This thesis explores various approaches of studying the long-range colour order of antiferromagnetic SU(N) Heisenberg models with the linear flavour-wave theory (LFWT). The LFWT is an extension of the well-known SU(2) spin-wave theory to SU(N), and this se ...
Physics beyond the Standard Model can appear as new particles too heavy to be produced in experiments (the energy frontier) or interacting too weakly to be seen in our measurements (the intensity frontier).In the first part of this thesis, we study two ...