, 9 (1), 3711

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# Quantum Theory Cannot Consistently Describe the Use of Itself

Daniela Frauchiger et al. Nat Commun.

## Abstract

Quantum theory provides an extremely accurate description of fundamental processes in physics. It thus seems likely that the theory is applicable beyond the, mostly microscopic, domain in which it has been tested experimentally. Here, we propose a Gedankenexperiment to investigate the question whether quantum theory can, in principle, have universal validity. The idea is that, if the answer was yes, it must be possible to employ quantum theory to model complex systems that include agents who are themselves using quantum theory. Analysing the experiment under this presumption, we find that one agent, upon observing a particular measurement outcome, must conclude that another agent has predicted the opposite outcome with certainty. The agents' conclusions, although all derived within quantum theory, are thus inconsistent. This indicates that quantum theory cannot be extrapolated to complex systems, at least not in a straightforward manner.

### Conflict of interest statement

The authors declare no competing interests.

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### References

1. Schrödinger E. Die gegenwärtige situation in der Quantenmechanik. Naturwissenschaften. 1935;23:823–828. doi: 10.1007/BF01491914. - DOI
1. Wigner, E. P. Remarks on the mind–body question. in Symmetries and Reflections, pp. 171–184. (Indiana University Press, 1967).
1. Hepp K. Quantum theory of measurement and macroscopic observables. Helv. Phys. Acta. 1972;45:237–248.
1. Bell JS. On wave packet reduction in the Coleman–Hepp model. Helv. Phys. Acta. 1975;48:93–98.
1. Fuchs, C. A. QBism, the perimeter of quantum Bayesianism. Preprint at http://arxiv.org/abs/1003.5209, (2010).
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