ABSTRACT
We briefly introduced Green’s function in the last chapter. In defining the different quantities, we also alluded to the use of the anticommutator relationship. Now, this turns out to be a very important concept for electrons that are required not only to satisfy Fermi- Dirac statistics but also to possess the anti-symmetry expected for such fermions. Hence, we need to distinguish between bosons and fermions. This is not only important for Green’s functions but for most advanced quantum transport, as we will encounter Green’s functions for both fermions (the electrons) and bosons (the phonons, or lattice vibrations). While the Green’s functions we will deal with in this chapter are called equilibrium Green’s functions, they are not strictly confined by this name. Perhaps more properly, we should refer to them as just being near to equilibrium and at low temperature.
