Skip to content

Commit

Permalink
added tests for perturbative compton
Browse files Browse the repository at this point in the history
  • Loading branch information
Uwe Hernandez Acosta committed Feb 22, 2024
1 parent 5054b76 commit 341bc8e
Show file tree
Hide file tree
Showing 5 changed files with 210 additions and 0 deletions.
26 changes: 26 additions & 0 deletions test/processes/one_photon_compton/groundtruths.jl
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@

"""
Klein-Nishina: differential cross section
source: Peskin, Schroeder. "Quantum field theory." (1995). eq: 5.91
note: we compute d sigma/ d Omega, and *not* d sigma/ d cos theta (the difference is a factor 2 pi)
"""
function _groundtruth_pert_compton_diffCS_spinsum_polsum(om, cth, mass)
prefac = ALPHA_SQUARE / 2
omp = QEDprocesses._pert_omega_prime(om, cth)
sth_sq = 1 - cth^2
return prefac * (omp / om)^2 * (omp / om + om / omp - sth_sq)
end

function _groundtruth_pert_compton_diffCS_spinsum_xpol(omega, ctheta, phi, mass)
om_prime = omega_prime(PerturbativeQED(), omega, ctheta; mass=mass)
om_prime_over_om = om_prime / omega
return 0.5 * ALPHA_SQUARE / mass^2 *
om_prime_over_om^2 *
(om_prime_over_om + 1.0 / om_prime_over_om - 2 * (1 - ctheta^2) * cos(phi)^2)
end

function _groundtruth_pert_compton_diffCS_spinsum_ypol(omega, ctheta, phi, mass)
return _groundtruth_pert_compton_diffCS_spinsum_xpol(omega, ctheta, phi + pi / 2, mass)
end
118 changes: 118 additions & 0 deletions test/processes/one_photon_compton/perturbative.jl
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,118 @@

using QEDbase
using QEDprocesses
using Random
using StaticArrays
using QuadGK

RNG = MersenneTwister(77697185)
ATOL = eps()
RTOL = sqrt(eps())

include("groundtruths.jl")

MODEL = PerturbativeQED()
PS_DEF = PhasespaceDefinition(SphericalCoordinateSystem(), ElectronRestFrame())
OMEGAS = (1e-6 * rand(RNG), 1e-3 * rand(RNG), rand(RNG), 1e3 * rand(RNG))
#OMEGAS = (rand(RNG),)

COS_THETAS = [-1.0, 2 * rand(RNG) - 1, 0.0, 1.0]
PHIS = [0, 2 * pi, rand(RNG) * 2 * pi]

@testset "perturbative kinematics" begin
PROC = Compton()
@testset "momentum generation" begin
@testset "$om, $cth, $phi" for (om, cth, phi) in
Iterators.product(OMEGAS, COS_THETAS, PHIS)
IN_COORDS = [om]
OUT_COORDS = [cth, phi]
IN_PS, OUT_PS = QEDprocesses._generate_momenta(
PROC, MODEL, PS_DEF, IN_COORDS, PS_DEF, OUT_COORDS
)
in_mom_square = getMass2.(IN_PS)
out_mom_square = getMass2.(OUT_PS)
in_masses = mass.(incoming_particles(PROC)) .^ 2
out_masses = mass.(outgoing_particles(PROC))
@test isapprox(in_mom_square, SVector(in_masses))
@test isapprox(out_mom_square, SVector(out_masses))
end
end
end

@testset "perturbative cross section" begin
@testset "$omega" for omega in OMEGAS
@testset "differential cross section" begin
@testset "spin and pol summed" begin
PROC = Compton()

@testset "$cos_theta $phi" for (cos_theta, phi) in
Iterators.product(COS_THETAS, PHIS)
IN_COORDS = [omega]
OUT_COORDS = [cos_theta, phi]
groundtruth = _groundtruth_pert_compton_diffCS_spinsum_polsum(
omega, cos_theta, 1.0
)
test_val = unsafe_differential_cross_section(
PROC, MODEL, PS_DEF, IN_COORDS, PS_DEF, OUT_COORDS
)
@test isapprox(test_val, groundtruth, atol=ATOL, rtol=RTOL)
end
end

@testset "x-pol and spin summed" begin
PROC = Compton(PolX())

@testset "$cos_theta $phi" for (cos_theta, phi) in
Iterators.product(COS_THETAS, PHIS)
IN_COORDS = [omega]
OUT_COORDS = [cos_theta, phi]
groundtruth = _groundtruth_pert_compton_diffCS_spinsum_xpol(
omega, cos_theta, phi, 1.0
)
test_val = unsafe_differential_cross_section(
PROC, MODEL, PS_DEF, IN_COORDS, PS_DEF, OUT_COORDS
)
@test isapprox(test_val, groundtruth, atol=ATOL, rtol=RTOL)
end
end

@testset "y-pol and spin summed" begin
PROC = Compton(PolY())

@testset "$cos_theta $phi" for (cos_theta, phi) in
Iterators.product(COS_THETAS, PHIS)
IN_COORDS = [omega]
OUT_COORDS = [cos_theta, phi]
groundtruth = _groundtruth_pert_compton_diffCS_spinsum_ypol(
omega, cos_theta, phi, 1.0
)
test_val = unsafe_differential_cross_section(
PROC, MODEL, PS_DEF, IN_COORDS, PS_DEF, OUT_COORDS
)
@test isapprox(test_val, groundtruth, atol=ATOL, rtol=RTOL)
end
end
end
end
# @testset "total cross section" begin
# @testset "spin and pol summed" begin
# PROC = Compton()
# # Klein-Nishina: total cross section
# function klein_nishina_total_cross_section(om, mass)
# function func(x)
# return differential_cross_section_on_coord(
# Compton(), PerturbativeQED(), om, [x, 0.0]
# )
# end
# res, err = quadgk(func, -1, 1)
#
# # note: mul by 2pi instead of the phi-integration
# return 2 * pi * res
# end
#
# groundtruth = klein_nishina_total_cross_section(OMEGA, MASS)
# test_val = @inferred total_cross_section_on_coord(PROC, MODEL, OMEGA)
# @test isapprox(test_val, groundtruth, atol=ATOL, rtol=RTOL)
# end
# end
end
57 changes: 57 additions & 0 deletions test/processes/one_photon_compton/process.jl
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,57 @@
using QEDprocesses
using Random
using QEDbase
using QEDprocesses

POLS = [PolX(), PolY(), AllPol()]
SPINS = [SpinUp(), SpinDown(), AllSpin()]
POL_AND_SPIN_COMBINATIONS = Iterators.product(SPINS, POLS, SPINS, POLS)
POL_COMBINATIONS = Iterators.product(POLS, POLS)

@testset "constructor" begin
@testset "default" begin
proc = Compton()
@test QEDprocesses._spin_or_pol(proc, Photon(), Incoming()) == AllPol()
@test QEDprocesses._spin_or_pol(proc, Electron(), Incoming()) == AllSpin()
@test QEDprocesses._spin_or_pol(proc, Photon(), Outgoing()) == AllPol()
@test QEDprocesses._spin_or_pol(proc, Electron(), Outgoing()) == AllSpin()
end

@testset "in_pol" begin
@testset "$pol" for pol in POLS
proc = Compton(pol)
@test QEDprocesses._spin_or_pol(proc, Electron(), Incoming()) == AllSpin()
@test QEDprocesses._spin_or_pol(proc, Photon(), Incoming()) == pol
@test QEDprocesses._spin_or_pol(proc, Electron(), Outgoing()) == AllSpin()
@test QEDprocesses._spin_or_pol(proc, Photon(), Outgoing()) == AllPol()
end
end

@testset "in_pol+out_pol" begin
@testset "$in_pol, $out_pol" for (in_pol, out_pol) in POL_COMBINATIONS
proc = Compton(in_pol, out_pol)
@test QEDprocesses._spin_or_pol(proc, Electron(), Incoming()) == AllSpin()
@test QEDprocesses._spin_or_pol(proc, Photon(), Incoming()) == in_pol
@test QEDprocesses._spin_or_pol(proc, Electron(), Outgoing()) == AllSpin()
@test QEDprocesses._spin_or_pol(proc, Photon(), Outgoing()) == out_pol
end
end
@testset "all spins+pols" begin
@testset "$in_spin, $in_pol, $out_spin, $out_pol" for (
in_spin, in_pol, out_spin, out_pol
) in POL_AND_SPIN_COMBINATIONS
proc = Compton(in_spin, in_pol, out_spin, out_pol)
@test QEDprocesses._spin_or_pol(proc, Electron(), Incoming()) == in_spin
@test QEDprocesses._spin_or_pol(proc, Photon(), Incoming()) == in_pol
@test QEDprocesses._spin_or_pol(proc, Electron(), Outgoing()) == out_spin
@test QEDprocesses._spin_or_pol(proc, Photon(), Outgoing()) == out_pol
end
end
end
@testset "particle content" begin
proc = Compton()
@test incoming_particles(proc) == (Electron(), Photon())
@test outgoing_particles(proc) == (Electron(), Photon())
@test number_incoming_particles(proc) == 2
@test number_outgoing_particles(proc) == 2
end
8 changes: 8 additions & 0 deletions test/processes/run_process_test.jl
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@

@time @safetestset "general one photon compton" begin
include("one_photon_compton/process.jl")
end

@time @safetestset "perturbative one photon compton" begin
include("one_photon_compton/perturbative.jl")
end
1 change: 1 addition & 0 deletions test/runtests.jl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,4 +21,5 @@ begin
@time @safetestset "cross section & probability" begin
include("cross_sections.jl")
end
include("processes/run_process_test.jl")
end

0 comments on commit 341bc8e

Please sign in to comment.