Hacker News Reader

They mention a "quantum noise limit", that must be the ultimate precision that is physically possible, right?

What is this ultimate precision? I imagine that at some point, even the most modest relative motion at ordinary velocities would introduce measurable time dilation at fine enough clock precision.

View on HN

Yes, there is a limit called "quantum projection noise" that determines how much frequency stability one can achieve with a single-atom clock [1]. With N independent atoms, this limit gets smaller by 1/sqrt(N), but with N entangled atoms one can achieve a 1/N scaling. This is the ultimate limit (Heisenberg limit).

[1] https://journals.aps.org/pra/abstract/10.1103/PhysRevA.47.35...

Not just time dilation, at those scales time apparently can flow backwards for a bit!

https://arxiv.org/abs/2409.03680

Reply on news.ycombinator.com