GLYPH<Minus> 10 GLYPH<Minus> 5 0 5 10 0.5 1.0 1.5 2.0 2.5 3.0 Attractive fermions PSfrag replacements ξ T /µ FIG. 8: The energy per particle scaling function ξ for attractive fermions as a function of T /µ . and In terms of the density: It is important to note that although the energy per particle scaling function ξ approaches the free field value at low temperatures, the above behavior is very different from the free field case. In the latter, the scaling function c = − 6Li$_{2}$( − z ) /π $^{2}$, which gives the diverging behavior at very low temperature: Finally, as µ/T → −∞ , y ≈ 1 + z , and c ≈ 6 z/π 2 and n ≈ mT z/ 2 π . This leads η s ≈ π $_{2}$√$_{2}$ (1 / (log( µ/T ) − 2) + T/ 2 µ ) (79) lim µ/T →∞ η s = π $_{2}$√$_{2 log(2}$$_{πn/mT}$$_{)}$ (80) η s ≈ 3 $_{4}$√$_{2}$$_{π}$ µ T , (free fermions) (81) 28