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QUANTUM MECHANICS

An inconsistent friend

Nature Physics volume 14, pages 977–978 (2018)Cite this article

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A Publisher Correction to this article was published on 12 October 2018

This article has been updated

Are there limits to the applicability of textbook quantum theory? Experiments haven’t found any yet, but a new theoretical analysis shows that treating your colleagues as quantum systems might be a step too far.

When a quantum mechanics textbook introduces the Schrödinger equation, it doesn’t specify any limit on the size of the system or the length of time that it is valid for. The long-standing tangle of questions about whether and how the equation applies to an observation is known as the measurement problem. Some have proposed ‘collapse models’ where the Schrödinger equation is an approximation that fails in sufficiently macroscopic regimes1, but no experimental signature of this failure has been detected, even as experiments create quantum superpositions in larger and larger systems2.

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Fig. 1: A friend in superposition.

Change history

  • 12 October 2018

    In the version of this News & Views originally published, the link for ref. 7 was incorrectly given as https://arxiv.org/abs/1604.07422; it should have been https://scirate.com/arxiv/1604.07422. This has now been corrected.

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  1. Department of Computer Science at the University of Oxford, Oxford, UK

    Matthew F. Pusey

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  1. Matthew F. Pusey
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Correspondence to Matthew F. Pusey.

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Pusey, M.F. An inconsistent friend. Nature Phys 14, 977–978 (2018). https://doi.org/10.1038/s41567-018-0293-7

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