Abstract:

Topological phases of matter connect mathematical principles to real materials, and may shape future electronic and quantum technologies. So far, this discipline has mostly focused on single-gap topology described by topological invariants such as Chern numbers. Here, based on a tunable kagome model, we observe non-Abelian band topology and its transitions in acoustic semimetals and insulators, in which the multi-gap Hilbert space plays a key role. In non-Abelian semimetals, the topological charges of band nodes are converted through the braiding of nodes in adjacent gaps, and their behaviour cannot be captured by conventional topological band theory. By controlling the geometry of the acoustic metamaterials, topological transitions are induced by the creation, annihilation, merging and splitting of band nodes. This reveals the underlying rules for the conversion and transfer of non-Abelian topological charges in multiple bandgaps. The resulting laws that govern the evolution of band nodes in non-Abelian multi-gap systems should inspire studies on multi-band topological semimetals and multi-gap topological out-of-equilibrium systems.

Acknowledgement : This work was supported by the National Nature Science Foundation of China (12125504, 12074281) and Jiangsu specially-appointed professor funding.

Bio:

蔣建華，蘇州大學(xué)教授。2000-2010年在中國(guó)科學(xué)技術(shù)大學(xué)學(xué)習(xí)，獲學(xué)士和博士學(xué)位。之后在以色列魏茨曼研究所和加拿大多倫多大學(xué)從事博士后研究。2015年起任蘇州大學(xué)教授，2021年獲得國(guó)家杰出青年基金項(xiàng)目的資助。主要從事拓?fù)涔庾訉W(xué)/聲子學(xué)、非平衡統(tǒng)計(jì)物理等方面的研究。拓展了利用室溫光子和聲子系統(tǒng)發(fā)現(xiàn)新穎拓?fù)湮锢硇?yīng)的研究，特別在拓?fù)潴w-缺陷對(duì)應(yīng)關(guān)系、高階拓?fù)鋺B(tài)、非阿貝爾拓?fù)鋺B(tài)等方面做出了一系列享有國(guó)際聲譽(yù)的工作，并在非平衡統(tǒng)計(jì)物理和非常規(guī)熱電效應(yīng)方面做了一系列基礎(chǔ)性、開拓性的工作。發(fā)表同行評(píng)審學(xué)術(shù)論文100余篇（含Nature、Nature子刊、Phys. Rev. Lett.等）。曾獲中國(guó)光學(xué)十大進(jìn)展等獎(jiǎng)項(xiàng)，并獲得江蘇特聘教授、教育部國(guó)家級(jí)青年人才等榮譽(yù)。2022年以首席科學(xué)家的身份獲得科技部國(guó)家重點(diǎn)研發(fā)計(jì)劃的支持。