Performance studies of entanglement swapping in quantum networks using NetSquid simulator

Quantum networks are essential for advancing quantum computing and secure communication, enabling quantum information to be shared across multiple nodes. These networks can support applications like distributed quantum computing, quantum cryptography, and enhanced sensing. Such technologies will pave the way for the future quantum internet. However, scaling such networks presents significant challenges, including maintaining qubit coherence over long distances and efficiently distributing and routing entanglement among numerous nodes. In this scenario, optical communications offer a promising solution to distribute qubits, due to its large bandwidth and low loss characteristics even over long distances. The work in this thesis leverages Netsquid, a quantum hardware and network simulator, to simulate a network in which multiple quantum nodes are interconnected. The goal is to implement such a quantum network and investigate the performances of entanglement distribution and swapping operations in the presence of noise and losses. Thus, the distributed entangled resources are used to perform teleportation operations. By simulating entanglement distribution, entanglement swapping, and quantum teleportation, we assess how these operations are affected by realistic conditions like channel noise and quantum hardware imperfections. Using NetSquid, we implemented a 4 x 4 nodes network with quantum and classical channels (the last ones needed for running the swapping and teleportation protocols and exchanging other network control plane data). It is worth to mention that the network can be extended to larger configurations if needed. In the simulated network, quantum nodes can both send and receive qubits, enabling scenarios of distributed quantum computing. We observed how noise, decoherence and loss can influence the fidelity of single-hop and multi-hop entanglement-swapping-based distribution and the success rates of quantum operations. These findings contribute to a better understanding of the design rules for robust quantum networks, laying the groundwork for future research towards the realization of a quantum internet.