Summer school 2018 / Alexander Lichtenstein / Part 4. Dual fermions and bosons

In the fourth lecture it is discussed how to go beyond Dynamical Mean Field Theory (DMFT) and take into account nonlocal effects. The lecture timeline is below. 00:00 DUAL FERMIONS AND BOSONS 02:54 Dual fermion (DF) scheme 16:10 Diagrammatics and self-consistency for dual fermions 26:46 APPLICATION OF DUAL FERMIONS. ARPES 28:15 Pseudogap in HTSC 30:10 Competing orders 30:55 Extended van Hove singularity 33:00 Problems with high-order vertices 33:51 DF-Diagrammatic Monte Carlo 35:20 DUAL BOSON FORMALISM (DB) 38:21 DB/DF scheme 45:34 Lattice GF and SCF-condition 46:32 GW+DMFT as DB limit 50:52 APPLICATIONS OF DUAL BOSONS. Plasmon in strongly correlated materials 53:57 Spin fluctuations in cuprates 01:00:07 Conservation in DMFT and DB 01:03:53 Exchange interactions in DB