CRC Press eBooks

Landau—Ginzburg and Fluctuations

Francesco Caravelli, Diego A. R. Dalvit

Published Jun 19, 2026• 0 citations

Abstract

In the previous chapter, we developed the Landau theory of phase transitions, emphasizing how macroscopic order parameters and symmetry considerations determine the general form of the free energy near criticality. There, spatial variations of the order parameter were neglected, corresponding to the mean-field approximation . However, as we have seen, close to the critical temperature T c the correlation length ξ diverges, and fluctuations occur over arbitrarily large scales. In this regime, the assumption of spatial uniformity breaks down, and a local field description becomes necessary.

DOI: 10.1201/9781003603528-18

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