Prethermal and Efimovian dynamics of the quenched unitary Bose gas

We study the quench of a degenerate ultracold Bose gas to the unitary regime, using a cumulant theory able to capture both higher-order interactions which break integrability and non-perturbative few-body physics including the Efimov effect. After an initial period of rapid quantum depletion, a universal prethermal stage is established, characterized by an emergent Bogoliubov dispersion law and an associated universal sound speed. Integrability is then broken by higher-order interactions, which leads to a momentum-dependent departure form the prethermal stage. We also find signatures of the Efimov effect in the many-body dynamics and make a precise identification between the observed beating phenomenon of short-distance three-body correlations and the binding energy of an Efimov trimer.