Non-conventional refractive index – an introduction to PT symmetry

The use of complex numbers facilitates the mathematical modeling of phenomena in some areas of physics. In optics, one can modulate refractive indices to reveal anomalous behaviors, such as unidirectional invisibility and asymmetric refraction. In quantum mechanics, Hamiltonians with complex potentials presenting symmetry conditions under spatial and temporal inversion can have an entire real energy spectrum. This condition of symmetry is known as PT-symmetry (parity-time reversion). PT symmetry can be used in optics to develop materials with complex refractive indices and new optical phenomena.

Keywords
Electric and magnetic fields; dielectric constant; complex numbers; PT symmetry