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Updated: Jun 29, 2026

Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh

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Published on: May 3, 2019

Quantum improvement of time transfer between remote clocks.

Brahim Lamine¹, Claude Fabre, Nicolas Treps

¹Laboratoire Kastler Brossel, Université Pierre et Marie Curie-Paris 6, ENS, CNRS, 4 place Jussieu, Paris, France. brahim.lamine@spectro.jussieu.fr

Physical Review Letters

|October 15, 2008

Summary

Scientists propose a new quantum physics scheme for ultra-precise space-time positioning using light pulses. This method could achieve yoctosecond-level accuracy, surpassing the standard quantum limit for time transfer.

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Published on: September 8, 2023

Area of Science:

Quantum Physics
Metrology
Optical Measurement

Background:

Accurate space-time positioning relies on exchanging light pulses, a process fundamentally limited by quantum mechanics.
The standard quantum limit (SQL) arises from quantum fluctuations in optical measurements, restricting positioning precision.
Current methods face inherent limitations due to the quantum nature of light.

Purpose of the Study:

To propose a novel scheme for enhanced space-time positioning.
To investigate methods for overcoming the standard quantum limit (SQL) in time transfer.
To explore the potential for achieving yoctosecond-level precision in positioning.

Main Methods:

Combining homodyne detection with mode-locked femtosecond lasers.
Utilizing appropriately multimode squeezed light as a quantum resource.
Developing an optimal detection strategy tailored to the quantum resource.

Main Results:

A new, lower standard quantum limit (SQL) for time transfer was established, potentially reaching the yoctosecond range (10^-21 to 10^-24 s).
Demonstrated that this enhanced SQL can be surpassed using specifically designed multimode squeezed light.
The proposed scheme shows significant potential for improving space-time positioning accuracy.

Conclusions:

The integration of homodyne detection, femtosecond lasers, and squeezed light offers a pathway to unprecedented precision in time transfer.
This approach pushes the boundaries of metrology, potentially enabling measurements at the yoctosecond scale.
The findings represent a substantial advancement in the field of high-precision space-time positioning.