Superinsulators: An Emergent Realisation of Confinement

Maria Cristina Diamantini,Carlo A Trugenberger

doi:10.3390/universe7060201

Maria Cristina Diamantini, Carlo A Trugenberger

Open Access

https://doi.org/10.3390/universe7060201

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Abstract

Superinsulators (SI) are a new topological state of matter, predicted by our collaboration and experimentally observed in the critical vicinity of the superconductor-insulator transition (SIT). SI are dual to superconductors and realise electric-magnetic (S)-duality. The effective field theory that describes this topological phase of matter is governed by a compact Chern-Simons in (2+1) dimensions and a compact BF term in (3+1) dimensions. While in a superconductor the condensate of Cooper pairs generates the Meissner effect, which constricts the magnetic field lines penetrating a type II superconductor into Abrikosov vortices, in superinsulators Cooper pairs are linearly bound by electric fields squeezed into strings (dual Meissner effect) by a monopole condensate. Magnetic monopoles, while elusive as elementary particles, exist in certain materials in the form of emergent quasiparticle excitations. We demonstrate that at low temperatures magnetic monopoles can form a quantum Bose condensate (plasma in (2+1) dimensions) dual to the charge condensate in superconductors. The monopole Bose condensate manifests as a superinsulating state with infinite resistance, dual to superconductivity. The monopole supercurrents result in the electric analogue of the Meissner effect and lead to linear confinement of the Cooper pairs by Polyakov electric strings in analogy to quarks in hadrons. Superinsulators realise thus one of the mechanism proposed to explain confinement in QCD. Moreover, the string mechanism of confinement implies asymptotic freedom at the IR fixed point. We predict thus for superinsulators a metallic-like low temperature behaviour when samples are smaller than the string scale. This has been experimentally confirmed. We predict that an oblique version of SI is realised as the pseudogap state of high-TC superconductors.

Highlights

Extremely successful in describing many aspects of particle physics, the standard model does not explain the mechanism of confinement that binds quarks into hadrons
In 1978, in a Gedanken experiment for quark confinement [1] ’t Hooft introduced the idea of a dual superconductor in which, in analogy to the Meissner effect, chromo-electric fields would be squeezed into thin flux tubes with quarks at their ends in a condensate of magnetic monopoles
One of the most promising ways to explain confinement is that confinement of colour is produced by dual superconductivity [1,7,10]: the chromoelectric field produced by quark–antiquark pairs is constrained by the dual Meissner effect into Abrikosov flux tubes in the same way as magnetic field is confined in usual superconductors of type II

Summary

Introduction

Extremely successful in describing many aspects of particle physics, the standard model does not explain the mechanism of confinement that binds quarks into hadrons. The characteristic of the superinsulating phase and show that in (3+1) dimensions this is a confinement phase in which Cooper pairs are bounded by electric flux tubes in a condensate of magnetic monopole. Equation (3) defines the mixed Chern-Simons (CS) action [23,24,25] and represents the local formulation of the topological interactions between charges and vortices Since it contains only one field derivative, it is the dominant contribution to the action at long distances and it is invariant under the gauge transformations aμ → aμ + ∂μλ and bμ → bμ + ∂μχ, re√flecting the conservation of √the charge and vortex numbers. In what follows we will concentrate on the superinsulating phase

Superinsulating Phase

Conclusions