Quantum Radio Sensors Could Change Communications in Heavy Jamming
Current trends are placing the burden of increasing stress on radio systems, highlighting a limitation in current technologies: traditional antennas and front-end electronics have a set configuration, operate within set boundaries, and have set tolerances towards electromagnetic interference. That is the reason why a trend toward atom-based radio sensing has recently emerged. Instead of regarding quantum technology as purely computational hardware, developers have started using excited atoms as effective radio receivers for navigation, communication, direction finding, and spectrum analysis.
Infleqtion Quantum Spectrum is an embodiment of such a shift in attitude. It involves exciting Rydberg atoms using lasers and measuring the effect of the perturbation caused by the incoming radio frequencies through the use of optical readouts. Such a method has been known in scientific circles for decades, but the modern objective is different: to substitute a part of the RF front end with a new kind of sensing medium that is broadband in its operation and independent from specific metal antennas.
The key aspect of such a design is precisely the broadband characteristic, which implies certain advantages compared to traditional RF solutions. Most RF receivers have to have individual hardware to receive different spectrum fragments, resulting in larger physical size, higher energy consumption, and complicated tuning routines. However, the sensing medium used in Rydberg receivers is inherently broadband, which promises a way to bypass these problems. According to a NATO overview published in 2024, Rydberg RF sensors have several distinctive features: electromagnetic transparency, self-calibration, broad carrier bandwidth, and optical readout, a combination impossible to obtain in traditional systems.
Anti-jamming applications might provide the strongest use case for quantum systems due to the inherent properties of modern interference. Modern jammers do not simply occupy the same band as the intended signal; they continuously vary their spectrum, leading to unpredictable overlapping with regular traffic. Dynamic interference recognition and rejection techniques prove highly effective when competing with static approaches: a neural network algorithm developed by researchers managed to achieve up to 95.23% interference detection rates. This particular example is based on algorithmic rather than quantum techniques, but the idea behind such an approach remains the same: a system will require tight integration between reception and classification capabilities.
At present, some quantum hardware is demonstrating promising performance. An experimental research project published in 2025 tested the bandwidth capabilities of a new-generation atomic RF receiver. The results revealed that the receiver was capable of working within the 100 kHz-20 GHz range with over 150,000 channels, and the receiver demonstrated up to 51 dB improvement in interference tolerance compared to a single-channel counterpart. The figures presented in that experiment cannot be treated as benchmarks due to its experimental nature, yet it illustrates the potential of quantum receivers quite effectively: a single receiver architecture able to cover a range of frequencies normally requiring different subsystems, while remaining resilient to interference.
Proving the capability of atoms to receive radio waves and converting that data into measurable signals does not imply the existence of practical hardware yet. The development of an adequate package remains the key challenge, which includes lasers, photonics, thermal management, vibration compensation, and many others. This problem is reflected in the Infleqtion’s emphasis on integrated photonics technology and the broader research on engineered vapor cells, optical cavities, and waveguide coupling. For instance, a recent attempt at creating an all-optical receiver was noted for its ability to perform self-calibration and avoid mechanical parts, yet this approach requires extremely precise engineering practices.
For defense purposes, this technology implies a new class of devices that would complement rather than replace traditional hardware in situations where current receivers struggle. These include, but not limited to, spectrum-wide monitoring, stealth receivers, assistance in GPS-denied environments, direction finding, etc.
