Einstein meets Schrodinger: The sequel - David Hobill

The Lorentz covariance of special relativity places restrictions and relationships (that do not exist in non-relativistic theories) on the dynamical variables describing the state of a physical system. This is true for both classical and quantum mechanics. In relativistic quantum theory a quantum observable must be coupled to the four-momentum of the particle carrying the quantum information. The Lorentz transformations act directly on the momentum of the particle and as a result induce unitary transformations on the other (secondary) quantum variables. In the case of the particle spin this transformation is known as a Wigner rotation. A simple example will be analyzed for a system consisting of two 1/2 spin particles entangled into an EPR pair. It will be shown that spin measurements made by two moving observers will find a new form of ``entanglement\'\' arising between the spin and momentum degrees of freedom and that the anti-correlation that exists in the non-relativistic case is modified so that it depends on the motion of both the particles and the observers. This will have implications in any form of quantum communication involving the motion of particles and observers.