Collège de France

May 1, 2024 | link.aps.org | Ivan Amelio |Nathan Goldman |Laboratoire Kastler Brossel |Collège de France

We show that lasing in flat-band lattices can be stabilized by means of the geometrical properties of the Bloch states, in settings where the single-particle dispersion is flat in both its real and imaginary parts. We illustrate a general projection method and compute the collective excitations, which display a diffusive behavior ruled by quantum geometry through a peculiar coefficient involving gain, losses and interactions, and entailing resilience against modulational instabilities.