Exceptional point photon BEC

Links
- https://www.pi.uni-bonn.de/kroha/en/news/non-hermitian-phase-transition/image.jpeg/image_view_fullscreen
- https://www.pi.uni-bonn.de/kroha/en/news/non-hermitian-phase-transition/image.jpeg/@@download/image/ExcPoint_photon-BEC.jpg