Quantum Memory interface based on multicolor unconditional quantum teleportation

Projektinformationen

EPRoxy

ID Finanzhilfevereinbarung: 101149150

DOI

10.3030/101149150

Projekt abgeschlossen

EK-Unterschriftsdatum 6 März 2024

Startdatum 1 April 2024

Enddatum 30 September 2025

Finanziert unter

• Marie Skłodowska-Curie Actions (MSCA)

Gesamtkosten

Keine Daten

EU-Beitrag

€ 161 200,80

Koordiniert durch

KOBENHAVNS UNIVERSITET
Denmark

Periodic Reporting for period 1 - EPRoxy (Quantum Memory interface based on multicolor unconditional quantum teleportation)

Berichtszeitraum: 2024-04-01 bis 2025-09-30

Zusammenfassung vom Kontext und den Gesamtzielen des Projekts

Quantum communication relies on quantum memories to store and retrieve information, but current technologies are limited by strict wavelength requirements. This prevents integration with standard telecom channels and hinders hybrid quantum networks. The EPRoxy project tackles this challenge by using unconditional quantum teleportation with two-colour EPR entanglement, enabling transfer of quantum states between different wavelengths and from atomic ensembles to light.
These breakthroughs will remove a major interoperability barrier, allowing quantum memories to connect directly to existing communication infrastructures. The results will support advanced protocols like quantum repeaters and entanglement swapping, essential for long-distance quantum communication. The impact is significant: EPRoxy will accelerate the development of a continental quantum internet, strengthen Europe’s digital sovereignty, and create opportunities for industrial applications through photonic integration. Public engagement activities will ensure societal understanding of quantum technologies and their implications.

Arbeit, die ab Beginn des Projekts bis zum Ende des durch den Bericht erfassten Berichtszeitraums geleistet wurde, und die wichtigsten bis dahin erzielten Ergebnisse

The project focused on developing a quantum memory interface based on multicolour unconditional quantum teleportation. Work began with optimising the two-colour EPR entanglement source for use in teleportation protocols. A new Coherent Control method was implemented to stabilise detection phases without degrading quantum properties, enabling improved Bell-state measurements and increasing two-mode squeezing to 9 dB. This innovation was reported in a preprint.
The second major achievement was demonstrating the coupling between an optical EPR state and an atomic spin oscillator. This hybrid interface allowed manipulation of the entangled light state without loss of quantum features and was validated in a Nature publication. These results confirm that two-colour EPR sources can match the performance of two-tone systems and can be integrated with atomic systems, advancing hybrid quantum network technology.
Although the full teleportation objectives were delayed due to technical issues, the project delivered key advances: a robust phase-locking technique, improved entanglement source performance, and proof-of-concept coupling between light and matter—laying the groundwork for future teleportation protocols.

Fortschritte, die über den aktuellen Stand der Technik hinausgehen und voraussichtliche potenzielle Auswirkungen (einschließlich der bis dato erzielten sozioökonomischen Auswirkungen und weiter gefassten gesellschaftlichen Auswirkungen des Projekts)

The project delivered two important advances. First, we developed a new Coherent Control method that stabilises phase references in two-colour EPR entanglement sources without compromising their quantum properties. This innovation improves Bell-state measurements and significantly enhances the performance of the source, making it competitive with the best technologies available today. Second, we demonstrated that an optical EPR state can be coupled to an atomic spin oscillator without degrading the quantum features of either system. This result, published in Nature, shows that hybrid quantum interfaces are feasible and can be used to manipulate quantum states of light through atomic systems.
These achievements have clear potential impacts. They open the way to hybrid quantum networks, which are essential for implementing quantum repeaters and secure communication protocols. They also provide tools for reducing quantum noise in gravitational wave detectors, a strategic area for Europe’s scientific leadership. However, to ensure full uptake and success, further steps are needed. Completing the unconditional teleportation from atoms to light remains a priority, as does scaling the technology for integrated photonic platforms. Industrial adoption will require miniaturisation, intellectual property protection for the Coherent Control technique, and engagement with quantum technology companies. Access to finance and partnerships through initiatives like the EU Quantum Flagship will be crucial, as will the development of interoperability standards to integrate these systems with existing telecom infrastructure. Finally, international collaboration will help accelerate adoption and maintain competitiveness in the global quantum technology race.

presentation of the Teleportation protocol