arXiv subjects

Tasdiqul Islam

Publications and source records attributed to Tasdiqul Islam.

4 recordsLinked to original sources

arXiv2026

Scalable Quantum Key Distribution via GHZ Entanglement and Qubit Reuse

Conventional Quantum Key Distribution (QKD) requires the transmission of qubits proportional to or exceeding the length of the key, as protocols such as BB84 transmit more qubits than the final key size due to basis sifting and privacy amplification. Since quantum networks are still in their infancy and have limited capacity, this overhead puts significant pressure on network resources. To address this issue, we propose a Multi-Qubit Greenberger--Horne--Zeilinger (GHZ) State-based QKD scheme that reduces the number of qubits transmitted over the quantum channel. The proposed method transmits one GHZ qubit between endpoints and reuses the resulting entanglement to convey multiple classical key bits with the help of Quantum Non-Demolition (QND) measurements. Under the stated assumptions on authenticated classical communication, local reset verification, and bounded-error QND discrimination, one can transfer $L$ classical bits by generating an (L+1)-qubit GHZ state and transferring one qubit to the remote party. We verify correctness using the NetSquid quantum network simulator: the protocol achieves 100\% raw-key fidelity for keys of length up to 12 bits under both ideal conditions and depolarizing noise up to p = 0.005 per round. We further show that the proposed QKD algorithm can be extended to multi-party QKD and server-client deployment. The proposed scheme offers a transmitted-qubit-efficient, noise-tolerant alternative for bandwidth-limited quantum networks.

quant-ph↗

arXiv2025

Adaptive Entanglement Generation for Quantum Routing

Entanglement generation in long-distance quantum networks is a difficult process due to resource limitations and the probabilistic nature of entanglement swapping. To maximize success probability, existing quantum routing algorithms employ computationally expensive solutions (e.g., linear programming) to determine which links to entangle and use for end-to-end entanglement generation. Such optimization methods, however, cannot meet the delay requirements of real-world quantum networks, necessitating swift yet efficient real-time optimization models. In this paper, we propose reinforcement learning (RL)-based models to determine which links to entangle and proactively swap to meet connection requests. We show that the proposed RL-based approach is 20x faster compared to linear programming. Moreover, we show that one can take advantage of the longevity of entanglements to (i) cache entangled links for future use and (ii) proactively swap entanglement on high-demand path segments, thereby increasing the likelihood of request success. Through comprehensive simulations, we demonstrate that caching unused entanglements leads to a 10-15% improvement in the performance of state-of-the-art quantum routing algorithms. Complementing caching with proactive entanglement swapping further enhances the request success rate by up to 52.55%.

cs.NI↗

arXiv2023

Quantum Key Distribution with Minimal Qubit Transmission Based on MultiQubit Greenberger Horne Zeilinger State

Conventional Quantum Key Distribution (QKD) requires the transmission of multiple qubits equivalent to the length of the key. As quantum networks are still in their infancy thus, they are expected to have a limited capacity, necessitating too many qubit transmissions for QKD might limit the effective use of limited network bandwidth of quantum networks. To address this challenge and enhance the practicality of QKD, we propose a Multi-Qubit Greenberger Horne Zeilinger (GHZ) State-based QKD scheme that requires a small number of qubit transmissions. The proposed method transmits one qubit between endpoints and reuses it for the transmission of multiple classical bits with the help of Quantum nondemolition (QND) measurements. We show that one can transfer L-1 classical bits by generating an L-qubit GHZ state and transferring one to the remote party. We further show that the proposed QKD algorithm can be extended to enable multi-party QKD. It can also support QKD between parties with minimal quantum resources. As a result, the proposed scheme offers a quantum network-efficient alternative QKD.

cs.NI↗

arXiv2023

Scalable Quantum Repeater Deployment Modeling

Long-distance quantum communication presents a significant challenge as maintaining the fidelity of qubits can be difficult. This issue can be addressed through the use of quantum repeaters to transmit entanglement information through Bell measurements. However, despite its necessity to enable wide-area quantum internet, the deployment cost of quantum repeaters can be prohibitively expensive, thus it is important to develop a quantum repeater deployment model that can strike a balance between cost and effectiveness. In this work, we present novel heuristic models to quickly determine a minimum number of quantum repeaters to deploy in large-scale networks to provide end-to-end connectivity between all end hosts. The results show that, compared to the linear programming approach, the heuristic methods can find near-optimal solutions while reducing the execution time from days to seconds when evaluated against several synthetic and real-world networks such as SURFnet and ESnet. As reliability is key for any network, we also demonstrate that the heuristic method can determine deployment models that can endure up to two link/node failures.

quant-ph↗