Quantum Internet: from Medium Access Control to Entanglement Access Control

TL;DR

The paper addresses entanglement access control in the Quantum Internet, proposing a distributed protocol to resolve contention and extract an EPR pair from a shared multipartite resource. The core method merges $|GHZ angle$-based deterministic EPR extraction with $|W angle$-based leader election, augmented by a leader-aware state that reveals transmitter/receiver roles only to the involved parties, avoiding broad classical signaling. The resulting protocol achieves collision-free, on-demand connectivity with deterministic EPR sharing while preserving anonymity of the participating nodes, and integrates signaling into quantum resources via LOCC and teleportation steps. This approach scales to many nodes within a time-slotted network model and offers a practical path toward anonymous, on-demand entanglement management in the Quantum Internet.

Abstract

Multipartite entanglement plays a crucial role for the design of the Quantum Internet, due to its potentiality of significantly increasing the network performance. In this paper, we design an entanglement access control protocol for multipartite state, which exhibits several attractive features. Specifically, the designed protocol is able to jointly extract in a distributed way an EPR pair from the original multipartite entangled state shared by the set of network nodes, and to univocally determines the identities of the transmitter node and the receiver node in charge of using the extracted EPR pair. Furthermore, the protocol avoids to delegate the signaling arising with entanglement access control to the classical network, with the exception of the unavoidable classical communications needed for EPR extraction and qubit teleportation. Finally, the protocol supports the anonymity of the entanglement accessing nodes.

Figures (6)

• Figure 1: A-priori vs. on-demand connectivity.
• Figure 2: Graphical representation of the slotted time organization, with uplink -- namely, end-nodes to orchestrator -- transmissions interleaved with downlink -- namely, orchestrator to end-nodes -- ones.
• Figure 3: Graphical representation of the multipartite quantum states shared among the nodes: (a) once entanglement has been distributed, and (b) once contention has been solved.
• Figure 4: Quantum circuit for generating the leader-aware state $\ket{\Lambda}_{6}$ by considering the example in Figure \ref{['fig:03']}. The input state of the circuit is $\ket{W}_4 \otimes \ket{00}$, with $\ket{W_i}$ denoting the $i$-th qubit of the $\ket{W}_4$ state. Accordingly $\ket{\Lambda}_6= \frac{1}{\sqrt{4}}[\ket{100000}+\ket{010010}+\ket{001001} +\ket{000111}]_{W_1,W_2,W_3,W_4,a_0,a_1}$.
• Figure 5: Quantum circuit for uplink entanglement access.