In their publication, researchers E. P. Lobo, J. Pauwels and S. Pironio study the “Routed Bell scenario”, which enhances robustness against losses in transmission channels. The fragility of quantum non-locality to losses, which increases with distance, has hindered the practical viability of device independent schemes. By allowing one of the parties to choose between two measurement locations, one close to the source and one far away, the routed Bell scenario presents a promising solution to certify quantum protocols over longer distances with minimal experimental overhead. The basic idea is to use the close device, which experiences less photon losses, as an additional test.

Quantum technologies, particularly in cryptography, need systems where the device functionality and security are guaranteed without dependence on the trust on device manufacturers. This publication paves the way for device-independent quantum key distribution (DIQKD), ensuring secure communication even when the integrity of the device is compromised.

The added value of this study lies in its novel approach to the challenge of losses in device-independent quantum. By introducing theoretical lower bounds on tolerable losses and providing a framework for routed Bell experiments, the study not only advances the field but also offers benchmarks for future experiments. Moreover, it opens new ways for designing and implementing protocols based on the idea of routing.

Building upon earlier works, the researchers devised the concept of routed Bell experiments to suit device-independent applications. Led by Pironio, the team contributed collectively to the development of ideas, proofs, and programs necessary for the study.

Taking a look into the future, the field of device-independent quantum information processing holds promising prospects. This publication provides the basic groundwork for studying routed Bell experiments, but there are still many directions to explore. Future research aims to refine protocols for even lower losses, applying them to tasks like quantum random number generation and quantum key distribution. This might involve coming up with new mathematical techniques. Experimental implementations of routed Bell experiments will provide empirical validation and comparison with theoretical predictions.

Secure quantum technologies, enabled by device-independent protocols, hold the potential to revolutionize sensitive domains such as critical government communications and banking. By ensuring unconditional security, these technologies offer unparalleled levels of protection in an increasingly interconnected world.

In conclusion, the introduction of routed Bell experiments represents a new step in the journey towards practical and secure quantum technologies. With its implications for device-independent quantum information processing, this discovery heralds a new era of communication and computation with untrusted devices.



“Certifying long-range quantum correlations through routed Bell tests”

Edwin Peter Lobo, Jef Pauwels and Stefano Pironio.

arXiv:2310.07484 [quant-ph]

Published 11 October 2023