Here's the [paper][1] on the arxiv.

I found it hard to believe that they accounted for other forces precisely enough that they could attribute the phase change to gravity, but this is beyond me so I trust the result.

At first I thought "they showed that you can measure a particle falling in gravity," which seemed dumb because we already know that particles fall in gravity. But they showed that you can measure a single (aggregate) particle falling in gravity, which is pretty cool because if gravity is quantum then that means that they observed an interaction between the graviton and their rubidium atom.

[1]: https://arxiv.org/pdf/2502.14535