Strongly interacting bosons and flat bands

Strongly interacting bosons and flat bands

Professor Sergej Flach

Institute for Basic Science, Daejeon, South Korea

‍

I will first discuss transport of interacting bosons through an Aharonov-Bohm cage - a building block of flat band networks. In the absence of interactions the cage is insulating due to destructive interference. The cage stays insulating up to a critical value of the pump strength in the presence of mean field interactions, while the quantum regime induces particle pair transport and weak conductance below the critical pump strength. A swift crossover from quantum into the classical regime upon further pump strength increase is observed. I will then take the interaction to infinity and discuss trapping of hard core bosons in flat band networks both in one and two dimensions. The trapping leads to Hilbert space fragmentation and survives in the presence of suitable correlated disorder.

‍

References

[1] A. R. Kolovsky, P. S. Muraev and S. Flach, Phys. Rev. A 108 (2023) L010201.

[2] S. Lee, A. Andreanov, T. Sedrakyan and S. Flach, Phys. Rev. B 109 (2024) 245137.

‍

‍

Date: 3 March 2025

Time: 11am

Venue: Massey Albany IC3.05 or Zoom