Continuous time quantum walk on an extended star graph: disorder enhanced trapping process

Saad Yalouz (1) , Vincent J.C. Pouthier (1)

1 UTINAM - Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213)

Using a tight binding model, we investigate the dynamics of an exciton on a disordered extended star graph whose central site acts as an energetic trap. Our results highlight the beneficial role of the disorder to improve the excitonic absorption at the core of the graph. In this context, we evidence the existence of an optimal disorder allowing to strongly minimize the absorption time. Numerical proofs are given to demonstrate that this enhancement originates from a disorder-induced restructuring process that positively affects the system eigenstates. In a complementary way, we also evidence the existence of an optimal value of absorption rate allowing to reduce even more the aborption time when the disorder is optimal. The resulting super optimized trapping process is interpreted as the positive interplay between the action of the disorder and the arising of the so-called superradiance transition.

Domaines: Autre [cond-mat.other]

Saad Yalouz, Vincent J.C. Pouthier. Continuous time quantum walk on an extended star graph: disorder enhanced trapping process. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, 2020, 101, pp.012310. ⟨10.1103/PhysRevE.101.012310⟩. ⟨hal-02434409⟩