  Lecture Goals: (i) Introduction to the basic concepts, meaning that the
emphasis is, in the first instance, on the single-particle aspects. (ii)
Service for Experimental Solid State Physics. (iii) Emphasis on the explanation
of concepts and basic ideas, not always quantitative, justification of the use
of simplified `model Hamiltonians'. (iv) Raise some understanding why many-body
physics is mostly phenomenology. (v) Convey the following main idea:
(Collective) elementary excitations are `quasi-particles' characterized by
their dispersion relation $\mathbf{p} \mapsto \varepsilon (\mathbf{p})$ and by
certain quantum numbers like spin and charge. The most important two are `the
phonon' (= quantized lattice vibration) and `the electron' (= quantized charge
excitation of the solid, which has as much to do with the electron of
elementary particle physics as water waves have to do with water).
