# Quantum Entanglement Measurement Breakthrough

> Physicists measure 'other' quantum entanglement after 25 years.
- Title: Quantum Entanglement Measurement Breakthrough · ScienceAlert
- Summary: Physicists measure 'other' quantum entanglement after 25 years. Physicists from Kyoto and Hiroshima universities measured W-state quantum entanglement in…
- Keywords: quantum entanglement, w-state, kyoto university, hiroshima university, science advances, quantum computing, photonic quantum computation, quantum communication, quantum cryptography, molecular tomography, science, Quantum
- Source: ScienceAlert — https://sciencealert.com/after-25-years-physicists-can-finally-measure-the-other-kind-of-quantum-entanglement
- Author: Ivan Farkas
- Published: 2026-10-05T01:30:34+00:00
- Read time: 1 min
- Topics: quantum entanglement, w-state, kyoto university, hiroshima university, science advances, quantum computing, photonic quantum computation, quantum communication, quantum cryptography, molecular tomography, science
## Quantum Entanglement Basics
Quantum entanglement connects particles so they share a quantum identity and exist in superposition until measured.
## Quantum Entanglement Limitations
Entangled particles transmit random results instantly across distances but cannot send information faster than light.
## W-State Entanglement
W-state entanglement retains useful quantum states even if one particle is lost, unlike GHZ states.
## Quantum Tomography Challenge
Traditional quantum tomography requires many identical systems and exponentially increases with particle count.
## New Measurement Technique
Researchers used a discrete Fourier transform optical circuit to measure W-state entanglement in three photons with one shot.
## Measurement Results
The technique achieved 87% accuracy in identifying W-state entanglement, exceeding the 66.7% threshold for proof.
## Next Steps
Researchers plan to develop on-chip photonic quantum circuits for improved quantum computing and cryptography.
## Key takeaway

Physicists from Kyoto and Hiroshima universities measured W-state quantum entanglement in three photons for the first time, achieving 87% accuracy.