Researchers from Kyoto University and Hiroshima University have announced a major advance in quantum physics that could accelerate the development of quantum teleportation, ultra-secure communication systems and next-generation quantum computing.
The breakthrough centers on the successful detection and measurement of elusive quantum “W states,” a complex form of quantum entanglement that scientists have struggled to identify for decades. Quantum entanglement describes a phenomenon in which particles become deeply connected, allowing their properties to remain linked even across large distances.
Until now, researchers had only demonstrated entangled measurements for another quantum state known as the GHZ state. The W state remained experimentally inaccessible despite its importance for future quantum technologies.
The Japanese team solved the problem by developing a photonic quantum circuit capable of identifying W states through a process based on cyclic shift symmetry and quantum Fourier transformation. Using a highly stable optical setup, the researchers successfully demonstrated the technique with three photons.
According to physicist Shigeki Takeuchi, the achievement comes more than 25 years after scientists first proposed similar measurements for GHZ states.
The experiment allowed the system to distinguish different types of three-photon W states while maintaining long operational stability without continuous manual adjustments — an important step toward scalable quantum technologies.
Researchers believe the advance could strengthen future quantum communication protocols, improve quantum networking and support new forms of measurement-based quantum computing. The technology may also play a role in quantum teleportation systems designed to transfer quantum information instantly across future networks.
