System

The basic building blocks used in CollectiveSpins.jl are, not surprisingly, spins. They are defined by their position and a frequency $\Delta$ describing a shift relative to the frequency of the rotating frame in use:

struct Spin{T1,T2} <: System
    position::T1
    delta::T2
end

Defining the frequency is optional and is set to zero by default:

Spin([0,0,0]; delta=1)
Spin([0,0,0])

Combining many spins into one big system can be done by using the SpinCollection type. All contained spins must have the same polarization axis and decay rate $\gamma$:

struct SpinCollection{S<:Spin,P<:Vector,G<:Real} <: System
    spins::Vector{S}
    polarizations::Vector{P}
    gammas::Vector{G}
end

For convenience one can create a SpinCollection without explicitly constructing the single spins first::

SpinCollection([[0,0,0], [1,0,0]], [0,0,1]; gammas=2, deltas=1)

SpinCollection{Spin{Vector{Int64}, Int64}, Vector{Int64}, Int64}(Spin{Vector{Int64}, Int64}[Spin{Vector{Int64}, Int64}([0, 0, 0], 1), Spin{Vector{Int64}, Int64}([1, 0, 0], 1)], [[0, 0, 1], [0, 0, 1]], [2, 2])

Adding a cavity can be done with the CavityMode type:

struct CavityMode{C<:Int,T1<:Number,T2<:Number,T3<:Number} <: System
    cutoff::C
    delta::T1
    eta::T2
    kappa::T3
end

which can be coupled to a spin collection with coupling strength g via the CavitySpinCollection type:

struct CavitySpinCollection{C<:CavityMode,S<:SpinCollection,G<:Number} <: System
    cavity::C
    spincollection::S
    g::Vector{G}
end