University of Cambridge

Quantum spin liquid, a state of matter predicted over forty years ago, has finally been discovered by a team of researchers.

The matter, which has been detailed in Nature Materials, causes electrons to "break into pieces" despite the fact they are usually "thought of as indivisible building blocks", and "has never been seen before" according to Johannes Knolle, one of the paper's co-authors.


The findings – published in the journal Nature – could have profound implications, with previously indivisible electrons splitting into pieces and potentially making quantum computers far faster than ever imagined. These pieces, known as "Majorana fermions", could be crucial to the development of quantum computers. The research was completed by an international team of researchers including those from Oak Ridge National Laboratory, US, the University of Cambridge, and the Max Planck Institute at Dresden, Germany.

Quantum spin liquid was first proposed in the 1970s and furthered in the 1980s. It had long been thought to be present in magnetic materials but had never been seen before. "Until recently, we didn't even know what the experimental fingerprints of a quantum spin liquid would look like," said Dmitry Kovrizhin, co-author of the study, from Cambridge. "One thing we've done in previous work is to ask, if I were performing experiments on a possible quantum spin liquid, what would I observe?"

Typically, electrons behave like "tiny bar magnets", the team explained, but materials containing a spin liquid state instead form an "entangled soup" instead of something more organised.

The team used "neutron scattering techniques" to look for evidence of this entanglement, illuminating a powder with neutrons to observe the pattern of ripples created by a magnetic field. Normally, magnetic fields produce "distinct, sharp lines", but powders containing quantum spin liquid instead produced "broad humps". "It's an important step for our understanding of quantum matter," said Kovrizhin. "It's fun to have another new quantum state that we've never seen before -- it presents us with new possibilities to try new things."

Updated 07/04/16, 09:50: This article has been updated to reflect all research institutes involved in the study.