The coupled cluster method (CCM) is a powerful and widely applied technique
of modern-day quantum many-body theory. It has been used with great success in
order to understand the properties of quantum magnets at zero temperature. This
is due largely to the application of computational techniques that allow the
method to be applied to high orders of approximation using localised
approximation schemes, e.g., such as the LSUBm scheme. In this article, the
high-order CCM formalism for the ground and excited states of quantum magnetic
systems are extended to those with spin quantum number s≥21​.
Solution strategies for the ket- and bra-state equations are also considered.
Aspects of extrapolation of CCM expectation values are discussed and future
topics regarding extrapolations are presented.Comment: 15 page