Researchers from the University of Innsbruck, Austria, have built the smallest quantum computer ever based on industry standards. The success of the new devices illustrates that quantum computers will soon be ready to be installed alongside classic computers in data centers.
The university has been working on quantum computers for three decades. This latest project, part of the EU Quantum Technologies Flagship, involved significantly downsizing their work.
“Our quantum computing experiments typically fill 30 to 50 square meters of labs,” said Dr Thomas Monz, who belongs to the university’s department of experimental physics.
“We were now looking to fit the technologies developed here in Innsbruck into the smallest space possible while meeting the standards commonly used in the industry.” Monz and his colleagues built a demonstrator for a compact quantum computer with trapped ions.
This type of quantum computer (to say with great simplicity) confines charged particles and suspends them using electromagnetic fields, with qubits corresponding to the stable electronic states of each particle.
With these systems, the fundamental operations of quantum computing have been demonstrated with great accuracy. Compressing a quantum computer with trapped ions required miniature versions of every single building block.
The researchers acquired the centerpiece of the system (the ion trap in a vacuum chamber) from a university spin-off that focused on building a commercial quantum computer.
A particular challenge in construction was ensuring the stability of the quantum computer; quantum devices are extremely sensitive to the slightest external disturbances, causing decoherence and disruption of operation.
However, the researchers were able to apply the necessary quality standard even for their miniaturized device. The compact quantum computer can be operated autonomously and will soon be programmable online.
“We have been able to show that compactness does not have to come at the expense of functionality,” says Dr Christian Marciniak, who worked on the project at Innsbruck.
Another determinant of the industrial use of quantum computers is the number of qubits available.
Innsbruck’s physicists were able to make the quantum computer work with 24 fully functional qubits — which could individually control and entangle 24 enclosed ions with their device — and achieve a recent German government goal with surprising speed.
“Next year, we want to be able to deliver a device with up to 50 individually controllable quantum bits,” Monz said. Last month, the German government announced it would spend billions of euros to support the development of the country’s first quantum computer and other quantum technologies.
The government hopes to build a competitive quantum computer in just five years while boosting a network of companies to develop applications.
In 2019, Google engineers published a paper saying they had achieved “quantum supremacy” (a milestone that refers to a quantum computer’s ability to perform calculations impossible for classical computers) with a 54-qubit quantum computer.