Researchers at Virginia Tech have shown in a laboratory environment how entangled qubits can be used to realize a form of communication in which classical eavesdropping methods remain ineffective due to the principle. The work is located in the field of quantum information research and investigates the extent to which quantum mechanical effects can be used for safety-critical communication scenarios.

The investigations focus on quantum entanglement, a physical phenomenon that Albert Einstein described as a spooky action at a distance. In entangled quantum states, the properties of individual particles cannot be described independently of each other, as measurements on one system allow direct conclusions to be drawn about the state of the other. These correlations exist regardless of the spatial distance as long as the entanglement is maintained.

PhD student Alexander DeRieux is working in Walid Saad ‘s laboratory on an approach to harness these properties for radio communication. The starting point is the observation that atoms oscillate permanently even under stable conditions and that these oscillations are coupled with each other in entangled systems. The state of a single atom can therefore not be considered in isolation, as every change in state is always accompanied by a corresponding change in the entangled partner.

This interdependence forms the basis of the proposed communication concept. Instead of transmitting information classically via electromagnetic signals, changes of state in an entangled qubit pair are used. If the state of a qubit is known, the state of the associated partner can be determined unambiguously. An external query or manipulation would disrupt the entanglement and thus become immediately detectable. This results in inherent protection against undetected eavesdropping.

The research team cites the use of autonomous drones in disaster areas as a possible application scenario. Sensory information such as audio or video data could be encoded directly into quantum states. As a single qubit can have a significantly higher information density compared to classic bits, extensive data can be represented with comparatively few state changes. Communication would not consist of conventional transmission, but rather the evaluation of correlated quantum states.

The researchers also see potential for safety-critical infrastructures such as the exchange of medical data between hospitals and doctors in private practice. Since quantum entanglement does not require explicit transmission via fiber optics or wireless networks, certain risks of conventional Internet communication could be circumvented. However, whether and to what extent this approach can be scaled up outside of controlled laboratory conditions remains the subject of further research. At present, it is not possible to verify any statements about practical implementation in the short term.

Conclusion

The experiments described show that quantum entanglement can, in principle, be used as the basis for a form of communication in which classical eavesdropping is physically detectable or impossible. The results prove the theoretical suitability of entangled qubits for safety-critical applications and expand the understanding of possible communication models beyond classical networks. However, practical use outside controlled laboratory environments, especially over longer distances and under real interference conditions, is currently not proven and cannot be verified on the basis of the information available.