WIP : Spin operators.

Author: amitjamadagni

src/arrays/ladderops.jl

@@ -37,7 +37,46 @@ function momentumop(n::Int)
     return scale(im/sqrt(2.), cop-cop')
 end
 
+function spin_h1(j)
+    m = reverse([-j:j-1])
+    N = length(m)+1
+    m_coeffs = [sqrt(j*(j+1.0) - (x+1.0)*x) for x in m]
+    return spdiagm(m_coeffs,1,N,N)
+end
+
+function spin_h2(j)
+    m = reverse([-j:j])
+    N = length(m)
+    return spdiagm(m,0,N,N)
+end
+
+function spin_jx(j)
+    return QuArray(0.5*(spin_h1(j)+spin_h1(j)'))
+end
+
+function spin_jy(j)
+    return QuArray(-0.5*im*(spin_h1(j)-spin_h1(j)'))
+end
+
+function spin_jz(j)
+    return QuArray(spin_h2(j))
+end
+
+function spin_jp(j)
+    return QuArray(spin_h1(j))
+end
+
+function spin_jm(j)
+    return QuArray(spin_h1(j)')
+end
+
 export raiseop,
     lowerop,
     positionop,
-    momentumop
+    momentumop,
+    spin_jx,
+    spin_jy,
+    spin_jz,
+    spin_jplus,
+    spin_jminus
+

src/arrays/quarray.jl

@@ -35,7 +35,7 @@
 
     rawbases(qarr::QuArray, i) = qarr.bases[i]
     bases(qarr::QuArray, i) = rawbases(qarr, i)
-    
+
     # works generally as long as the single index form is defined
     rawbases(qarr::AbstractQuArray) =  ntuple(ndims(qarr), i->rawbases(qarr, i))
     bases(qarr::AbstractQuArray) = ntuple(ndims(qarr), i->bases(qarr, i))
@@ -105,11 +105,11 @@
 # LabelQuArray #
 ################
     typealias LabelQuArray{B<:LabelBasis,T,N,A} QuArray{B,T,N,A}
-    typealias TupleArray{T<:Tuple,N} Array{T,N} 
+    typealias TupleArray{T<:Tuple,N} Array{T,N}
 
     Base.getindex(larr::LabelQuArray, tups::Union(Tuple,TupleArray)...) = getindex(larr, map(getindex, bases(larr), tups)...)
     Base.setindex!(larr::LabelQuArray, x, tups::Union(Tuple,TupleArray)...) = setindex!(larr, x, map(getindex, bases(larr), tups)...)
-    
+
 ######################
 # Printing Functions #
 ######################