0206103v5

related topics
{classical, space, random}
{let, theorem, proof}
{equation, function, exp}
{qubit, qubits, gate}
{cos, sin, state}
{operator, operators, space}
{phase, path, phys}
{state, algorithm, problem}
{algorithm, log, probability}

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

Norio Konno

abstract: 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.

oai_identifier:
oai:arXiv.org:quant-ph/0206103
categories:
quant-ph
comments:
Final version; Journal-ref added; 14 pages; this arXiv version has no figures
arxiv_id:
quant-ph/0206103
journal_ref:
Journal of the Mathematical Society of Japan, Vol.57, No.4, pp.1179-1195 (2005)
created:
2002-06-17
updated:
2005-10-31

Full article ▸

related documents
0406072v1
9910068v2
0308164v2
0407128v1
9706014v1
0602007v1
0508057v2
0509141v2
0102032v1
0109076v1
0403154v1
0401142v2
0108054v1
0211034v2
0304013v1
0502050v1
0208130v1
0606077v1
0406226v1
0408169v1
0302192v2
0402060v2
0302011v2
0406010v1
0309192v1