skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Investigation of the fine structure of antihydrogen

Abstract

At the historic Shelter Island Conference on the Foundations of Quantum Mechanics in 1947, Willis Lamb reported an unexpected feature in the fine structure of atomic hydrogen: a separation of the 2S1/2 and 2P1/2 states. The observation of this separation, now known as the Lamb shift, marked an important event in the evolution of modern physics, inspiring others to develop the theory of quantum electrodynamics. Quantum electrodynamics also describes antimatter, but it has only recently become possible to synthesize and trap atomic antimatter to probe its structure. Mirroring the historical development of quantum atomic physics in the twentieth century, modern measurements on anti-atoms represent a unique approach for testing quantum electrodynamics and the foundational symmetries of the standard model. Here we report measurements of the fine structure in the n = 2 states of antihydrogen, the antimatter counterpart of the hydrogen atom. Using optical excitation of the 1S–2P Lyman-α transitions in antihydrogen, we determine their frequencies in a magnetic field of 1 tesla to a precision of 16 parts per billion. Assuming the standard Zeeman and hyperfine interactions, we infer the zero-field fine-structure splitting (2P1/2–2P3/2) in antihydrogen. The resulting value is consistent with the predictions of quantum electrodynamics to amore » precision of 2 per cent. Using our previously measured value of the 1S–2S transition frequency, we find that the classic Lamb shift in antihydrogen (2S1/2–2P1/2 splitting at zero field) is consistent with theory at a level of 11 per cent. Our observations represent an important step towards precision measurements of the fine structure and the Lamb shift in the antihydrogen spectrum as tests of the charge–parity–time symmetry8 and towards the determination of other fundamental quantities, such as the antiproton charge radius, in this antimatter system.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]
  1. Univ. of California, Berkeley, CA (United States)
Publication Date:
Research Org.:
Univ. of California, Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
Contributing Org.:
The ALPHA Collaboration
OSTI Identifier:
1603472
Grant/Contract Number:  
SC0019346
Resource Type:
Accepted Manuscript
Journal Name:
Nature (London)
Additional Journal Information:
Journal Name: Nature (London); Journal Volume: 578; Journal Issue: 7795; Journal ID: ISSN 0028-0836
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Fajans, Joel, and Wurtele, Jonathan. Investigation of the fine structure of antihydrogen. United States: N. p., 2020. Web. doi:10.1038/s41586-020-2006-5.
Fajans, Joel, & Wurtele, Jonathan. Investigation of the fine structure of antihydrogen. United States. doi:https://doi.org/10.1038/s41586-020-2006-5
Fajans, Joel, and Wurtele, Jonathan. Wed . "Investigation of the fine structure of antihydrogen". United States. doi:https://doi.org/10.1038/s41586-020-2006-5. https://www.osti.gov/servlets/purl/1603472.
@article{osti_1603472,
title = {Investigation of the fine structure of antihydrogen},
author = {Fajans, Joel and Wurtele, Jonathan},
abstractNote = {At the historic Shelter Island Conference on the Foundations of Quantum Mechanics in 1947, Willis Lamb reported an unexpected feature in the fine structure of atomic hydrogen: a separation of the 2S1/2 and 2P1/2 states. The observation of this separation, now known as the Lamb shift, marked an important event in the evolution of modern physics, inspiring others to develop the theory of quantum electrodynamics. Quantum electrodynamics also describes antimatter, but it has only recently become possible to synthesize and trap atomic antimatter to probe its structure. Mirroring the historical development of quantum atomic physics in the twentieth century, modern measurements on anti-atoms represent a unique approach for testing quantum electrodynamics and the foundational symmetries of the standard model. Here we report measurements of the fine structure in the n = 2 states of antihydrogen, the antimatter counterpart of the hydrogen atom. Using optical excitation of the 1S–2P Lyman-α transitions in antihydrogen, we determine their frequencies in a magnetic field of 1 tesla to a precision of 16 parts per billion. Assuming the standard Zeeman and hyperfine interactions, we infer the zero-field fine-structure splitting (2P1/2–2P3/2) in antihydrogen. The resulting value is consistent with the predictions of quantum electrodynamics to a precision of 2 per cent. Using our previously measured value of the 1S–2S transition frequency, we find that the classic Lamb shift in antihydrogen (2S1/2–2P1/2 splitting at zero field) is consistent with theory at a level of 11 per cent. Our observations represent an important step towards precision measurements of the fine structure and the Lamb shift in the antihydrogen spectrum as tests of the charge–parity–time symmetry8 and towards the determination of other fundamental quantities, such as the antiproton charge radius, in this antimatter system.},
doi = {10.1038/s41586-020-2006-5},
journal = {Nature (London)},
number = 7795,
volume = 578,
place = {United States},
year = {2020},
month = {2}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 3 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Improved Measurement of the Hydrogen 1 S 2 S Transition Frequency
journal, November 2011


Aspects of 1 S -2 S spectroscopy of trapped antihydrogen atoms
journal, September 2017

  • Rasmussen, C. Ø; Madsen, N.; Robicheaux, F.
  • Journal of Physics B: Atomic, Molecular and Optical Physics, Vol. 50, Issue 18
  • DOI: 10.1088/1361-6455/aa854c

QED and the Men Who Made It: Dyson, Feynman, Schwinger and Tomonaga
journal, December 1994

  • Schweber, Silvan S.; Treiman, Sam
  • Physics Today, Vol. 47, Issue 12
  • DOI: 10.1063/1.2808749

The Rydberg constant and proton size from atomic hydrogen
journal, October 2017


Quantum Energy Flow in Atomic Ions Moving in Magnetic Fields
journal, February 2000


Observation of the 1S–2P Lyman-α transition in antihydrogen
journal, August 2018


Positron trapping in an electrostatic well by inelastic collisions with nitrogen molecules
journal, November 1992


Real-time Detection of Antihydrogen Annihilations and Applications to Spectroscopy
journal, January 2014


Lifetime of magnetically trapped antihydrogen in ALPHA
journal, January 2019


Characterization of the 1S–2S transition in antihydrogen
journal, April 2018


Lorentz and C P T tests with hydrogen, antihydrogen, and related systems
journal, September 2015


Precision measurements on trapped antihydrogen in the ALPHA experiment
journal, February 2018

  • Eriksson, S.
  • Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 376, Issue 2116
  • DOI: 10.1098/rsta.2017.0268

Space-Time Approach to Quantum Electrodynamics
journal, September 1949


Description and first application of a new technique to measure the gravitational mass of antihydrogen
journal, April 2013


Antiproton charge radius
journal, September 2016


The size of the proton
journal, July 2010

  • Pohl, Randolf; Antognini, Aldo; Nez, François
  • Nature, Vol. 466, Issue 7303
  • DOI: 10.1038/nature09250

Precision physics of simple atoms: QED tests, nuclear structure and fundamental constants
journal, December 2005


Fine Structure of the Hydrogen Atom by a Microwave Method
journal, August 1947


Observation of the hyperfine spectrum of antihydrogen
journal, August 2017

  • Ahmadi, M.; Alves, B. X. R.; Baker, C. J.
  • Nature, Vol. 548, Issue 7665
  • DOI: 10.1038/nature23446

In situ electromagnetic field diagnostics with an electron plasma in a Penning–Malmberg trap
journal, January 2014


Trapped antihydrogen
journal, November 2010

  • Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.
  • Nature, Vol. 468, Issue 7324
  • DOI: 10.1038/nature09610

A critical compilation of experimental data on spectral lines and energy levels of hydrogen, deuterium, and tritium
journal, November 2010


Observation of the 1S–2S transition in trapped antihydrogen
journal, December 2016

  • Ahmadi, M.; Alves, B. X. R.; Baker, C. J.
  • Nature, Vol. 541, Issue 7638
  • DOI: 10.1038/nature21040

A proposal for laser cooling antihydrogen atoms
journal, January 2013

  • Donnan, P. H.; Fujiwara, M. C.; Robicheaux, F.
  • Journal of Physics B: Atomic, Molecular and Optical Physics, Vol. 46, Issue 2
  • DOI: 10.1088/0953-4075/46/2/025302

On Quantum-Electrodynamics and the Magnetic Moment of the Electron
journal, February 1948


Enhanced Control and Reproducibility of Non-Neutral Plasmas
journal, January 2018


CODATA recommended values of the fundamental physical constants: 2014
journal, September 2016


Antihydrogen accumulation for fundamental symmetry tests
journal, September 2017


Precise Theory of the Zeeman Spectrum for Atomic Hydrogen and Deuterium and the Lamb Shift
journal, November 1967


Continuous Coherent Lyman- α Excitation of Atomic Hydrogen
journal, June 2001


Narrowband solid state vuv coherent source for laser cooling of antihydrogen
journal, May 2015

  • Michan, J. Mario; Polovy, Gene; Madison, Kirk W.
  • Hyperfine Interactions, Vol. 235, Issue 1-3
  • DOI: 10.1007/s10751-015-1186-0

On a Relativistically Invariant Formulation of the Quantum Theory of Wave Fields*
journal, August 1946

  • Tomonaga, S.
  • Progress of Theoretical Physics, Vol. 1, Issue 2
  • DOI: 10.1143/PTP.1.27

Lyman-α spectroscopy of magnetically trapped atomic hydrogen
journal, February 1993


Measurement of the Lamb Shift in Hydrogen, n = 2
journal, January 1981


Lyman-α source for laser cooling antihydrogen
journal, January 2018

  • Gabrielse, G.; Glowacz, B.; Grzonka, D.
  • Optics Letters, Vol. 43, Issue 12
  • DOI: 10.1364/OL.43.002905

New Measurement of the 1 S 3 S Transition Frequency of Hydrogen: Contribution to the Proton Charge Radius Puzzle
journal, May 2018


Separated oscillatory field measurement of hydrogen 2 S 1 / 2 -2 P 3 / 2 fine structure interval
journal, February 1994