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

Recently, the transformation from random to chaotic behavior in the statistics of Fano-Feshbach resonances was observed in thulium atoms with rising ensemble temperature. We performed random matrix theory simulations of such spectra and analyzed the resulting statistics in an attempt to understand the mechanism of the transformation. Our simulations show that, when evaluated in terms of the Brody parameter, resonance statistics do not change or change insignificantly when higher temperature resonances are appended to the statistics.

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

Here, we report on the observation of a random to chaotic temperature transformation in the statistics of nearest-neighbor spacings of Fano-Feshbach resonances in the ultracold polarized gas of thulium-169 atoms. We associate this transformation to the appearance of so-called d resonances as well as the shift of other resonances with the temperature. In addition to this statistical change, it has been observed that the characters of s- and d-resonance temperature shifts are quite different: s resonances experience almost no shift or even negative shift with the temperature, while d resonances experience an obvious positive shift.

Inner-shell clock transition in atomic thulium with a small blackbody radiation shift.

One of the key systematic effects limiting the performance of state-of-the-art optical clocks is the blackbody radiation (BBR) shift. Here, we demonstrate unusually low sensitivity of a 1.14 μm inner-shell clock transition in neutral Tm atoms to BBR.