Topological magnetoplasmon
  Classical wave fields are real-valued, ensuring the wave states at opposite frequencies and momenta to be inherently identical. Such a particle-hole symmetry can open up new possibilities for topological phenomena in classical systems. Here we show that the historically studied two-dimensional (2D) magnetoplasmon, which bears gapped bulk states and gapless one-way edge states near zero frequency, is topologically analogous to the 2D topological $p+\Ii p$ superconductor with chiral Majorana edge states and zero modes. We further predict a new type of one-way edge magnetoplasmon at the interface of opposite magnetic domains, and demonstrate the existence of zero-frequency modes bounded at the peripheries of a hollow disk. These findings can be readily verified in experiment, and can greatly enrich the topological phases in bosonic and classical systems. 
Dafei Jin, Ling Lu, Zhong Wang, Chen Fang, John D. Joannopoulos, Marin   Solja\v{c}i\'c, Liang Fu, and Nicholas X. Fang
cond-mat.mes-hall cond-mat.mtrl-sci physics.optics