D. Chisholm: Distinguishing between redundancy and consensus when quantifying quantum objectivity
Channel: Centrum Fizyki Teoretycznej PAN
Date: 2024-03-21

Diana Chisholm (Queen's University Belfast).
Distinguishing between redundancy and consensus when quantifying quantum objectivity.

We give rigorous definitions of "redundancy" and "consensus", two different measures of the degree of objectivity of quantum states, with clear operative interpretations that reflect their meaning in the English language. Although the two terms are often used interchangeably in discussions on quantum objectivity, they actually represent distinct concepts that capture different aspects of the quantum to classical transition. Moreover, the key frameworks employed in the study of quantum objectivity, namely spectrum broadcast structure and quantum Darwinism, naturally arise from these measures. While discussing the differences between redundancy and consensus, and their usefulness in interpreting the degree of objectivity of quantum states, we will employ them to show that, in the framework of quantum Darwinism, failing to use the averaged mutual information can lead to misleading results. [1] D.A. Chisholm, et. al., Quantum 7, 1074 (2023). [2] D.A. Chisholm, et. al., arXiv:2401.04769 (2024).

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