Greiner Lab
Welcome to the Greiner Lab!
We use ultracold quantum gases on optical lattices to simulate models from condensed matter physics. Thanks to the microscopy technique developed here, we can see and manipulate individual atoms to perform experiments with remarkable levels of control and accuracy.
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Recent Publications
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Coupling a mobile hole to an antiferromagnetic spin background: transient dynamics of a magnetic polaron
04/2021
Phys. Rev. X 11, 021022 (2019)
arXiv:2006.06672
Understanding the interplay between charge and spin and its effects on transport is a ubiquitous challenge in quantum many-body systems. In the Fermi-Hubbard model, this interplay is thought to give rise to magnetic polarons, whose dynamics may explain emergent properties of quantum materials such as high-temperature superconductivity. In this work, we use a cold-atom quantum simulator to directly observe the formation dynamics and subsequent spreading of individual magnetic polarons. Measuring the density- and spin-resolved evolution of a single hole in a 2D Hubbard insulator with short-range antiferromagnetic correlations reveals fast initial delocalization and a dressing of the spin background, indicating polaron formation. At long times, we find that dynamics are slowed down by the spin exchange time, and they are compatible with a polaronic model with strong density and spin coupling. Our work enables the study of out-of-equilibrium emergent phenomena in the Fermi-Hubbard model, one dopant at a time.