Quantum Spin Behavior Altered by Gravity

Researchers from the University of Science and Technology of China investigated the coupling effect between neutron spin and gravitational force using a high-precision xenon isotope magnetometer. The weight difference between neutron's spin-up and spin-down states was found to be less than two sextillionths, setting a new upper limit on the coupling strength of this effect. The study improves the precision of various fundamental physical effects by an order of magnitude and compresses the upper limit of the neutron's spin-gravity coupling strength by a factor of 17.