Kerr-enhanced optical spring for next-generation gravitational wave detectors

- "Physicists Have Figured Out a Way to Measure Gravity on a Quantum Scale" with tantalum https://news.ycombinator.com/item?id=39495482 :

> "Measuring gravity with milligram levitated masses" (2024) https://www.science.org/doi/10.1126/sciadv.adk2949 :

> Here, we show gravitational coupling between a levitated submillimeter-scale magnetic particle inside a type I superconducting trap and kilogram source masses, placed approximately half a meter away. Our results extend gravity measurements to low gravitational forces of attonewton and underline the importance of levitated mechanical sensors.