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arXiv quant-ph/0206103quant-ph
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一维量子随机游动的一类新的极限定理

A New Type of Limit Theorems for the One-Dimensional Quantum Random Walk

Norio Konno

摘要:

本文考虑从2乘2酉矩阵U确定的初始量子比特态varphi出发的一维量子随机行走X^{varphi} _n在n时刻的情形。给出了X^{varphi}_n的特征函数的组合表达式.该表达式阐明了它对酉矩阵U的分量和初始量子比特态varphi的依赖性。作为上述结果的结果,我们给出了量子随机游动的一个新的极限定理。与de Moivre-Laplace极限定理相反,我们的对称情况意味着X^{varphi}_n /n在分布上收敛于极限Z^{varphi},因为n到infty,其中Z^{varphi}的密度为1 / pi(1-x^2)sqrt{1-2x^2},x在(- 1/sqrt{2},1/sqrt{2})中。此外,我们讨论了一些已知的模拟结果的基础上,我们的极限定理。

英文摘要:

In this paper we consider the one-dimensional quantum random walk X^{varphi} _n at time n starting from initial qubit state varphi determined by 2 times 2 unitary matrix U. We give a combinatorial expression for the characteristic function of X^{varphi}_n. The expression clarifies the dependence of it on components of unitary matrix U and initial qubit state varphi. As a consequence of the above results, we present a new type of limit theorems for the quantum random walk. In contrast with the de Moivre-Laplace limit theorem, our symmetric case implies that X^{varphi}_n /n converges in distribution to a limit Z^{varphi} as n to infty where Z^{varphi} has a density 1 / pi (1-x^2) sqrt{1-2x^2} for x in (- 1/sqrt{2}, 1/sqrt{2}). Moreover we discuss some known simulation results based on our limit theorems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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