Issue
EPL
Volume 84, Number 5, December 2008
Article Number 50001
Number of page(s) 6
Section General
DOI http://dx.doi.org/10.1209/0295-5075/84/50001
Published online 26 November 2008
EPL, 84 (2008) 50001
DOI: 10.1209/0295-5075/84/50001

Optimal controlled teleportation

T. Gao1, 2, F. L. Yan2, 3 and Y. C. Li3

1   College of Mathematics and Information Science, Hebei Normal University - Shijiazhuang 050016, China
2   Max-Planck-Institut für Quantenoptik - Hans-Kopfermann-Str. 1, D-85748 Garching, Germany, EU
3   College of Physics Science and Information Engineering, Hebei Normal University - Shijiazhuang 050016, China

gaoting@hebtu.edu.cn

received 18 March 2008; accepted in final form 22 October 2008; published December 2008
published online 26 November 2008

Abstract
We study the general case of controlled quantum teleportation and give analytic expressions for the maximal probabilities of successful controlled teleportation of an unknown qubit via every kind of three-qubit state. We also give an explicit expression for the three-qubit states that can be used as quantum channel for controlled teleportation of an unknown state with unit probability and with unit fidelity. In addition, an exact value of localizable entanglement is determined. We obtain the necessary and sufficient condition that a three-qubit state can be collapsed to an EPR pair by a measurement on one qubit.

PACS
03.67.Hk - Quantum communication.

© EPLA 2008