On the 28th, it was learned from Nanjing University that an international team led by Professor Du Lingjie from the School of Physics at the university used polarized light scattering technology under extreme conditions to measure the collective excitation of fractional quantum Hall effect in gallium arsenide quantum wells. For the first time in the world, graviton excitation, a novel quasi particle of gravitons in condensed matter, was observed. The related research results were published online on March 28th in the journal Nature. The study of gravitons has always been one of the ultimate problems in physics research. In recent years, theoretical physicists have proposed that there may be excitation of gravitons in the fractional quantum Hall effect, also known as the fractional quantum Hall effect graviton. "The excitation of gravitons is a quasi particle or collective excitation phenomenon in condensed matter, which has the characteristics of gravitons but is not a true particle." Du Lingjie told Science and Technology Daily reporters that the excitation of gravitons, as an important conclusion of the geometric theory of fractional quantum Hall effect, is of great significance for the study of condensed matter physics. Unfortunately, the existence of fractional quantum Hall effect gravitons, like a mystery, has not been discovered before. In 2019, Du Lingjie's team discovered a new collective excitation in the fractional quantum Hall effect, which was immediately recognized by theoretical physicists as a possible fractional quantum Hall effect graviton, and proposed a key spin measurement scheme to detect this graviton. Searching for fractional quantum Hall effect gravitons has become a new goal for the Du Lingjie team. They spent over three years independently designing and assembling an extremely low temperature strong magnetic field resonance inelastic polarized light scattering system at Nanjing University. This system is like a special "telescope" with two floors high, capable of capturing weak excitation phenomena up to 10G Hz at minus 273.1 degrees Celsius and determining its spin. "With this sharp tool, we successfully observed fractional quantum Hall effect gravitons in gallium arsenide semiconductor quantum wells. The team measured the lowest energy long wave collective excitation through resonant inelastic light scattering, and observed that the excitation has spin 2 characteristics by changing the spin of incident and scattered light." Du Lingjie said, these results provide sufficient experimental evidence for graviton excitation from the perspectives of spin, momentum, and energy. These findings are the first experimental discoveries of quasi particles with graviton characteristics since the concept of gravitons was proposed. The experimental results have opened up a new perspective for studying quantum gravity related physics in condensed matter systems, laid the experimental foundation for the verification of fractional state wave functions in topological quantum computing, and opened up a new direction for experimental research on geometric effects of topological correlated states. (Lai Xin She)