No abstract

Superinsulators, realizing a single-color version of quantum chromodynamics, offer a unique laboratory for exploring the fundamentals of confinement and asymptotic freedom via desktop experiments. Recent experiments [1] evidenced that superinsulators are the mirror-twins of superconductors, with reversed electric and magnetic field effects. Cooper pairs and Cooper holes in the superinsulator are confined into neutral pions by electric strings, with the Cooper pairs playing the role of quarks [1,2]. Here we report the non-equilibrium relaxation of the electric pions in superinsulating films. We find that the time delay t sh of the current passage in the superinsulator is related to the applied voltage V via the power law, t sh ∝ (V − V p ) −µ , where V p is the effective threshold voltage. Two distinct critical exponents are found, µ = 1/2 and µ = 3/4, corresponding to jumps from the electric Meissner state to the mixed state and to the superinsulating resistive state with broken charge confinement, respectively. The exponent µ = 1/2 establishes a direct experimental evidence for the electric strings' linear potential confining the charges of opposite signs in the electric Meissner state. We further report memory effects and their corresponding dynamic critical exponents arising upon the sudden reversal of the applied voltage.

Planar superconductors, thin films with thickness comparable to the superconducting coherence length, differ crucially from their bulk counterparts. The Coulomb interaction is logarithmic up to distances exceeding typical sample sizes and the Anderson-Higgs mechanism is ineffective to screen the resulting infrared divergences of the resulting (2+1)-dimensional QED because the Pearl length is also typically larger than sample sizes. As a consequence, the system decomposes into superconducting droplets with the typical size of the coherence length. We show that the two possible phases of the system match the two known mechanisms by which (2+1)dimensional QED cures its infrared divergences, either by generating a mixed topological Chern-Simons mass or by magnetic monopole instantons. The former is realized in superconductors, the latter governs mirror-dual superinsulators. Planar superconductors are thus described by a topological Chern-Simons gauge (TCSG) theory which replaces the Ginzburg-Landau model in two dimensions. In the TCSG model, the Higgs field is absent. Accordingly, in planar superconductors Abrikosov vortices do not form, and only Josephson vortices with no normal core can emerge.

Despite more than three decades of tireless efforts, the nature of high-temperature superconductivity (HTS) remains a mystery [1][2][3]. A recently proposed long-distance effective field theory [4] accounting for all the universal features of HTS and the equally mysterious pseudogap phase, related them to the coexistence of a charge condensate with a condensate of dyons, particles carrying both magnetic and electric charges. Central to this picture are magnetic monopoles emerging in the proximity of the topological quantum superconductor-insulator transition (SIT) that dominates the HTS phase diagram. However, the mechanism responsible for spatially localized electron pairing, characteristic of HTS [5], remains puzzling. Here we show that real-space, localized electron pairing is mediated by magnetic monopoles and occurs well above the superconducting transition temperature T c . Localized electron pairing promotes the formation of superconducting granules connected by Josephson links. Global superconductivity sets in when these granules form an infinite cluster at T c which is estimated to fall in the range from hundred to thousand Kelvins. Our findings pave the way to tailoring materials with elevated superconducting transition temperatures.