Closed kbarros closed 6 months ago
This all looks good 👍 and the classical dynamics as implemented in #217 fixes the Nm
and n_omega
factors.
One caveat: everything mentioned above includes only up to the output of calc_intensity
. There are additional normalization considerations that need to be made on case-by-case basis for each of the following functions, which consume the output of calc_intensity
:
intensities_interpolated
(no change)intensities_binned
(normalization having to do with bin width; implemented on 217 )intensities_bands
(normalization of delta functions needs to be documented)intensities_band_structure
(new in 217 ; normalization of delta functions within the BandStructure
struct needs to be documented)intensities_broadened
(normalization of the broadening kernel needs to be documented)~2|q|
)Work in progress at https://github.com/SunnySuite/Sunny.jl/pull/240 is going to use the convention that the extensive intensity will be normalized by the number of chemical unit cells, i.e., in terms of the lattice vectors that define the RLU system. This has the advantages: (1) consistency with SpinW, (2) adding more magnetic ions adds more intensity (3) avoid ambiguity, e.g., when working with entangled units, where the number of "sites" is not well defined.
Note that the shape of the chemical cell is an invariant in Sunny. Reshaping the System will not change the reference ("original") chemical cell.
Dynamical correlations calculated with spin wave theory and with classical dynamics currently follow different normalization conventions with respect to
natoms
(the number of atoms in the magnetic cell). The current state is:natoms
natoms
natoms
.@Lazersmoke argued on Slack that (2) is correct (even though it differs from the SpinW convention), and that (3) should be changed to match (2).
Here is my lightly edited summary of @Lazersmoke's argument: