Photonic Axion Insulator

Zhang Baile

Nanyang Technological University, Singapore

Abstract: Axions are hypothetical particles originally proposed to solve the strong charge-parity (CP) problem in the Standard Model and later predicted to constitute the elusive dark matter. While still not observed as elementary particles, axions can arise as quasiparticles in three-dimensional topological crystals known as axion insulators. The bulk of the crystal is characterized by a quantized axion field angle θ = π, which induces half-quantized Chern numbers across all surfaces. Here, we will discuss how to realize a three-dimensional axion insulator in photonic crystals. This line of research follows our previous works on three-dimensional photonic topological insulators with and without magnetic materials.  

Bio: Baile Zhang is a professor of physics in the School of Physical and Mathematical Sciences at Nanyang Technological University, Singapore. He received his Ph.D. in electrical engineering from the Massachusetts Institute of Technology (MIT) in 2009. After a two-year postdoc period in the Singapore-MIT Alliance for Research and Technology Centre, he joined Nanyang Technological University in 2011 as an assistant professor. He became an associate professor in 2017 and full professor in 2021. His research interests include waves in complex media, metamaterials, photonic and phononic crystals, and acoustics.