Hi,all we all know, for the angular momentum, the operator matrix element of Jplus is sqrt(J*(J+1)-Jz(Jz+1)) and for Jminus, it is sqrt(J*(J+1)-Jz(Jz-1)). Just as ALPS defines in SITEBASIS "spin". So, it is straightforward that the spin-1/2 fermion with S=1/2, the matrix elements of Splus and Sminus shall be sqrt((1/2)*(1/2+1)-(-1/2)(-1/2+1))=1 and sqrt((1/2)*(1/2+1)-1/2(1/2-1))=1 respectively. If I am right, then why you guys define the matrix element of Splus and Sminus in SITEBASIS "fermion" and "alternative fermion" all equal to 1/2?
Bo-Nan