Magnon dispersion

Method is based on the [1]. with matrix diagonalisation via [2].

We believe that in original paper [1] there is a mistake in the derivation, which is discussed in much details here: magnon-dispersion.pdf.

References

[1] (1,2)

Toth, S. and Lake, B., 2015. Linear spin wave theory for single-Q incommensurate magnetic structures. Journal of Physics: Condensed Matter, 27(16), p.166002.

[2]

Colpa, J.H.P., 1978. Diagonalization of the quadratic boson hamiltonian. Physica A: Statistical Mechanics and its Applications, 93(3-4), pp.327-353.