half-quantum vortices tagged posts

For the first time, researchers have documented the long-predicted occurrence of ‘walls bound by strings’ in superfluid helium-3. The existence of such an object, originally foreseen by cosmology theorists, may help explaining how the universe cooled down after the Big Bang. With the newfound ability to recreate these structures in the lab, earth-based scientists finally have a way to study some of the possible scenarios that might have taken place in the early universe more closely. The findings, to be published 16th January in Nature Communications, came after two successive symmetry-breaking phase transitions at Aalto University’s Low Temperature Laboratory.

Helium stays a liquid at atmospheric pressure even wh...

A half-quantum vortex combines circular spin flow and circular mass flow, leading to the formation of vortex pairs that can be observed experimentally. Image: Ella Maru Studio.

Gained understanding in quantum physics may be a step towards quantum computers. Researchers in Aalto University, Finland, and P.L. Kapitza Institute in Moscow have discovered half-quantum vortices in superfluid helium. This vortex is a topological defect, exhibited in superfluids and superconductors, which carries a fixed amount of circulating current. ‘This discovery of half-quantum vortices culminates a long search for these objects originally predicted to exist in superfluid helium in 1976,’ says Samuli Autti, Doctoral Candidate at Aalto University in Finland.

‘In the future, our discovery will provide access to...