A team of physicists is claiming to have coaxed sparks from the vacuum of empty space1. If verified, the finding would be one of the most unusual experimental proofs of quantum mechanics in recent years and “a significant milestone”, says John Pendry, a theoretical physicist at Imperial College London who was not involved in the study.

The researchers, based at the Chalmers University of Technology in Gothenburg, Sweden, will present their findings early next week at a workshop in Padua, Italy. They have already posted a paper on the popular pre-print server arXiv.org, but have declined to talk to reporters because the work has not yet been peer-reviewed. High-profile journals, including Nature, discourage researchers from talking to the press until their findings are ready for publication.

Nevertheless, scientists not directly connected with the group say that the result is impressive. “It is a major development,” says Federico Capasso, an experimental physicist at Harvard University in Cambridge, Massachusetts, who has worked on similar quantum effects.