Theories of non-Fermi liquid behavior in heavy fermions

TL;DR

This paper reviews current theories on non-Fermi liquid behavior in heavy fermion systems at quantum critical points, highlighting the role of antiferromagnetic fluctuations and contrasting different theoretical perspectives.

Contribution

It offers a comparative analysis of weak and strong-coupling theories, emphasizing unresolved puzzles and experimental challenges in understanding heavy fermion quantum phase transitions.

Findings

Critical antiferromagnetic fluctuations may break up the heavy fermion structure.

Contrasts weak and strong-coupling views of quantum phase transitions.

Raises questions about the nature of the Fermi surface in non-Fermi liquids.

Abstract

I review our incomplete understanding of non-Fermi liquid behavior in heavy fermion systems at a quantum critical point. General considerations suggest that critical antiferromagnetic fluctuations do not destroy the Fermi surface by scattering the heavy electrons- but by actually breaking up the internal structure of the heavy fermion. I contrast the weak, and strong-coupling view of the quantum phase transition, emphasizing puzzles and questions that recent experiments raise.