Citation: Shankar, R. "Effective field theory in condensed matter physics." Conceptual foundations of quantum field theory (1999): 47-55.
Web: https://arxiv.org/abs/cond-mat/9703210
Tags: Physical, Pedagogical
In this cute little paper, Ramamurti Shankar describes his perspective on effective field theory and its application to condensed matter physics. His perspective is explained almost entirely by means of one example - interacting fermions. He shows how effective field theory allows you to zoom-in on the behavior of the system near the Fermi surface, because low-energy excitations correspond to the tunneling of fermions below the Fermi surface to above the Fermi surface. This is in contrast to using increasingly accurate field theories, which zoom on the the low-momentum part of the system.
It is for this reason that Shankar says the following quote: "Even when one knows the theory at a microscopic level, there is often a good reason to deliberately move away to an effective theory".
This paper is a popular summary of the much longer seminal paper that Shankar published four years prior:
> Shankar, Rev. "Renormalization-group approach to interacting fermions." Reviews of Modern Physics 66.1 (1994): 129.
In the first page and a half, Shankar gives a biographical sketch of himself. It's an absolutely hilarious read, which I recommend highly.