Abstract

Experiments on ultra-cold Fermi gases at micro-Kelvin temperatures are revolutionizing many areas of physics. Their exceptional simplicity allows tests of many-body theory in areas long thought to be inaccessible. The broad Feshbach resonance in gases of ⁶Li and ⁴⁰K has already permitted the examination of the strongly interacting regime — the so-called unitarity limit, which leaves the inter-atomic distance as the only relevant length scale. At this point, the gas is expected to exhibit a universal thermodynamic behaviour, independent of any microscopic details of the underlying interactions. Substantial experimental efforts have been carried out to verify the existence of universality, though so far there has been no conclusive confirmation. This situation has dramatically improved in the most recent thennody namic measurements on strongly interacting Fermi gases of ⁴⁰K and ⁶Li atoms[l], which allow accurate estimates of temperature. These groundbreaking investigations provide a precise measurement, accurate to the level of a few percent, which is an exceptional accuracy in this challenging field of ultra-low temperature physics.

© 2007 IEEE