Decoherence Implies Information Gain

Brody, D C and Hughston, L P. 2025. Decoherence Implies Information Gain. Physical Review Research, 7, L012040. ISSN 2643-1564 [Article]

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Abstract or Description

It is shown that if the wave function of a quantum system undergoes an arbitrary random transformation such that the diagonal elements of the density matrix in the decoherence basis associated with a preferred observable remain constant, then (i) the off-diagonal elements of the density matrix become smaller in magnitude, and (ii) the state of the system gains information about the preferred observable from its environment in the sense that the uncertainty of the observable is reduced in the transformed state. These results do not depend on the details of how the system-environment interaction generates the random state transformation, and together imply that decoherence leads in general to information gain, not information loss.

Item Type:

Article

Identification Number (DOI):

https://doi.org/10.1103/PhysRevResearch.7.L012040

Additional Information:

Funding: DCB acknowledges support from EPSRC (EP/X019926) and the John Templeton Foundation (grant 62210).

Departments, Centres and Research Units:

Computing

Dates:

DateEvent
4 November 2024Accepted
24 February 2025Published

Item ID:

37817

Date Deposited:

08 Nov 2024 09:37

Last Modified:

25 Feb 2025 09:32

Peer Reviewed:

Yes, this version has been peer-reviewed.

URI:

https://research.gold.ac.uk/id/eprint/37817

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