Localisation and transport in many-body two-dimensional quasiperiodic systems

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• Antonio Strkalj, University of Cambridge
• Monday 22 May 2023, 14:30-15:00
• Cavendish Laboratory, Small Lecture Theatre.

If you have a question about this talk, please contact Dr M. Simoncelli.

https://zoom.us/j/92447982065?pwd=RkhaYkM5VTZPZ3pYSHptUXlRSkppQT09

Many-body localisation (MBL) provides a mechanism to avoid thermalisation in interacting systems. It is well understood that the MBL phase can exist in closed one-dimensional systems subjected to random disorder, quasiperiodic modulations, or homogeneous electric fields. However, the fate of MBL in higher dimensions remains unclear. Although some experiments on randomly disordered two-dimensional (2D) systems observe a stable MBL phase on intermediate time scales, recent theoretical works show that the phenomenon cannot persist forever and in a thermodynamic limit due to the rare regions and the avalanche instability. On the other hand, quasiperiodic systems do not host rare regions, and the avalanche instability is avoided; yet, the existence of an MBL phase in these systems remains largely unexplored. In this talk, I will discuss the localisation properties of the many-body 2D Aubry-André quasiperiodic model. By studying the out-of-equilibrium dynamics of the interacting model, I will show that quasiperiodic systems can host a stable localised phase on experimentally relevant timescales. The numerical calculations show that this nonergodic phase remains stable upon scaling the system size, which hints towards its stability in the thermodynamic limit, and it is in stark contrast to random disorder. Furthermore, I will discuss how deterministic lines of weak potential, which appear in the 2D Aubry-André model, support sub-dimensional transport while keeping the localised parts of the system unchanged. These findings are of direct experimental relevance and can be tested using state-of-the-art cold atomic systems.

This talk is part of the Lennard-Jones Centre series.

This talk is included in these lists:

• Cavendish Laboratory, Small Lecture Theatre
• Hanchen DaDaDash
• Lennard-Jones Centre

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