Speaker's Brief Introduction：Hanns-Christoph Nägerl studied physics in Göttingen, San Diego, and Innsbruck and completed his doctoral thesis in 1998 on the subject of “Ion Strings for Quantum Computation” with Prof. R. Blatt. As a postdoctoral researcher he work at the California Institute of Technology (Caltech) with Prof. J. Kimble on single ultracold neutral atoms for quantum information purposes. In 2000 he joined Prof. R. Grimm in Innsbruck to set up an ultracold-atom group and to work on atomic and molecular quantum gases and matter waves. He received his “habilitation” in 2006, with this became associate professor, and then advanced to full professor for experimental physics at the University of Innsbruck in 2011. Presently, he is the director of the Institute for Experimental Physics of the University of Innsbruck. His scientific interests center on quantum many-body physics and quantum simulation on the basis of ultracold atoms and molecules.
Abstract: I will give a sketchy overview over our recent experimental activities on interaction-tunable quantum-degenerate Bose gases, ranging from effects such as anyonization [1], super-fermionization [2], and many-body dynamical localization in 1D [3] and 3D [4] to the observation of Bethe strings [5], of dissipationless flow beyond the Landau paradigm [6], and of the velocity hierarchy in interacting 1D bosons on a lattice [7,8]. Interaction-tuning is the key to all these experiments. Some of the effects (see e.g. [1], [2], [5] and [6]) are peculiar to one-dimensional geometry, but, to our surprise, dynamical localization in Hilbert space occurs also in 3D and leads a localization-delocalization quantum phase transition, which we observe in momentum space and in real space [4].
References
[1] Observing anyonization of bosons in a quantum gas, S. Dhar, et al., Nature 642, 53 (2025).
[2] Realization of Fractional Fermi Seas, Y. Zeng, A. Bastianello, et al., arXiv:2602.17657 (2026).
[3] Observation of many-body dynamical localization, Y. Guo, S. Dhar, et al., Science 389, 716 (2025).
[4] Observation of an interaction-enabled metal-insulator phase transition in a driven quantum gas, C. Cantillano, K. Ramanathan, et al., arxiv:2605.22449 (2026).
[5] Observing Bethe strings in an attractive Bose gas far from equilibrium, M. Horvath, A. Bastianello, et al., arXiv:2505.10550 (2025), Nature Communications in print.
[6] Observing dissipationless flow of an impurity in a strongly repulsive quantum fluid
M. Horvath, S. Dhar, et al., arXiv:2602.12320 (2026).
[7] Observing the emergence of a velocity hierarchy in strongly interacting bosons, X. Yu, W. Chen, et al., arXiv:2608.05241 (2026).
[8] Observing higher bands in strongly interacting bosons, W. Chen, X. Yu, et al., in preparation (2026).