ABSTRACT
The role of nonlinearity in classifying the topology of a system has drawn intense interest recently. Through nonlinear terms, the parameters of a system depend on field intensity. It is easy to imagine situations where the topology of a system changes due to the intensity dependence of some parameters. In this talk, I will discuss two consequences of nonlinearity that make the topology of nonlinear systems fundamentally different from linear ones. In the first part, I show that unstable solutions in nonlinear systems can contribute to hidden dimensions. With the help of these hidden dimensions, some higher-dimensional topological singularities can be realized within lower-dimensional physical systems. In the second part, I demonstrate that nonlinearity can enable topological mode shapeshifting into arbitrarily designed profiles, such as square, isosceles triangular, and sinusoidal waves. These nonlinear topological modes are robust against disorders while remaining uniquely controllable through external sources.
References:
[1] Phys. Rev. Lett. 130, 266901 (2023)
[2] Natl. Sci. Rev. 10, nwac259 (2023)
[3] Phys. Rev. Lett. 132, 073802 (2024)
[4] arXiv:2402.07224 (2024)
BIOGRAPHY
Professor Meng Xiao received his BSc degree from Wuhan University in 2010 and his Ph.D. from the Hong Kong University of Science and Technology (HKUST) in 2014. After that, he worked as a postdoc fellow with Prof. C. T. Chan (at HKUST) and Prof. Shanhui Fan (at Stanford). He joined Wuhan University in 2018. Professor Xiao's research focuses on novel topology-related phenomena in classical waves (such as electromagnetic and acoustic waves), non-Hermitian and nonlinear systems, synthetic dimensions, and wave functional materials. He has published tens of papers in various high-impact journals. His work has been cited more than 8500 times with an H-index of 43 and around 2000 citations per year (Google Scholar).
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