Mean Field Theory
The classical Landau theory (aka mean field theory) values for a scalar field are
If we add derivative terms turning it into a mean field Ginzburg–Landau theory, we get
One of the major discoveries in the study of critical points is that mean field theory is completely wrong in the vicinity of critical points in two and three dimensions. In four dimensions, we have logarithmic corrections.
Read more about this topic: Critical Exponent
Famous quotes containing the words field and/or theory:
“The poet will write for his peers alone. He will remember only that he saw truth and beauty from his position, and expect the time when a vision as broad shall overlook the same field as freely.”
—Henry David Thoreau (1817–1862)
“Freud was a hero. He descended to the “Underworld” and met there stark terrors. He carried with him his theory as a Medusa’s head which turned these terrors to stone.”
—R.D. (Ronald David)