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arXiv · 2601.16840

Protocols for sharing genuine multipartite entanglement by employing copies of biseparable states

Swati Choudhary·Ujjwal Sen·Saronath Halder
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Abstract

Sharing genuine multipartite entanglement by considering collective use of copies of biseparable states, which are entangled across all bipartitions but lack genuine multipartite entanglement at the single-copy level, plays a central role in several quantum information processing protocols, and has been referred as genuine multipartite entanglement activation. We present a protocol for three-qutrit systems showing that two copies of rank-two biseparable states, entangled across every bipartition, are sufficient to generate a genuinely multipartite entangled state with nonzero probability. This contrasts with the three-qubit scenario where many copies of biseparable states might be required for sharing genuine multipartite entanglement. We subsequently generalize our protocols to the case of an arbitrary number of parties. Interestingly, the proposed construction naturally leads to the activation of genuinely nonlocal correlations, yielding a result that is stronger than genuine multipartite entanglement activation alone.

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Swati Choudhary, Ujjwal Sen, Saronath Halder. 2026-01-23. Protocols for sharing genuine multipartite entanglement by employing copies of biseparable states. https://doi.org/10.1103/3b7n-g94w

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