IQIM Postdoctoral and Graduate Student Seminar

Special IQIM Seminar, Monday, June 27 at 2:30 in 114 E. Bridge

Abstract: Exotic quantum statistics generalize the familiar dichotomy of bosons and fermions to a spectrum. On it lie anyons, allowing particles to partially share one state, and "super fermions", where particles occupy several states. My talk explores how strongly interacting 1D Bose gases provide a platform to realize these unconventional statistics. I present the observation of emergent anyonic correlations induced by spin-charge separation, where a mobile impurity generates a system with a tunable statistical phase [1,2], providing a continuous transmutation from bosons through anyons to fermions. This is revealed through an asymmetric momentum-distribution and dynamical fermionization. I then report the realization of fractional Fermi seas [3,4,5]. These are many-body systems in which each particle occupies an integer number of states larger than 1. One might call the resulting statistics "super-fermionic", under the framework of Haldane's generalized exclusion statistics. For this, we drive our 1D Bose system via ramping interaction cycles into excited states. Observed Friedel oscillations in the one-body correlations directly expose the underlying Fermi surfaces. Together, these results demonstrate a powerful and controllable route to exploring the full landscape of low-dimensional quantum statistics beyond the boson-fermion paradigm.

References

[1] Sudipta Dhar, Botao Wang, Milena Horvath, Amit Vashisht, Yi Zeng, Mikhail B. Zvonarev, Nathan Goldman, Yanliang Guo, Manuele Landini, and Hanns-Christoph Nägerl, Observing anyonization of bosons in a quantum gas, Nature 642, 53 (2025).

[2] Botao Wang, Amit Vashisht, Yanliang Guo, Sudipta Dhar, Manuele Landini, Hanns-Christoph Nägerl, Nathan Goldman, Anyonization of bosons in one dimension: an effective swap model, Physical Review Letters 135, 253403 (2025).

[3] Yi Zeng, Alvise Bastianello, Sudipta Dhar, Zekui Wang, Xudong Yu, Milena Horvath, Grigori Astrakharchik, Yanliang Guo, Hanns-Christoph Nägerl and Manuele Landini, Realization of Fractional Fermi Seas, arXiv:2602.17657

[4] Maciej Marciniak, Grigori E. Astrakharchik, Krzysztof Pawlowski, and Bruno Julia-Diaz, Fermionizing the ideal Bose gas via topological pumping, arXiv:2504.19569.

[5] Alvise Bastianello, Yi Zeng, Sudipta Dhar, Zekui Wang, Xudong Yu, Milena Horvath, Grigori E. Astrakharchik, Yanliang Guo, Hanns-Christoph Nägerl, and Manuele Landini, Exotic critical states as fractional Fermi seas in the one-dimensional Bose gas, arXiv:2602.17656