The Single Impurity Anderson Model

We apply the formalism developed so far to describe transport properties of the single impurity Anderson model (SIAM). It represents the simplest but yet not trivial system where Coulomb interaction permeates the transport properties. Coulomb blockade physics is the characteristic signature of the weak tunneling regime. Higher order tunneling processes, like cotunneling, become relevant in the parameter regime where sequential tunneling is exponentially suppressed due to charging effects. As the temperature is lowered below a characteristic temperature, known as the Kondo temperature, charge and spin fluctuations enable transport despite the Coulomb blockade. A non-perturbative approach is required to cope with this effect.