Interorbital Interactions in an SU(2)xSU(6)-Symmetric Fermi-Fermi Mixture

TL;DR

This study measures and characterizes interorbital interactions in an SU(2)xSU(6)-symmetric Fermi-Fermi mixture of ytterbium isotopes, revealing symmetry properties and spin-exchange interactions through high-precision spectroscopy.

Contribution

It provides the first detailed experimental characterization of interorbital interactions and confirms the SU(2)xSU(6) symmetry in ytterbium mixtures.

Findings

Interisotope elastic interactions are weakly attractive and similar.

Two-body loss coefficients differ significantly between isotopes.

Spin-exchange interaction is antiferromagnetic.

Abstract

We characterize inter- and intraisotope interorbital interactions between atoms in the 1S0 ground state and the 3P0 metastable state in interacting Fermi-Fermi mixtures of 171Yb and 173Yb. We perform high-precision clock spectroscopy to measure interaction-induced energy shifts in a deep 3D optical lattice and determine the corresponding scattering lengths. We find the elastic interaction of the interisotope mixtures 173Yb_e-171Yb_g and 173Yb_g-171Yb_e to be weakly attractive and very similar, while the corresponding two-body loss coefficients differ by more than two orders of magnitude. By comparing different spin mixtures we experimentally demonstrate the SU(2)xSU(6) symmetry of all elastic and inelastic interactions. Furthermore, we measure the spin-exchange interaction in 171Yb and confirm its previously observed antiferromagnetic nature.