The Pauli-Lubanski operator is defined as Wα=12εαβμνPβMμν,(ε0123=+1,ε0123=−1) where Mμν is the generators of Lorentz group.
The commutation relation between generators of Poincare group is know as i[Mμν,Mρσ]=ηνρMμσ−ημρMνσ−ημσMρν+ηνσMρμ, i[Pμ,Mρσ]=ημρPσ−ημσPρ.
I try to derive the commutator between Pauli-Lubanski operator and a generator of Lorentz group, which is also given in our lecture i[Wα,Mρσ]=ηαρWσ−ηασWρ.
But I only get i[Wα,Mρσ]=i[12εαβμνPβMμν,Mρσ]=12εαβμνPβ(δρνMμσ−δρμMνσ−δσμMρν+δσνMρμ)+12εαβμν(δρβPσ−δσβPρ)Mμν.
Obviously I can contract out the delta's, but that does not get me any closer to the simpler result of (*). Can anyone point out what to do next?
No comments:
Post a Comment