A small international team of nanotechnologists, engineers and physicists has developed a way to force laser light into becoming a supersolid. Their paper is published in the journal Nature. The editors at Nature have published a Research Briefing in the same issue summarizing the work.
Supersolids are entities that exist only in the quantum world, and, up until now, they have all been made using atoms. Prior research has shown that they have zero viscosity and are formed in crystal-like structures similar to the way atoms are arranged in salt crystals.
Because of their nature, supersolids have been created in extremely cold environments where the quantum effects can be seen. Notably, one of the team members on this new effort was part of the team that demonstrated more than a decade ago that light could become a fluid under the right set of circumstances.