A new Bar-Ilan University study points to a major advance in quantum information processing, demonstrating a way to send, manipulate, and measure quantum information across many frequency channels simultaneously, rather than one at a time. The study was recently published in the journal Science Advances .
The approach could allow quantum communication technologies, including secure key distribution and quantum teleportation, to operate far more efficiently by taking advantage of the enormous bandwidth already available in quantum light sources.
Today, one of the main limits in quantum information processing is not the light source itself, but the measurement technology. Quantum light sources can operate across an extremely broad optical spectrum, but standard detectors can measure only a tiny fraction of that bandwidth. As a result, much of the available capacity goes unused.
To overcome this bandwidth bottleneck, researchers from Bar-Ilan University harnessed a method they invented for ultrafast quantum detection (namely parametric homodyne detection) that allows to detect the quantum entanglement of light across many frequency channels simultaneously.
In this work, the same group takes this method a major step forward, demonstrating parallel quantum processing of information. Using broadband squeezed light, spectral shaping, and parametric homodyne detection, they were able to generate, manipulate, and measure several quantum channels simultaneously.
As a proof of principle, the team experimentally demonstrated continuous-variable quantum key distribution (CV-QKD) over 23 independent spectral channels, with the ability to detect eavesdropping in each one. They also demonstrated multiplexed quantum teleportation.
The results suggest that quantum systems do not have to operate one channel at a time. Instead, many channels can be used simultaneously across the optical spectrum, potentially increasing the throughput of quantum protocols by orders of magnitude.
“We’re sitting on an enormous quantum bandwidth, and until now we’ve barely used it,” said Prof. Avi Pe’er, of the Department of Physics and Institute of Nanotechnology and Advanced Materials at Bar-Ilan University, who led the study. “This work shows how to open that bottleneck and run many quantum channels in parallel — a step that could dramatically boost the speed of secure communication and other quantum technologies.”
The researchers say the method could eventually enable massively parallel quantum processing, with realistic systems potentially supporting thousands of channels.
“This is how we begin to scale quantum communication to real-world levels,” Pe’er added. “By using many channels at once, we can dramatically increase what these systems are capable of.”
The study highlights a path toward faster and more scalable quantum networks by making fuller use of the bandwidth already available in light.
Science Advances
Multiplexed processing of quantum information across an ultrawide optical bandwidth
11-Mar-2026