Editorial Notes

The theoretical descriptions presented in Chapters 10–14 have a stark distinction from most approaches presented in Part II.A, in that they abandon the idea of a well-defined single-mode condensate coupled to its excitations, in favour of a cumulative description of the low-lying modes of the system; these modes are intended to encompass both the condensate and the modes that become significantly affected by its presence. While such theories have a common scope and philosophy, there are subtle differences between the models used, and even in their respective implementations…