Energy-dependent 3-body loss in 1D Bose gases

We study atom loss in high density quantum Newton's cradles (QNCs) with a range of energies and transverse confinements and find that it is strongly energy dependent. A center-of-mass energy (E$_{\mathrm{cm}})$ dependent 3-body loss rate, K$_{\mathrm{3}}^{\mathrm{1D}}$(E$_{\mathrm{cm}})$, has been predicted for a one-dimensional Bose gas [1], but has not previously been observed. We adapt the 1D theory to quasi-1D gases using the assumption that the loss rate never exceeds the 3D value. Using precise measurements of the QNC momentum distributions and a semiclassical approximation, we infer the E$_{\mathrm{cm\thinspace }}$of all 3-body collisions that occur in the system. We then compare the calculated losses as a function of time to the observed losses, doing a least squares fit of two free parameters using 48 decay curves. The model conforms well with our experimental results [2]. [1] Mehta, N. P., Esry, B. D. {\&} Greene, C. H. Three-body recombination in one dimension. \textit{Phys. Rev. A.} \textbf{76}, 022711 (2007). [2] Zundel, L. A. et al., Energy-dependent 3-body loss in 1D Bose gases. \textit{Phys. Rev. Lett.}~\textbf{122}, 013402 (2019).