L.B. Ioffe a, b
A.J. Millis c
a Landau Institute for Theoretical Physics, Russian Academy of Sciences, ul. Kosygina 2, Moscow, 119334, Russian Federation
b Physics Department, Rutgers University, Piscataway, New Jersey, USA
c Department of Physics and Astronomy The Johns Hopkins University, 3400 North Charles St., Baltimore, MD, 21218, USA
The experimental discovery of a number of ’strange metals’ has reopened the question of the low temperature behavior of interacting Fermi systems. Here we provide a subjective overview of some aspects of the resulting theoretical work. It seems to us that from a theoretical standpoint Landau’s Fermi-liquid theory has proven to be a remarkably robust description of clean Fermi systems. The only well documented theoretical examples of non-Fermi-liquid behavior are metals subject to gauge interactions or at quantum critical points. The experimental anomalies which prompted the reexamination of Fermi-liquid theory remain in many cases mysterious.