Stability of quantum Fourier transformation on Ising quantum computer

TL;DR

This paper investigates how errors affect the quantum Fourier transform on an Ising quantum computer and proposes methods to significantly improve its stability and fidelity.

Contribution

It introduces error suppression techniques for spurious transitions and external perturbations, enhancing the robustness of QFT on IQC.

Findings

Fidelity improved by several orders of magnitude

Error scaling with system size explained

Enhanced stability across physical parameters

Abstract

We analyze the influence of errors on the implementation of the quantum Fourier transformation (QFT) on the Ising quantum computer (IQC). Two kinds of errors are studied: (i) due to spurious transitions caused by pulses and (ii) due to external perturbation. The scaling of errors with system parameters and number of qubits is explained. We use two different procedures to fight each of them. To suppress spurious transitions we use correcting pulses (generalized $2\pi k$ method) while to suppress errors due to external perturbation we use an improved QFT algorithm. As a result, the fidelity of quantum computation is increased by several orders of magnitude and is thus stable in a much wider range of physical parameters.