Measurement disturbance and conservation laws in quantum mechanics



Université Libre de Bruxelles

November 3, 2021 3:15 PM

The disturbance caused by measurements in quantum mechanics depends on the interaction between system and apparatus. If this interaction obeys a conservation law, the observables that may be non-disturbed will be restricted. We obtain general bounds that indicate the necessary conditions for non-disturbance in the presence of a conservation law and show that an observable not commuting with the conserved quantity admits a repeatable measurement – a special instance of a non-disturbing measurement – only if it is unsharp, and the apparatus is prepared in a state with a large uncertainty in the conserved quantity. This generalises the well-known Wigner-Araki-Yanase theorem.

Zoom meeting details

Topic: Quantum Information and Quantum Computing Working Group
Time: Wednesday, 03.11.2021, 15:15 Warsaw (CET)

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