Physics and Metaphysics of Wigner’s Friends: Even Performed Premeasurements Have No Results
Marek Żukowski, Marcin Markiewicz
Abstract
"The unambiguous account of proper quantum phenomena must, in principle, include a description of all relevant features of experimental arrangement" (Bohr). The measurement process is composed of premeasurement (quantum correlation of the system with the pointer variable) and an irreversible decoherence via interaction with an environment. The system ends up in a probabilistic mixture of the eigenstates of the measured observable. For the premeasurement stage, any attempt to introduce an "outcome" leads, as we show, to a logical contradiction, 1=i. This nullifies claims that a modified concept of Wigner's friend, who just premeasures, can lead to valid results concerning quantum theory.
Topics & Concepts
PhysicsObservableBohr modelQuantum decoherenceQuantumQuantum mechanicsContradictionTheoretical physicsStatistical physicsQuantum systemMesoscopic physicsEigenvalues and eigenvectorsOnticEpistemologyPhilosophyQuantum Mechanics and ApplicationsPhilosophy and History of ScienceQuantum Information and Cryptography