Équipe de Recherche en Physique de l'Information Quantique


Year = {2013},
Abstract = {Due to the great di±culty in scalability, quantum computers are limited in the number of
qubits during the early stages of the quantum computing regime. In addition to the required
qubits for storing the corresponding eigenvector, suppose we have additional k qubits available.
Given such a constraint k, we propose an approach for the phase estimation for an eigenphase
of exactly n-bit precision. This approach adopts the standard recursive circuit for quantum
Fourier transform (QFT) in [R. Cleve and J. Watrous, Fast parallel circuits for quantum
fourier transform, Proc. 41st Annual Symp. on Foundations of Computer Science (2000),
pp. 526536.] and adopts classical bits to implement such a task. Our algorithm has the complexity
of O(n log k), instead of O(n^2) in the conventional QFT, in terms of the total invocation
of rotation gates. We also design a scheme to implement the factorization algorithm by using
k available qubits via either the continued fractions approach or the simultaneous Diophantine
author = {Chiang, Chen-Fu},
title = {Quantum phase estimation with an arbitrary number of qubits},
journal = {Int. J. Quant. Info.},
volume = {11},
pages = {1350008},
local-url = {C13.pdf}}