Anderson localization in synthetic photonic lattice with random coupling

Photonic Mpemba effect

The Mpemba effect (ME) is the counterintuitive phenomenon in statistical physics for which a far-from-equilibrium state can relax toward equilibrium faster than a state closer to equilibrium. This effect has raised great curiosity for a long time and has been studied extensively in many classical and quantum systems. Here, it is shown that the Mpemba effect can be observed in optics as well. Specifically, the process of light diffusion in finite-sized photonic lattices under incoherent (dephasing) dynamics is considered. Rather surprisingly, it is shown that certain highly localized initial light distributions can diffuse faster than initial broadly delocalized distributions. The effect is illustrated by considering the random walk of optical pulses in fiber-based temporal mesh lattices, which should provide an experimentally accessible setup for the demonstration of the Mpemba effect in optics.

Dephasing-Induced Mobility Edges in Quasicrystals

Mobility edges (ME), separating Anderson-localized states from extended states, are known to arise in the single-particle energy spectrum of certain one-dimensional lattices with aperiodic order. Dephasing and decoherence effects are widely acknowledged to spoil Anderson localization and to enhance transport, suggesting that ME and localization are unlikely to be observable in the presence of dephasing. Here it is shown that, contrary to such a wisdom, ME can be created by pure dephasing effects in quasicrystals in which all states are delocalized under coherent dynamics. Since the lifetimes of localized states induced by dephasing effects can be extremely long, rather counterintuitively decoherence can enhance localization of excitation in the lattice. The results are illustrated by considering photonic quantum walks in synthetic mesh lattices.

Integrated density of states algorithm for one-dimensional randomly layered optical media

Anderson localization simulations in one-dimensional disordered optical systems usually focus on the localization length or its inverse, but the calculation of the density of states has appeared less frequently for such models. In this paper a technique originally used to calculate the integrated density of states for one-dimensional disordered crystals supporting electron propagation is modified for use with randomly layered optical media. The density of states is then readily available via differentiation. The algorithm is demonstrated on one-dimensional quarter-wave stack and non-quarter-wave stack models with layer thicknesses disordered.

Disorder-aided pulse stabilization in dissipative synthetic photonic lattices

We consider a discrete time evolution of light in dissipative and disordered photonic lattice presenting a generalization of two popular non-Hermitian models in mathematical literature: Hatano-Nelson and random clock model and suggest a possible experimental implementation using coupled fiber loops. We show that if the model is treated as non-unitary Floquet operator rather than the effective Hamiltonian the combination of controlled photon loss and static phase disorder leads to pulse stabilization in the ring topology. We have also studied the topological invariant associated with the system and found additional evidence for the absence of Anderson transition.