Optimal encoding and decoding of a spin direction -: art. no. 052309

被引：54

作者：

Bagan, E ^{[1
]}

Baig, M

Brey, A

Muñoz-Tapia, R

Tarrach, R

机构：

[1] Univ Autonoma Barcelona, Edifici Cn, Fac Ciencies, Fis Teor Grp, E-08193 Barcelona, Spain

[2] Univ Autonoma Barcelona, Edifici Cn, Fac Ciencies, IFAE, E-08193 Barcelona, Spain

[3] Univ Barcelona, Dept Estructura & Constituents Mat, E-08028 Barcelona, Spain

来源：

PHYSICAL REVIEW A | 2001年 / 63卷 / 05期

关键词：

D O I：

10.1103/PhysRevA.63.052309

中图分类号：

O43 [光学];

学科分类号：

070207 ; 0803 ;

摘要：

For a system of N spins there are quantum states that can encode a direction in an intrinsic way. Information on this direction can later be decoded by means of a quantum measurement. We present here the optimal encoding and decoding procedure using the fidelity as a figure of merit. We compute the maximal fidelity and prove that it is directly related to the largest zeros of the Legendre and Jacobi polynomials. We show that this maximal fidelity approaches unity quadratically in 1/N. We also discuss this result in terms of the dimension of the encoding Hilbert space.

引用

页码：523091 / 523091

页数：11