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Title: Observation of the 1S–2P Lyman-α transition in antihydrogen

Journal Article · · Nature (London)
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  1. Univ. of Liverpool (United Kingdom). Dept. of Physics
  2. Aarhus Univ. (Denmark). Dept. of Physics and Astronomy
  3. Swansea Univ. (United Kingdom). College of Science. Dept. of Physics
  4. Univ. of Manchester (United Kingdom). School of Physics and Astronomy; Sci-Tech Daresbury, Warrington (United Kingdom). Cockcroft Inst.
  5. TRIUMF, Vancouver, BC (Canada)
  6. Univ. of California, Berkeley, CA (United States). Dept. of Physics
  7. Univ. Federal do Rio de Janeiro (Brazil). Inst. de Fisica
  8. Ben-Gurion Univ. of the Negev, Beer-Sheva (Israel). Dept. of Physics
  9. Univ. of Calgary, AB (Canada). Dept. of Physics and Astronomy
  10. Univ. of British Columbia, Vancouver, BC (Canada). Dept. of Physics and Astronomy
  11. Aarhus Univ. (Denmark). Dept. of Physics and Astronomy; Univ. of Calgary, AB (Canada). Dept. of Physics and Astronomy
  12. Simon Fraser Univ., Burnaby, BC (Canada). Dept. of Physics
  13. Aarhus Univ. (Denmark). Dept. of Physics and Astronomy; Swansea Univ. (United Kingdom). College of Science. Dept. of Physics
  14. Stockholm Univ. (Sweden). Dept. of Physics
  15. York Univ., Toronto, ON (Canada). Dept. of Physics and Astronomy
  16. TRIUMF, Vancouver, BC (Canada); Ecole Polytechnique Federale Lausanne (Switzlerland). Swiss Plasma Center (SPC)
  17. Univ. of British Columbia, Vancouver, BC (Canada). Dept. of Physics and Astronomy; Univ. of British Columbia, Vancouver, BC (Canada). Dept. of Chemistry
  18. TRIUMF, Vancouver, BC (Canada); Univ. of Victoria, BC (Canada). Dept. of Physics and Astronomy
  19. Purdue Univ., West Lafayette, IN (United States). Dept. of Physics and Astronomy
  20. Univ. of Manchester (United Kingdom). School of Physics and Astronomy
  21. Israel Atomic Energy Commission (IAEC), Yavne (Israel). Soreq Nuclear Research Centre (Soreq NRC)
  22. niv. of Calgary, AB (Canada). Dept. of Physics and Astronomy
  23. Marquette Univ., Milwaukee, WI (United States). Physics Dept.
  24. TRIUMF, Vancouver, BC (Canada); Univ. of Calgary, AB (Canada). Dept. of Physics and Astronomy
  25. Swansea Univ. (United Kingdom). College of Science. Dept. of Physics; IRFU, CEA/Saclay, Gif-sur-Yvette Cedex (France)
+ Show Author Affiliations

In 1906, Theodore Lyman discovered his eponymous series of transitions in the extreme-ultraviolet region of the atomic hydrogen spectrum1,2. The patterns in the hydrogen spectrum helped to establish the emerging theory of quantum mechanics, which we now know governs the world at the atomic scale. Since then, studies involving the Lyman-α line—the 1S–2P transition at a wavelength of 121.6 nanometres—have played an important part in physics and astronomy, as one of the most fundamental atomic transitions in the Universe. For example, this transition has long been used by astronomers studying the intergalactic medium and testing cosmological models via the so-called ‘Lyman-α forest’3 of absorption lines at different redshifts. Here we report the observation of the Lyman-α transition in the antihydrogen atom, the antimatter counterpart of hydrogen. Using narrow-line-width, nanosecond-pulsed laser radiation, the 1S–2P transition was excited in magnetically trapped antihydrogen. The transition frequency at a field of 1.033 tesla was determined to be 2,466,051.7 ± 0.12 gigahertz (1σ uncertainty) and agrees with the prediction for hydrogen to a precision of 5 × 10-8. Comparisons of the properties of antihydrogen with those of its well-studied matter equivalent allow precision tests of fundamental symmetries between matter and antimatter. Alongside the ground-state hyperfine4,5 and 1S–2S transitions6,7 recently observed in antihydrogen, the Lyman-α transition will permit laser cooling of antihydrogen8,9, thus providing a cold and dense sample of anti-atoms for precision spectroscopy and gravity measurements10. In addition to the observation of this fundamental transition, this work represents both a decisive technological step towards laser cooling of antihydrogen, and the extension of antimatter spectroscopy to quantum states possessing orbital angular momentum.

Research Organization:
University of California, Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
FG02-04ER63917
OSTI ID:
1624269
Journal Information:
Nature (London), Vol. 561, Issue 7722; ISSN 0028-0836
Publisher:
Nature Publishing GroupCopyright Statement
Country of Publication:
United States
Language:
English

References (41)

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Characterization of the 1S–2S transition in antihydrogen journal April 2018
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Codata Recommended Values Of The Fundamental Physical Constants: 2014 text January 2015
Evaporative Cooling of Antiprotons to Cryogenic Temperatures text January 2010
Trapped Antihydrogen in Its Ground State text January 2012
A proposal for laser cooling antihydrogen atoms text January 2012
In situ electromagnetic field diagnostics with an electron plasma in a Penning-Malmberg trap text January 2014
The Lyman-alpha Forest as a Cosmological Tool text January 2003
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Cited By (11)

Atom femto trap: experimental realization journal January 2020
Trapping of C 2 − in a digital ion trap journal October 2019
Separated oscillatory field measurement of hydrogen 2 S 1 / 2 -2 P 3 / 2 fine structure interval journal February 1994
Investigation of the fine structure of antihydrogen journal February 2020
Formation of antihydrogen beams from positron–antiproton interactions journal July 2019
Estimation of antihydrogen properties in experiments with small signal deficit journal March 2019
Laser-driven production of the antihydrogen molecular ion journal October 2019
Simulations of Majorana spin flips in an antihydrogen trap journal July 2019
Artificially structured boundary plasma trap journal September 2019
Simulations of Majorana spin flips in an antihydrogen trap text January 2019
A hydrogen beam to characterize the ASACUSA antihydrogen hyperfine spectrometer
  • Malbrunot, C.; Diermaier, M.; Simon, M. C.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 935 https://doi.org/10.1016/j.nima.2019.04.060
journal August 2019

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