We report an observation of a dynamical super E movian expansion in a two-component strongly interacting Fermi gas by engineering time dependent external harmonic trap frequencies. When trap frequency is followed as [1/4t2+1/t2λ log(t/tж)]1/2, where tж and λ are two control parameters, and the change is faster than a critical value, the expansion of such the quantum gas shows a novel dynamics due to its spatial and dynamical scaling symmetry. A clear double-log periodicity,which is a hallmark of the super E mov e ect, is emergent for the cloud size in the expansion. The universality of such scaling dynamics is veri ed both in the non-interacting limit and in the unitarity limit. Observing super-Efmovian evolution represents a paradigm in probing universal propertiesand allows in a new way to study many-body nonequilibrium dynamics with experiments.
图1（a）实验装置简图（b）超级Efimov膨胀的实验观测过程示意图
图2 强相互作用费米气体和无相互作用费米气体超级Efimov膨胀动力学的实验观测结果，图（a）、（b）表示幺正费米气体，图（c）、（d）表示无相互作用费米气体。点为实验测量结果，实线为理论预测，右侧图片中原子气体在双对数标度下呈现出正弦振荡的现象表征超级Efimov膨胀动力学
Phys. Rev. Lett. 120,125301(2018)pdf.pdf
