We introduce a strong coupling dual super-perturbation scheme starting from the general reference system optimised for a given many-body problem. We discuss the physics of high-temperature cuprate superconductors starting from the highly degenerate four-site plaquette of the Hubbard model as a reference system. The degeneracy causes strong fluctuations when a lattice of plaquettes is...
In the recent literature, the concept of topological Mott insulator has been spelled out in quite different ways. Most of the proposed realizations rely either on Hartree-Fock approximations or on appropriately defined auxiliary degrees of freedom. I will discuss a novel, remarkably simple way of describing a topological Mott insulator without long-range order based on the topological...
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...
Using appropriate terminology, we say more with fewer words. A useful terminology to describe two-particle electronic correlations was introduced by Hedin [1] and in the context of the spin-fermion model [2,3]. In this spirit, we show that re-expressing two-particle correlations through exchange bosons [4,5] greatly enhances the computational power of algorithms and, at the same time, gives us...
