Quantum Cafe: Mike Zalatel

Title: Chiral Superconductivity at Topological Phase Transitions: Field Theories and DMRG

Abstract: Two-dimensional moire systems have realized a panoply of fractionalized states and superconductivity. As in the quantum Hall effect, these systems feature band topology and strong interactions, but they are distinguished by bands which are not perfectly flat. The competition between dispersion and interactions introduces unique features, such as band-width driven topological phase transitions and the possibility of “anyon superconductivity.” I will present two surprisingly simple model systems in which this competition results in all-electronic superconductivity. Using infinite-cylinder DMRG, we find clear evidence for superconductivity that survives in the 2D limit, with much less phase competition than found in the doped Hubbard model. I’ll explain how to identify 2D superconductivity in infinite-cylinder DMRG numerics, and in particular how to explore the pairing symmetry and topology of the superconductor.