Physical Review · 1960 · 363 citations · 0 references
Natural SciencesPhysicsMathematical PhysicsQuantum MechanicsTheoretical PhysicsHilbert Space FormalismMeasurement In ScienceMeasurement TheoryOperator TheoryQuantum MeasurementQuantum OperatorsCommuting ObservablesQuantum Measurement OperatorsQuantum Measurement Theory
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.