Emergence

Behaviour that belongs to the whole, not the parts — the reason many-body physics is more than a sum of one-body problems.

Every topic that illustrates this idea, drawn from across all subjects.

• Cuprates and the Mott Problem Mott Physics in Correlated Lattices Why high-temperature superconductivity forced condensed-matter physics to take strong electron correlation seriously — and why the story begins with an insulator that band theory says should be a metal.
• Strong Coupling: Perturbation Theory and Superexchange Mott Physics in Correlated Lattices In the opposite limit U ≫ t, treating hopping as a perturbation and projecting out doubly occupied sites with a Schrieffer–Wolff transformation maps the half-filled Hubbard model onto the antiferromagnetic Heisenberg model, with superexchange J = 4t²/U.