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Quantum states and space-time causality

Dorje C. Brody·Lane P. Hughston
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Abstract

Space-time symmetries and internal quantum symmetries can be placed on equal footing in a hyperspin geometry. Four-dimensional classical space-time emerges as a result of a decoherence that disentangles the quantum and the space-time degrees of freedom. A map from the quantum space-time to classical space-time that preserves the causality relations of space-time events is necessarily a density matrix.

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Dorje C. Brody, Lane P. Hughston. 2006-01-03. Quantum states and space-time causality. https://arxiv.org/abs/quant-ph/0601020

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