Kastner, Ruth (2017) Demystifying weak measurements. [Preprint]

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Abstract

A large literature has grown up around the proposed use of 'weak measurements' to allegedly provide information about hidden ontological features of quantum systems. This paper attempts to clarify the fact that 'weak measurements' are simply strong (projective) measurements on one member of an entangled pair, and that all such measurements thus effect complete disentanglement of the pair. The only thing 'weak' about them is that the correlation established via the entanglement does not correspond to eigenstates of the 'weakly measured observable' for the component system that is subject to the weak measurement. It is observed that complete disentanglement always occurs, whether post-­‐selection is performed before or after the pointer detection. Assertions in the literature that weak measurements leave a system negligibly disturbed are therefore inaccurate, and claims based on those assertions need to be critically reassessed.

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Item Type:	Preprint
Creators:	Creators Email ORCID Kastner, Ruth rkastner@umd.edu
Additional Information:	Accepted version, to be published in Foundations of Physics
Keywords:	Weak measurements, Two-state vector, entanglement, unsharp measurements
Subjects:	Specific Sciences > Physics > Quantum Mechanics
Depositing User:	Ruth E. Kastner
Date Deposited:	14 Feb 2017 15:40
Last Modified:	14 Feb 2017 15:40
Item ID:	12821
Subjects:	Specific Sciences > Physics > Quantum Mechanics
Date:	13 February 2017
URI:	https://philsci-archive.pitt.edu/id/eprint/12821

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