Variational consistent histories as a hybrid algorithm for quantum foundations

Although quantum computers are predicted to have many commercial applications, less attention has been given to their potential for resolving foundational issues in quantum mechanics. Here we focus on quantum computers' utility for the Consistent Histories formalism, which has previously been e...

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Bibliographic Details
Published in:Nature communications, Vol. 10, No. 1 (2019), p. 3438
Main Author: Arrasmith, Andrew
Other Involved Persons: Cincio, Lukasz ; Sornborger, Andrew T ; Zurek, Wojciech H ; Coles, Patrick J
Format: electronic Article
Language:English
ISSN:2041-1723
Item Description:Date Revised 23.09.2019
published: Electronic
Citation Status PubMed-not-MEDLINE
Copyright: From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Physical Description:Online-Ressource
DOI:10.1038/s41467-019-11417-0
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  • Although quantum computers are predicted to have many commercial applications, less attention has been given to their potential for resolving foundational issues in quantum mechanics. Here we focus on quantum computers' utility for the Consistent Histories formalism, which has previously been employed to study quantum cosmology, quantum paradoxes, and the quantum-to-classical transition. We present a variational hybrid quantum-classical algorithm for finding consistent histories, which should revitalize interest in this formalism by allowing classically impossible calculations to be performed. In our algorithm, the quantum computer evaluates the decoherence functional (with exponential speedup in both the number of qubits and the number of times in the history) and a classical optimizer adjusts the history parameters to improve consistency. We implement our algorithm on a cloud quantum computer to find consistent histories for a spin in a magnetic field and on a simulator to observe the emergence of classicality for a chiral molecule