Searching for signatures of Efimov physics in universal many-body dynamics

According to the universality hypothesis, in a degenerate unitary gas the dynamics depend solely on the gas density as the s-wave scattering length diverges and drops out of the problem. However, for Bose gases Efimov physics introduces additional lengthscales and remains a part of the problem. Here we explore the dynamics of ³⁹K Bose gases quenched to unitarity, initially preparing degenerate homogeneous clouds of varying density in different internal spin states and at different Feshbach resonances, the positions of which we calibrate using high-precision binding energy measurements. We rapidly quench the magnetic field to the unitary regime, wait for a variable hold time, before returning to weak interactions and observing the samples. By comparing the different spin states with varying Efimov parameters we explore the quasi-equilibrium prethermal state that is reached at intermediate times, and study the loss, energy, and molecular correlation dynamics as the cloud decays and heats.