Entanglement and disentanglement in relativistic quantum mechanics

• Relativistic quantum mechanics requires attention to the measurement problem.
• This paper presents two stories of spacelike entangled systems.
• Together, they are a litmus test for a satisfactory relativistic quantum mechanics.
• To tell them, one must opt for a clear resolution to the measurement problem.

A satisfactory formulation of relativistic quantum mechanics requires that one be able to represent the entangled states of spacelike separated systems and describe how such states evolve. This paper presents two stories that one must be able to tell coherently in order to understand relativistic entangled systems. These stories help to illustrate why one׳s understanding of entanglement in relativistic quantum mechanics must ultimately depend on the details of one׳s strategy for addressing the quantum measurement problem.