Signature of the universal super Efimov effect: Three-body contact in two-dimensional Fermi gases

摘要

A class of universal "three-body" bound states has been recently predicted theoretically for identical fermions interacting at p-wave resonance in two dimensions. This phenomenon is called the super Efimov effect since the binding energies of the states follow a intriguing double exponential scaling. However, experimental resolution of this scaling is expected to meet formidable challenges. In this work, we introduce a thermodynamic quantity, the three-body contact C_θ , to quantify three-body correlations in a two-dimensional gas composed of the resonantly interacting fermions; the contact C_θ is the consequence of the underlying universal super Efimov effect in the many-body context. We show how C_θ affects physical observables such as the radio-frequency spectrum, the momentum distribution, and the atom loss rate. The signature of the elusive super Efimov effect can be pinned down by the detection of the three-body contact C_θ via these observables in the many-body system.