Measurement outcomes provide data for a physical theory. Unless they are objective they support no objective scientific knowledge. So the outcome of a quantum measurement must be an objective physical fact. But recent arguments purport to show that if quantum theory is universally applicable then there is no such fact. This calls for a reappraisal of the notions of fact and objectivity. If quantum theory is universally applicable the facts about the physical world include a fact about each quantum measurement outcome. These physical facts lack an ideal kind of objectivity but their more modest objectivity is all that science needs.Measurement outcomes provide data for a physical theory. Unless they are objective they support no objective scientific knowledge. So the outcome of a quantum measurement must be an objective physical fact. But recent arguments purport to show that if quantum theory is universally applicable then there is no such fact. This calls for a reappraisal of the notions of fact and objectivity. If quantum theory is universally applicable the facts about the physical world include a fact about each quantum measurement outcome. These physical facts lack an ideal kind of objectivity but their more modest objectivity is all that science needs.

arXiv:2010.01013The British Journal for the Philosophy of ScienceJul 6, 202125 citations

Objectivity in Quantum Mechanics

Henry Margenau, James L Park

Studies in the foundations methodology and philosophy of scienceJan 1, 196710 citations

“Interaction-free” measurements of quantum objects?

Andrew G. White, Paul G. Kwiat, Daniel F. V. James

It is now well established that the presence of an opaque classical object can be unambiguously determined by an "interaction-free" measurement (IFM), where the object and the probe never directly interact. For quantum objects, we examine "interaction-free" measurement (the object wavefunction is unchanged) and "interaction-free" preparation (the object wavefunction is changed without physical interaction) and find that in general, neither is possible. We propose using high efficiency IFM's as a quantum information bus to connect disjoint quantum systems.It is now well established that the presence of an opaque classical object can be unambiguously determined by an "interaction-free" measurement (IFM), where the object and the probe never directly interact. For quantum objects, we examine "interaction-free" measurement (the object wavefunction is unchanged) and "interaction-free" preparation (the object wavefunction is changed without physical interaction) and find that in general, neither is possible. We propose using high efficiency IFM's as a quantum information bus to connect disjoint quantum systems.

Mysteries, Puzzles, and Paradoxes in Quantum MechanicsJan 1, 19990 citations

Quantum Mechanics and Objectivity

Patrick A. Heelan

Springer eBooksJan 1, 196566 citations

Quantum Mechanics and Objectivity

J J MacMahon

Philosophical StudiesJan 1, 19671 citation

Objectivity of Quantum Measurement in Many-Observer World

Chang-Pu Sun

The objectivity of quantum measurement is treated as an emergent phenomenon with $N$ observers who can agree to the same result of measurement, and meanwhile, they can identify their records with each other. In this many-observer world (MOW), an objective quantum measurement is dealt with as a multipartite [ $(N+1)$ -body] quantum correlation among the measured system and $N$ observers when its bipartite reductions are the same classical correlations. With this conceptual clarification, we find that, an objective quantum measurement is implemented if and only if the MOW is initially factorized in a pure state and then the total system can evolve into a generalized GHZ state with respect to the orthogonal basis preferred by each observer. Especially, such objective quantum measurement is recast in ideal classical correlation when the observer world is macroscopic for $N\rightarrow\infty$ .The objectivity of quantum measurement is treated as an emergent phenomenon with $N$ observers who can agree to the same result of measurement, and meanwhile, they can identify their records with each other. In this many-observer world (MOW), an objective quantum measurement is dealt with as a multipartite [$(N+1)$-body] quantum correlation among the measured system and $N$ observers when its bipartite reductions are the same classical correlations. With this conceptual clarification, we find that, an objective quantum measurement is implemented if and only if the MOW is initially factorized in a pure state and then the total system can evolve into a generalized GHZ state with respect to the orthogonal basis preferred by each observer. Especially, such objective quantum measurement is recast in ideal classical correlation when the observer world is macroscopic for $N\rightarrow\infty$.

Aug 3, 20150 citations

The objectivity of quantum measurement is treated as an emergent phenomenon with

N

observers who can agree to the same result of measurement, and meanwhile, they can identify their records with each other. In this many-observer world (MOW), an objective quantum measurement is dealt with as a multipartite [

(N+1)

-body] quantum correlation among the measured system and

N

observers when its bipartite reductions are the same classical correlations. With this conceptual clarification, we find that, an objective quantum measurement is implemented if and only if the MOW is initially factorized in a pure state and then the total system can evolve into a generalized GHZ state with respect to the orthogonal basis preferred by each observer. Especially, such objective quantum measurement is recast in ideal classical correlation when the observer world is macroscopic for

N\rightarrow\infty