2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/17222We show that quantum vortex-loop proliferation may be one possible explanation of the super-long-range proximity effect observed in an insulating underdoped cuprate, using the dual theory of quantum vortices. As a test of this scenario, we propose that a dual proximity effect experiment can confirm the superfluid motion of the quantum vortices in the vortex-proliferated insulator and can measure the divergent correlation lengths near the superconductor-insulator transition.4 pages, 1 eps figure; revised presentationSuperconductivitytext