We will use the shorthand p and h for particle and hole states, and also their combinations (i.e. pp, ph, hp, hh).
For single particle subindices, we will use for hole states, for particle states and for generic states. Note that will be used also exclusively when referring to paired particles in HF-Bogoliubov, which is a bit confusing.
We will often use the "antisymmetrized potential", defined like so:whereand is the most general from of a two-particle potential.