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arXiv · 1109.5154

Perfect discrimination of no-signalling channels via quantum superposition of causal structures

G. Chiribella
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Abstract

A no-signalling channel transforming quantum systems in Alice's and Bob's laboratories is compatible with two different causal structures: (A < B) Alice's output causally precedes Bob's input and (B< A) Bob's output causally precedes Alice's input. I show that a quantum superposition of circuits operating within these two causal structures enables the perfect discrimination between no-signalling channels that can not be perfectly distinguished by any ordinary circuit.

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G. Chiribella. 2012-11-27. Perfect discrimination of no-signalling channels via quantum superposition of causal structures. https://doi.org/10.1103/physreva.86.040301

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