Particles of light that effectively exist in 37 dimensions at once have been used to test an extreme version of a quantum paradox.

“This experiment shows that quantum physics is more nonclassical than many of us thought. It could be [that] 100 years after its discovery, we are still only seeing the tip of the iceberg,” says Zhenghao Liu at the Technical University of Denmark.

He and his colleagues focused on the Greenberger-Horne-Zeilinger (GHZ) paradox, which shows quantum particles can…