Quantum mechanics for fields everywhere.

Theory combining all fundamental forces.

Electron interaction theory in complexes.

(chemistry, physics) a theory, a combination of the earlier crystal field theory with molecular orbital theory, that describes the structure of coordination compounds

In mathematics, class field theory is the fundamental branch of algebraic number theory whose goal is to describe all the abelian Galois extensions of local and global fields using objects associated to the ground field.

A classical field theory is a physical theory that predicts how one or more fields in physics interact with matter through field equations, without considering effects of quantization; theories that incorporate quantum mechanics are called quantum field theories.

In physics, lattice field theory is the study of lattice models of quantum field theory.

In gauge theory and mathematical physics, a topological quantum field theory (or topological field theory or TQFT) is a quantum field theory which computes topological invariants.