1209.4440 (Taeseung Choi)

Relativistic spin operator and Lorentz transformation of spin state of a
massive Dirac particle    [PDF]

Taeseung Choi

We have shown the covariant relativistic spin operator is equivalent to the spin operator commuting with the free Dirac Hamiltonian. Based on this equivalence we have obtained the transformation matrix of Dirac spinors under the Lorentz transformation. As a result we have shown the change in the entropy of a reduced spin density matrix sweeps through the whole range according to the relative motion of an observer.

View original: http://arxiv.org/abs/1209.4440