If gravity isn't 'quantum,' it should be making a constant humming noise that we can use to figure out what reality is actually made of.
March 30, 2026
Original Paper
Minimal noise in non-quantized gravity
arXiv · 2603.26075
The Takeaway
Physics has long struggled to prove if gravity follows quantum rules or classical ones. This paper proves that if gravity is classical, it must inject a specific amount of 'static' into the universe; if we can build an experiment that is 'quieter' than that limit, we will have finally proven that gravity is quantum.
From the abstract
An elementary prediction of the quantization of the gravitational field is that the Newtonian interaction can entangle pairs of massive objects. Conversely, in models of gravity in which the field is not quantized, the gravitational interaction necessarily comes with some level of noise, i.e., non-reversibility. Here, we give a systematic classification of all possible such models consistent with the basic requirements that the non-relativistic limit is Galilean invariant and reproduces the Newt