Random to Chaotic Statistic Transformation in Low-Field Fano-Feshbach Resonances of Cold Thulium Atoms

Abstract

Here, we report on the observation of a random to chaotic temperature transition in the spacing of Fano-Feshbach resonances in the ultracold polarized gas of thulium atoms. This transition is due to the appearance of so-called d -resonances, which are not accessible at low temperatures, in the spectra at high temperatures, which drastically changes thulium's overall resonance statistic. In addition to this statistical change, it has been observed that s -and d -resonances experience quite different temperature shifts: s -resonances experience almost no shift with the temperature, while d -resonances experience an obvious positive shift. In addition, careful analysis of the broad Fano-Feshbach resonances enabled the determination of the sign of thulium's background scattering length. A rethermalization experiment made it possible to estimate a length value of 144 38 a.u. bg a    . This proves

Random Matrix Theory Analysis of a Temperature-Related Transformation in Statistics of Fano–Feshbach Resonances in Thulium Atoms

“…Finally, the fact that the temperature changes simultaneously with ODT depth can cause an additional shift in the resonance position, which can also affect the statistics. Such an additional shift in resonance position was indeed detected in previous work [10].…”

“…These resonances enable the scattering lengths of the elastic binary collisions [3][4][5] to be changed, turning on and off specific interactions, making Fano-Feshbach resonances a key instrument in quantum simulations [6][7][8]. In the case of lanthanide atoms, Fano-Feshbach resonances have recently attracted a large amount of attention due to the theoretical and experimental demonstration of chaotic statistics in the distribution of these resonances [9][10][11]. We note that, prior to the lanthanide, chaotic spectra were considered in highly excited (Rydberg) states H and He [12] as well as complex atoms and ions [13].…”

“…Contrary to the case of erbium and dysprosium, in which chaotic behavior is an intrinsic property of the atomic system, thulium atoms demonstrate both random and chaotic statistics, depending on the temperature of the atomic ensemble [10], in experiments performed in an optical dipole trap (ODT) when temperature was changed together with the trap depth.…”

Feshbach Resonances in p -Wave Three-Body Recombination within Fermi-Fermi Mixtures of Open-Shell Li6 and Closed-Shell Green1, Li2, Toh3 et al. 2020Phys. Rev. X551270View full textAdd to dashboardCite

“…In our fermionic system, recombination is dominated by trimer p-wave collisions and, as we show, has an asymmetric line shape and a temperature-independent maximum loss rate coefficient. Previously, such temperature-dependent studies have only been performed in bosonic systems [30][31][32][33][34] where the rate coefficients are controlled by either s-or d-wave trimer collisions and p-wave collisions do not play a role.…”

Microwave Spectroscopy of Ultracold Thulium Atoms

“…B in the ground state along with a relatively simple level structure compared to other highly magnetic rare earth elements [6,7] and could thus be useful for quantum simulations. In the case of the thulium atom, similar to other rare earth elements [8][9][10][11], Fano-Feshbach resonances are accessible at low (Gauss level) magnetic fields [12].…”