In this talk I will discuss two of our latest works.
On the one hand, many quantum network applications rely on the availability of high-quality entanglement distributed among distant parties. Entanglement buffers are designed to store high-quality entanglement, ensuring it is readily available for consumption when needed. Our work establishes a systematic framework for the study and design of entanglement buffers [1]. We introduce two fundamental metrics for evaluating the performance of an entanglement buffer: the probability that entanglement is available at any given time and the average entanglement quality upon consumption. We then investigate a bipartite system, where each party possesses one memory for long-term entanglement storage and multiple memories for entanglement generation. An important finding is that maximising entanglement quality upon consumption requires frequent purification, even if this process often fails and results in the loss of high-quality buffered entanglement.
On the other hand, distributing quantum states reliably among distant locations is a key challenge in quantum networks. One-way quantum networks address this by using one-way communication and quantum error correction. We propose and analyze quantum circuit switching as a protocol to distribute quantum states in one-way quantum networks [2]. Using tools from queuing theory, we show that frequency multiplexing increases the rate at which quantum states are delivered, but it decreases the number of users supported by the network. We also show that using a large number of repeaters to combat channel losses limits the maximum distance between users, as each repeater introduces additional processing delays.
[1] https://arxiv.org/abs/2311.10052
[2] https://arxiv.org/abs/2405.19049

#### Speaker's Bio

Álvaro is a senior Casimir PhD candidate in Prof. Wehner’s group at TU Delft (the Netherlands). His work focuses on the design and performance analysis of protocols for entanglement distribution in quantum networks. Some of his recent works include the design of an entanglement buffering system and the proposal of a circuit switching protocol for delivering entanglement in multi-user large-scale networks. More broadly, Álvaro is interested in probability theory, algorithms, and mathematical puzzles. He is also the director of the yearly tech fair NoveldaTech (Spain).