Anomalous localization in a kicked quasicrystal

• Published in: Nature physics Vol. 20; no. 3; pp. 409 - 414
• Main Authors: Shimasaki, Toshihiko, Prichard, Max, Kondakci, H. Esat, Pagett, Jared E., Bai, Yifei, Dotti, Peter, Cao, Alec, Dardia, Anna R., Lu, Tsung-Cheng, Grover, Tarun, Weld, David M.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2024; Nature Publishing Group
• Subjects: 639/766/119/2795; 639/766/36/1125; 639/766/483/3926; Atomic; Classical and Continuum Physics; Complex Systems; Condensed Matter Physics; Eigenvectors; Localization; Mathematical and Computational Physics; Molecular; Optical and Plasma Physics; Phase diagrams; Phases; Physics; Physics and Astronomy; Quantum transport; Quasicrystals; Theoretical; Transport properties
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/s41567-023-02329-4

Quantum transport can distinguish between dynamical phases of matter. For instance, ballistic propagation characterizes the absence of disorder, whereas in many-body localized phases, particles do not propagate for exponentially long times. Additional possibilities include states of matter exhibiting anomalous transport in which particles propagate with a non-trivial exponent. Here we report the experimental observation of anomalous transport across a broad range of the phase diagram of a kicked quasicrystal. The Hamiltonian of our system has been predicted to exhibit a rich phase diagram, including not only fully localized and fully delocalized phases but also an extended region comprising a nested pattern of localized, delocalized and multifractal states, which gives rise to anomalous transport. Our cold-atom realization is enabled by new Floquet engineering techniques, which expand the accessible phase diagram by five orders of magnitude. Mapping transport properties throughout the phase diagram, we observe disorder-driven re-entrant delocalization and sub-ballistic transport, and we present a theoretical explanation of these phenomena based on eigenstate multifractality. Phases of matter can host different transport behaviours, ranging from diffusion to localization. Anomalous transport has now been observed in an interacting Bose gas in a one-dimensional lattice subject to a pulsed incommensurate potential.