rubydragon/FeynmanDiagrams.jl
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Anton Reinhard 2024-06-19 22:30:34 +02:00
parent 29071a9cb2
commit 2dd7627bcf
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src/diagrams/interface.jl
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@ -25,14 +25,15 @@ Return the specific `QEDprocesses.AbstractProcessDefinition` which the given dia
function process end function process end
""" """
virtual_particles(::AbstractTreeLevelFeynmanDiagram)::NTuple{N, Tuple{QEDbase.AbstractParticleType, BitArray}} virtual_particles(::AbstractTreeLevelFeynmanDiagram)::NTuple{N, Tuple{QEDbase.AbstractParticleType, BitArray, BitArray}}
Interface function that must be implemented for an instance of [`AbstractTreeLevelFeynmanDiagram`](@ref). Interface function that must be implemented for an instance of [`AbstractTreeLevelFeynmanDiagram`](@ref).
Return an `NTuple` with N elements, where N is the number of virtual particles in this diagram. For tree-level Feynman diagrams, \$N = k - 3\$, where \$k\$ is the number of external particles. Return an `NTuple` with N elements, where N is the number of virtual particles in this diagram. For tree-level Feynman diagrams, \$N = k - 3\$, where \$k\$ is the number of external particles.
The elements of the `NTuple` are themselves `Tuple`s, containing for each virtual particle its `QEDbase.AbstractParticleType` and a `BitArray` (`Vector{Boolean}`) of length \$k\$, indicating The elements of the `NTuple` are themselves `Tuple`s, containing for each virtual particle its `QEDbase.AbstractParticleType` and a `BitArray` (`Vector{Boolean}`), indicating
with a `1` that an external particle's momentum contributes to the virtual particle's momentum, and a `0` otherwise. Outgoing particles will contribute their momentum negatively. with a `1` that an incoming external particle's momentum contributes to the virtual particle's momentum, and a `0` otherwise. The second BitArray does the same for the outgoing external
From this definition follows that a particles' `BitArray` is equivalent to the inverse `BitArray`, i.e., a `BitArray` where every bit is negated. particles, which contribute their momentum negatively.
From this definition follows that a particles' `BitArray`s are equivalent to the inverse `BitArray`s, i.e., `BitArray`s where every bit is negated.
Example: Consider the Compton scattering process \$e^- + \\gamma \\to e^- + \\gamma\$ with the diagram where the incoming electron interacts with the incoming photon first. Example: Consider the Compton scattering process \$e^- + \\gamma \\to e^- + \\gamma\$ with the diagram where the incoming electron interacts with the incoming photon first.
For this diagram there is exactly one virtual particle, which is an electron. This electron's momentum can be represented as the sum of the two incoming particles' momenta, or For this diagram there is exactly one virtual particle, which is an electron. This electron's momentum can be represented as the sum of the two incoming particles' momenta, or