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arXiv · 2602.16426

Remote predictability of quantum measurement outcomes

Chirag Srivastava·Aparajita Bhattacharyya·Sheikh Parvez Mandal·Mahasweta Pandit·Ujjwal Sen
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Abstract

Predicting quantum measurement outcomes for a local observer makes sense before, but not after, the measurement. However, for a remote observer, predicting measurement outcomes even after measurement remains a valid question. We define remote predictability as the degree to which one observer can predict a measurement outcome of a spatially separated observer, given full knowledge of the shared quantum state and measurement setting. We show that the remote predictability before and after the measurement remains the same for product states, whereas it increases for all pure entangled states and for some classically correlated states. Perfect remote predictability for arbitrary projective measurements occurs only for maximally entangled states among all pure states, underscoring their special role. Comparing pure entangled states with their dephased versions, we find that dephasing on one subsystem can enhance remote predictability for a broad class of states and measurements - a counterintuitive, noise-induced advantage that vanishes for maximally entangled states under any projective measurement.

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Chirag Srivastava, Aparajita Bhattacharyya, Sheikh Parvez Mandal, Mahasweta Pandit, Ujjwal Sen. 2026-02-18. Remote predictability of quantum measurement outcomes. https://arxiv.org/abs/2602.16426

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