PauliSigma
PauliSigma[x, dim]
is the internal representation of a Pauli matrix with a Lorentz or Cartesian index or a contraction of a Pauli matrix and a Lorentz or Cartesian vector.
PauliSigma[x,3]
simplifies to PauliSigma[x]
.
See also
Overview, SI, CSI.
Examples
PauliSigma[LorentzIndex[\[Alpha]]]
σˉα
PauliSigma[CartesianIndex[i]]
σi
A Pauli matrix contracted with a Lorentz or Cartesian vector is displayed as σ⋅p
σˉ⋅p
PauliSigma[CartesianMomentum[p]]
σ⋅p
PauliSigma[Momentum[q]] . PauliSigma[Momentum[p - q]]
% // PauliSigmaExpand
(σˉ⋅q).(σˉ⋅(p−q))
(σˉ⋅q).(σˉ⋅p−σˉ⋅q)
PauliSigma[CartesianMomentum[q]] . PauliSigma[CartesianMomentum[p - q]]
% // PauliSigmaExpand
(σ⋅q).(σ⋅(p−q))
(σ⋅q).(σ⋅p−σ⋅q)