QST Seminar - Localization and delocalization of a flat band system
Supporting the below United Nations Sustainable Development Goals:支持以下聯合國可持續發展目標：支持以下联合国可持续发展目标：
Bose-Einstein condensate in the momentum lattice is a versatile platform for studying novel physics. By introducing the multi-frequency Raman couplings with a BEC, a momentum lattice is formed with tunable tunneling rates, detunings, and the relative phase of the couplings in different sites, thus quantum simulating the topological models. Here we report a realization of the AB cage system which holds flat bands. Such flat-band systems induce geometric localization. By introducing disorders, such flat-band localization can be broken down, and inverse Anderson localization is observed. Another effective way to induce transport in a flat-band system is floquet modulation. A staggered-flux AB cage system is realized in the momentum lattice and the flat-band induced breathing mode is observed. By swapping the flux between the nearest neighbor, and fine-tuning the free parameters, a quantized topological chiral transport is observed. Our findings provide insight into understanding the interplay of localization, transport, and topology.
Prof. Bo Yan is from the School of Physics, Zhejiang University, Hangzhou, Zhejiang, China. Prof. Yan’s research activities are focused on quantum simulation with ultracold atoms in the momentum space and laser cooling of polar molecules.