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Added all potentials and support for protons

This commit is contained in:
Nuwan Yapa 2024-06-18 19:26:34 -04:00
parent ea69624e31
commit d23792b977
2 changed files with 20 additions and 16 deletions
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26
dirac.jl
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@ -5,31 +5,35 @@ M_n = 939.5654133 # Neutron mass in MeV/c2
M_p = 938.2720813 # Proton mass in MeV/c2
"The spherical Dirac equation that returns du=[dg, df] in-place where
(g, f) are the reduced radial components evaluated at r,
u=[g, f] are the reduced radial components evaluated at r,
κ is the generalized angular momentum,
M is the mass in MeV/c2,
p is true for proton and false for neutron,
E in the energy in MeV,
Φ0, W0 are the mean-field potentials (couplings included) in MeV as functions of r in fm,
Φ0, W0, B0, A0 are the mean-field potentials (couplings included) in MeV as functions of r in fm,
r is the radius in fm.
Reference: P. Giuliani, K. Godbey, E. Bonilla, F. Viens, and J. Piekarewicz, Frontiers in Physics 10, (2023)"
function dirac!(du, (g, f), (κ, M, E, Φ0, W0), r)
du[1] = -(κ/r) * g + (E + M - Φ0(r) - W0(r)) * f / ħc
du[2] = (κ/r) * f - (E - M + Φ0(r) - W0(r)) * g / ħc
function dirac!(du, u, (κ, p, E, Φ0, W0, B0, A0), r)
M = p ? M_p : M_n
common1 = E - W0(r) - (p - 0.5) * B0(r) - p * A0(r)
common2 = M - Φ0(r)
(g, f) = u
du[1] = -(κ/r) * g + (common1 + common2) * f / ħc
du[2] = (κ/r) * f - (common1 - common2) * g / ħc
end
"Solve the Dirac equation and return g(r=r_max) for given scalar and vector potentials where
r_max is the outer boundary in fm,
r_min (=r_max/1000) is inside boundary in fm which cannot be 0 due to the centrifugal term,
the other parameters are the same from dirac!(...)."
function boundaryValue(κ, M, E, Φ0, W0, r_max, r_min=r_max/1000)
function boundaryValue(κ, p, E, Φ0, W0, B0, A0, r_max, r_min=r_max/1000)
prob = ODEProblem(dirac!, [0, 1], (r_min, r_max))
sol = solve(prob, RK4(), p=(κ, M, E, Φ0, W0))
sol = solve(prob, RK4(), p=(κ, p, E, Φ0, W0, B0, A0))
return sol(r_max)[1]
end
"Find all bound energies between E_min (=0) and E_max (=M) where
"Find all bound energies between E_min (=0) and E_max (=mass) where
the other parameters are the same from dirac!(...)."
function findEs(κ, M, Φ0, W0, r_max, r_min=r_max/1000, E_min=0, E_max=M)
f(E) = boundaryValue(κ, M, E, Φ0, W0, r_max, r_min)
function findEs(κ, p, Φ0, W0, B0, A0, r_max, r_min=r_max/1000, E_min=0, E_max=(p ? M_p : M_n))
f(E) = boundaryValue(κ, p, E, Φ0, W0, B0, A0, r_max, r_min)
return find_zeros(f, (E_min, E_max))
end

10
test/Pb208.jl
View File

@ -16,16 +16,16 @@ R_interp = linear_interpolation(xs, Rs)
A_interp = linear_interpolation(xs, As)
κ = -1
M = M_n
p = true
r_max = maximum(xs)
E_min = M - 100
E_max = M
E_min = 850
E_max = 939
boundEs = findEs(κ, M_n, S_interp, V_interp, r_max, r_max/1000, E_min, E_max)
boundEs = findEs(κ, p, S_interp, V_interp, R_interp, A_interp, r_max, r_max/1000, E_min, E_max)
println("bound E = $boundEs")
Es = collect(E_min:0.5:E_max)
boundaryVals = [boundaryValue(κ, M_n, E, S_interp, V_interp, r_max)^2 for E in Es]
boundaryVals = [boundaryValue(κ, p, E, S_interp, V_interp, R_interp, A_interp, r_max)^2 for E in Es]
plot(Es, boundaryVals, yscale=:log10, label="g(r_max)^2")
vline!(boundEs, label="bound E")