Unidirectional zero reflection as gauged Parity-time symmetry
PT-symmetry can be gauged by a Unitary transformation. It corresponds to a familary of equivalent PT-symmetric systems from a given seed system with conventional PT-symmetry.
New J. Phys. 19, 123041 (2017)
A particular gauge can be taken so that eps(x) = mu(-x)* is regarded as PT-symmetric.
Phys. Rev. A 91, 033825 (2015)
Laser-absorber can be designed by detailed matching of permittivity and permeability.
New J. Phys. 18, 085004 (2016)
Hamiltonian of a pair of bright and dark atom in the intermediate coupling regime is found to have an effective PT-symmetric Hamiltonian. Phase transition of coherent perfect absorption is observed.
Theory: Phys. Rev. A 87, 053824 (2013)
Experiment: Phys. Rev. Lett. 112, 143903 (2014)