A.A. Zyablovskya,b,
A.P. Vinogradova,c,b,
A.A. Pukhova,c,b,
A.V. Dorofeenkoa,c,b,
A.A. Lisyanskyd aMoscow Institute of Physics and Technology (National Research University), Institutskii per. 9, Dolgoprudny, Moscow Region, 141701, Russian Federation bDukhov Research Institute of Automatics, ul. Sushchevskaya 22, Moscow, 119017, Russian Federation cInstitute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, ul. Izhorskaya 13/19, Moscow, 127412, Russian Federation dDepartment of Physics, Queens College of the City University of New York, Flushing, New York, USA
Quantum-mechanical and optical pseudo-Hermitian systems are reviewed with emphasis on PT-symmetric systems important for optics and electrodynamics. One of the most interesting and much discussed consequences of PT-symmetry is a phase transition with the breaking of the symmetry of the system's eigenstates. We show in the review that, although this phase transition is difficult to realize experimentally, a similar transition can be observed in quasi-PT-symmetric systems. Other effects predicted for PT-symmetric systems are not specific for these systems and can be observed in ordinary fully-passive systems.