Interconnected quantum system boosts long-distance secure communication

Interconnected quantum system boosts long-distance secure communication
by Sophie Jenkins
London, UK (SPX) Apr 22, 2024

Quantum networking, pivotal for distributed computing and secure communication, relies on the seamless sharing of quantum information. However, the transmission of quantum data over extended distances has traditionally faced significant obstacles due to data loss. A collaborative breakthrough by researchers at Imperial College London, the University of Southampton, and German universities in Stuttgart and Wurzburg tackles this challenge by interfacing quantum memory with quantum data generation devices.

This novel system, described in a recent publication in Science Advances, facilitates the transmission of quantum information using standard optical fibers and marks a key advancement in quantum networking technologies. The innovation stems from linking two essential components: a quantum memory device and a device for quantum information creation, which communicate effectively to maintain the integrity of quantum data over distances.

Dr. Sarah Thomas from Imperial College London highlighted the importance of this development: "Interfacing two key devices together is a crucial step forward in allowing quantum networking, and we are really excited to be the first team to have been able to demonstrate this."

In conventional telecommunications, repeaters amplify signals across distances to prevent loss. Quantum information, sensitive to interference, cannot utilize classical repeaters without risking data integrity. To circumvent this, the team employed a quantum dot to produce photons stored within a rubidium atom cloud, which acts as the quantum memory. This system operates on the same wavelength used in current telecommunications, enabling compatibility with existing infrastructure.

"The success of using a consistent wavelength across devices signifies a major milestone for integrating quantum technologies with conventional systems," explained co-first author Lukas Wagner from the University of Stuttgart. The integration process was perfected in a lab at Imperial College London, combining expertise and technology from across Europe.

While the system currently demonstrates a foundational capability, further enhancements are planned. These include aligning photon production wavelengths more precisely and improving photon storage durations. Such advancements promise to refine the effectiveness and reduce the size of quantum networking systems, paving the way for more robust and extensive quantum networks.

Research Report:Deterministic Storage and Retrieval of Telecom Light from a Quantum Dot Single-Photon Source Interfaced with an Atomic Quantum Memory