Line defects as building blocks of a defect-based quantum computer

A quantum computer is a device that exploits the quantum behaviour of its constituents (""qubits"") to solve a computational problem.

One of the most promising ""hardware"" options proposed to build such a device are point defects in solids, which hold promise of scalability and integration with current semiconductor technology.

However, it remains challenging to position the point defects in a deterministic array and to integrate them into large networks.

In order to address these two issues, we propose to use line defects (dislocations) as a “quantum bus” able to both create a deterministic pattern of relevant point defects and to connect them by means of localized phonons.

Such idea represents a technological leap and paves the way for a quantum computer implementation that is fully defect-based, from its construction to its functioning.

We remark that our proposal opens a completely new area of research, aligned with the quantum technologies flagship policy of the European commission and that will help putting Europe at the forefront of the development of quantum technologies.

In order to carry out the project, it is necessary to combine the theoretical study of the stability and geometry of point and line defects with advanced electronic structure calculations of their spectroscopic properties.

This is the basic strength of our proposal: it brings together the two complementary research profiles needed to carry the project.

On the one hand, Dr Barragan is an expert on the physics of dislocations and their interactions with point defects and, on the other hand, Prof Wirtz is an expert on many-body perturbation theory.

In addition, this project will open up a new research line for the Dr Barragan and will give him the opportunity to investigate problems at the interface of condensed matter/quantum technologies, increase his network of collaborations and thus serve as an important step preparing him to become an independent group leader in a European context.