3. Landau introduced the notion of antiferromagnetism as a special phase of a magnet (1936)
4. He also introduced the equation for the plasma in the case of the Coulomb interaction and established the form of the collision integral for charged particles (1936)
5. He also created the theory of phase transitions of the second kind (1935-1937)
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@VergaraLautaro AFAIK, in the Course they introduced thermal fluctiations in mesoscopic hydrodynamics. Their description is nowadays the standard.