The strength of weak coupling
Quantum Physics
2025-12-10 v1 Combinatorics
Abstract
A paradoxical idea in quantum transport is that attaching weakly-coupled edges to a large base graph creates high-fidelity quantum state transfer. We provide a mathematical treatment that rigorously prove this folklore idea. Our proofs are elementary and build upon the Feshbach-Schur method from perturbation theory. We also show the idea is effective in circumventing Anderson localization in spin chains and finding speedups in hitting times useful for quantum search.
Cite
@article{arxiv.2512.08141,
title = {The strength of weak coupling},
author = {Alastair Kay and Christino Tamon},
journal= {arXiv preprint arXiv:2512.08141},
year = {2025}
}
Comments
17 pages, 4 figures, 1 table