Cross-talk compensation of hyperfine control in donor qubit architectures

TL;DR

This paper models and analyzes cross-talk effects in hyperfine gate control of donor qubits, proposing compensation protocols to mitigate errors in quantum architectures like Kane's.

Contribution

It provides a detailed numerical investigation of cross-talk in donor qubit systems and explores compensation strategies to improve quantum gate fidelity.

Findings

Cross-talk causes measurable errors in hyperfine control at 20-30nm gate distances.

Compensation bias protocols can reduce cross-talk effects significantly.

Architectural considerations are crucial for scalable donor qubit quantum computers.

Abstract

We theoretically investigate cross-talk in hyperfine gate control of donor-qubit quantum computer architectures, in particular the Kane proposal. By numerically solving the Poisson and Schr\"{o}dinger equations for the gated donor system, we calculate the change in hyperfine coupling and thus the error in spin-rotation for the donor nuclear-electron spin system, as the gate-donor distance is varied. We thus determine the effect of cross-talk - the inadvertent effect on non-target neighbouring qubits - which occurs due to closeness of the control gates (20-30nm). The use of compensation protocols is investigated, whereby the extent of crosstalk is limited by the application of compensation bias to a series of gates. In light of these factors the architectural implications are then considered.