The three-body parameter for Efimov states in lithium-6

Huang Bo 1 O'Hara Kenneth M. 2, 3 Grimm Rudolf 1, 3 Hutson Jeremy M. 4 Petrov Dmitry S. 5

Physical Review A, American Physical Society, 2014, 90, pp.043636

We present a state-of-the-art reanalysis of experimental results on Efimov resonances in the three-fermion system of $^6$Li. We discuss different definitions of the 3-body parameter (3BP) for Efimov states, and adopt a definition that excludes effects due to deviations from universal scaling for low-lying states. We develop a finite-temperature model for the case of three distinguishable fermions and apply it to the excited-state Efimov resonance to obtain the most accurate determination to date of the 3BP in an atomic three-body system. Our analysis of ground-state Efimov resonances in the same system yields values for the three-body parameter that are consistent with the excited-state result. Recent work has suggested that the reduced 3BP for atomic systems is a near-universal quantity, almost independent of the particular atom involved. However, the value of the 3BP obtained for $^6$Li is significantly ($\sim 20$%) different from that previously obtained from the excited-state resonance in Cs. The difference between these values poses a challenge for theory.

  • 1. Institut für Experimentalphysik
  • 2. Pennsylvania State University
  • 3. ICOQI - Institut für Quantenoptik und Quanteninformation
  • 4. JQC - Joint Quantum Centre
  • 5. LPTMS - Laboratoire de Physique Théorique et Modèles Statistiques