You are here: Home Events Seminar Series 2018 … 16.10.2018 - Florian Meinert - …

16.10.2018 - Florian Meinert - Rydberg atoms in ultracold gases - from electron to ion impurities

5. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Freiburg
When Oct 16, 2018
from 01:00 PM to 02:00 PM
Where HS II, Physik Hochhaus, Hermann-Herder-Str. 3
Add event to calendar vCal
iCal











Rydberg atoms immersed in ultracold and degenerate atomic gases offer a rich experimental platform for studying giant impurities interacting with single, few, or many ground-state atoms from the host gas which reside within the Rydberg electron orbit. In this seminar, I will report on our endeavor to explore single Rydberg excitations with principal quantum number up to n=190 embedded in gases of different density regimes, ranging from comparatively dilute thermal ensembles to high-density Bose-Einstein condensates.

More specifically, a Rydberg atom interacts with an ultracold atomic gas via electron-neutral and ion-neutral interaction. Typically, the electron-neutral interaction constitutes the far dominant scattering process and, in a low-density sample, leads to the formation of ultralong-range Rydberg molecules [1]. In this context, we have recently demonstrated photo-association of strongly polar “trilobite” molecules facilitated by the complex molecular spin-couplings [2]. Differently, in the regime of a high-density Bose-Einstein condensate typically thousands of ground-state atoms collectively interact with the Rydberg impurity and the role of the Rydberg ionic core starts to play a role. By working with Rydberg electron orbits that by far exceed the size of the condensate, we suppress the typically dominant electron-neutral scattering and access the low-temperature ion-neutral interaction [3]. These results may open up ways to enter the quantum regime of ion-atom scattering for the exploration of charged quantum impurities and associated polaron physics.

Finally, I will discuss very recent results demonstrating Rydberg excitation blockade induced by a single low-energy ion, which we directly produce from the ultracold ensemble via a novel two-photon ionization scheme [4].


Reference:
[1] V. Bendkowsky, B. Butscher, J. Nipper, J. P. Shaffer, R. Löw, and T. Pfau, Nature 458, 1005 (2009).
[2] K. S. Kleinbach, F. Meinert, F. Engel, W. J. Kwon, R. Löw, T. Pfau, and G. Raithel, Phys. Rev. Lett. 118, 223001 (2017).
[3] K. S. Kleinbach, F. Engel, T. Dieterle, R. Löw, T. Pfau, and F. Meinert, Phys. Rev. Lett. 120, 193401 (2018).
[4] F. Engel, T. Dieterle, T. Schmid, C. Tomschitz, C. Veit, N. Zuber, R. Löw, T. Pfau, and F. Meinert, arXiv:1809.00993 (2018).


See poster.