Kyoto, Hiroshima Universities Detect 3-Photon W States Instantly, Opening Path to Quantum Teleportation
Updated
Updated · ScienceDaily · Jun 14
Kyoto, Hiroshima Universities Detect 3-Photon W States Instantly, Opening Path to Quantum Teleportation
2 articles · Updated · ScienceDaily · Jun 14
Summary
A Kyoto-Hiroshima team experimentally identified 3-photon quantum W states in a single shot, solving a long-standing measurement problem that had resisted researchers for years.
The method uses W states' cyclic-shift symmetry and a photonic quantum circuit that applies a quantum Fourier transform, avoiding the measurement-heavy bottleneck of quantum tomography.
Their optical device ran stably for extended periods without active control and distinguished different 3-photon W states while the team evaluated measurement fidelity.
The result could strengthen quantum teleportation, communication and measurement-based computing, and the researchers now aim to scale the approach to larger entangled states and on-chip photonic circuits.
This breakthrough uses light to detect quantum states, but will this photonic approach ultimately win the quantum computing race?
Beyond the lab, what is the key obstacle preventing this quantum discovery from powering our future computers and networks?
With this quantum leap, how close are we to a 'quantum internet' that makes today's encryption obsolete?
Quantum Leap in 2025: Direct Measurement of W States Solves Decades-Old Challenge in Quantum Information Science
Overview
In September 2025, researchers from Kyoto University and Hiroshima University achieved the first direct and high-fidelity measurement of the quantum W state, solving a long-standing experimental challenge in quantum information science. Their breakthrough used a practical scheme based on the discrete Fourier transformation (DFT) of bosonic modes, leveraging the unique cyclic shift symmetry of W states. This method enables efficient and robust identification of W states, which are notable for maintaining entanglement even if a particle is lost. The advance paves the way for more reliable quantum communication systems and marks a major step forward for practical quantum technologies.