Superinsulators: a toy realization of QCD in condensed matter

TL;DR

This paper demonstrates that superinsulators can be modeled as a condensed matter analog of QCD, exhibiting confinement and asymptotic freedom, with experimental evidence from thin film materials.

Contribution

It provides a quantum field theory description of superinsulators as a toy model of QCD, including quantization and entanglement analysis.

Findings

Superinsulators exhibit confinement similar to QCD.

Experimental signatures of asymptotic freedom observed in thin films.

Superinsulators act as a condensed matter analog of QCD with Cooper pairs as quarks.

Abstract

Superinsulators are dual superconductors, dissipationless magnetic monopole condensates with infinite resistance. The long-distance field theory of such states of matter is QED with dynamical matter coupled via a compact BF topological interaction. We will quantize the 2D model in the functional Schr\"odinger picture and show how strong entanglement of charges leads to a phase which is a single-color, asymptotically free version of QCD in which the infinite resistance is caused by the linear confinement of charges. This phase has been experimentally detected in TiN, NbTiN and InO thin films, including signatures of asymptotically free behaviour and of the dual, electric Meissner effect. This makes superinsulators a ``toy realization" of QCD with Cooper pairs playing the role of quarks.