CC BY 4.0 UnportedTrugenberger, CarloDiamantini, M.CristinaPoccia, NicolaNogueira, Flavio S.Vinokur, Valerii M.2021-01-192021-01-192020https://doi.org/10.34657/4692https://oa.tib.eu/renate/handle/123456789/6063Electric-magnetic duality or S-duality, extending the symmetry of Maxwell’s equations by including the symmetry between Noether electric charges and topological magnetic monopoles, is one of the most fundamental concepts of modern physics. In two-dimensional systems harboring Cooper pairs, S-duality manifests in the emergence of superinsulation, a state dual to superconductivity, which exhibits an infinite resistance at finite temperatures. The mechanism behind this infinite resistance is the linear charge confinement by a magnetic monopole plasma. This plasma constricts electric field lines connecting the charge–anti-charge pairs into electric strings, in analogy to quarks within hadrons. However, the origin of the monopole plasma remains an open question. Here, we consider a two-dimensional Josephson junction array (JJA) and reveal that the magnetic monopole plasma arises as quantum instantons, thus establishing the underlying mechanism of superinsulation as two-dimensional quantum tunneling events. We calculate the string tension and the dimension of an electric pion determining the minimal size of a system capable of hosting superinsulation. Our findings pave the way for study of fundamental S-duality in desktop experiments on JJA and superconducting films.enghttps://creativecommons.org/licenses/by/4.0/530S-dualitymagnetic monopolessuperinsulationJosephson junction arrayselectric stringsinstantonsArticle