Observation of spin-exchange dynamics between itinerant and localized ${}^{171}\mathrm{Y}\mathrm{b}$ atoms

We report on the observation of the spin-exchange dynamics of ${}^{171}\mathrm{Y}\mathrm{b}$ atoms in the ground state ${}^1{\mathrm{S}}_0$ and in the metastable state ${}^3{\mathrm{P}}_0$. We implement the mixed-dimensional two-orbital system using a near-resonant and magic-wavelength optical lattices, where the ${}^1{\mathrm{S}}_0$ and ${}^3{\mathrm{P}}_0$ atoms are itinerant in a one-dimensional tube and localized in three dimensions, respectively. By exploiting an optical Stern-Gerlach method, we observe the spin depolarization of the ${}^1{\mathrm{S}}_0$ atoms induced by the spin-exchange interaction with the ${}^3{\mathrm{P}}_0$ atom. Our work could open the way to the quantum simulation of the Kondo effect.