The Future of Quantum Networking

The world of quantum networking is advancing at a rapid pace, with researchers facing the challenge of overcoming the fragility of entangled states in fiber cables. Scientists at Qunnect Inc. in Brooklyn, New York, have made significant progress in this area by successfully operating a quantum network under the streets of New York City. While previous attempts have been marred by noise and polarization drift in fiber environments, the team at Qunnect has managed to achieve remarkable results, paving the way for the future of quantum networking.

Achieving Stability and Efficiency

The key to success lies in the team’s innovative network design, methods, and results as published in PRX Quantum. Using a leased 34-kilometer-long fiber circuit known as the GothamQ loop, the researchers transmitted polarization-entangled photons for 15 continuous days, with an impressive uptime of 99.84%. This groundbreaking achievement demonstrates the team’s commitment to ensuring stable and efficient signal delivery in quantum networks.

Polarization-entangled photons play a crucial role in the development of quantum networks, enabling researchers to build large-scale quantum repeaters, distributed quantum computing, and distributed quantum sensing networks. By entangling an infrared photon with a near-infrared photon, the team at Qunnect has harnessed the power of quantum entanglement to create a robust and reliable communication system.

Overcoming Technical Challenges

One of the main challenges faced by quantum networks is polarization drift, which can be both wavelength and time-dependent. To address this issue, Qunnect has developed equipment for active compensation at the same wavelengths, ensuring the stability of entangled photon pairs. By generating entangled dual-colored photon pairs through vapor cell enrichment with rubidium-78, the team has been able to overcome technical obstacles and achieve impressive results.

To mitigate disturbances caused by vibrations, bending, pressure, and temperature fluctuations in optical cables, the Qunnect team has implemented automated polarization compensation (APC) devices. By sending classical photon pairs down the fiber to measure polarization drift, the researchers were able to correct for these disturbances and maintain the integrity of the entangled pairs. This innovative approach has revolutionized the way quantum networks can be built and maintained.

Qunnect’s GothamQ loop demonstration represents a significant step towards the realization of a fully automated practical entanglement network, a crucial component of a quantum internet. By making their equipment rack-mounted and easily deployable, the team has laid the groundwork for a future where quantum networking is accessible and reliable. With their innovative technology, known as Qu-Val, Qunnect is leading the way towards a quantum future where communication is secure, efficient, and sustainable.