Raising and lowering operators for spin
I think that is a Math method.
Example:
angular momentum: After "operate" with Math signals, Lz will be raised or lowered. (with operation L+=Lx+iLy)

If define [tex]L \pm = L_x \pm iL_y [/tex]
When comute them:
[tex][L_z ,L \pm ] = ... = \pm \hbar (L_x \pm iL_y )[/tex]
(Griffiths D.J_Quantum Mechanics...)
If define "left hand" the signal will become to convert.
+ become +
That is not good!
