Laser Cooling of Antihydrogen Atoms

Authors

C. J. Baker, Swansea UniversityFollow
W. Bertsche, University of ManchesterFollow
A. Capra, TRIUMF
C. Carruth, University of California - Berkeley
C. L. Cesar, Universidade Federal do Rio de JaneiroFollow
M. Charlton, Seansea UniversityFollow
A. Christensen, University of California - Berkeley
R. Collister, TRIUMFFollow
A. Cridland Mathad, Swansea University
S. Eriksson, Swansea UniversityFollow
A. Evans, University of Calgary
N. Evetts, University of British Columbia - VancouverFollow
J. Fajans, University of California - Berkeley
T. Friesen, University of CalgaryFollow
M. C. Fujiwara, TRIUMFFollow
D. R. Gill, TRIUMFFollow
P. Grandemange, TRIUMF
P. Granum, Aarhus University
J. S. Hangst, Aarhus UniversityFollow
W. N. Hardy, University of British ColumbiaFollow
M. E. Hayden, Simon Fraser UniversityFollow
D. Hodgkinson, University of Manchester
E. D. Hunter, , University of California - Berkeley
C. A. Isaac, Swansea UniversityFollow
M. A. Johnson, University of ManchesterFollow
J. M. Jones, Swansea University
S. A. Jones, Aarhus UniversityFollow
S. Jonsell, Stockholm University
A. Khramov, TRIUMF
P. Knapp, Swansea University
L. Kurchaninov, TRIUMF
N. Madsen, Swansea University
D. Maxwell, Swansea University
J. T. K. McKenna, TRIUMFFollow
S. Menary, York University
J. M. Michan, TRIUMFFollow
T. Momose, University of British Columbia - VancouverFollow
P. S. Mullan, Swansea University
K. Olchanski, TRIUMF
A. Olin, TRIUMFFollow
J. Peszka, Swansea University
A. Powell, Swansea University
P. Pusa, University of Liverpool
C. O. Rasmussen, Aarhus UniversityFollow
F. Robicheaux, Purdue University
R. L. Sacramento, Universidade Federal do Rio de JaneiroFollow
M. Sameed, University of ManchesterFollow
E. Sarid, Soreq NRCFollow
D. M. Silveira, Universidade Federal do Rio de JaneiroFollow
D, M. Starko, York University
C. So, TRIUMF
G. Stutter, Aarhus University
Timothy Tharp, Marquette UniversityFollow
A. Thibeault, TRIUMF
R. I. Thompson, University of CalgaryFollow
D. P. van der Werf, Swansea UniversityFollow
J. S. Wurtele, University of California - BerkeleyFollow

Document Type

Article

Publication Date

4-2021

Publisher

Nature Publishing Group (Macmillan Publishers Ltd.)

Source Publication

Nature

Source ISSN

0028-0836

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^6,7,8, 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 observed 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^11,12,13 and gravitational¹⁴ studies 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.

Comments

Accepted version. Nature, Vol. 592 (April 2021): 35-42. DOI. © 2021 Nature Publishing Group (Macmillan Publishers Limited). Used with permission.

Recommended Citation

Baker, C. J.; Bertsche, W.; Capra, A.; Carruth, C.; Cesar, C. L.; Charlton, M.; Christensen, A.; Collister, R.; Cridland Mathad, A.; Eriksson, S.; Evans, A.; Evetts, N.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Grandemange, P.; Granum, P.; Hangst, J. S.; Hardy, W. N.; Hayden, M. E.; Hodgkinson, D.; Hunter, E. D.; Isaac, C. A.; Johnson, M. A.; Jones, J. M.; Jones, S. A.; Jonsell, S.; Khramov, A.; Knapp, P.; Kurchaninov, L.; Madsen, N.; Maxwell, D.; McKenna, J. T. K.; Menary, S.; Michan, J. M.; Momose, T.; Mullan, P. S.; Olchanski, K.; Olin, A.; Peszka, J.; Powell, A.; Pusa, P.; Rasmussen, C. O.; Robicheaux, F.; Sacramento, R. L.; Sameed, M.; Sarid, E.; Silveira, D. M.; Starko, D, M.; So, C.; Stutter, G.; Tharp, Timothy; Thibeault, A.; Thompson, R. I.; van der Werf, D. P.; and Wurtele, J. S., "Laser Cooling of Antihydrogen Atoms" (2021). Physics Faculty Research and Publications. 180.
https://epublications.marquette.edu/physics_fac/180