We study localization properties of principal eigenvector (PEV) of multilayer
networks. Starting with a multilayer network corresponding to a delocalized
PEV, we rewire the network edges using an optimization technique such that the
PEV of the rewired multilayer network becomes more localized. The framework
allows us to scrutinize structural and spectral properties of the networks at
various localization points during the rewiring process. We show that rewiring
only one-layer is enough to attain a multilayer network having a highly
localized PEV. Our investigation reveals that a single edge rewiring of the
optimized multilayer network can lead to the complete delocalization of a
highly localized PEV. This sensitivity in the localization behavior of PEV is
accompanied by a pair of almost degenerate eigenvalues. This observation opens
an avenue to gain a deeper insight into the origin of PEV localization of
networks. Furthermore, analysis of multilayer networks constructed using
real-world social and biological data show that the localization properties of
these real-world multilayer networks are in good agreement with the simulation
results for the model multilayer network. The study is relevant to applications
that require understanding propagation of perturbation in multilayer networks.Comment: 10 pages, 8 figure