Sung-Sik Lee

Title: Low energy field theories for non-Fermi liquids

Abs: Non-Fermi liquids are unconventional metallic states which do not support well defined quasiparticles. Due to strong quantum fluctuations and the presence of extensive gapless modes near the Fermi surface, it has been difficult to understand universal low energy properties of non-Fermi liquids reliably.  In these lectures, I will review 1) Landau Fermi liquid theory, 2) earlier theoretical approaches to non-Fermi liquids and their limitations, 3) recent progress made on non-Fermi liquid theories based on a dimensional regularization scheme and a non-perturbative interaction driven scaling.