Maps generated by entangled momenta: exploring spin entanglement in relativity

We study relativistic entanglement of a bipartite system consisting of massive spin-1=2 particles with momenta. The spin state is described by the maximally entangled Bell state and momenta are given by entangled Gaussian distributions. We conceptualize the dependency between spin and momentum in relativity along the lines of controlled operations in quantum information theory. This leads to a systematic study of maps that Wigner rotations generate on the spin degree of freedom of the total system in different boost scenarios. We use a visualization tool from quantum information theory in order to get better insight into how and why the entanglement changes in different boost geometries.