Alexander Szameit, Mikael C. Rechtsman, Omri Bahat-Treidel, Mordechai Segev

We apply gain/loss to honeycomb photonic lattices and show that the dispersion relation is identical to tachyons – particles with imaginary mass that travel faster than the speed of light. This is accompanied by PT-symmetry breaking in this structure. We further show that the PT-symmetry can be restored by deforming the lattice.

http://arxiv.org/abs/1103.3389

Optics (physics.optics)