A team led by Holger Hofmann at Hiroshima University reported in May that a modified double-slit experiment showed single photons behaving as if in two places at once, potentially undermining the multiverse concept. The findings, which suggest the wave function guides real particle paths, have faced significant skepticism from other physicists. Despite pushback, the researchers stand by their results and continue their work.
In May, researchers at Hiroshima University, headed by Holger Hofmann, published results from an adapted version of the classic double-slit experiment, first conducted in 1801. This setup typically reveals light's wave-like interference patterns, even when photons pass through slits one by one, hinting at their dual wave-particle nature.
Hofmann's group claimed their modification demonstrated individual photons as "delocalised," meaning they could not be pinned to a single location but appeared to traverse both slits simultaneously. They argued this provides direct proof that the quantum wave function, which mathematically outlines a particle's possible positions in superposition, reflects actual physical behavior rather than just a calculational tool. Such evidence, they said, contradicts the many-worlds interpretation of quantum mechanics, which posits overlapping universes where particles take different paths and interfere across realities.
The experiment drew sharp criticism. Andrew Jordan, a physicist at Chapman University in California, questioned the method's validity, stating, "I think you can’t make claims about a single photon with this." Critics contended that aggregating statistical data from multiple measurements cannot reliably describe a single particle's properties. Hofmann acknowledged the resistance, noting, "We are stepping on several people’s feet," as their approach challenges assumptions in most quantum interpretations, including the extreme many-worlds view.
Hofmann emphasized that reality lies in measurable outcomes, not hypothetical superpositions: "Superpositions make it look as if the state is described by such hypothetical measurement outcomes, but the actual experimental evidence contradicts such overinterpretations." Though publication in journals has proven difficult, the team has received invitations to present at other institutions and plans further refinements.
Hofmann remains undeterred: "I fully expected some pushback. In fact, it would hardly be worth doing this work if it was easy. Minds need to be changed, and that takes a lot of time." This debate underscores ongoing tensions in understanding quantum reality after a century of theory.