of a wide range of quantum states with controllable degrees of entanglement and entropy using an optical two-qubit source based on spontaneous parametric downconversion. The states are characterised using measures of entanglement and entropy determined from tomographically determined density matrices. The Tangle-Entropy plane is introduced as a graphical representation of these states, and the theoretic upper bound for the maximum amount of entanglement possible for a given entropy is presented. Such a combination of general quantum state creation and accurate characterisation is an essential prerequisite for quantum device development. ------------------------------------------------------------------------------- Quantum Computation with Coherent States, Linear Interactions and Superposed Resources T.C.Ralph, W.J.Munro, G.J.Milburn quant-ph/0110115 We show that quantum computation circuits with coherent states as the logical qubits can be constructed using very simple linear networks, conditional measurements and coherent superposition resource states. ------------------------------------------------------------------------------- Weak force detection with superposed coherent states W.J.Munro, K.Nemoto, G.J.Milburn, S.L.Braunstein quant-ph/0109049 We investigate the utility of non classical states of simple harmonic oscillators, particularly a superposition of coherent states, for sensitive force detection. We find that a superposition of coherent states offers the same advantage as squeezed states and that, like squeezed states, entangling these states offers no significant advantage. ------------------------------------------------------------------------------- Universal Continuous-Variable Quantum Computation: Requirement of Optical Nonlinearity for Photon Counting Stephen D. Bartlett, Barry C. Sanders quant-ph/0110039 Although universal continuous-variable quantum computation cannot be achieved via linear optics (including squeezing), homodyne detection and feed-forward, inclusion of ideal photon counting measurements overcomes this obstacle. We show that ideal photon counting cannot be achieved with existing photodetection systems, even in principle, and that such counting measurements necessarily involve nonlinear evolution. However, this requirement of nonlinearity can be moved `offline', thereby permitting universal continuous-variable quantum computation with linear optics. ------------------------------------------------------------------------------- Quantum Computation with Qudits in Spin Systems and Harmonic Oscillators Stephen D. Bartlett, Hubert de Guise, Barry C. Sanders quant-ph/0109066 We show that qudits (higher-dimensional versions of qubits) can be encoded into spin systems and into harmonic oscillators, yielding important advantages for quantum computation. Whereas qubit-based quantum computation is adequate for analyses of quantum vs classical computation, in practice qubits are often realized in higher-dimensional systems by truncating all but two levels, thereby reducing the size of the precious Hilbert space. We develop natural qudit gates for universal quantum computation, and exploit the entire accessible Hilbert space. Mathematically we give representations of the generalized Pauli group for qudits in coupled spin systems and harmonic oscillators, and include analyses of the qubit and the infinite-dimensional limits. ------------------------------------------------------------------------------- Efficient Classical Simulation of Continuous Variable Quantum Information Processes Stephen D. Bartlett, Barry C. Sanders, Samuel L. Braunstein, Kae Nemoto quant-ph/0109047 We obtain sufficient conditions for the efficient simulation of a continuous variable quantum algorithm or process on a classical computer. The resulting theorem is an extension of the Gottesman-Knill theorem to continuous variable quantum information. For a collection of harmonic oscillators, any quantum process that begins with unentangled Gaussian states, performs only transformations generated by Hamiltonians that are quadratic in the canonical operators, and involves only measurements of canonical operators (including finite losses) and suitable operations conditioned on these measurements can be simulated efficiently on a classical computer. =============================================================================== 2. CONFERENCES / WORKSHOPS =============================================================================== ACOLS 2001: Australasian Conference on Optics, Lasers and Spectroscopy 3 - 6 December 2001 Early Bird registration: 9th of November Brisbane, Australia http://www.physics.uq.edu.au/acols2001/ ACOLS 2001 is the fifth conference in the ACOLS series. It incorporates the 14th Australian Optical Society Conference, the 10th Australian Laser Conference, and the 20th Australian Spectroscopy Conference. ACOLS 2001 is the region's showcase of research and development in all aspects of optics, lasers and spectroscopy, and provides a broad forum for discussion of these important areas at the modern facilities of the University of Queensland. A Technical Exhibition will be run in conjunction with the conference and adjacent to poster presentation sites ------------------------------------------------------------------------------- Bat-Sheva Seminar on Quantum Mechanics of Ultracold Matter and Quantum Information 17 - 22 February 2002 Ein Gedi, Israel http://www.weizmann.ac.il/conferences/qumran/ The Bat-sheva seminar on QUANTUM MECHANICS OF ULTRACOLD MATTER AND QUANTUM INFORMATION (QUMRAN) is a joint winter school and conference which brings together leading researchers with the goal of educating students/non-experts while functioning as a high level scientific conference. This meeting will be held in conjunction with FRISNO-7, the seventh French Israeli Conference on Non-linear Optics. ------------------------------------------------------------------------------- Quantum Information: Quantum Entanglement 23 - 28 March 2002 Applications by 17 December 2001 San Feliu de Guixols, Spain http://www.esf.org/euresco This meeting aims at bringing together experts from various areas in the rapidly growing field of quantum information. This first conference will focus on the fundamental concept of quantum entanglement, which is at the heart of many tasks in quantum information processing. The main topics will include detection, characterization and quantification of entanglement, as well as its experimental creation and manipulation. The scope of this conference is to encourage and promote the interaction between leading figures in the field and young researchers in a friendly environment. ------------------------------------------------------------------------------- IQEC/LAT 2002: International Quantum Electronics Conference and International Conference on Lasers, Applications and Technologies 22-28 June 2002 Abstract and summary deadline 15 January 2002 Moscow, Russia http://www.ilc.msu.su/iqec2002/ The International Quantum Electronics Conference (IQEC) is the largest international conference featuring the fundamentals of quantum electronics, basic research in lasers, nonlinear and quantum optics, quantum information, and fundamental laser spectroscopy of atoms and condensed matter. IQEC 2002 is organized by the Russian Academy of Sciences and M. V. Lomonosov Moscow State University under the aegis of the International Council on Quantum Electronics (ICQE). The Conference on Lasers, Applications, and Technologies (LAT) provides a forum for an update and review of a wide range of laser technologies and applications including laser device development, processing of advanced materials, optical information technologies, biomedicine and ecology applications. The meeting serves to stimulate the use of more mature optical technologies in different fields. LAT 2002 is organized by the Russian Academy of Sciences, Ministry of Industry, Science and Technology of the Russian Federation, and SPIE/Russia. =============================================================================== 4. SITUATIONS VACANT =============================================================================== Dear colleagues: We are hiring into a tenure-track position in experimental AMO physics, in the expectation of bringing in a researcher in the general areas of quantum optics, atom optics, quantum information, atomic coherence effects, et cetera, to start in July of 2002. I would like to ask for your help in publicizing this position; if you know of excellent candidates, please encourage them to apply. The job ad can be found at http://www.physics.utoronto.ca/~qocmp/quinf/QOCRCAD-02.pdf and we would be grateful if you would post it and/or bring it to the attention of any potential candidates. Thank you in advance, Aephraim Steinberg ------------------------------------------------------------------------------- ** Addendum ** =============================================================================== 0. EDITORIAL NOTE =============================================================================== Two items requiring special attention: * Quantum Information and Computation Summer School, Registration closing December 15, 2001 * University of Hertfordshire Research Fellow, Applications Closing November 30, 2001 As expected there where a few rubber emails on the first mailout, any help in locating the intended target of these addresses would be greatly appreciated: bg@james.lsr.ph.ic.ac.uk aesch@lamar.colostate.edu dyrting@uxmail.ust.hk hari@dap.csiro.au jshi@zeus.mpce.mq.edu.au mjh105@phyvs1.anu.edu.au peterf@dap.csiro.au pmarzlin@zeus.mpce.mq.edu.au john@wotan.opt-sci.arizona.edu tajijoseph@usa.net d.tang@oftc.usyd.edu.au Regards, Alexei =============================================================================== 2. CONFERENCES / WORKSHOPS =============================================================================== QICSS: Quantum Information and Computation Summer School 11 - 15 February 2002 The registration deadline is December 15, 2001. Brisbane, Australia http://www.physics.uq.edu.au/people/nielsen/qicss/index.html Quantum information and quantum computation is one of the most exciting and dynamic research areas of modern science. The aim of this summer school is to introduce undergraduates, postgraduates, and researchers in computer science, mathematics and physics to the basic notions of quantum information and quantum computation. Prior knowledge of computer science and quantum mechanics will not be assumed, however participants should have mathematical maturity at least the equal of a fourth year undergraduate in one or more of these disciplines. Program: On each of the first three days there will be three one-hour tutorial lectures, followed at the end of the day by a one-hour tutorial session in which participants will split up into small groups to discuss some example problems with expert tutors. On each of the final two days the morning session will consist of two one-hour tutorials, followed in the afternoon by four half-hour research seminars to give participants the flavour of recent research. The tutorial lectures will be given by four lecturers: * Assoc/Prof Michael Nielsen (Qld): Introductory lectures on quantum mechanics, computer science, quantum information and computation * Dr Andrew White (Qld): The physical implementation of quantum computation * Mr Ben Travaglione (Qld): Quantum algorithms * Dr David Bacon (Caltech): Quantum error-correction An outline of the tutorial topics is as follows: * Introduction to quantum mechanics * Introduction to computer science * Basic elements of quantum computation * Quantum algorithms, including Shor's and Grover's algorithm * Physical implementation of quantum computation * Quantum error-correction, noise, and fault-tolerance * Entanglement * Quantum entropy =============================================================================== 4. SITUATIONS VACANT =============================================================================== University Research Fellow University of Hertfordshire UK Applications are invited for a university supported Research Fellowship working in one of the following areas: astronomy, instrumentation associated with light scattering, microfluidics and theoretical quantum physics (including quantum information theory, quantum optics and Bose-Einstein condensation). The post is available for 2 years in the first instance, and can start from 1st January 2002. Candidates should have a PhD, or expect to be awarded a PhD in the next few months. The appointment will be on a salary scale ranging from £17,785 to £22,236, but might be higher for exceptional candidates. Informal enquiries to Professor James Hough (jhh @star.herts.ac.uk). Also see http://strc.herts.ac.uk for additional information on research programmes. Further details of the above post and application forms can be obtained from the Personnel Department at the University of Hertfordshire, College Lane, Hatfield, Hertfordshire AL10 9AB, England, or telephone 01707 284802, quoting reference number 2984. Applications (which should be accompanied by a full CV and personal statement) should be returned to the Personnel Department. Applicants should arrange for 2 references to be sent directly to Personnel by the closing date. Closing date is November 30, 2001 The University is located in Hatfield just outside the M25 and 40 minutes from the centre of London by train. Hatfield lies a few miles from St Albans, the site of a Roman town (Verulamium). Old Hatfield is a historic town and includes an Elizabethan palace (Hatfield House). Hatfield lies a few miles from St Albans which is the site of a Roman town (Verulamium). The University is an equal opportunity employer.