Multidimensional Reconciliation in Continuous-Variable QKD: Review, Coding Schemes, and Open Source Simulation

Wed, 10 Jun 2026 00:00:00 +0000

Continuous-variable quantum key distribution (CV-QKD) requires highly efficient reconciliation techniques to operate at low signal-to-noise ratios and long distances. Multidimensional reconciliation addresses this challenge by transforming the physical Gaussian quantum channel into a virtual binary-input additive white Gaussian noise (BIAWGN) channel, enabling the use of modern errorcorrecting codes. In this work, we review the principles of multidimensional reconciliation, with a particular focus on high-dimensional constructions beyond the algebraic dimensions 1, 2, 4, 8. We describe the construction of the virtual channel, discuss practical coding schemes for reverse reconciliation, and analyse their integration with linear error-correcting codes. We also present an opensource simulation framework, HDirac, implementing multidimensional reconciliation for arbitrary dimensions, and use it to evaluate state-of-the-art LDPC codes. The results highlight key trade-offs between dimension, reconciliation efficiency, and frame error rate, providing practical guidance for CV-QKD system design.

Violating Bell inequalities using photon path encoding

Wed, 12 Nov 2025 00:00:00 +0000

In this work we investigate the use of photon path entanglement for the violation of a Bell inequality. The advantage of this encoding is that Bell pairs can be distributed with a rate scaling as the square root of the transmitivity of the channel in an heralding protocol, instead of a linear scaling in e.g. polarisation-based schemes. The drawback is that it is hard to implement generic Pauli measurements. We explore different ways to implement tackle this issue.

Alexis Rosio | LIP6 - Équipe QI

Multidimensional Reconciliation in Continuous-Variable QKD: Review, Coding Schemes, and Open Source Simulation

Violating Bell inequalities using photon path encoding