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Updated: Nov 28, 2025
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Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
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Two-photon frequency comb spectroscopy of atomic hydrogen
Alexey Grinin1, Arthur Matveev2, Dylan C Yost2
1Laser Spectroscopy Division Max-Planck-Institut für Quantenoptik, Garching, Germany. alexey.grinin@mpq.mpg.de.
Science (New York, N.Y.)
|November 27, 2020
Summary
This study uses advanced spectroscopy on atomic hydrogen to address the proton radius puzzle. The new measurements refine the Rydberg constant and proton charge radius, favoring the muonic hydrogen value.
Area of Science:
- Atomic, Molecular, and Optical (AMO) Physics
- Quantum Electrodynamics (QED)
Background:
- The proton radius puzzle highlights a significant discrepancy in proton size measurements between muonic hydrogen and conventional atomic hydrogen experiments.
- This discrepancy challenges current understanding within quantum electrodynamics.
Purpose of the Study:
- To investigate the proton radius puzzle using two-photon ultraviolet direct frequency comb spectroscopy.
- To demonstrate the potential of frequency comb spectroscopy for high-precision atomic measurements.
Main Methods:
- Performed two-photon ultraviolet direct frequency comb spectroscopy on the 1S-3S transition in atomic hydrogen.
- Combined the measured 1S-3S transition frequency with a previous 1S-2S transition frequency measurement.
Main Results:
- Obtained a precise measurement of the 1S-3S transition frequency in atomic hydrogen.
- Derived new values for the Rydberg constant (R_∞ = 10,973,731.568226(38) m⁻¹) and the proton charge radius (rₚ = 0.8482(38) fm).
Conclusions:
- The obtained proton charge radius favors the value derived from muonic hydrogen experiments.
- The results suggest a need for re-evaluation of existing data and theoretical models concerning the proton radius puzzle.
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