@conference{
author = "Mančić, Ana and Nedić, Milica and Leykam, D. and Maluckov, Aleksandra",
year = "2023",
abstract = "Photonic lattices represent a fruitful testbed for investigating various topological phases, nonlinear phenomena, and intriguing consequences of the development of modulational instability in topologically nontrivial media, as the inter-relation between topological edge states [1], edge solitons [2] and bulk solitons [3]. They provide the possibility not only to highlight the equivalent phenomena in condensed matter systems but to go beyond them into new land of exotic nonlinearly driven topologically moderated states. Recently, we have shown that the modulational instability of nonlinear Bloch modes could be used to probe the band topology in non-driven lattices [4]. As an extension, here, we report on the results of the study of the relaxation of the optical wave fields in nonlinear two-dimensional Chern insulators [5]. They undergo a transition from an ordered bulk state to a disordered state, triggered by the modulational instability [6]. The phenomenon of the memory loss of the initial state is related to nonlinear wave-mixing and ergodization within the gapped bands [7]. The testbed for our numerical study is two-dimensional π-flux square lattice in which we investigate the population of topological bands by the wave mixing of nonlinear Bloch waves. We tune the strength of the nonlinearity and lattice parameters in order to observe different dynamical regimes: toplogical transitions, stable and unstable propagation. We have found that the unstable propagation gives rise to a new quasi-steady state characterized by a convergence of certain wave field characteristics (participation ratio, Chern number, purity gap) to constant values. Next, in order to find the correspondence between this steady state and thermalized wave field we apply a grand canonical approach to calculate the effective temperature and chemical potential of the wave field. We have found that the effective temperature and chemical potential exhibit a strong k – dependence throughout the Brillouin zone. This implies the existence of a long-lived pre-thermalized regime and the absence of thermalization.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences",
journal = "PHOTONICA2023 : 9th International School and Conference on Photonics : book of abstracts; August 28 - September 1, 2023; Belgrade",
title = "The modulation instability triggered band relaxation in photonic Chern insulator",
pages = "52-52",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11802"
}
