noninteracting

Note that the noninteracting Green function is diagonal, but this will not be true in the interacting case.

Consider a collection of N noninteracting particles, which can each be in one of two quantum states, and .

This causes quarks and gluons to behave as effectively free noninteracting particles at high energies.

Consider two noninteracting systems and , with respective Hilbert spaces and .

For example, for a three-dimensional noninteracting electron gas at absolute zero temperature, the relation is .

(Strictly speaking, this is only true in the noninteracting case or in the low energy density limit of renormalized quantum field theories)

The two-channel Kondo model is a variant of the Kondo model which has the spin-1/2 coupled to two independent noninteracting bands.

The Thomas-Fermi model of 1927 used a kinetic energy functional for a noninteracting uniform electron gas in a first attempt of density-functional theory of electronic structure:

Phillip Anderson devised a perturbative renormalization group method, known as Poor Man's Scaling, which involves perturbatively eliminating excitations to the edges of the noninteracting band.

Thus a noninteracting Fermi gas, unlike a Bose gas, is prohibited from condensing into a Bose-Einstein condensate, although interacting Fermi gases might.

This process is described by the full Hamiltonian H, but once it's over, all of the new bound states separate again and one finds a new noninteracting state called the out state.

An extensive property is defined by the IUPAC Green Book as a physical quantity which is the sum of the properties of separate noninteracting subsystems that compose the entire system.