Condensed Matter Seminar: Ultracold ion-atom collisions in the quantum regime

Michal Tomza (University of Warsaw)
Hybrid systems of laser-cooled trapped ions and ultracold atoms combined in a single experimental setup have recently emerged as a new platform for fundamental research in quantum physics [1].

March 09, 2020

Michal Tomza (University of Warsaw)
Online Seminar
Mon 09. March 2020, 11:30 am (MEZ)

Abstract:

Hybrid systems of laser-cooled trapped ions and ultracold atoms combined in a single experimental setup have recently emerged as a new platform for fundamental research in quantum physics [1]. Reaching the ultracold s-wave quantum regime has been one of the most critical challenges in this field for a long time. Unfortunately, the lowest attainable temperatures in experiments using the Paul ion trap are limited by the possible rf-field-induced heating related to the micromotion [2]. Recently, buffer gas cooling of a single ion in a Paul trap to the quantum regime of ion-atom collisions was realized, and a deviation from classical Langevin theory was observed by studying the spin-exchange dynamics, indicating quantum effects in the ion-atom collisions [3]. In my seminar, I will present how quantum chemical calculations of electronic structure and scattering dynamics can support and explain quantum physics experiments. In particular, I will describe how, in collaboration with experimental groups from Amsterdam [3] and Stuttgart [4], we have overcome the micromotion limitation. I will also discuss incoming applications, including observation and application of magnetic Feshbach resonances, to control ultracold ion-atom collisions.

References

[1] Tomza et al, Rev. Mod. Phys. 91, 035001 (2019)
[2] Cetina et al., Phys. Rev. Lett. 109, 253201 (2012)
[3] Feldker et al, Nat. Phys. doi:10.1038/s41567-019-0772-5 (2020)
[4] Schmid et al, Phys. Rev. Lett. 120, 153401 (2018)

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