Review Article

Partition Function in One, Two, and Three Spatial Dimensions from Effective Lagrangian Field Theory

Figure 2

Ferromagnet in two spatial dimensions and QCD: Feynman diagrams of the low-temperature expansion of the partition function up to three loops . Loops in are suppressed by two powers of momentum. In the case of the ferromagnet, the temperature-independent diagrams 4b, 6c, and 8h do not occur [4].
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