Jae-Mo Lihm, Dominik Kiese, Seung-Sup B. Lee, and Fabian B. Kugler

Systems of interacting electrons can show emergent, strong-correlation phenomena. The parquet equations self-consistently relate various propagation amplitudes of many-electron systems and thereby allow one to distill the microscopic mechanisms behind such emergent phenomena. However, solving them is notoriously hard, particularly when interactions are strong. Here, we present a method for solving the parquet equations, which circumvents divergences that arise when using nonperturbative input. We apply our method to the paradigmatic Hubbard model and analyze the pseudogap characterizing the underdoped high-temperature normal state of cuprate superconductors. We find that an enhanced scattering amplitude between electrons and antiferromagnetic spin fluctuations, or paramagnons, is crucial for forming the strong-coupling pseudogap, and that this enhancement requires the cooperation of multiple paramagnons.

 

URL: https://www.pnas.org/doi/10.1073/pnas.2525308123