This is a real study, and the post is a fair summary of it, with one caveat about what it shows.
The team at the Okinawa Institute of Science and Technology (OIST) reported it in Science Advances (Nayak et al., DOI 10.1126/sciadv.aeh0566), with OIST's news release dated 8 October 2026. The apparatus is a centimetre-scale diamond with nitrogen-vacancy centres, hung above a magnet and linked by a graphite rod to a diamagnetically levitated graphite plate. Short green laser pulses flip the spin states of electrons in the diamond, which creates small magnetic forces, and a laser interferometer tracks the motion down to picometre precision.
The "hundred million times heavier" figure is a rough version of the authors' own comparison. Professor Jason Twamley says the object is eight to nine orders of magnitude more massive than earlier spin-mechanical experiments, and 10⁸ falls within that range.
The caveat is that the study shows a classical mechanical response to a quantum-spin force. It does not show the diamond itself in a quantum superposition, which is the phenomenon that would bear on gravity. The authors present it as a platform for testing those ideas later, not as a test already done.
The OIST release has the figures and the diagram: First observation of quantum spins shifting a centimeter-scale obje….
