Jun 20 – 23, 2022
Max Planck Institut für Festkörperforschung
Europe/Berlin timezone

Single- and two-particle properties of the weakly interacting two-dimensional Hubbard model in proximity to the van Hove singularity.

Jun 23, 2022, 3:45 PM
2D5 (Max Planck Institut für Festkörperforschung)


Max Planck Institut für Festkörperforschung


James LeBlanc (Memorial University of Newfoundland)


Leveraging the power of algorithmic Matsubara integration (AMI) we can generate pseudo-analytic results for virtually any diagrammatic expansion. Here we generate the longitudinal spin and charge susceptibilities for the 2D Hubbard model and employ our AMI toolset to obtain expressions that are explicit functions of chemical potential, temperature, interaction strength and frequency (both real and Matsubara).
We study the weak coupling limit for finite next-nearest neighbour hopping where we resolve features in real frequency spectra that appear to be missed in numerical analytic continuation of Matsubara axis data. We track these features throughout the phase diagram and find that their existence has a simple explanation made clear when considering the $\chi_{\uparrow\uparrow}$ and $\chi_{\uparrow\downarrow}$ susceptibilities. We further find that incompressibility in the model at weak coupling originates from vector nesting near the van Hove point and present evidence that this may be distinct from Mott insulating behaviour.

Primary author

James LeBlanc (Memorial University of Newfoundland)

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