Evrim Yazgin
Cosmos science journalist
For the first time, physicists have been able to trap molecules and get them to perform quantum operations, opening a new line of research for future ultra-powerful quantum computing.
Molecules have often been overlooked in quantum computing. Their internal structures have been considered too complicated, delicate and unpredictable to be useful in quantum devices. Instead, physicists and engineers have focused on trying to build quantum architecture using single atoms, ions and superconducting circuits as quantum bits (qubits).
The experiment conducted at Harvard University introduces molecules onto the quantum computing scene. The results are published in Nature.
“As a field we have been trying to do this for 20 years,” says senior co-author Kang-Kuen Ni. “And we’ve finally been able to do it.”
The team cooled sodium-caesium (NaCs) molecules to temperatures approaching absolute zero. They used optical tweezers – highly focused laser beams – to trap the molecules in place.
They then formed an iSWAP gate – a quantum logic circuit that creates entanglement. This is a key ingredient which makes quantum computing such a powerful and tantalising prospect.
Controlling how the molecules rotate with respect to one another, the team entangled 2 molecules with 94% accuracy.
“Our work marks a milestone in trapped molecule technology and is the last building block necessary to build a molecular quantum computer,” says co-author Annie Park. “The unique properties of molecules, such as their rich internal structure, offer many opportunities to advance these technologies.”
“There’s a lot of room for innovations and new ideas about how to leverage the advantages of the molecular platform,” Ni said. “I’m excited to see what comes out of this.”
