Anderson orthogonality theorem
Encyclopedia
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
that the impurity creates. The N-electron ground state
for the system when
, which corresponds to the absence of the impurity and 
, which corresponds to the introduction of the impurity are orthogonal.
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
by the physicist P. W. Anderson.
It relates to the introduction of a magnetic impurity
Magnetic impurity
A magnetic impurity is an impurity in a host metal that has a magnetic moment. The magnetic impurity can then interact with the conduction electrons of the metal, leading to interesting physics such as the Kondo effect, and heavy fermion behaviour. Some examples of magnetic impurities that metals...
in a metal. When a magnetic impurity is introduced into a metal, the conduction electrons will tend to screen
Electric field screening
Screening is the damping of electric fields caused by the presence of mobile charge carriers. It is an important part of the behavior of charge-carrying fluids, such as ionized gases and conduction electrons in semiconductors and metals....
the potential
that the impurity creates. The N-electron ground stateGround state
The ground state of a quantum mechanical system is its lowest-energy state; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than the ground state...
for the system when
, which corresponds to the absence of the impurity and , which corresponds to the introduction of the impurity are orthogonal.