Feshbach resonances in fermionic ${}^6\mathrm{Li}$

Feshbach resonances in ${}^6\mathrm{Li}$ were experimentally studied and theoretically analyzed. In addition to two previously known $s$-wave resonances, three $p$-wave resonances were found. Four of these resonances are narrow and yield a precise value of the singlet scattering length. The position of the broad $s$-wave resonance near $83\mathrm{mT}$ is mostly sensitive to the triplet potential. It was previously determined in a molecule-dissociation experiment for which we, here, discuss systematic shifts.

Figure 1

$p$-wave resonances for $\mid 1⟩+\mid 1⟩$ (a), $\mid 1⟩+\mid 2⟩$ (b), and $\mid 2⟩+\mid 2⟩$ (c) collisions. Dashed lines are Lorentzian fits to the data. The results are summarized in Table .

Figure 2

Determination of the position of the broad $s$-wave Feshbach resonance. (a) Onset of dissociation of molecules into atoms at $821\pm 1\mathrm{G}$. (b) The resonance position was obtained by fitting two lines to the data points near the threshold, one horizontal through the points showing no atomic signal and a second line following the initial rise in atom number. The intersection of the two lines gives the resonance position; the estimated uncertainty of this point is $\pm 1\mathrm{G}$.