Researchers in China tested Feynman’s thought experiment directly.

The idea has always been confirmed by inference, never by direct measurement until now.

For nearly 80 years, physicists relied on Feynman’s trick only as a calculation method, not an observation.

The team has not yet said whether the technique scales beyond this test.

How each outlet framed it
Phys.org leans favorable
experimentally validates Feynman's path integral using photons for first time in 78 years

Sources: Phys.org