Methods

The many-body toolkit. The same techniques recur across very different problems, so here you can browse by method — every topic that uses it, drawn from across all subjects.

Quantum embedding

• Dynamical mean-field theory Mapping the lattice onto a self-consistent quantum impurity — exact in infinite dimensions, the workhorse for strong correlation. 2 topics

Field-theoretic

• Green's functions Single- and many-particle propagators — the central objects that carry spectra, lifetimes, and response. 1 topic

Impurity solvers

• Iterated perturbation theory A cheap second-order solver for the DMFT impurity problem — transparent, and surprisingly faithful at half filling. 1 topic

Mean-field & decoupling

• Mean-field theory Decoupling interactions into a self-consistent background field; the first window onto broken symmetry. 1 topic

Perturbative

• Perturbation theory Controlled expansions in a small parameter — here, hopping over interaction, giving superexchange. 1 topic

Exact & non-interacting

• Tight binding Diagonalising the non-interacting lattice in momentum space — bands, Fermi surfaces, density of states. 1 topic