FIG. 20.

Aharonov-Bohm interferometer around a Dirac point. Starting from a wave packet localized at the center of the BZ of a graphenelike optical lattice, one measures the phase difference φ between the two paths of an interferometer ending at the quasimomentum (k_x = 0, k_y). When one of the Dirac points K or K′ is inside the enclosed area of the interferometer, the measured value for φ is in good agreement with the prediction φ = π. From Duca et al., 2015.