CPS Lunch Forum: Jørn Kløvfjell Mjelva

Abstract

In textbook treatments of quantum mechanics, the physical state of a quantum system is assumed to be represented by the state vector |Ψ⟩. Furthermore, properties are attributet to the system through the eigenstate-eigenvalue link: a system has the property “A=a” of some observable A if the state vector |Ψ⟩ is an eigenstate of A with the eigenvalue a. However, it can easily be demonstrated that the standard account encounters  difficulties when combined with relativistic considerations.

In this talk, I will discuss the issues that arise from applying the standard account to entangled quantum systems in a relativistic context. In particular, I will consider the case of spacelike entanglement swapping, which I take to pose the most serious problem for the standard account. I will then discuss some proposals as to how these issues might be resolved. I suggest that relativistic considerations might require us to adopt an altogether different account of quantum states and properties than the standard account.