Abstract
The limitation on the measurement of an operator imposed by the presence of a conservation law is studied. It is shown that an operator which does not commute with a conserved (additive) quantity cannot be measured exactly (in the sense of von Neumann). It is also shown for a simple case that an approximate measurement of such an operator is possible to any desired accuracy.
- Received 17 May 1960
DOI:https://doi.org/10.1103/PhysRev.120.622
©1960 American Physical Society