Accurate determination of the scattering length of erbium atoms

Autor: Patscheider, A., Chomaz, L., Natale, G., Petter, D., Mark, M. J., Baier, S., Yang, B., Wang, R. R. W., Bohn, J. L., Ferlaino, F.
Rok vydání: 2021
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1103/PhysRevA.105.063307
Popis: An accurate knowledge of the scattering length is fundamental in ultracold quantum gas experiments and essential for the characterisation of the system as well as for a meaningful comparison to theoretical models. Here, we perform a careful characterisation of the s-wave scattering length $a_s$ for the four highest-abundance isotopes of erbium, in the magnetic field range from 0G to 5G. We report on cross-dimensional thermalization measurements and apply the Enskog equations of change to numerically simulate the thermalization process and to analytically extract an expression for the so-called number of collisions per re-thermalization (NCPR) to obtain $a_s$ from our experimental data. We benchmark the applied cross-dimensional thermalization technique with the experimentally more demanding lattice modulation spectroscopy and find good agreement for our parameter regime. Our experiments are compatible with a dependence of the NCPR with $a_s$, as theoretically expected in the case of strongly dipolar gases. Surprisingly, we experimentally observe a dependency of the NCPR on the density, which might arise due to deviations from an ideal harmonic trapping configuration. Finally, we apply a model for the dependency of the background scattering length with the isotope mass, allowing to estimate the number of bound states of erbium.
Comment: 13 pages, 8 figures
Databáze: arXiv