Auxiliary-boson approach to strongly correlated electrons in condensed matter

by Frank Lechermann (Univ. Hamburg)

Thursday 20 Jun 2013, 16:30 → 17:30 Europe/Berlin

Sem. Raum 2 (DESY Hamburg)

The problem of correlated electrons is at the origin of many fascinating phenomena in solid-state physics. Theoretical approaches have to cope with an exploding Hilbert space that eventually gives rise to the intriguing dichotomy of the electronic character in the large-system limit. Namely the appearance of coherent low-energy quasiparticles coexisting with high-energy multiplet excitations. Auxiliary (or slave) boson techniques are designed to perform efficient Hilbert-space projections by decomposing the electron's multiple character on an operator level. We will review the methodology starting from the infinite-Hubbard-U limit for the one-band problem and working the way towards a general multi-orbital rotational-invariant framework. A scheme how to utilize the technique within first-principles studies of realistic matter will be discussed.