Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:quant-ph/0005092 · Physical Review Letters

Quantum Algorithm for Distributed Clock Synchronization

Isaac L. Chuang

Published Aug 28, 2000• 140 citations
arXivHTMLPDF

Abstract

The clock synchronization problem is to determine the time difference Delta between two spatially separated clocks. When message delivery times between the two clocks are uncertain, O(2(2n)) classical messages must be exchanged between the clocks to determine n digits of Delta. On the other hand, as we show, there exists a quantum algorithm to obtain n digits of Delta while communicating only O(n) quantum messages.

DOI
10.1103/physrevlett.85.2006

Related papers

Iterative quantum algorithm for distributed clock synchronization

Hong‐Fu Wang, Shou Zhang

Clock synchronization is a well-studied problem with many practical and scientific applications. We propose an arbitrary accuracy iterative quantum algorithm for distributed clock synchronization using only three qubits. The n bits of the time difference Δ between two spatially separated clocks can be deterministically extracted by communicating only O ( n ) messages and executing the quantum iteration process n times based on the classical feedback and measurement operations. Finally, we also give the algorithm using only two qubits and discuss the success probability of the algorithm.

Chinese Physics B•Oct 1, 2012•1 citation

Iterative quantum algorithm for distributed clock synchronization

王洪福, 张寿

Clock synchronization is a well-studied problem with many practical and scientific applications.We propose an arbitrary accuracy iterative quantum algorithm for distributed clock synchronization using only three qubits.The n bits of the time difference between two spatially separated clocks can be deterministically extracted by communicating only O(n) messages and executing the quantum iteration process n times based on the classical feedback and measurement operations.Finally,we also give the algorithm using only two qubits and discuss the success probability of the algorithm.

中国物理B：英文版•Jan 1, 2012•0 citations

Quantum Clock Synchronization with one qubit

Chris Harrelson, Iordanis Kerenidis

The clock synchronization problem is to determine the time difference T between two spatially separated parties. We improve on I. Chuang's quantum clock synchronization algorithm and show that it is possible to obtain T to n bits of accuracy while communicating only one qubit in one direction and using an O(2^n) frequency range. We also prove a quantum lower bound of Ω(2^n) for the product of the transmitted qubits and the range of frequencies, thus showing that our algorithm is optimal.

arXiv:cs/0103021•Mar 28, 2001•2 citations

Review of Clock Synchronization in Quantum Communications

Nur Shahirah Azahari, Nur Ziadah Harun, Chuah Chai Wen +2 more

Industrial networks are frequently utilized for safety-critical applications that demand real-time requirements. Message scheduling or timestamp is typically a key component of such applications, which are typically time-triggered. Timestamps at each party in quantum communication must be synchronized or share a common understanding of time for secure communication. Clock synchronization is thus a key component of real-time networks. Despite the benefits of time synchronization, enforcing clock synchronization on behalf of several quantum channel parties and preventing attacks from an adversary is still tricky. This paper identifies a possible attack on time synchronization and a way to solve the aforementioned issues. Therefore, we need a protocol that establishes a secure environment in terms of security with time synchronization so that various parties may freely and openly communicate. This paper also addresses significant research gaps in time synchronization and how it might be realized and applied to quantum communication. These include recommendations for new directions to be taken based on existing protocols.

International Conference on Software and Computer Applications (ICSCA)•Feb 1, 2024•8 citations

Review on quantum clock synchronization schemes

Yin-Ping Yao, Tongyi Zhang, Ren-Gang Wan +1 more

Accurate remote clock synchronization is the backbone of applications such as high-accuracy satellite navigation, digital and/or cryptographic communication systems, space-based interferometric surveillance, coherent distributed-aperture sensing at high frequencies, and geolocation. During the last decade, several clock synchronization schemes have been proposed based on quantum mechanical concepts. Quantum clock synchronization promises more precision and better security. In this paper, the various proposed quantum clock synchronization schemes are reviewed. We compare and discuss several different quantum clock synchronization schemes. The advantages and disadvantages of these schemes are investigated with emphasis on the application in space-based satellite navigation systems.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Nov 19, 2011•3 citations

Analytical Model of Clock Drift in Quantum Key Distribution and a Simple Synchronization Algorithm

Loïc Millet, Boris Korzh, Rob Thew +1 more

Clock synchronization is critical for maintaining low error rates in quantum key distribution. Here, we describe how a frequency mismatch between the transmitter and receiver clocks affects the quantum bit error rate in quantum key distribution, and derive from this model a simple synchronization algorithm together with clock stability requirements for practical operation. Our algorithm continuously compensates for both frequency mismatch and time-offset fluctuations directly from detection timestamps. It does not require a dedicated synchronization channel or auxiliary qubit sequence, converges from a large frequency mismatch within approximately one second of photon acquisition, and remains effective in low-photon-count regimes (more than 30 dB of channel loss) using standard hardware. We validate our approach by demonstrating successful key exchange over 100 km of fiber and continuous operation over 24 hours in a 16 km metropolitan network using commercial systems, with performance equivalent to using a service channel for clock synchronization.

quant-pharXiv:2605.26705•May 27, 2026•0 citations
The clock synchronization problem is to determine the time difference Delta between two spatially separated clocks. When message delivery times between the two clocks are uncertain, O(2(2n)) classical messages must be exchanged between the clocks to determine n digits of Delta. On the other hand, as we show, there exists a quantum algorithm to obtain n digits of Delta while communicating only O(n) quantum messages.
Clock synchronization is a well-studied problem with many practical and scientific applications. We propose an arbitrary accuracy iterative quantum algorithm for distributed clock synchronization using only three qubits. The n bits of the time difference Δ between two spatially separated clocks can be deterministically extracted by communicating only O ( n ) messages and executing the quantum iteration process n times based on the classical feedback and measurement operations. Finally, we also give the algorithm using only two qubits and discuss the success probability of the algorithm.
Clock synchronization is a well-studied problem with many practical and scientific applications.We propose an arbitrary accuracy iterative quantum algorithm for distributed clock synchronization using only three qubits.The n bits of the time difference between two spatially separated clocks can be deterministically extracted by communicating only O(n) messages and executing the quantum iteration process n times based on the classical feedback and measurement operations.Finally,we also give the algorithm using only two qubits and discuss the success probability of the algorithm.
Industrial networks are frequently utilized for safety-critical applications that demand real-time requirements. Message scheduling or timestamp is typically a key component of such applications, which are typically time-triggered. Timestamps at each party in quantum communication must be synchronized or share a common understanding of time for secure communication. Clock synchronization is thus a key component of real-time networks. Despite the benefits of time synchronization, enforcing clock synchronization on behalf of several quantum channel parties and preventing attacks from an adversary is still tricky. This paper identifies a possible attack on time synchronization and a way to solve the aforementioned issues. Therefore, we need a protocol that establishes a secure environment in terms of security with time synchronization so that various parties may freely and openly communicate. This paper also addresses significant research gaps in time synchronization and how it might be realized and applied to quantum communication. These include recommendations for new directions to be taken based on existing protocols.
Accurate remote clock synchronization is the backbone of applications such as high-accuracy satellite navigation, digital and/or cryptographic communication systems, space-based interferometric surveillance, coherent distributed-aperture sensing at high frequencies, and geolocation. During the last decade, several clock synchronization schemes have been proposed based on quantum mechanical concepts. Quantum clock synchronization promises more precision and better security. In this paper, the various proposed quantum clock synchronization schemes are reviewed. We compare and discuss several different quantum clock synchronization schemes. The advantages and disadvantages of these schemes are investigated with emphasis on the application in space-based satellite navigation systems.
Clock synchronization is critical for maintaining low error rates in quantum key distribution. Here, we describe how a frequency mismatch between the transmitter and receiver clocks affects the quantum bit error rate in quantum key distribution, and derive from this model a simple synchronization algorithm together with clock stability requirements for practical operation. Our algorithm continuously compensates for both frequency mismatch and time-offset fluctuations directly from detection timestamps. It does not require a dedicated synchronization channel or auxiliary qubit sequence, converges from a large frequency mismatch within approximately one second of photon acquisition, and remains effective in low-photon-count regimes (more than 30 dB of channel loss) using standard hardware. We validate our approach by demonstrating successful key exchange over 100 km of fiber and continuous operation over 24 hours in a 16 km metropolitan network using commercial systems, with performance equivalent to using a service channel for clock synchronization.