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Title: Purification of single qubits by collinear photons

Abstract

We have demonstrated purification of a single qubit by two collinear photons, one of which was time-delayed. Our method can be applied to a single qubit many times, and the qubit can be purified to an arbitrarily high degree of purity. Thus, by repeating this method we can make the statistical error that single qubits incur along a transmission channel much smaller.

Authors:
; ;  [1];  [2];  [3];  [3];  [4]
  1. Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corporation (JST), Department of Physics, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033 (Japan)
  2. (CREST), Japan Science and Technology Corporation (JST), Department of Physics, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033 (Japan)
  3. (Japan)
  4. (China)
Publication Date:
OSTI Identifier:
20982417
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.75.034306; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; INFORMATION THEORY; MATHEMATICAL OPERATORS; OPTICS; PHOTONS; QUANTUM COMPUTERS; QUANTUM MECHANICS; QUBITS; TIME DELAY; TRANSMISSION

Citation Formats

Odate, Satoru, Takeno, Yuishi, Kobayashi, Takayoshi, Core Research for Evolutional Science and Technology, Department of Applied Physics and Chemistry, Institute of Laser Research, The University of Electro-Communications, Chofugaoka 1-5-1, Chofu, Tokyo 182-8585, Institute of Laser Engineering, Osaka University, Yamada-oka 2-6, Suita, Osaka 565-0971, and Department of Electrophysics, National Chiao-Tung University, Hsinchu 3005, Taiwan. Purification of single qubits by collinear photons. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.034306.
Odate, Satoru, Takeno, Yuishi, Kobayashi, Takayoshi, Core Research for Evolutional Science and Technology, Department of Applied Physics and Chemistry, Institute of Laser Research, The University of Electro-Communications, Chofugaoka 1-5-1, Chofu, Tokyo 182-8585, Institute of Laser Engineering, Osaka University, Yamada-oka 2-6, Suita, Osaka 565-0971, & Department of Electrophysics, National Chiao-Tung University, Hsinchu 3005, Taiwan. Purification of single qubits by collinear photons. United States. doi:10.1103/PHYSREVA.75.034306.
Odate, Satoru, Takeno, Yuishi, Kobayashi, Takayoshi, Core Research for Evolutional Science and Technology, Department of Applied Physics and Chemistry, Institute of Laser Research, The University of Electro-Communications, Chofugaoka 1-5-1, Chofu, Tokyo 182-8585, Institute of Laser Engineering, Osaka University, Yamada-oka 2-6, Suita, Osaka 565-0971, and Department of Electrophysics, National Chiao-Tung University, Hsinchu 3005, Taiwan. Thu . "Purification of single qubits by collinear photons". United States. doi:10.1103/PHYSREVA.75.034306.
@article{osti_20982417,
title = {Purification of single qubits by collinear photons},
author = {Odate, Satoru and Takeno, Yuishi and Kobayashi, Takayoshi and Core Research for Evolutional Science and Technology and Department of Applied Physics and Chemistry, Institute of Laser Research, The University of Electro-Communications, Chofugaoka 1-5-1, Chofu, Tokyo 182-8585 and Institute of Laser Engineering, Osaka University, Yamada-oka 2-6, Suita, Osaka 565-0971 and Department of Electrophysics, National Chiao-Tung University, Hsinchu 3005, Taiwan},
abstractNote = {We have demonstrated purification of a single qubit by two collinear photons, one of which was time-delayed. Our method can be applied to a single qubit many times, and the qubit can be purified to an arbitrarily high degree of purity. Thus, by repeating this method we can make the statistical error that single qubits incur along a transmission channel much smaller.},
doi = {10.1103/PHYSREVA.75.034306},
journal = {Physical Review. A},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • Abstract not provided.
  • We characterize entanglement in two-qubit pure states encoded in transverse momenta of twin photons obtained from spontaneous parametric down-conversion. Two alternate methods are employed: (i) measurement of conditional interference patterns and (ii) measurement of the marginal probability that yields the single-photon interference pattern. Both methods are local with classical communication and rely on Schmidt decomposition of the quantum state, which is generated by letting the photons propagate through an appropriate lens system. In both cases we can obtain the concurrence either through the Schmidt coefficients in the first method or directly relating the concurrence to the visibility of the interferencemore » pattern in the second one.« less
  • A method of purification, purification through Zeno-like measurements [H. Nakazato, T. Takazawa, and K. Yuasa, Phys. Rev. Lett. 90, 060401 (2003)], is discussed extensively and applied to a few simple qubit systems. It is explicitly demonstrated how it works and how it is optimized. As possible applications, schemes for initialization of multiple qubits and entanglement purification are presented, and their efficiency is investigated in detail. Simplicity and flexibility of the idea allow us to apply it to various kinds of settings in quantum information and computation, and would provide us with useful and practical methods of state preparation.
  • An apparatus has been constructed to produce well-characterized fast beams of rare gas metastable atoms for subsequent scattering experiments. Optical pumping by a collinear laser beam can be used to selectively remove either of the two metastable components from the beam. Laser-induced-fluorescence (LIF) techniques can be used to determine the original beam composition and to monitor composition changes resulting from optical absorption. These techniques have been successfully applied to a metastable neon beam produced by near-resonant charge transfer of Ne/sup +/ in Na. A simple model has been developed which accurately reproduces the observed LIF lineshape generated by tuning themore » laser throught the optical transition frequency.« less