Entangled coherent states can be used to determine the entanglement fidelity for a device that is designed to teleport coherent states. This entanglement fidelity is universal in that the calculation is independent of...
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Entangled coherent states can be used to determine the entanglement fidelity for a device that is designed to teleport coherent states. This entanglement fidelity is universal in that the calculation is independent of the use of entangled coherent states and applies generally to the teleportation of entanglement using coherent states. The average fidelity is shown to be a poor indicator of the capability of teleporting entanglement; i.e., very high average fidelity for the quantum teleportation apparatus can still result in low entanglement fidelity for one-mode of the two-mode entangled coherent states.
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 th...
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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. These measurements are sometimes described by arrays of beam splitters to distribute the photons across several modes. We show that such a scheme cannot be used to implement ideal photon counting and that such measurements necessarily involve nonlinear evolution. However, this requirement of nonlinearity can be moved “off-line,” thereby permitting universal continuous-variable quantum computation with linear optics.
Summary form only given. We show that universal continuous-variable (CV) quantum computation can be obtained using linear optics (phase-space displacements and squeezing), homodyne measurement with classical feed-forw...
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Summary form only given. We show that universal continuous-variable (CV) quantum computation can be obtained using linear optics (phase-space displacements and squeezing), homodyne measurement with classical feed-forward, and a realization of the photon counting projective value measurements (PVM). We describe the PVM for current (ideal) photodetectors, and demonstrate that such detectors cannot be used to implement the photon counting PVM with linear optics alone. Specifically, proposals to implement photon counting using arrays of beamsplitters to distribute the photons across several modes is insufficient for universal CV quantum computation. The photon counting PVM carries with it an implicit nonlinearity, and we discuss how it can be implemented in a CV system using a Kerr interaction (or another nonlinear Hamiltonian) and homodyne measurement. The resource requirements of this measurement scheme compared with using linear optics and current photodetectors are outlined.
The 9th Australasian Conference on Information Security and Privacy (ACISP 2004) was held in Sydney, 13–15 July, 2004. The conference was sponsored by the centre for advancedcomputing – algorithms and cryptography ...
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ISBN:
(数字)9783540278009
ISBN:
(纸本)9783540223795
The 9th Australasian Conference on Information Security and Privacy (ACISP 2004) was held in Sydney, 13–15 July, 2004. The conference was sponsored by the centre for advancedcomputing – algorithms and cryptography (ACAC), Information and Networked Security Systems Research (INSS), Macquarie U- versity and the Australian Computer Society. Theaimsoftheconferencearetobringtogetherresearchersandpractitioners working in areas of information security and privacy from universities, industry and government sectors. The conference program covered a range of aspects including cryptography, cryptanalysis, systems and network security. The program committee accepted 41 papers from 195 submissions. The - viewing process took six weeks and each paper was carefully evaluated by at least three members of the program committee. We appreciate the hard work of the members of the program committee and external referees who gave many hours of their valuable time. Of the accepted papers, there were nine from Korea, six from Australia, ?ve each from Japan and the USA, three each from China and Singapore, two each from Canada and Switzerland, and one each from Belgium, France, Germany, Taiwan, The Netherlands and the UK. All the authors, whether or not their papers were accepted, made valued contributions to the conference. In addition to the contributed papers, Dr Arjen Lenstra gave an invited talk, entitled Likely and Unlikely Progress in Factoring. ThisyeartheprogramcommitteeintroducedtheBestStudentPaperAward. The winner of the prize for the Best Student Paper was Yan-Cheng Chang from Harvard University for his paper Single Database Private Information Retrieval with Logarithmic Communication.
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