Dilute Fermi and Bose Gases

Abstract

I give a unified perspective on the properties of a variety of quantum liquids using the theory of quantum phase transitions. A central role is played by a zero density quantum critical point which is argued to control the properties of the dilute gas. An exact renormalization group analysis of such quantum critical points leads to a computation of the universal properties of the dilute Bose gas and the spinful Fermi gas near a Feshbach resonance.Comment: 28 pages, 8 figures; adapted from Chapter 16 of Quantum Phase Transitions, Second Edition (see http://sachdev.physics.harvard.edu/qptweb/toc.html); contribution to Lecture Notes in Physics, "BCS-BEC crossover and the Unitary Fermi Gas" edited by W. Zwerge