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] K. Bai, J.-Z. Li, T.-R. Liu, L. Fang, D. Wan, and M. Xiao, Phys. Rev. Lett. 130, 266901 (2023).
[2] K. Bai, L. Fang, T.-R. Liu, J.-Z. Li, D. Wan, and M. Xiao, Natl. Sci. Rev. 10, nwac259 (2023).
[3] K. Bai, T.-R. Liu, L. Fang, J.-Z. Li, C. Lin, D. Wan, and M. Xiao, Phys. Rev. Lett. 132, 073802 (2024).
[4] K. Bai, J.-Z. Li, T.-R. Liu, L. Fang, D. Wan, and M. Xiao, arXiv:2402.07224 (2024).
Please contact phweb@ust.hk should you have questions about the talk.
