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Decoherence, Branching, and the Born Rule in a Mixed-State Everettian Multiverse: Conclusionby@multiversetheory
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Decoherence, Branching, and the Born Rule in a Mixed-State Everettian Multiverse: Conclusion

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In conclusion, Everettian quantum mechanics presents a choice between wave function and density matrix realism, with implications for understanding decoherence, branching, and the Born rule. Explore the theoretical crossroads and empirical underdetermination in quantum interpretation, leaving open avenues for future research. TLDR: Everettian quantum mechanics offers two versions - wave function and density matrix realism - with implications for key concepts like decoherence and the Born rule. The choice between these theories isn't based on empirical grounds but involves other theoretical considerations, highlighting the empirical underdetermination in quantum interpretation. Future research will delve deeper into these implications and potential resolutions.
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Authors:

(1) Eugene Y. S. Chua, Division of the Humanities and Social Sciences, California Institute of Technology;

(2) Eddy Keming Chen, ‡Department of Philosophy, University of California.

Abstract & Introduction

Decoherence and Branching

The Born Rule

Discussion

Conclusion and References

5 Conclusion

We suggest that the Evere‹ian understanding of decoherence and branching, as well as the justifications for the Born rule, apply to both WFRE and DMRE. Hence, the theoretical benefits of DMR are available on EQM. Another consequence is that Everettians face a choice between two types of theories, one allowing only pure states for the multiverse and the other allowing mixed states also. The choice will not be based on different understandings of the branching structure or the Born rule, as the Everettian justifications equally apply in both theories, but must involve some other theoretical considerations. In any case, the availability of different versions of EQM is an interesting example of empirical underdetermination. Its implications and possible resolutions are questions we leave for future work.

Acknowledgements

For helpful feedback, we thank Jefferey Barrett, Charles Sebens, Kelvin McQueen, Katie Robertson, Simon Saunders, Tony Short, Karim Thebault, David Wallace, and the ´ participants at the 2023 Workshop on Relational Clocks, Decoherence, and the Arrow of Time at the University of Bristol, and the 2022 California Quantum Interpretation Network Conference at Chapman University.

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This paper is available on arxiv under CC 4.0 license.