Practical Quantum Clock Synchronization Using Weak Coherent Pulses

• URL: http://arxiv.org/abs/2510.00199v1
• Date: Tue, 30 Sep 2025 19:21:59 GMT
• Title: Practical Quantum Clock Synchronization Using Weak Coherent Pulses
• Authors: Noah Crum, Md Mehdi Hassan, George Siopsis,
• Abstract summary: We numerically evaluate a quantum-enhanced clock synchronization protocol based on attenuated weak coherent pulses.<n>We simulate that sub-nanosecond clock-offset accuracy and precision can be achieved under these operating conditions.
• Score: 0.0
• License: http://creativecommons.org/licenses/by-nc-sa/4.0/
• Abstract: Establishing and maintaining a common time reference across spatially separated devices is a prerequisite for networked quantum experiments and secure communications. Classical two-way timing protocols such as Network Time Protocol (NTP) or Precision Time Protocol (PTP) are vulnerable to asymmetric channel delays and cannot provide the picosecond-level precision demanded by quantum repeater networks. We propose and numerically evaluate a quantum-enhanced clock synchronization protocol based on attenuated weak coherent pulses (WCPs) and bidirectional Hong--Ou--Mandel (HOM) interferometry. Our simulations assume telecom-band photons ($1550\,\mathrm{nm}$) with a temporal width of $10.0\,\mathrm{ns}$, a repetition rate of $f = 10\,\mathrm{MHz}$, effective mean photon number $\mu = 1.0$, detector efficiency $\eta = 85\%$, detector timing jitter of $150\,\mathrm{ps}$, and channel loss of $0.2\,\mathrm{dB/km}$. We simulate that sub-nanosecond clock-offset accuracy and precision can be achieved under these operating conditions. This work demonstrates that high-repetition-rate WCPs combined with HOM interference can provide flexible and secure quantum clock synchronization at sub-nanosecond precision.

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