Erlangen 2022 – scientific programme

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A: Fachverband Atomphysik

A 31: Ultra-cold atoms, ions and BEC IV (joint session A/Q)

A 31.3: Talk

Friday, March 18, 2022, 11:15–11:30, A-H1

An Artificial Bosonic Atom in One Spatial Dimension — •Fabian Brauneis¹, Timothy Backert¹, Simeon Mistakidis², Mikhail Lemeshko³, Hans-Werner Hammer^1,4, and Artem Volosniev³ — ¹Technische Universität Darmstadt, Department of Physics, Institut für Kernphysik, 64289 Darmstadt, Germany — ²ITAMP, Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA 02138 USA — ³Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria — ⁴ExtreMe Matter Institute EMMI and Helmholtz Forschungsakademie Hessen für FAIR (HFHF), GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany

We study an analogue of an atom realized by a one-dimensional Bose gas. Repelling bosons (``electrons'') are attracted to an impurity, the ``nucleus''. The interplay between the attractive impurity-boson and repulsive boson-boson interaction leads to a crossover between different states of the system when the parameters are varied. For a non-interacting Bose gas, an arbitrary number of bosons can be bound to the impurity. In contrast, if they are impenetrable, the bosons fermionize and only one boson is bound. This observation implies that there is a critical number of bosons that can be bound to the impurity for finite values of the boson-boson interaction strength. We discuss the three resulting states of the system - bound, transition and scattering - within the mean-field approximation. In particular, we calculate the critical particle number supporting a bound state. To validate our mean-field results, we use the flow equation approach.