Cleanup

src/SpinWaveTheory/SWTCalculations.jl

@@ -65,12 +65,8 @@ function swt_hamiltonian!(swt::SpinWaveTheory, k̃ :: Vector{Float64}, Hmat::Mat
             isculled && break
 
             ### Bilinear exchange
-            if coupling.bilin isa Number
-                J = Mat3(coupling.bilin*I)
-            else
-                J = coupling.bilin
-            end
-
+
+            J = Mat3(coupling.bilin*I)
             sub_i, sub_j, ΔRδ = bond.i, bond.j, bond.n
 
             tTi_μ = s̃_mat[:, :, :, sub_i]

src/System/Interactions.jl

@@ -316,10 +316,11 @@ function set_forces_aux!(B, dipoles::Array{Vec3, 4}, ints::Interactions, sys::Sy
         if !iszero(coupling.biquad)
             J = coupling.biquad
             if sys.mode == :dipole
+                # Renormalization procedure introduces a factor r and a
+                # Heisenberg term, https://arxiv.org/abs/2304.03874.
                 Sᵢ = (sys.Ns[site1]-1)/2
                 Sⱼ = (sys.Ns[site2]-1)/2
                 S = √(Sᵢ*Sⱼ)
-                # Renormalization introduces a factor r and a Heisenberg term
                 r = (1 - 1/S + 1/4S^2)
                 B[site1] -= J * (2r*sⱼ*(sᵢ⋅sⱼ) - sⱼ/2)
                 B[site2] -= J * (2r*sᵢ*(sᵢ⋅sⱼ) - sᵢ/2)

src/System/OnsiteCoupling.jl

@@ -49,6 +49,8 @@ function OnsiteCoupling(sys::System, matrep::Matrix{ComplexF64}, N)
 end
 
 
+# k-dependent renormalization of Stevens operators O[k,q] as derived in
+# https://arxiv.org/abs/2304.03874.
 function anisotropy_renormalization(N)
     S = (N-1)/2
     return ((1), # k=1

src/System/System.jl

@@ -436,8 +436,8 @@ spin_operators(sys::System{N}, site::Site) where N = spin_matrices(N=sys.Ns[to_a
     stevens_operators(sys, site::Int)
 
 Returns a generator of Stevens operators appropriate to an atom or
-[`Site`](@ref) index. The return value `O` can be indexed as `O[q,m]`, where ``0
-≤ q ≤ 6`` labels an irrep and ``m = -q, …, q``. This will produce an ``N×N``
+[`Site`](@ref) index. The return value `O` can be indexed as `O[k,q]`, where ``0
+≤ k ≤ 6`` labels an irrep and ``q = -k, …, k``. This will produce an ``N×N``
 matrix of appropriate dimension ``N``.
 """
 stevens_operators(sys::System{N}, i::Int) where N = StevensMatrices(sys.Ns[i])

src/System/Types.jl

@@ -65,7 +65,7 @@ mutable struct System{N}
     # inhomogeneous (defined for every cell in the system).
     interactions_union     :: Union{Vector{Interactions}, Array{Interactions,4}}
 
-    # Optional long-range dipole-dipole interactions (Vector is mutable box)
+    # Optional long-range dipole-dipole interactions
     ewald                  :: Union{Ewald, Nothing}
 
     # Dynamical variables and buffers