%0 Journal Article
%A Scheurer, Mathias S.
%A Chatterjee, Shubhayu
%A Wu, Wei
%A Ferrero, Michel
%A Georges, Antoine
%A Sachdev, Subir
%T Topological order in the pseudogap metal
%D 2018
%R 10.1073/pnas.1720580115
%J Proceedings of the National Academy of Sciences
%P E3665-E3672
%V 115
%N 16
%X The copper oxide-based high-temperature superconductors display a mysterious “pseudogap” metal phase at temperatures just above the critical temperature in a regime of low hole density. Extensive experimental and numerical studies have yielded much information on the nature of the electron corrections, but a fundamental theoretical understanding has been lacking. We show that a theory of a metal with topological order and emergent gauge fields can model much of the numerical data. Our study opens up a route to a deeper understanding of the long-range quantum entanglement in these superconductors and to the direct detection of the topological characteristics of the many-body quantum state.We compute the electronic Green’s function of the topologically ordered Higgs phase of a SU(2) gauge theory of fluctuating antiferromagnetism on the square lattice. The results are compared with cluster extensions of dynamical mean field theory, and quantum Monte Carlo calculations, on the pseudogap phase of the strongly interacting hole-doped Hubbard model. Good agreement is found in the momentum, frequency, hopping, and doping dependencies of the spectral function and electronic self-energy. We show that lines of (approximate) zeros of the zero-frequency electronic Green’s function are signs of the underlying topological order of the gauge theory and describe how these lines of zeros appear in our theory of the Hubbard model. We also derive a modified, nonperturbative version of the Luttinger theorem that holds in the Higgs phase.
%U https://www.pnas.org/content/pnas/115/16/E3665.full.pdf