On the reality of the quantum state

By Matthew F Pusey, Jonathan Barrett, Terry Rudolph. Nature Physics, 2011

917 citations recorded by the source corpus.

Quantum states are the key mathematical objects in quantum theory. It is therefore surprising that physicists have been unable to agree on what a quantum state truly represents. One possibility is that a pure quantum state corresponds directly to reality. However, there is a long history of suggestions that a quantum state (even a pure state) represents only knowledge or information about some aspect of reality. Here we show that any model in which a quantum state represents mere information about an underlying physical state of the system, and in which systems that are prepared independently have independent physical states, must make predictions that contradict those of quantum theory. A no-go theorem on the reality of the quantum state is demonstrated. If the quantum state merely represents information about the physical state of a system, then predictions that contradict those of quantum theory are obtained.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/cc6c8142b65f607af69367f45bc24e0bcc54bdcb

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Citations in the corpus

Measurements on the reality of the wavefunction (2014, background): “els framework—such as preparation independence[11, 22], symmetry[15] or continuity[13, 14, 24]—allowing us in particular to rule out a strictly larger class of ψepistemic models than the experiment of Ref.”
An introduction to QBism with an application to the locality of quantum mechanics (2013, background): “— Erwin Schrödinger, 1931 letter to Arnold Sommerfeld31 [Some] factors crucial to the perception of scientific work [are] . . . that the task of science is described in full if we limit it to showing how, because of our unique organization, the world must inevitably appear to us; that the eventual ”
Rethinking Superdeterminism (2019, background): “What, then, does it take to describe quantum physics with a deterministic, local theory that is reductionist in the sense that the theory allows us to derive the behavior of detectors from the behavior of the theory’s primitive elements? The PuseyBarrett-Rudolph (PBR) theorem [3, 4] tells us that su”
Higher-order interference and single-system postulates characterizing quantum theory (2014, background): “These range from studies of the information processing capabilities of theories similar to quantum theory [10, 15, 35–37], to reconstructions of the formalism from information-theoretic principles [42, 43, 48, 50, 51, 71], to no-go theorems regarding interpretations and generalizations of the formal”
Do We Really Understand Quantum Mechanics? (2012, background): “This is done in Reference [308] by introducing more than two systems.”
Is the Quantum State Real? An Extended Review of -ontology Theorems (2014, methodology): “Apart from criticism of the PIP, several other criticisms of the Pusey–Barrett–Rudolph Theorem have been raised.”
Algorithmic Pseudorandomness in Quantum Setups. (2014, background): “Its foundations, intensely debated in the early days of the theory [1, 2], remain an active area of research with many recent insightful results, such as the possibility to derive quantum theory from physical axioms [3], proving the completeness of quantum theory [4], or establishing that quantum st”