Related Experiment Video
Updated: Jun 1, 2026

05:30
Large Scale Energy Efficient Sensor Network Routing Using a Quantum Processor Unit
Published on: September 8, 2023
Field test of quantum key distribution in the Tokyo QKD Network
M Sasaki1, M Fujiwara, H Ishizuka
1Quantum ICT Laboratory, National Institute of Information and Communication Technology, 4-2-1 Nukui-kitamachi, Koganei, Tokyo 184-8795, Japan. psasaki@nict.co.jp
Optics Express
|June 7, 2011
Summary
Researchers developed a secure metropolitan quantum key distribution (QKD) network. This network enables the first secure TV conferencing over 45km using QKD technology.
Area of Science:
- Quantum Information Science
- Network Security
- Applied Physics
Background:
- Metropolitan-scale quantum key distribution (QKD) networks are crucial for secure communication.
- Integrating diverse QKD systems presents significant technical challenges.
- Previous QKD implementations have been limited in scope and application.
Purpose of the Study:
- To report the development and demonstration of a secure metropolitan QKD network.
- To showcase the integration of multiple QKD systems into a functional network.
- To establish a platform for advanced secure communication applications.
Main Methods:
- Integration of six different QKD systems into a mesh-type network architecture.
- Utilization of GHz-clocked QKD links for high-speed secure data transmission.
- Incorporation of a commercial QKD product for operational stability and a mobile interface.
Main Results:
- Demonstration of the world's first secure TV conferencing over a 45km distance using QKD.
- Successful implementation of eavesdropper detection and dynamic rerouting to secure paths.
- Validation of key relay functionality via trusted nodes within the network.
Conclusions:
- The developed metropolitan QKD network provides a robust platform for secure communication.
- The integration of diverse QKD systems is feasible and enables advanced applications.
- This work represents a significant advancement towards practical, large-scale quantum-secured networks.
Related Concept Videos
Detection of Gross Error: The Q Test
When one or more data points appear far from the rest of the data, there is a need to determine whether they are outliers and whether they should be eliminated from the data set to ensure an accurate representation of the measured value. In many cases, outliers arise from gross errors (or human errors) and do not accurately reflect the underlying phenomenon. In some cases, however, these apparent outliers reflect true phenomenological differences. In these cases, we can use statistical methods...
Kendall's Tau Test
Kendall's tau test, also known as the Kendall rank coefficient test, is a nonparametric method for assessing association between two variables. This test is particularly useful for identifying significant correlations when the distributions of the sample and population are unknown. Developed in 1938 by the British statistician Sir Maurice George Kendall, the tau coefficient (denoted as τ) serves as a rank correlation coefficient, with values ranging from -1 to +1.
A τ value of +1 indicates that...
A τ value of +1 indicates that...
Quantum Numbers
It is said that the energy of an electron in an atom is quantized; that is, it can be equal only to certain specific values and can jump from one energy level to another but not transition smoothly or stay between these levels.
Atomic Fluorescence Spectroscopy
Atomic fluorescence spectroscopy (AFS) is an analytical technique that involves the electronic transitions of atoms in a flame, furnace, or plasma being excited by electromagnetic (EM) radiation. When these atoms absorb energy, they become excited and subsequently release energy as they return to their original state. This emitted light, or "fluorescence," is observed at a right angle to the incident beam. Both absorption and emission processes transpire at distinct wavelengths, which are...
Wald-Wolfowitz Runs Test II
The Wald-Wolfowitz runs test, commonly referred to as the runs test, is a nonparametric test used to assess the randomness of ordered data. The test evaluates the number of runs, which are consecutive sequences of similar elements within the data. If the number of runs is significantly higher or lower than expected, the data is considered non-random, indicating a detectable pattern or structure.
For binary data, runs are identified using symbols such as + and −, or equivalently, 1s and 0s. In...
For binary data, runs are identified using symbols such as + and −, or equivalently, 1s and 0s. In...
Wald-Wolfowitz Runs Test I
The Wald-Wolfowitz test, also known as the runs test, is a nonparametric statistical test used to assess the randomness of a sequence of two different types of elements (e.g., positive/negative values, successes/failures). It examines whether the order of the elements in a sequence is random or if there is a pattern or trend present. This nonparametric test applies to any ordered data despite the population and sample data distribution, even if a higher sample size is available.
The test works...
The test works...