First real-time measurement of quantum uncertainty with ultrafast squeezed light

The uncertainty principle, proposed by Werner Heisenberg nearly a century ago, has remained a central pillar of quantum mechanics, dictating that certain properties of light and matter cannot be simultaneously measured with arbitrary precision. Until now, however, the uncertainty principle had never been directly observed and tracked in real time.

In a new paper published in Light: Science & Applications, an international team led by Dr. Mohammed Th. Hassan (University of Arizona, USA) and colleagues from ICFO (Spain), including Dynamite project team members, and Ludwig-Maximilians-Universität München (Germany) achieved the first-ever measurement of quantum uncertainty dynamics with attosecond resolution.

The researchers generated ultrafast squeezed light pulses through a nonlinear four-wave mixing process, producing some of the shortest quantum-synthesized light pulses to date. By controlling and switching between amplitude and phase squeezing, the team revealed that quantum uncertainty is a dynamic, tunable property rather than a fixed limit, a breakthrough with far-reaching implications.

To showcase the potential, the team demonstrated a novel petahertz-scale secure quantum communication protocol. By encoding data directly onto ultrafast squeezed waveforms, the scheme provides multiple layers of protection against eavesdropping and could underpin the future of high-speed encrypted communication networks.

“This represents a paradigm shift in quantum optics,” said Dr. Hassan. “We have shown that uncertainty is not only measurable in real time, but also controllable. This opens an entirely new window into quantum science and technology.”

This landmark achievement establishes a foundation for ultrafast quantum optics, quantum communication, and petahertz-scale optoelectronics, setting the stage for future exploration of real-time quantum dynamics.

(Adapted from First real-time measurement of quantum uncertainty with ultrafast squeezed light , originally published by Light Publishing Center)

Original article

Sennary, M., Rivera-Dean, J., ElKabbash, M. et al. Attosecond quantum uncertainty dynamics and ultrafast squeezed light for quantum communication. Light Sci Appl 14, 350 (2025). https://doi.org/10.1038/s41377-025-02055-x