Conceptual Problems Related to Time and Mass in Quantum Theory

Understand

The concept of proper time cannot be just taken over from classical theory and applied to quantum theory.

• There are a number of serious ambiguities related to it.
• Similarly, the concept of mass has some inconsistencies attached to it.
• We argue that both of these concepts only make sense if they are included in the theory as dynamical variables, and subsequently as conjugate operators.