Entanglement-Assisted Communication Under Locality Constraints: From Correlated Contingencies to Scalable Quantum Networks

Large-scale entanglement-based quantum key distribution (QKD) networks are commonly assumed to require authentication resources scaling quadratically with the number of users. We show that realistic quantum communication networks operating under loss, decoherence, and LOCC constraints exhibit fundamentally different scaling laws. Using Pauli transfer matrix (PTM) transport, we demonstrate that Bell correlations decay exponentially along entanglement-swapping paths, generating finite operational correlation lengths and sparse operational entanglement graphs. In sparse metropolitan quantum networks, the number of CHSH-usable Bell pairs consequently scales linearly with network size, while authentication complexity scales as $Θ(N\log N),$ under sparse-mixing assumptions. We further present an ancilla-assisted distributed Bell-state verification framework for realistic E91 quantum metropolitan infrastructures. Our results suggest that scalable authentication in quantum communication networks emerges directly from the physics of entanglement transport.Large-scale entanglement-based quantum key distribution (QKD) networks are commonly assumed to require authentication resources scaling quadratically with the number of users. We show that realistic quantum communication networks operating under loss, decoherence, and LOCC constraints exhibit fundamentally different scaling laws. Using Pauli transfer matrix (PTM) transport, we demonstrate that Bell correlations decay exponentially along entanglement-swapping paths, generating finite operational correlation lengths and sparse operational entanglement graphs. In sparse metropolitan quantum networks, the number of CHSH-usable Bell pairs consequently scales linearly with network size, while authentication complexity scales as \[ Θ(N\log N), \] under sparse-mixing assumptions. We further present an ancilla-assisted distributed Bell-state verification framework for realistic E91 quantum metropolitan infrastructures. Our results suggest that scalable authentication in quantum communication networks emerges directly from the physics of entanglement transport.

quant-pharXiv:2605.27434May 25, 20260 citations

Entanglement assisted communication complexity measured by distinguishability

Satyaki Manna, Ankush Pandit, Anubhav Chaturvedi +1 more

We investigate the quantum advantage that can arise in typical two-party communication scenarios, where the sender and the receiver are allowed to share prior correlations. Focusing on communication tasks constrained by the distinguishability of the sender's inputs, we demonstrate that entanglement-assisted communication with both classical and quantum message can outperform classical communication supplemented with shared randomness. We begin by developing a general framework for communication tasks with pre-shared correlations. Within this framework, we establish an equivalence among entanglement-assisted classical communication, entanglement-assisted quantum communication, and quantum communication, showing that no hierarchy exists between these three paradigms. We then investigate the scenario where the receiver has no input and prove that no advantage can arise in this case. However, an advantage in the entanglement-assisted setting emerges once additional constraints are imposed on the dimension of the communicated message. This further highlights the superiority of entanglement-assisted classical communication over standard quantum communication. Then we demonstrate several tasks where the entanglement-assisted protocol using one-bit communication proves to be advantageous over classical communication. Finally, by constructing an explicit class of communication tasks, we show that a non-maximally entangled states outperform the maximally entangled state as a pre-shared resource between the communicating parties.We investigate the quantum advantage that can arise in typical two-party communication scenarios, where the sender and the receiver are allowed to share prior correlations. Focusing on communication tasks constrained by the distinguishability of the sender's inputs, we demonstrate that entanglement-assisted communication with both classical and quantum message can outperform classical communication supplemented with shared randomness. We begin by developing a general framework for communication tasks with pre-shared correlations. Within this framework, we establish an equivalence among entanglement-assisted classical communication, entanglement-assisted quantum communication, and quantum communication, showing that no hierarchy exists between these three paradigms. We then investigate the scenario where the receiver has no input and prove that no advantage can arise in this case. However, an advantage in the entanglement-assisted setting emerges once additional constraints are imposed on the dimension of the communicated message. This further highlights the superiority of entanglement-assisted classical communication over standard quantum communication. Then we demonstrate several tasks where the entanglement-assisted protocol using one-bit communication proves to be advantageous over classical communication. Finally, by constructing an explicit class of communication tasks, we show that a non-maximally entangled states outperform the maximally entangled state as a pre-shared resource between the communicating parties.

quant-pharXiv:2603.19105Mar 20, 20260 citations

Quantum entanglement, quantum communication and the limits of quantum computing

Andris Ambainis

Jan 1, 20010 citations

A Lower Bound on Entanglement-Assisted Quantum Communication Complexity

Ashley Montanaro, Andreas Winter

Lecture notes in computer scienceAug 25, 20076 citations

Entanglement characterization in Quantum Networks based on entanglement distance

Qi Han, Shijiao Xing, Xiao Wu +2 more

Physica A Statistical Mechanics and its ApplicationsJul 22, 20260 citations

Θ(N\log N),

under sparse-mixing assumptions. We further present an ancilla-assisted distributed Bell-state verification framework for realistic E91 quantum metropolitan infrastructures. Our results suggest that scalable authentication in quantum communication networks emerges directly from the physics of entanglement transport.