- Physicists used LIGO’s mirrors to approach a quantum limit. A large object has gotten closer to a realm usually reserved for the very small. The researchers reduced the mirrors’ relative motions to about 10.8 phonons, or quantum units of vibration, close to the zero-phonon quantum limit. https://www.sciencenews.org/article/physics-ligo-mirrors-lasers-quantum-mechanics-limit 4 comments science