Reliable Quantum Communications Based on Asymmetry in Distillation and Coding

The reliable provision of entangled qubits is an essential precondition in a variety of schemes for distributed quantum computing. This is challenged by multiple nuisances, such as errors during the transmission over quantum links, but also due to degradation of the entanglement over time due to decoherence. The latter can be seen as a constraint […]

Variational Estimation of Optimal Signal States for Quantum Channels

This article explores the performance of quantum communication systems in the presence of noise and focuses on finding the optimal encoding for maximizing the classical communication rate, approaching the classical capacity in some scenarios. Instead of theoretically bounding the ultimate capacity of the channel, we adopt a signal processing perspective to estimate the achievable performance […]

On the Bipartite Entanglement Capacity of Quantum Networks

We consider the problem of multipath entanglement distribution to a pair of nodes in a quantum network consisting of devices with nondeterministic entanglement swapping capabilities. Multipath entanglement distribution enables a network to establish end-to-end entangled links across any number of available paths with preestablished link-level entanglement. Probabilistic entanglement swapping, on the other hand, limits the […]

Rateless Protograph LDPC Codes for Quantum Key Distribution

Information reconciliation (IR) is a key step in quantum key distribution (QKD). In recent years, blind reconciliation based on low-density parity-check (LDPC) codes has replaced Cascade as a standard de facto since it guarantees efficient IR without a priori quantum bit error rate estimation and with limited interactivity between the parties, which is essential in […]

Tools for the Analysis of Quantum Protocols Requiring State Generation Within a Time Window

Quantum protocols commonly require a certain number of quantum resource states to be available simultaneously. An important class of examples is quantum network protocols that require a certain number of entangled pairs. Here, we consider a setting in which a process generates a quantum resource state with some probability p in each time step and […]

A Linear Algebraic Framework for Dynamic Scheduling Over Memory-Equipped Quantum Networks

Quantum internetworking is a recent field that promises numerous interesting applications, many of which require the distribution of entanglement between arbitrary pairs of users. This article deals with the problem of scheduling in an arbitrary entanglement swapping quantum network—often called first-generation quantum network—in its general topology, multicommodity, loss-aware formulation. We introduce a linear algebraic framework […]

A Linear Algebraic Framework for Dynamic Scheduling Over Memory-Equipped Quantum Networks

Quantum internetworking is a recent field that promises numerous interesting applications, many of which require the distribution of entanglement between arbitrary pairs of users. This article deals with the problem of scheduling in an arbitrary entanglement swapping quantum network—often called first-generation quantum network—in its general topology, multicommodity, loss-aware formulation. We introduce a linear algebraic framework […]

Scalable QKD Postprocessing System With Reconfigurable Hardware Accelerator

Key distillation is an essential component of every quantum key distribution (QKD) system because it compensates for the inherent transmission errors of a quantum channel. However, the interoperability and throughput aspects of the postprocessing components are often neglected. In this article, we propose a high-throughput key distillation framework that supports multiple QKD protocols, implemented in […]

DQRA: Deep Quantum Routing Agent for Entanglement Routing in Quantum Networks

Quantum routing plays a key role in the development of the next-generation network system. In particular, an entangled routing path can be constructed with the help of quantum entanglement and swapping among particles (e.g., photons) associated with nodes in the network. From another side of computing, machine learning has achieved numerous breakthrough successes in various […]

Estimation of the CHSH Parameter Using HOM Interference

The Clauser–Horne–Shimony–Holt (CHSH) experiment is an essential test of nonlocality in quantum mechanics and can be used to validate the principle of entanglement. In addition to verifying entanglement, the measurable CHSH parameter can also be used to gauge the quality of the entanglement present in a system. The measurement of Hong–Ou–Mandel (HOM) interference is another […]