Mathias S. Scheurer
Room 10.01, 10th Floor, Bldg. 30.23, KIT Campus South
Harvard University, Cambridge, MA, USA
Prof. Dr. Jörg Schmalian
One of the most mysterious phases of the cuprate high-temperature superconductors is the “pseudogap” state: despite its Fermi-liquid-like electrical transport properties, the size of the Fermi surface is smaller than that predicted by the Luttinger theorem of Fermi liquid theory. In this talk, I will discuss gauge theories of doped antiferromagnets that we propose as effective field theories for the pseudogap phase. By virtue of exhibiting “topological order”, these theories allow to circumvent Luttinger’s theorem while exhibiting the charge transport of a Fermi liquid. The presentation will focus on a direct comparison of predictions of these gauge theories with both numerical studies of the strongly coupled Hubbard model [1,2] and with high-resolution photoemission data . The good agreement can be seen as at least indirect evidence for topological order in the phase diagram of the cuprate superconductors. We will also discuss bound-state formation  and additional symmetry breaking [5,6], such as the formation of charge-density-wave, nematic, or loop-current order, that can occur at low temperature and comment on the quantum critical point in our theory.
 Scheurer, Chatterjee, Wu, Ferrero, Georges, and Sachdev, PNAS 115 E3665 (2018).
 Wu, Scheurer, Chatterjee, Sachdev, Georges, and Ferrero, PRX 8, 021048 (2018).
 He, Rotundu, Scheurer, He, Hashimoto, Xu, Wang, Huang, Jia, Chen, Moritz, Lu, Lee, Devereaux, and Shen, arXiv:1811.04992.
 Sachdev, Scammell, Scheurer, and Tarnopolsky, arXiv:1811.04930.
 Chatterjee, Sachdev, and Scheurer, PRL 119, 227002 (2017).
 Scheurer and Sachdev, arXiv:1808.04826.