Probing Efimov Physics in ⁷Li–¹³³Cs Mixtures

Universality and scaling invariance appear widely in physics. They manifest as an infinite series of universal states with discrete scaling invariance in quantum three-body systems, as predicted by Vitaly Efimov. This invariance is associated with a relatively large scaling constant, approximately 22.7, for systems comprising three identical bosons. For systems with unequal masses, the scaling constant can be much smaller, yielding a tighter spectrum. Previously, studies of Efimov physics in extremely mass-imbalanced mixtures have primarily focused on ⁶Li–¹³³Cs systems, where three consecutive Efimov resonances have been observed. Here, we report our investigation of Efimov physics in ⁷Li–¹³³Cs mixtures, demonstrating the emergence of this appealing phenomenon in the special setting of such mixtures.