ABSTRACT
In the previous chapter, we introduced the basic formalisms of
quantum transport calculations. The Kubo formula is derived
from particle description and the Landauer formula is derived
from wave description. These are expressed in mathematics using
Green’s functions in the framework of quantum field approach,
which describes both particle and wave natures in the second
quantization operators. Linear-response conductance is described
by the equilibrium Green’s functions, while we need nonequilibrium
Green’s function (NEGF) to describe the transport with a finite bias
voltage.
