Dynamics of almost strong edge modes in spin chains away from integrability

Understand

Results are presented for the dynamics of an almost strong edge mode which is the quasi-stable Majorana edge mode occurring in non-integrable spin chains.

• The dynamics of the edge mode is studied using exact diagonalization, and compared with time-evolution with respect to an effective semi-infinite model in Krylov space obtained from the recursion method.
• The effective Krylov Hamiltonian is found to resemble a spatially inhomogeneous SSH model where the hopping amplitude increases linearly with distance into the bulk, typical of thermalizing systems, but also has a staggered or dimerized structure superimposed on it.
• The non-perturbatively long lifetime of the edge mode is shown to be due to this staggered structure which diminishes the effectiveness of the linearly growing hopping amplitude.