BergEC-jl/ho_basis.jl

99 lines
2.9 KiB
Julia

using NuclearToolkit
using SpecialFunctions
# Gaussian potentials in HO space
N_nl(n, l) = (-1)^n * sqrt(1/sqrt(pi) * (1/2)^(l+1) * 2^(n+2*l+3) * factorial(n) / Iterators.prod((2*n+2*l+1):-2:1))
prefactor(n, l, k) = (-1)^k * binomial(n + l + 1/2, n - k) / factorial(k)
Talmi(l, R, k1, k2) = (1/2) / (1 + 1/R^2)^(3/2 + l + k1 + k2) * gamma(3/2 + l + k1 + k2)
V_Gaussian(R, l, n1, n2) = N_nl(n1, l) * N_nl(n2, l) * sum([prefactor(n1, l, k1) * prefactor(n2, l, k2) * Talmi(l, R, k1, k2) for (k1, k2) in Iterators.product(0:n1, 0:n2)])
function get_sp_basis(E_max)
Es = Int[]
ns = Int[]
ls = Int[]
# E = 2*n + l
for E in 0 : E_max
for n in 0 : E ÷ 2
l = E - 2*n
push!(Es, E)
push!(ns, n)
push!(ls, l)
end
end
return (Es, ns, ls)
end
function get_2p_basis(E_max)
Es = Int[]
n1s = Int[]
l1s = Int[]
n2s = Int[]
l2s = Int[]
# E = 2*n1 + l1 + 2*n2 + l2
for E in 0 : 2*E_max
for n1 in 0 : E ÷ 2
for n2 in 0 : (E - 2*n1) ÷ 2
for l1 in 0 : (E - 2*n1 - 2*n2)
l2 = E - 2*n1 - 2*n2 - l1
push!(Es, E)
push!(n1s, n1)
push!(l1s, l1)
push!(n2s, n2)
push!(l2s, l2)
end
end
end
end
return (Es, n1s, l1s, n2s, l2s)
end
get_V_matrix(V_l, ls, ns) = throw("unimplemented")
function sp_T_matrix(ns, ls)
mat = zeros(length(ns), length(ns))
for idx in CartesianIndices(mat)
(i, j) = Tuple(idx)
if ls[i] == ls[j]
mat[idx] = ls[i]
if ns[i] == ns[j]
mat[idx] += 1/4 * (4*ns[j] + 3)
elseif ns[i] == ns[j] + 1
mat[idx] += -1/4 * sqrt((2*ns[j] + 2) * (2*ns[j] + 3))
elseif ns[i] == ns[j] - 1
mat[idx] += -1/4 * sqrt((2*ns[j] + 1) * 2*ns[j])
end
end
end
return mat
end
get_H_matrix(V_l, ns, ls) = get_T_matrix(ns, ls) + get_V_matrix(V_l, ns, ls)
function Moshinsky_transform(Es, n1s, l1s, n2s, l2s, Λ)
l_max = 2*max(maximum(l1s), maximum(l2s)) # OPTIMIZE
E_max = maximum(Es) # OPTIMIZE
j_max = l_max # OPTIMIZE
to = 0 # unused
dtri = NuclearToolkit.prep_dtri(l_max) ; println("dtri prepared")
dcgm0 = NuclearToolkit.prep_dcgm0(l_max) ; println("dcgm0 prepared")
d6j = NuclearToolkit.prep_d6j_int(E_max, j_max, to) ; println("d6j prepared")
mat = zeros(length(Es), length(Es))
s = hcat(Es, n1s, l1s, n2s, l2s)
for idx in CartesianIndices(mat)
(i, j) = Tuple(idx)
(Elhs, N, L, n, l) = s[i, :]
(Erhs, n1, l1, n2, l2) = s[j, :]
if Elhs == Erhs
mat[i, j] = NuclearToolkit.HObracket_d6j(N, L, n, l, n1, l1, n2, l2, Λ, 1.0, dtri, dcgm0, d6j, to)
end
end
return mat
end