There are many different approaches in the field of quantum technology: to harness the properties of the quantum world, one can, for example, use individual ions or superconducting circuits. At TU Wien, however, a new type of quantum hardware is now being developed, offering decisive advantages. The “POLMOL” technique couples the electric states of polar molecules to the electric field of superconducting circuits on a chip. The result is a system that can be miniaturised, reproduced, and extended – a new building block from which increasingly complex, tailor-made quantum systems can be assembled in the future.

The foundation for this technology is the ERC grant “Emergence in Quantum Physics”, which was awarded to Prof. Jörg Schmiedmayer (Atominstitut TU Wien, Vienna Center for Quantum Science and Technology) in 2023. The project proved so successful that, building on these results, Jörg Schmiedmayer has now secured an additional Proof of Concept Grant from the European Research Council. With an extra €150,000, a prototype is to be developed over the next 18 months that will make it possible to couple a single polar molecule to a superconducting resonator.

Many possibilities – but also many drawbacks

“The laws of quantum physics can be studied in very different kinds of systems,” says Jörg Schmiedmayer. “In atoms, in molecules, in circuits, in solids. Accordingly, there is a wide range of quantum technologies in use today for different purposes – such as quantum computers or quantum sensors.”

However, all of these technologies have specific disadvantages. Superconducting qubits store quantum information in small electrical circuits on a chip – they are fast, but their coherence time is short, meaning that their quantum properties are lost very quickly.

Ions trapped in electromagnetic fields are much more stable. Their quantum coherence time is far longer, but they require highly complex infrastructure, and it is difficult to integrate them in large numbers into compact devices.

Quantum states in solids (usually based on dopants and defects) can also store information over longer periods of time – but they have other disadvantages and interact only weakly with the outside world. As a result, they are difficult to control, to feed with information, or to read out.

The POLMOL technique

The research group led by Jörg Schmiedmayer is taking a different approach: it uses polar molecules that are electrically coupled to microwave photons in superconducting circuits. “This electrical interaction is so strong that a single microwave photon can manipulate the state of a molecule,” explains Jörg Schmiedmayer. The molecule thus takes on the role of a switchable qubit.

In this way, two key advantages are combined: on the one hand, the ability to store quantum information reliably over relatively long periods of time, and on the other hand, the ability to manipulate it in a technically simple and fast manner.

“We have already completed the essential preparatory work. The next crucial step is now to embed polar molecules in crystals, to study the coupling between superconductors and molecules in detail, and then to tailor it in a targeted way. This will allow us to create a new quantum platform that can be flexibly combined with other types of quantum hardware depending on the application, expanded in a modular fashion, and assembled like building blocks into more complex systems,” says Schmiedmayer.

Towards market readiness

From quantum computers and quantum communication to quantum sensors – the range of potential applications for this new technology is broad. With the help of the ERC Proof of Concept Grant, the aim is now to demonstrate that the existing research results can be combined into a practically viable instrument.

The new platform will be tested carefully and compared with existing quantum technologies. Close collaboration with established European quantum technology companies is planned, along with preparations for a spin-off company that will bring the new quantum platform to market.

Rückfragehinweise

Prof. Jörg Schmiedmayer
Atominstitut, Vienna Center for Quantum Science and Technology (VCQ)
Technische Universität Wien
Stadionallee 2, 1020 Wien
+43 1 58801 141801
hannes-joerg.schmiedmayer@tuwien.ac.at

Dr. Florian Aigner
PR und Marketing
Technische Universität Wien
+43 664 60588 412
florian.aigner@tuwien.ac.at