Dirac spectrum

The Dirac spectrum refers to the set of eigenvalues associated with the Dirac operator, which is a key operator in quantum mechanics and quantum field theory that describes fermionic particles. The Dirac operator is a first-order differential operator that combines both the spatial derivatives and the mass term of fermions, incorporating the principles of relativity. In a more mathematical context, the Dirac operator is typically defined on a manifold and acts on spinor fields, which transform under the action of the rotation group.