Title: Laser cooling of antihydrogen atoms

Abstract

The photon—the quantum excitation of the electromagnetic field—is massless but carries momentum. A photon can therefore exert a force on an object upon collision¹. Slowing the translational motion of atoms and ions by application of such a force^2,3, known as laser cooling, was first demonstrated 40 years ago^4,5. It revolutionized atomic physics over the following decades^6–8, and it is now a workhorse in many fields, including studies on quantum degenerate gases, quantum information, atomic clocks and tests of fundamental physics. However, this technique has not yet been applied to antimatter. Here we demonstrate laser cooling of antihydrogen⁹, the antimatter atom consisting of an antiproton and a positron. By exciting the 1S–2P transition in antihydrogen with pulsed, narrow-linewidth, Lyman-α laser radiation^10,11, we Doppler-cool a sample of magnetically trapped antihydrogen. Although we apply laser cooling in only one dimension, the trap couples the longitudinal and transverse motions of the anti-atoms, leading to cooling in all three dimensions. We observe a reduction in the median transverse energy by more than an order of magnitude—with a substantial fraction of the anti-atoms attaining submicroelectronvolt transverse kinetic energies. We also report the observation of the laser-driven 1S–2S transition in samples of laser-cooled antihydrogen atoms. The observedmore » spectral line is approximately four times narrower than that obtained without laser cooling. The demonstration of laser cooling and its immediate application has far-reaching implications for antimatter studies. A more localized, denser and colder sample of antihydrogen will drastically improve spectroscopic^11–13and gravitational¹⁴studies of antihydrogen in ongoing experiments. Furthermore, the demonstrated ability to manipulate the motion of antimatter atoms by laser light will potentially provide ground-breaking opportunities for future experiments, such as anti-atomic fountains, anti-atom interferometry and the creation of antimatter molecules.« less

Authors:

Baker, C. J. ^[1]; Bertsche, W. ^[2]; Capra, A. ^[3]; Carruth, C. ^[4]; Cesar, C. L. ^[5]; Charlton, M. ^[1]; Christensen, A. ^[4]; Collister, R. ^[3]; Mathad, A. Cridland  ^[1];

• Search DOE PAGES for author "Mathad, A. Cridland"
• Search DOE PAGES for ORCID "0000-0003-4361-0266"

Eriksson, S. ^[1]; Evans, A. ^[6]; Evetts, N. ^[7]; Fajans, J.  ^[4];

• Search DOE PAGES for author "Fajans, J."
• Search DOE PAGES for ORCID "0000-0002-4403-6027"

Friesen, T. ^[6]; Fujiwara, M. C.  ^[3];

• Search DOE PAGES for author "Fujiwara, M. C."
• Search DOE PAGES for ORCID "0000-0002-9371-4904"

Gill, D. R. ^[3]; Grandemange, P. ^[8]; Granum, P.  ^[9];

• Search DOE PAGES for author "Granum, P."
• Search DOE PAGES for ORCID "0000-0002-2710-266X"

Hangst, J. S. ^[9]; Hardy, W. N. ^[7] more »; Hayden, M. E.; Hodgkinson, D.; Hunter, E.; Isaac, C. A.; Johnson, M. A.; Jones, J. M.; Jones, S. A.; Jonsell, S. ;

• Search DOE PAGES for author "Jonsell, S."
• Search DOE PAGES for ORCID "0000-0003-4969-1714"

Khramov, A. ;

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• Search DOE PAGES for ORCID "0000-0001-7218-8549"

Knapp, P.; Kurchaninov, L.; Madsen, N.; Maxwell, D.; McKenna, J. T. K.; Menary, S.; Michan, J. M.; Momose, T.; Mullan, P. S.; Munich, J. J. ;

• Search DOE PAGES for author "Munich, J. J."
• Search DOE PAGES for ORCID "0000-0001-7475-3070"

Olchanski, K.; Olin, A. ;

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• Search DOE PAGES for ORCID "0000-0001-8055-7180"

Peszka, J. ;

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• Search DOE PAGES for ORCID "0000-0002-5140-8079"

Powell, A.; Pusa, P.; Rasmussen, C. Ø. ;

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• Search DOE PAGES for ORCID "0000-0002-6029-1730"

Robicheaux, F. ;

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• Search DOE PAGES for ORCID "0000-0002-8054-6040"

Sacramento, R. L.; Sameed, M.; Sarid, E.; Silveira, D. M.; Starko, D. M.; So, C.; Stutter, G.; Tharp, T. D.; Thibeault, A.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.

• Search DOE PAGES for author "Wurtele, J. S."
• Search DOE PAGES for ORCID "0000-0001-8401-0297"

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+ Show Author Affiliations

1. Swansea Univ. (United Kingdom). College of Science. Dept. of Physics
2. Univ. of Manchester (United Kingdom). School of Physics and Astronomy; Cockcroft Inst., Sci-Tech Daresbury, Warrington (United Kingdom)
3. TRIUMF, Vancouver, British Columbia (Canada)
4. Univ. of California, Berkeley, CA (United States). Dept. of Physics
5. Universidade Federal do Rio de Janeiro (Brazil). Instituto de Fisica
6. Univ. of Calgary, AB (Canada). Dept. of Physics and Astronomy
7. Univ. of British Columbia, Vancouver, BC (Canada). Dept. of Physics and Astronomy
8. TRIUMF, Vancouver, British Columbia (Canada); Univ. of British Columbia, Vancouver, BC (Canada). Dept. of Physics and Astronomy
9. Aarhus Univ. (Denmark). Dept. of Physics and Astronomy

Publication Date:

Wed Mar 31 00:00:00 EDT 2021

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division

Contributing Org.:

ALPHA Collaboration

OSTI Identifier:

1816445

Grant/Contract Number:  

SC0012704

Resource Type:

Accepted Manuscript

Journal Name:

Nature (London)

Additional Journal Information:

Journal Name: Nature (London); Journal Volume: 592; Journal Issue: 7852; Journal ID: ISSN 0028-0836

Publisher:

Nature Publishing Group

Country of Publication:

United States

Language:

English

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; exotic atoms and molecules; experimental particle physics