Magnetic Feshbach resonances between atoms in 2S and 3P0 states: Mechanisms and dependence on atomic properties

Magnetically tunable Feshbach resonances exist in ultracold collisions between atoms in 2S and 3P0 states, such as an alkali-metal atom colliding with Yb or Sr in a clock state. We investigate the mechanisms of these resonances and identify the terms in the collision Hamiltonian responsible for them. They involve indirect coupling between the open and closed channels, via intermediate channels involving atoms in 3P1 states. The resonance widths are generally proportional to the square of the magnetic field and are strongly enhanced when the magnitude of the background scattering length is large. For any given pair of atoms, the scattering length can be tuned discretely by choosing different isotopes of the 3P0 atom. For each combination of an alkali-metal atom and either Yb or Sr, we consider the prospects of finding an isotopic combination that has both a large background scattering length and resonances at a high but experimentally accessible field. We conclude that 87Rb +Yb, Cs+Yb, and 85Rb +Sr are particularly promising combinations.

Automated summary

We investigate the mechanisms of magnetically tunable Feshbach resonances in ultracold collisions between atoms in 2S and 3P0 states, and identify the relevant terms in the collision Hamiltonian. These resonances involve indirect coupling between the open and closed channels, via intermediate channels involving atoms in 3P1 states. The resonance widths are generally proportional to the square of the magnetic field and are strongly enhanced when the background scattering length is large. By choosing different isotopes of the 3P0 atom, the scattering length can be discretely tuned. Promising combinations for large background scattering length and resonances at experimentally accessible field are 87Rb + Yb, Cs + Yb, and 85Rb + Sr.