Unbounded pairs of observers can achieve quantum advantage in random access codes with a single pair of qubits.
Debarshi Das, Arkaprabha Ghosal, Som Kanjilal, Ananda G. Maity, Arup Roy · arXiv (Cornell University) · 2021
Recycling a single quantum resource in information processing and communication tasks multiple times is of paramount significance from foundational and practical perspective. Here we consider a scenario involving multiple independent pairs of observers acting with unbiased inputs on a single pair of spatially separated qubits sequentially. In this scenario, we address whether more than one pair of observers can demonstrate quantum advantage in some specific $2 \rightarrow 1$ and $3 \rightarrow 1$ random access codes. Interestingly, we not only address these in the affirmative, but also illustrate that an unbounded pairs can exhibit quantum advantage. Furthermore, these results remain valid even when all observers perform suitable projective measurements and an appropriate separable state is initially shared.