Making quantum systems more scalable is one of the key requirements for the further development of quantum computers as the advantages they offer become increasingly apparent as the systems are miniaturized. Researchers at TU Darmstadt have recently taken a decisive step towards achieving this goal.

Quantum processors based on two-dimensional arrays of optical tweezers, fabricated using focused laser beams, are one of the most promising technologies for developing quantum computing and simulations that enable highly beneficial applications in the future. will make A diverse range of applications will benefit from this technology, from drug development to improving traffic flow.

These processors have so far been able to house several hundred single-atom quantum systems, whereby each atom represents a quantum bit or qubit as the basic unit of quantum information. To make further progress, the number of qubits in processors must be increased. This has now been achieved by a team led by Prof. Gerhard Berkel of the “Atoms — Photons — Quanta” research group at TU Darmstadt’s Department of Physics.

In a research article, which was first published on the arXiv preprint server in early October 2023 and has now been published in the scientific peer-reviewed journal OPTICA, the team explores the world to realize quantum processing. The first successful experience has been reported. Architectures that contain more than 1,000 atomic qubits in a single plane.

“We are very pleased that we were the first to break the mark of 1,000 individually controllable atomic qubits as many other prominent competitors are hot on our heels,” Burkle says of his results.

The researchers were able to demonstrate in their experiments that their approach of combining advanced quantum optical methods with state-of-the-art micro-optical technology enabled them to significantly expand the current limits of accessible number of qubits.

This was achieved by introducing a new method of “quantum bit supercharging”. This allowed them to overcome the limitations imposed by the limited efficiency of lasers on the number of usable qubits. 1305 single-atom qubits were loaded into a quantum array with 3,000 trap sites and recombined into a defect-free target structure with up to 441 qubits. By using several laser sources in parallel, this concept has broken technical limits that were considered almost insurmountable until now.

For many different applications, 1,000 qubits is seen as the threshold value beyond which the performance gains promised by quantum computers can now be made for the first time. Thus, researchers around the world are working hard to be the first to break this limit. Recently published research work shows that this breakthrough for nuclear qubits was achieved for the first time in the world by the research group led by Prof. Berkle. The scientific publication also describes how further increases in the number of laser sources will enable qubit numbers of 10,000 and above in just a few years.