A topological quantum field theory (or topological field theory or TQFT) is a quantum field theory which computes topological invariants.

A topological quantum field theory (or topological field theory or TQFT) is a quantum field theory which computes topological invariants.

It's related to knot theory and the theory of four-manifolds in algebraic topology, and to the theory of moduli spaces in algebraic geometry in mathematics.

See https://en.wikipedia.org/wiki/Topological_quantum_field_theory for more complete information.