Using light to perform tasks beyond the reach of classical computers.

Scientists at RIKEN have proposed a new way to make quantum systems synchronize in only one direction—like a one-way street for sound particles known as phonons. The breakthrough combines two quantum effects to create a form of one-way quantum synchronization that remains surprisingly stable even when exposed to manufacturing flaws and environmental noise, two major obstacles that have long hindered real-world quantum technologies.

Physicists at University College Cork have developed a new approach in the search for a quantum spin liquid, a long-sought state of quantum matter resembling a magnetic liquid whose quantum properties mean it never freezes. The work is a key step in the search for quantum silicon, a mineral that could be used to create quantum computers, just as silicon is used in traditional computers. The resulting paper appears in Nature Physics.

Lead author Prof. Seamus Davis said, “By introducing the quantum witness technique we provide a completely new perspective on the physics of quantum spin liquids and access their internal quantum excitations or ‘spinons’ directly for the first time at UCC.”

As liquids cool, they freeze into solids as their atoms cease to move. But some liquids, such as helium, never freeze. Predominant quantum effects mean they flow as superfluids even at absolute zero (the coldest possible temperature).