Theorem in physics
The Anderson orthogonality theorem is a theorem in physics by the physicist P. W. Anderson.
It relates to the introduction of a magnetic impurity in a metal. When a magnetic impurity is introduced into a metal, the conduction electrons will tend to screen the potential formula_1 that the impurity creates. The N-electron ground state for the system when formula_2, which corresponds to the absence of the impurity and formula_3, which corresponds to the introduction of the impurity are orthogonal in the thermodynamic limit formula_4.