Coupling and Level Repulsion in the Localized Regime: From Isolated to Quasi-Extended Modes

TL;DR

This paper investigates how localized states in a 1D random system interact and evolve into quasi-extended modes, revealing level repulsion phenomena through experiments and a coupled resonator model.

Contribution

It introduces a detailed experimental and theoretical analysis of mode coupling and level repulsion in localized regimes, linking spectral features to resonator parameters.

Findings

Observation of level repulsion in localized states

Transformation into quasi-extended modes near resonance

Model explaining spectral and spatial evolution

Abstract

We study the interaction of Anderson localized states in an open 1D random system by varying the internal structure of the sample. As the frequencies of two states come close, they are transformed into multiply-peaked quasi-extended modes. Level repulsion is observed experimentally and explained within a model of coupled resonators. The spectral and spatial evolution of the coupled modes is described in terms of the coupling coefficient and Q-factors of resonators.