Testing the universality of the Feynman-Tan relation in interacting Bose gases using high-order Bragg spectra

The Feynman-Tan relation, obtained by combining Feynman energy relation with Tan’s two-body contact, explained excitation spectra of strongly interacting quantum gases of 39K atoms. However, whether Feynman-Tan relation is universal for other atomic species has remained out of reach. Now, this problem has been confirmed by Chinese scientists using high-momentum excitation spectra of interacting Bose gases of 133Cs atoms. This result provides significant insights for understanding the profound properties of interacting Bose gases.