Harnessing high-dimensional temporal entanglement using limited interferometric setups

TL;DR

This paper presents a comprehensive analysis of high-dimensional temporal entanglement in quantum communication, enabling efficient certification of entanglement and security parameters for QKD, along with noise models and improved setups.

Contribution

It introduces the first complete analysis of polarization-time-domain entanglement and proposes a novel setup to enhance noise resistance in free-space quantum communication.

Findings

Efficient certification of density matrix elements for QKD.

Development of physical noise models for high-dimensional entanglement.

Proposal of a new setup to improve noise resistance in quantum communication.

Abstract

High-dimensional entanglement has shown to have significant advantages in quantum communication. It is available in many degrees of freedom and in particular in the time-domain routinely produced in down-conversion (SPDC). While advantageous in the sense that only a single detector channel is needed locally, it is notoriously hard to analyze, especially in an assumption-free manner that is required for quantum key distribution applications. We develop the first complete analysis of high-dimensional entanglement in the polarization-time-domain and show how to efficiently certify relevant density matrix elements and security parameters for Quantum Key Distribution (QKD). In addition to putting past experiments on rigorous footing, we also develop physical noise models and propose a novel setup that can further enhance the noise resistance of free-space quantum communication.