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Anderson EK, Baker CJ, Bertsche W, Bhatt NM, Bonomi G, Capra A, Carli I, Cesar CL, Charlton M, Christensen A, Collister R, Cridland Mathad A, Duque Quiceno D, Eriksson S, Evans A, Evetts N, Fabbri S, Fajans J, Ferwerda A, Friesen T, Fujiwara MC, Gill DR, Golino LM, Gomes Gonçalves MB, Grandemange P, Granum P, Hangst JS, Hayden ME, Hodgkinson D, Hunter ED, Isaac CA, Jimenez AJU, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Madsen N, Martin L, Massacret N, Maxwell D, McKenna JTK, Menary S, Momose T, Mostamand M, Mullan PS, Nauta J, Olchanski K, Oliveira AN, Peszka J, Powell A, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Schoonwater J, Silveira DM, Singh J, Smith G, So C, Stracka S, Stutter G, Tharp TD, Thompson KA, Thompson RI, Thorpe-Woods E, Torkzaban C, Urioni M, Woosaree P, Wurtele JS. Observation of the effect of gravity on the motion of antimatter. Nature 2023; 621:716-722. [PMID: 37758891 PMCID: PMC10533407 DOI: 10.1038/s41586-023-06527-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 08/09/2023] [Indexed: 09/29/2023]
Abstract
Einstein's general theory of relativity from 19151 remains the most successful description of gravitation. From the 1919 solar eclipse2 to the observation of gravitational waves3, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the gravitating content of the universe. Singularities in the general theory of relativity and the lack of a quantum theory of gravity suggest that our picture is incomplete. It is thus prudent to explore gravity in exotic physical systems. Antimatter was unknown to Einstein in 1915. Dirac's theory4 appeared in 1928; the positron was observed5 in 1932. There has since been much speculation about gravity and antimatter. The theoretical consensus is that any laboratory mass must be attracted6 by the Earth, although some authors have considered the cosmological consequences if antimatter should be repelled by matter7-10. In the general theory of relativity, the weak equivalence principle (WEP) requires that all masses react identically to gravity, independent of their internal structure. Here we show that antihydrogen atoms, released from magnetic confinement in the ALPHA-g apparatus, behave in a way consistent with gravitational attraction to the Earth. Repulsive 'antigravity' is ruled out in this case. This experiment paves the way for precision studies of the magnitude of the gravitational acceleration between anti-atoms and the Earth to test the WEP.
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Affiliation(s)
- E K Anderson
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - C J Baker
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, UK.
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK.
| | - N M Bhatt
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - G Bonomi
- University of Brescia, Brescia and INFN Pavia, Pavia, Italy
| | - A Capra
- TRIUMF, Vancouver, British Columbia, Canada
| | - I Carli
- TRIUMF, Vancouver, British Columbia, Canada
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Charlton
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - A Christensen
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - R Collister
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - A Cridland Mathad
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - D Duque Quiceno
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - S Eriksson
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - A Evans
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - S Fabbri
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Accelerator and Technology Sector, CERN, Geneva, Switzerland
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.
| | - A Ferwerda
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - T Friesen
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | | | - D R Gill
- TRIUMF, Vancouver, British Columbia, Canada
| | - L M Golino
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - M B Gomes Gonçalves
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | | | - P Granum
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - D Hodgkinson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - E D Hunter
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C A Isaac
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | | | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - J M Jones
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - S A Jones
- Van Swinderen Institute for Particle Physics and Gravity, University of Groningen, Groningen, The Netherlands
| | - S Jonsell
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - A Khramov
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Physics, British Columbia Institute of Technology, Burnaby, British Columbia, Canada
| | - N Madsen
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - L Martin
- TRIUMF, Vancouver, British Columbia, Canada
| | | | - D Maxwell
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - J T K McKenna
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - T Momose
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - M Mostamand
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - P S Mullan
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
- Institute for Particle Physics and Astrophysics, ETH, Zurich, Switzerland
| | - J Nauta
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | | | - A N Oliveira
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - J Peszka
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
- Institute for Particle Physics and Astrophysics, ETH, Zurich, Switzerland
| | - A Powell
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - C Ø Rasmussen
- Experimental Physics Department, CERN, Geneva, Switzerland
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Sameed
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Accelerator Systems Department, CERN, Geneva, Switzerland
| | - E Sarid
- Soreq NRC, Yavne, Israel
- Department of Physics, Ben Gurion University, Beer Sheva, Israel
| | - J Schoonwater
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - J Singh
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - G Smith
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - C So
- TRIUMF, Vancouver, British Columbia, Canada
| | | | - G Stutter
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- School of Mathematical and Physical Sciences, University of Sussex, Brighton, UK
| | - T D Tharp
- Physics Department, Marquette University, Milwaukee, WI, USA
| | - K A Thompson
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - R I Thompson
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - E Thorpe-Woods
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - C Torkzaban
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - M Urioni
- University of Brescia, Brescia and INFN Pavia, Pavia, Italy
| | - P Woosaree
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
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2
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Baker CJ, Bertsche W, Capra A, Cesar CL, Charlton M, Mathad AC, Eriksson S, Evans A, Evetts N, Fabbri S, Fajans J, Friesen T, Fujiwara MC, Grandemange P, Granum P, Hangst JS, Hayden ME, Hodgkinson D, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Momose T, Mullan P, Olchanski K, Olin A, Peszka J, Powell A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stutter G, So C, Tharp TD, Thompson RI, van der Werf DP, Wurtele JS. Sympathetic cooling of positrons to cryogenic temperatures for antihydrogen production. Nat Commun 2021; 12:6139. [PMID: 34686658 PMCID: PMC8536749 DOI: 10.1038/s41467-021-26086-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 09/13/2021] [Indexed: 11/25/2022] Open
Abstract
The positron, the antiparticle of the electron, predicted by Dirac in 1931 and discovered by Anderson in 1933, plays a key role in many scientific and everyday endeavours. Notably, the positron is a constituent of antihydrogen, the only long-lived neutral antimatter bound state that can currently be synthesized at low energy, presenting a prominent system for testing fundamental symmetries with high precision. Here, we report on the use of laser cooled Be+ ions to sympathetically cool a large and dense plasma of positrons to directly measured temperatures below 7 K in a Penning trap for antihydrogen synthesis. This will likely herald a significant increase in the amount of antihydrogen available for experimentation, thus facilitating further improvements in studies of fundamental symmetries.
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Affiliation(s)
- C J Baker
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, WA4 4AD, UK
| | - A Capra
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - A Cridland Mathad
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
| | - S Fabbri
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720-7300, USA
| | - T Friesen
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - P Grandemange
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - P Granum
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
| | - D Hodgkinson
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK
| | - J M Jones
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - S A Jones
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - S Jonsell
- Department of Physics, Stockholm University, SE-10691, Stockholm, Sweden
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK.
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK.
| | - J T K McKenna
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, ON, M3J 1P3, Canada
| | - T Momose
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
| | - P Mullan
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - J Peszka
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - A Powell
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, UK
| | - C Ø Rasmussen
- Experimental Physics Department, CERN, Geneva, 1211, Switzerland
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - M Sameed
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK
| | - E Sarid
- Soreq NRC, 81800, Yavne, Israel
- Department of Physics, Ben Gurion University, 8410501, Beer Sheva, Israel
| | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - C So
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - T D Tharp
- Physics Department, Marquette University, P.O. Box 1881, Milwaukee, WI, 53201-1881, USA
| | - R I Thompson
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720-7300, USA
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3
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Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Christensen A, Collister R, Mathad AC, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Grandemange P, Granum P, Hangst JS, Hardy WN, Hayden ME, Hodgkinson D, Hunter E, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Knapp P, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Mullan PS, Munich JJ, Olchanski K, Olin A, Peszka J, Powell A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Starko DM, So C, Stutter G, Tharp TD, Thibeault A, Thompson RI, van der Werf DP, Wurtele JS. Laser cooling of antihydrogen atoms. Nature 2021; 592:35-42. [PMID: 33790445 PMCID: PMC8012212 DOI: 10.1038/s41586-021-03289-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 01/26/2021] [Indexed: 11/08/2022]
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 force2,3, known as laser cooling, was first demonstrated 40 years ago4,5. It revolutionized atomic physics over the following decades6-8, 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 radiation10,11, 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 spectroscopic11-13 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.
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Affiliation(s)
- C J Baker
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - A Capra
- TRIUMF, Vancouver, British Columbia, Canada
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - A Christensen
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | | | - A Cridland Mathad
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - T Friesen
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | | | - D R Gill
- TRIUMF, Vancouver, British Columbia, Canada
| | - P Grandemange
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - P Granum
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - D Hodgkinson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - E Hunter
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - J M Jones
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S A Jones
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - S Jonsell
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - A Khramov
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Physics, British Columbia Institute of Technology, Burnaby, British Columbia, Canada
| | - P Knapp
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | | | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - J T K McKenna
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - J M Michan
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - T Momose
- TRIUMF, Vancouver, British Columbia, Canada.
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada.
| | - P S Mullan
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | | | - A Olin
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada
| | - J Peszka
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - A Powell
- Department of Physics, College of Science, Swansea University, Swansea, UK
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool, UK
| | - C Ø Rasmussen
- Experimental Physics Department, CERN, Geneva, Switzerland
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Sameed
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - E Sarid
- Soreq NRC, Yavne, Israel
- Department of Physics, Ben Gurion University, Beer Sheva, Israel
| | - D M Silveira
- TRIUMF, Vancouver, British Columbia, Canada
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - D M Starko
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - C So
- TRIUMF, Vancouver, British Columbia, Canada
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - T D Tharp
- Physics Department, Marquette University, Milwaukee, WI, USA
| | - A Thibeault
- TRIUMF, Vancouver, British Columbia, Canada
- Faculté de Génie, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - R I Thompson
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
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4
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Granum P, Hangst JS, Hardy WN, Hayden ME, Hunter ED, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Knapp P, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, So C, Starko DM, Stutter G, Tharp TD, Thompson RI, van der Werf DP, Wurtele JS. Investigation of the fine structure of antihydrogen. Nature 2020; 578:375-380. [PMID: 32076225 PMCID: PMC7162817 DOI: 10.1038/s41586-020-2006-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 12/20/2019] [Indexed: 10/29/2022]
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 states1. 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 electrodynamics2-5. 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 antihydrogen6, 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 frequency6,7, 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 radius9,10, in this antimatter system.
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5
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayden ME, Hunter ED, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Knapp P, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Starko DM, Stutter G, So C, Tharp TD, Thompson RI, van der Werf DP, Wurtele JS. Observation of the 1S-2P Lyman-α transition in antihydrogen. Nature 2018; 561:211-215. [PMID: 30135588 PMCID: PMC6786973 DOI: 10.1038/s41586-018-0435-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 07/05/2018] [Indexed: 11/09/2022]
Abstract
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.
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Affiliation(s)
- M Ahmadi
- Department of Physics, University of Liverpool, Liverpool, UK
| | - B X R Alves
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - C J Baker
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - A Capra
- TRIUMF, Vancouver, British Columbia, Canada
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S Cohen
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - T Friesen
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | | | - D R Gill
- TRIUMF, Vancouver, British Columbia, Canada
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - E D Hunter
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - J M Jones
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S A Jones
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S Jonsell
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - A Khramov
- TRIUMF, Vancouver, British Columbia, Canada
| | - P Knapp
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | | | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | | | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - J M Michan
- TRIUMF, Vancouver, British Columbia, Canada
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), Lausanne, Switzerland
| | - T Momose
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada.
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | | | - A Olin
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool, UK
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Sameed
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | | | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - D M Starko
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - C So
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - T D Tharp
- Physics Department, Marquette University, Milwaukee, WI, USA
| | - R I Thompson
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea, UK
- IRFU, CEA/Saclay, Gif-sur-Yvette Cedex, France
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
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6
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Knapp P, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Momose T, Munich JJ, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stutter G, So C, Tharp TD, Thompson RI, van der Werf DP, Wurtele JS. Characterization of the 1S-2S transition in antihydrogen. Nature 2018; 557:71-75. [PMID: 29618820 PMCID: PMC6784861 DOI: 10.1038/s41586-018-0017-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/06/2018] [Indexed: 11/09/2022]
Abstract
In 1928, Dirac published an equation 1 that combined quantum mechanics and special relativity. Negative-energy solutions to this equation, rather than being unphysical as initially thought, represented a class of hitherto unobserved and unimagined particles-antimatter. The existence of particles of antimatter was confirmed with the discovery of the positron 2 (or anti-electron) by Anderson in 1932, but it is still unknown why matter, rather than antimatter, survived after the Big Bang. As a result, experimental studies of antimatter3-7, including tests of fundamental symmetries such as charge-parity and charge-parity-time, and searches for evidence of primordial antimatter, such as antihelium nuclei, have high priority in contemporary physics research. The fundamental role of the hydrogen atom in the evolution of the Universe and in the historical development of our understanding of quantum physics makes its antimatter counterpart-the antihydrogen atom-of particular interest. Current standard-model physics requires that hydrogen and antihydrogen have the same energy levels and spectral lines. The laser-driven 1S-2S transition was recently observed 8 in antihydrogen. Here we characterize one of the hyperfine components of this transition using magnetically trapped atoms of antihydrogen and compare it to model calculations for hydrogen in our apparatus. We find that the shape of the spectral line agrees very well with that expected for hydrogen and that the resonance frequency agrees with that in hydrogen to about 5 kilohertz out of 2.5 × 1015 hertz. This is consistent with charge-parity-time invariance at a relative precision of 2 × 10-12-two orders of magnitude more precise than the previous determination 8 -corresponding to an absolute energy sensitivity of 2 × 10-20 GeV.
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Affiliation(s)
- M Ahmadi
- Department of Physics, University of Liverpool, Liverpool, UK
| | - B X R Alves
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - C J Baker
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - A Capra
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S Cohen
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - R Collister
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - T Friesen
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - D R Gill
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - J M Jones
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S A Jones
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S Jonsell
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - A Khramov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - P Knapp
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - J T K McKenna
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - T Momose
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool, UK
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Sameed
- Department of Physics, College of Science, Swansea University, Swansea, UK
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | | | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - C So
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - T D Tharp
- Physics Department, Marquette University, Milwaukee, WI, USA
| | - R I Thompson
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea, UK
- IRFU, CEA/Saclay, Gif-sur-Yvette Cedex, France
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
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7
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Abstract
I give an overview of experimental and theoretical results for antiproton and antihydrogen scattering with atoms and molecules (in particular H, He). At low energies ([Formula: see text]1 keV) there are practically no experimental data available. Instead I compare the results from different theoretical calculations, of various degrees of sophistication. At energies up to a few tens of eV, I focus on simple approximations that give reasonably accurate results, as these allow quick estimates of collision rates without embarking on a research project.This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'.
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Affiliation(s)
- S Jonsell
- Department of Physics, Stockholm University, 10691 Stockholm, Sweden
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8
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Butler E, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Ishida A, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Nolan P, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stracka S, Stutter G, So C, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Erratum: Observation of the hyperfine spectrum of antihydrogen. Nature 2018; 553:530. [PMID: 29258296 DOI: 10.1038/nature24663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This corrects the article DOI: 10.1038/nature23446.
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9
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Momose T, Munich JJ, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, So C, Stutter G, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Enhanced Control and Reproducibility of Non-Neutral Plasmas. Phys Rev Lett 2018; 120:025001. [PMID: 29376718 DOI: 10.1103/physrevlett.120.025001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Indexed: 06/07/2023]
Abstract
The simultaneous control of the density and particle number of non-neutral plasmas confined in Penning-Malmberg traps is demonstrated. Control is achieved by setting the plasma's density by applying a rotating electric field while simultaneously fixing its axial potential via evaporative cooling. This novel method is particularly useful for stabilizing positron plasmas, as the procedures used to collect positrons from radioactive sources typically yield plasmas with variable densities and particle numbers; it also simplifies optimization studies that require plasma parameter scans. The reproducibility achieved by applying this technique to the positron and electron plasmas used by the ALPHA antihydrogen experiment at CERN, combined with other developments, contributed to a 10-fold increase in the antiatom trapping rate.
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Affiliation(s)
- M Ahmadi
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - B X R Alves
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - C J Baker
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
- Cockcroft Institute, Sci-Tech Daresbury, Warrington WA4 4AD, United Kingdom
| | - A Capra
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - C L Cesar
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - S Cohen
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - R Collister
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - N Evetts
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - T Friesen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - D R Gill
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - W N Hardy
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - S A Jones
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - S Jonsell
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - M Mathers
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - J T K McKenna
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - T Momose
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - R L Sacramento
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - M Sameed
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - E Sarid
- Soreq NRC, Yavne 81800, Israel
| | - D M Silveira
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - C So
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - T D Tharp
- Physics Department, Marquette University, P.O. Box 1881,Milwaukee, Wisconsin 53201-1881, USA
| | - J E Thompson
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - R I Thompson
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
- IRFU, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
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10
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Butler E, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Ishida A, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Nolan P, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stracka S, Stutter G, So C, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Observation of the hyperfine spectrum of antihydrogen. Nature 2017; 548:66-69. [PMID: 28770838 DOI: 10.1038/nature23446] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 06/30/2017] [Indexed: 11/09/2022]
Abstract
The observation of hyperfine structure in atomic hydrogen by Rabi and co-workers and the measurement of the zero-field ground-state splitting at the level of seven parts in 1013 are important achievements of mid-twentieth-century physics. The work that led to these achievements also provided the first evidence for the anomalous magnetic moment of the electron, inspired Schwinger's relativistic theory of quantum electrodynamics and gave rise to the hydrogen maser, which is a critical component of modern navigation, geo-positioning and very-long-baseline interferometry systems. Research at the Antiproton Decelerator at CERN by the ALPHA collaboration extends these enquiries into the antimatter sector. Recently, tools have been developed that enable studies of the hyperfine structure of antihydrogen-the antimatter counterpart of hydrogen. The goal of such studies is to search for any differences that might exist between this archetypal pair of atoms, and thereby to test the fundamental principles on which quantum field theory is constructed. Magnetic trapping of antihydrogen atoms provides a means of studying them by combining electromagnetic interaction with detection techniques that are unique to antimatter. Here we report the results of a microwave spectroscopy experiment in which we probe the response of antihydrogen over a controlled range of frequencies. The data reveal clear and distinct signatures of two allowed transitions, from which we obtain a direct, magnetic-field-independent measurement of the hyperfine splitting. From a set of trials involving 194 detected atoms, we determine a splitting of 1,420.4 ± 0.5 megahertz, consistent with expectations for atomic hydrogen at the level of four parts in 104. This observation of the detailed behaviour of a quantum transition in an atom of antihydrogen exemplifies tests of fundamental symmetries such as charge-parity-time in antimatter, and the techniques developed here will enable more-precise such tests.
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Affiliation(s)
- M Ahmadi
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - B X R Alves
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - C J Baker
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester M12 9PL, UK.,Cockcroft Institute, Sci-Tech Daresbury, Warrington WA4 4AD, UK
| | - E Butler
- Physics Department, CERN, CH-1211 Geneve 23, Switzerland
| | - A Capra
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - S Cohen
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - R Collister
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - T Friesen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - D R Gill
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - A Gutierrez
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.,Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, UK
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - A Ishida
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester M12 9PL, UK.,Cockcroft Institute, Sci-Tech Daresbury, Warrington WA4 4AD, UK
| | - S A Jones
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - S Jonsell
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - M Mathers
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - J T K McKenna
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - J M Michan
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.,École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), Lausanne CH-1015, Switzerland
| | - T Momose
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - P Nolan
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.,Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - M Sameed
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - E Sarid
- Soreq NRC, Yavne 81800, Israel
| | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - S Stracka
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.,Universita di Pisa and Sezione INFN di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - C So
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - T D Tharp
- Physics Department, Marquette University, PO Box 1881, Milwaukee, Wisconsin 53201-1881, USA
| | - J E Thompson
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - R I Thompson
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK.,IRFU, CEA/Saclay, F-91191, Gif-sur-Yvette Cedex, France
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
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11
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Butler E, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Ishida A, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Nolan P, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stracka S, Stutter G, So C, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Antihydrogen accumulation for fundamental symmetry tests. Nat Commun 2017; 8:681. [PMID: 28947794 PMCID: PMC5613003 DOI: 10.1038/s41467-017-00760-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 07/20/2017] [Indexed: 11/18/2022] Open
Abstract
Antihydrogen, a positron bound to an antiproton, is the simplest anti-atom. Its structure and properties are expected to mirror those of the hydrogen atom. Prospects for precision comparisons of the two, as tests of fundamental symmetries, are driving a vibrant programme of research. In this regard, a limiting factor in most experiments is the availability of large numbers of cold ground state antihydrogen atoms. Here, we describe how an improved synthesis process results in a maximum rate of 10.5 ± 0.6 atoms trapped and detected per cycle, corresponding to more than an order of magnitude improvement over previous work. Additionally, we demonstrate how detailed control of electron, positron and antiproton plasmas enables repeated formation and trapping of antihydrogen atoms, with the simultaneous retention of atoms produced in previous cycles. We report a record of 54 detected annihilation events from a single release of the trapped anti-atoms accumulated from five consecutive cycles. Antihydrogen studies are important in testing the fundamental principles of physics but producing antihydrogen in large amounts is challenging. Here the authors demonstrate an efficient and high-precision method for trapping and stacking antihydrogen by using controlled plasma.
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Affiliation(s)
- M Ahmadi
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, UK
| | - B X R Alves
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - C J Baker
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK.,Cockcroft Institute, Sci-Tech Daresbury, Warrington, WA4 4AD, UK
| | - E Butler
- Physics Department, CERN, CH-1211, Geneve 23, Switzerland
| | - A Capra
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720-7300, USA
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - S Cohen
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - R Collister
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada, T2N 1N4
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, V6T 1Z1
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720-7300, USA
| | - T Friesen
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark.
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - D R Gill
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - A Gutierrez
- Department of Medical Physics and Biomedical Engineering, University College London, London, WC1E 6BT, UK
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, V6T 1Z1
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - A Ishida
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Tokyo, 113-0033, Japan
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK.,Cockcroft Institute, Sci-Tech Daresbury, Warrington, WA4 4AD, UK
| | - S A Jones
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - S Jonsell
- Department of Physics, Stockholm University, SE-10691, Stockholm, Sweden
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK.
| | - M Mathers
- Department of Physics and Astronomy, York University, Toronto, ON, Canada, M3J 1P3
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - J T K McKenna
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, ON, Canada, M3J 1P3
| | - J M Michan
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3.,École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015, Lausanne, Switzerland
| | - T Momose
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, V6T 1Z1
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - P Nolan
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, UK
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3.,Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada, V8P 5C2
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, UK
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - M Sameed
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - E Sarid
- Soreq NRC, Yavne, 81800, Israel
| | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - S Stracka
- Universita di Pisa and Sezione INFN di Pisa, Largo Pontecorvo 3, 56127, Pisa, Italy
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - C So
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada, T2N 1N4
| | - T D Tharp
- Physics Department, Marquette University, P.O. Box 1881, Milwaukee, WI, 53201-1881, USA
| | - J E Thompson
- Department of Physics and Astronomy, York University, Toronto, ON, Canada, M3J 1P3
| | - R I Thompson
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada, T2N 1N4
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK.,IRFU, CEA/Saclay, F-91191, Gif-sur-Yvette, France
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720-7300, USA
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12
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Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Butler E, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Ishida A, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Nolan P, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stracka S, Stutter G, So C, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Observation of the 1S–2S transition in trapped antihydrogen. Nature 2016; 541:506-510. [DOI: 10.1038/nature21040] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 12/07/2016] [Indexed: 11/09/2022]
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13
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Amole C, Ashkezari MD, Baquero-Ruiz M, Bertsche W, Butler E, Capra A, Cesar CL, Charlton M, Eriksson S, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Jonsell S, Kurchaninov L, Little A, Madsen N, McKenna JTK, Menary S, Napoli SC, Nolan P, Olchanski K, Olin A, Povilus A, Pusa P, Rasmussen CØ, Robicheaux F, Sarid E, Silveira DM, So C, Tharp TD, Thompson RI, van der Werf DP, Vendeiro Z, Wurtele JS, Zhmoginov AI, Charman AE. An experimental limit on the charge of antihydrogen. Nat Commun 2014; 5:3955. [PMID: 24892800 PMCID: PMC4279174 DOI: 10.1038/ncomms4955] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Accepted: 04/24/2014] [Indexed: 11/09/2022] Open
Abstract
The properties of antihydrogen are expected to be identical to those of hydrogen, and any differences would constitute a profound challenge to the fundamental theories of physics. The most commonly discussed antiatom-based tests of these theories are searches for antihydrogen-hydrogen spectral differences (tests of CPT (charge-parity-time) invariance) or gravitational differences (tests of the weak equivalence principle). Here we, the ALPHA Collaboration, report a different and somewhat unusual test of CPT and of quantum anomaly cancellation. A retrospective analysis of the influence of electric fields on antihydrogen atoms released from the ALPHA trap finds a mean axial deflection of 4.1 ± 3.4 mm for an average axial electric field of 0.51 V mm(-1). Combined with extensive numerical modelling, this measurement leads to a bound on the charge Qe of antihydrogen of Q=(-1.3 ± 1.1 ± 0.4) × 10(-8). Here, e is the unit charge, and the errors are from statistics and systematic effects.
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Affiliation(s)
- C Amole
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada M3J 1P3
| | - M D Ashkezari
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - M Baquero-Ruiz
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - W Bertsche
- 1] School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK [2] The Cockcroft Institute, Daresbury Laboratory, Warrington WA4 4AD, UK
| | - E Butler
- 1] Centre for Cold Matter, Imperial College, London SW7 2BW, UK [2] Physics Department, CERN, CH-1211 Geneva 23, Switzerland
| | - A Capra
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada M3J 1P3
| | - C L Cesar
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - J Fajans
- 1] Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA [2] Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - T Friesen
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3
| | - D R Gill
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3
| | - A Gutierrez
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - J S Hangst
- 1] Physics Department, CERN, CH-1211 Geneva 23, Switzerland [2] Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - W N Hardy
- 1] Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1 [2] Canadian Institute of Advanced Research, Toronto, Ontario, Canada M5G 1ZA
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - S Jonsell
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3
| | - A Little
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - J T K McKenna
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada M3J 1P3
| | - S C Napoli
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - P Nolan
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3
| | - A Povilus
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - F Robicheaux
- Department of Physics, Purdue University, West Lafayette, Indiana 47907, USA
| | - E Sarid
- Department of Physics, NRCN-Nuclear Research Center Negev, Beer Sheva IL-84190, Israel
| | - D M Silveira
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - C So
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - T D Tharp
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - R I Thompson
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - Z Vendeiro
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - J S Wurtele
- 1] Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA [2] Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A I Zhmoginov
- 1] Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA [2] Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A E Charman
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
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14
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Jonsell S. Observations on Vaginal Metastases in Carcinoma of the Cervix Uteri at Radiumhemmet. Acta Radiol 2013. [DOI: 10.1177/028418513701800408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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15
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16
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Amole C, Ashkezari MD, Baquero-Ruiz M, Bertsche W, Butler E, Capra A, Cesar CL, Chapman S, Charlton M, Eriksson S, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Jonsell S, Kurchaninov L, Little A, Madsen N, McKenna JTK, Menary S, Napoli SC, Nolan P, Olchanski K, Olin A, Povilus A, Pusa P, Rasmussen CØ, Robicheaux F, Sarid E, Silveira DM, Stracka S, So C, Thompson RI, Turner M, van der Werf DP, Wurtele JS, Zhmoginov A. Autoresonant-spectrometric determination of the residual gas composition in the ALPHA experiment apparatus. Rev Sci Instrum 2013; 84:065110. [PMID: 23822381 DOI: 10.1063/1.4811527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Knowledge of the residual gas composition in the ALPHA experiment apparatus is important in our studies of antihydrogen and nonneutral plasmas. A technique based on autoresonant ion extraction from an electrostatic potential well has been developed that enables the study of the vacuum in our trap. Computer simulations allow an interpretation of our measurements and provide the residual gas composition under operating conditions typical of those used in experiments to produce, trap, and study antihydrogen. The methods developed may also be applicable in a range of atomic and molecular trap experiments where Penning-Malmberg traps are used and where access is limited.
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Affiliation(s)
- C Amole
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
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Charman AE, Amole C, Ashkezari MD, Baquero-Ruiz M, Bertsche W, Butler E, Capra A, Cesar CL, Charlton M, Eriksson S, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Jonsell S, Kurchaninov L, Little A, Madsen N, McKenna JTK, Menary S, Napoli SC, Nolan P, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sarid E, Silveira DM, So C, Thompson RI, van der Werf DP, Wurtele JS, Zhmoginov AI. Description and first application of a new technique to measure the gravitational mass of antihydrogen. Nat Commun 2013; 4:1785. [PMID: 23653197 PMCID: PMC3644108 DOI: 10.1038/ncomms2787] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 03/22/2013] [Indexed: 11/24/2022] Open
Abstract
Physicists have long wondered whether the gravitational interactions between matter and antimatter might be different from those between matter and itself. Although there are many indirect indications that no such differences exist and that the weak equivalence principle holds, there have been no direct, free-fall style, experimental tests of gravity on antimatter. Here we describe a novel direct test methodology; we search for a propensity for antihydrogen atoms to fall downward when released from the ALPHA antihydrogen trap. In the absence of systematic errors, we can reject ratios of the gravitational to inertial mass of antihydrogen >75 at a statistical significance level of 5%; worst-case systematic errors increase the minimum rejection ratio to 110. A similar search places somewhat tighter bounds on a negative gravitational mass, that is, on antigravity. This methodology, coupled with ongoing experimental improvements, should allow us to bound the ratio within the more interesting near equivalence regime.
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Amole C, Ashkezari MD, Baquero-Ruiz M, Bertsche W, Bowe PD, Butler E, Capra A, Cesar CL, Charlton M, Deller A, Donnan PH, Eriksson S, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Humphries AJ, Isaac CA, Jonsell S, Kurchaninov L, Little A, Madsen N, McKenna JTK, Menary S, Napoli SC, Nolan P, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sarid E, Shields CR, Silveira DM, Stracka S, So C, Thompson RI, van der Werf DP, Wurtele JS. Resonant quantum transitions in trapped antihydrogen atoms. Nature 2012; 483:439-43. [PMID: 22398451 DOI: 10.1038/nature10942] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 02/07/2012] [Indexed: 11/09/2022]
Abstract
The hydrogen atom is one of the most important and influential model systems in modern physics. Attempts to understand its spectrum are inextricably linked to the early history and development of quantum mechanics. The hydrogen atom's stature lies in its simplicity and in the accuracy with which its spectrum can be measured and compared to theory. Today its spectrum remains a valuable tool for determining the values of fundamental constants and for challenging the limits of modern physics, including the validity of quantum electrodynamics and--by comparison with measurements on its antimatter counterpart, antihydrogen--the validity of CPT (charge conjugation, parity and time reversal) symmetry. Here we report spectroscopy of a pure antimatter atom, demonstrating resonant quantum transitions in antihydrogen. We have manipulated the internal spin state of antihydrogen atoms so as to induce magnetic resonance transitions between hyperfine levels of the positronic ground state. We used resonant microwave radiation to flip the spin of the positron in antihydrogen atoms that were magnetically trapped in the ALPHA apparatus. The spin flip causes trapped anti-atoms to be ejected from the trap. We look for evidence of resonant interaction by comparing the survival rate of trapped atoms irradiated with microwaves on-resonance to that of atoms subjected to microwaves that are off-resonance. In one variant of the experiment, we detect 23 atoms that survive in 110 trapping attempts with microwaves off-resonance (0.21 per attempt), and only two atoms that survive in 103 attempts with microwaves on-resonance (0.02 per attempt). We also describe the direct detection of the annihilation of antihydrogen atoms ejected by the microwaves.
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Affiliation(s)
- C Amole
- Department of Physics and Astronomy, York University, Toronto, Ontario, M3J 1P3, Canada
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19
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Andresen GB, Ashkezari MD, Baquero-Ruiz M, Bertsche W, Bowe PD, Butler E, Cesar CL, Chapman S, Charlton M, Deller A, Eriksson S, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Humphries AJ, Hydomako R, Jonsell S, Madsen N, Menary S, Nolan P, Olin A, Povilus A, Pusa P, Robicheaux F, Sarid E, Silveira DM, So C, Storey JW, Thompson RI, van der Werf DP, Wurtele JS, Yamazaki Y. Centrifugal separation and equilibration dynamics in an electron-antiproton plasma. Phys Rev Lett 2011; 106:145001. [PMID: 21561196 DOI: 10.1103/physrevlett.106.145001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Indexed: 05/30/2023]
Abstract
Charges in cold, multiple-species, non-neutral plasmas separate radially by mass, forming centrifugally separated states. Here, we report the first detailed measurements of such states in an electron-antiproton plasma, and the first observations of the separation dynamics in any centrifugally separated system. While the observed equilibrium states are expected and in agreement with theory, the equilibration time is approximately constant over a wide range of parameters, a surprising and as yet unexplained result. Electron-antiproton plasmas play a crucial role in antihydrogen trapping experiments.
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Affiliation(s)
- G B Andresen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
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20
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Zelan M, Hagman H, Labaigt G, Jonsell S, Dion CM. Experimental measurement of efficiency and transport coherence of a cold-atom Brownian motor in optical lattices. Phys Rev E Stat Nonlin Soft Matter Phys 2011; 83:020102. [PMID: 21405800 DOI: 10.1103/physreve.83.020102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Indexed: 05/30/2023]
Abstract
The rectification of noise into directed movement or useful energy is utilized by many different systems. The peculiar nature of the energy source and conceptual differences between such Brownian motor systems makes a characterization of the performance far from straightforward. In this work, where the Brownian motor consists of atoms interacting with dissipative optical lattices, we adopt existing theory and present experimental measurements for both the efficiency and the transport coherence. We achieve up to 0.3% for the efficiency and 0.01 for the Péclet number.
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Affiliation(s)
- M Zelan
- Department of Physics, Umeå University, SE-90187 Umeå, Sweden.
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21
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Andresen GB, Ashkezari MD, Baquero-Ruiz M, Bertsche W, Bowe PD, Butler E, Carpenter PT, Cesar CL, Chapman S, Charlton M, Fajans J, Friesen T, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayden ME, Humphries AJ, Hurt JL, Hydomako R, Jonsell S, Madsen N, Menary S, Nolan P, Olchanski K, Olin A, Povilus A, Pusa P, Robicheaux F, Sarid E, Silveira DM, So C, Storey JW, Thompson RI, van der Werf DP, Wurtele JS, Yamazaki Y. Autoresonant excitation of antiproton plasmas. Phys Rev Lett 2011; 106:025002. [PMID: 21405235 DOI: 10.1103/physrevlett.106.025002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Indexed: 05/30/2023]
Abstract
We demonstrate controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense, and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a fraction of the antiprotons in a warm plasma can be similarly excited. Antihydrogen was produced and trapped by using this technique to drive antiprotons into a positron plasma, thereby initiating atomic recombination.
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Affiliation(s)
- G B Andresen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
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22
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23
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Andresen GB, Ashkezari MD, Baquero-Ruiz M, Bertsche W, Bowe PD, Butler E, Cesar CL, Chapman S, Charlton M, Deller A, Eriksson S, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Humphries AJ, Hydomako R, Jenkins MJ, Jonsell S, Jørgensen LV, Kurchaninov L, Madsen N, Menary S, Nolan P, Olchanski K, Olin A, Povilus A, Pusa P, Robicheaux F, Sarid E, Nasr SSE, Silveira DM, So C, Storey JW, Thompson RI, van der Werf DP, Wurtele JS, Yamazaki Y. Trapped antihydrogen. Nature 2010; 468:673-6. [DOI: 10.1038/nature09610] [Citation(s) in RCA: 265] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 10/27/2010] [Indexed: 11/09/2022]
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24
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Andresen GB, Ashkezari MD, Baquero-Ruiz M, Bertsche W, Bowe PD, Butler E, Cesar CL, Chapman S, Charlton M, Fajans J, Friesen T, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayano RS, Hayden ME, Humphries A, Hydomako R, Jonsell S, Kurchaninov L, Lambo R, Madsen N, Menary S, Nolan P, Olchanski K, Olin A, Povilus A, Pusa P, Robicheaux F, Sarid E, Silveira DM, So C, Storey JW, Thompson RI, van der Werf DP, Wilding D, Wurtele JS, Yamazaki Y. Evaporative cooling of antiprotons to cryogenic temperatures. Phys Rev Lett 2010; 105:013003. [PMID: 20867439 DOI: 10.1103/physrevlett.105.013003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Indexed: 05/29/2023]
Abstract
We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9 K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal.
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Affiliation(s)
- G B Andresen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
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25
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Armour EAG, Cooper JN, Gregory MR, Jonsell S, Plummer M, Todd AC. Detailed calculations on low-energy positron-hydrogen-molecule and helium-antihydrogen scattering. ACTA ACUST UNITED AC 2010. [DOI: 10.1088/1742-6596/199/1/012007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Sjölund P, Petra SJH, Dion CM, Jonsell S, Nylén M, Sanchez-Palencia L, Kastberg A. Demonstration of a controllable three-dimensional Brownian motor in symmetric potentials. Phys Rev Lett 2006; 96:190602. [PMID: 16803094 DOI: 10.1103/physrevlett.96.190602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Indexed: 05/10/2023]
Abstract
We demonstrate a Brownian motor, based on cold atoms in optical lattices, where isotropic random fluctuations are rectified in order to induce controlled atomic motion in arbitrary directions. In contrast to earlier demonstrations of ratchet effects, our Brownian motor operates in potentials that are spatially and temporally symmetric, but where spatiotemporal symmetry is broken by a phase shift between the potentials and asymmetric transfer rates between them. The Brownian motor is demonstrated in three dimensions and the noise-induced drift is controllable in our system.
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Affiliation(s)
- P Sjölund
- Department of Physics, Umeå University, Sweden
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27
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Jonsell S, Heiselberg H, Pethick CJ. Universal behavior of the energy of trapped few-boson systems with large scattering length. Phys Rev Lett 2002; 89:250401. [PMID: 12484868 DOI: 10.1103/physrevlett.89.250401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2002] [Indexed: 05/24/2023]
Abstract
We calculate energy levels of two and three bosons trapped in a harmonic oscillator potential with oscillator length a(osc). The atoms are assumed to interact through a short-range potential with a scattering length a, and the short-distance behavior of the three-body wave function is characterized by a parameter theta. For large positive a/a(osc), the energies of states that, in the absence of the trap, correspond to three free atoms approach values independent of a and theta. For other states, the theta dependence of the energy is strong, but the energy is independent of a for |a/a(osc)|>>1.
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Affiliation(s)
- S Jonsell
- NORDITA, Blegdamsvej 17, DK-2100 Copenhagen Ø, Denmark
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28
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Forrey RC, Cote R, Dalgarno A, Jonsell S, Saenz A, Froelich P. Collisions between metastable hydrogen atoms at thermal energies. Phys Rev Lett 2000; 85:4245-4248. [PMID: 11060609 DOI: 10.1103/physrevlett.85.4245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2000] [Indexed: 05/23/2023]
Abstract
The complex interaction potentials arising in the approach of two metastable hydrogen 2s atoms are calculated and the cross sections for ionization, excitation transfer, and elastic scattering are predicted. The measured cross section for associative ionization at E = 4.1 meV equals 2x10(-15) cm (2). We calculate a total ionization cross section of 2x10(-13) cm (2), varying as E(-2/3) at higher energies. Thus it appears that dissociative ionization is the major ionization channel. We find also that double excitation transfer into two excited H(2p) atoms is still more probable with the large cross section of 9x10(-12) cm (2) at E = 4.1 meV varying as E(-1/2) at higher energies. The detection of the resulting Lyman alpha photons would provide a diagnostic test of our predictions.
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Affiliation(s)
- RC Forrey
- Penn State University, Berks-Lehigh Valley College, Reading, Pennsylvania 19610-6009 and Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA
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Abstract
Matter-antimatter interactions are investigated using hydrogen-antihydrogen collisions as an example. Cross sections for elastic scattering and for the antihydrogen loss (either through the rearrangement reaction, resulting in formation of protonium and positronium according to H+&Hmacr;-->p&pmacr;+e(+)e(-), or via annihilation in flight) are calculated for the first time in a fully quantum mechanical approach. Implications for experiments intending to trap and cool antihydrogen are discussed.
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Affiliation(s)
- P Froelich
- Department of Quantum Chemistry, Uppsala University, Box 518, 75120 Uppsala, Sweden
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30
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Saenz A, Jonsell S, Froelich P. Improved molecular final-state distribution of HeT+ for the beta-decay process of T2. Phys Rev Lett 2000; 84:242-245. [PMID: 11015881 DOI: 10.1103/physrevlett.84.242] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/1999] [Indexed: 05/23/2023]
Abstract
An improved theoretical final-state distribution of HeT+ (and HeH+) resulting from the beta decay of molecular tritium T2 (HT) is presented to accommodate the needs of increased accuracy in the analysis of ongoing and future tritium neutrino-mass experiments. The previously available theoretical spectrum has been improved in many respects, and adopted approximations have been validated.
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Affiliation(s)
- A Saenz
- Max-Planck-Institute for Quantum Optics, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
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31
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Jonsell S, Monkhorst HJ. Effects from changes in the final state spectrum on the neutrino mass determination from T2 beta decay experiments. Phys Rev Lett 1996; 76:4476-4479. [PMID: 10061301 DOI: 10.1103/physrevlett.76.4476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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