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Ahokas J, Semakin A, Järvinen J, Hanski O, Laptiyenko A, Dvornichenko V, Salonen K, Burkley Z, Crivelli P, Golovizin A, Nesvizhevsky V, Nez F, Yzombard P, Widmann E, Vasiliev S. A large octupole magnetic trap for research with atomic hydrogen. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:023201. [PMID: 35232145 DOI: 10.1063/5.0070037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
We describe the design and performance of a large magnetic trap for storage and cooling of atomic hydrogen (H). The trap operates in the vacuum space of a dilution refrigerator at a temperature of 1.5 K. Aiming at a large volume of the trap, we implemented the octupole configuration of linear currents (Ioffe bars) for the radial confinement, combined with two axial pinch coils and a 3 T solenoid for the cryogenic H dissociator. The octupole magnet consists of eight race-track segments, which are compressed toward each other with magnetic forces. This provides a mechanically stable and robust construction with a possibility of replacement or repair of each segment. A maximum trap depth of 0.54 K (0.8 T) was reached, corresponding to an effective volume of 0.5 l for hydrogen gas at 50 mK. This is an order of magnitude larger than ever used for trapping atoms.
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Affiliation(s)
- J Ahokas
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland
| | - A Semakin
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland
| | - J Järvinen
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland
| | - O Hanski
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland
| | - A Laptiyenko
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland
| | - V Dvornichenko
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland
| | - K Salonen
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland
| | - Z Burkley
- ETH Zurich, Institute for Particle Physics and Astrophysics, 8093 Zurich, Switzerland
| | - P Crivelli
- ETH Zurich, Institute for Particle Physics and Astrophysics, 8093 Zurich, Switzerland
| | - A Golovizin
- P.N. Lebedev Physical Institute, 53 Leninsky pr., Moscow, Ru-119991, Russia
| | - V Nesvizhevsky
- Institut Max von Laue-Paul Langevin, 71 Avenue des Martyrs, Grenoble F-38042, France
| | - F Nez
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Université, Collège de France, 75252 Paris, France
| | - P Yzombard
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Université, Collège de France, 75252 Paris, France
| | - E Widmann
- Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, Kegelgasse 27, A-1030 Wien, Austria
| | - S Vasiliev
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland
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2
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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] [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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3
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Chen X, Fan B. The emergence of picokelvin physics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2020; 83:076401. [PMID: 32303019 DOI: 10.1088/1361-6633/ab8ab6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The frontier of low-temperature physics has advanced to the mid-picokelvin (pK) regime but progress has come to a halt because of the problem of gravity. Ultracold atoms must be confined in some type of potential energy well: if the depth of the well is less than the energy an atom gains by falling through it, the atom escapes. This article reviews ultracold atom research, emphasizing the advances that carried the low-temperature frontier to 450 pK. We review microgravity methods for overcoming the gravitational limit to achieving lower temperatures using free-fall techniques such as a drop tower, sounding rocket, parabolic flight plane and the International Space Station. We describe two techniques that promise further advancement-an atom chip and an all-optical trap-and present recent experimental results. Basic research in new regimes of observation has generally led to scientific discoveries and new technologies that benefit society. We expect this to be the case as the low-temperature frontier advances and we propose some new opportunities for research.
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Affiliation(s)
- Xuzong Chen
- Institute of Quantum Electronics, Department of Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, People's Republic of China
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4
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5
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YAMAZAKI Y. Cold and stable antimatter for fundamental physics. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2020; 96:471-501. [PMID: 33390386 PMCID: PMC7859084 DOI: 10.2183/pjab.96.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 10/07/2020] [Indexed: 06/12/2023]
Abstract
The field of cold antimatter physics has rapidly developed in the last 20 years, overlapping with the period of the Antiproton Decelerator (AD) at CERN. The central subjects are CPT symmetry tests and Weak Equivalence Principle (WEP) tests. Various groundbreaking techniques have been developed and are still in progress such as to cool antiprotons and positrons down to extremely low temperature, to manipulate antihydrogen atoms, to construct extremely high-precision Penning traps, etc. The precisions of the antiproton and proton magnetic moments have improved by six orders of magnitude, and also laser spectroscopy of antihydrogen has been realized and reached a relative precision of 2 × 10-12 during the AD time. Antiprotonic helium laser spectroscopy, which started during the Low Energy Antiproton Ring (LEAR) time, has reached a relative precision of 8 × 10-10. Three collaborations joined the WEP tests inventing various unique approaches. An additional new post-decelerator, Extra Low ENergy Antiproton ring (ELENA), has been constructed and will be ready in 2021, which will provide 10-100 times more cold antiprotons to each experiment. A new era of the cold antimatter physics will emerge soon including the transport of antiprotons to other facilities.
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6
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Hulet RG, Nguyen JHV, Senaratne R. Methods for preparing quantum gases of lithium. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:011101. [PMID: 32012609 DOI: 10.1063/1.5131023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/24/2019] [Indexed: 06/10/2023]
Abstract
Lithium is an important element in atomic quantum gas experiments because its interactions are highly tunable due to broad Feshbach resonances and zero-crossings and because it has two stable isotopes: 6Li, a fermion, and 7Li, a boson. Although lithium has special value for these reasons, it also presents experimental challenges. In this article, we review some of the methods that have been developed or adapted to confront these challenges, including beam and vapor sources, Zeeman slowers, sub-Doppler laser cooling, laser sources at 671 nm, and all-optical methods for trapping and cooling. Additionally, we provide spectral diagrams of both 6Li and 7Li and present plots of Feshbach resonances for both isotopes.
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Affiliation(s)
- Randall G Hulet
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Jason H V Nguyen
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Ruwan Senaratne
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
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7
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Liu Y, Grimes DD, Hu MG, Ni KK. Probing ultracold chemistry using ion spectrometry. Phys Chem Chem Phys 2020; 22:4861-4874. [DOI: 10.1039/c9cp07015j] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactions between KRb molecules at sub-microkelvin temperatures were probed using ion spectrometry.
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Affiliation(s)
- Yu Liu
- Department of Physics
- Harvard University
- Cambridge
- USA
- Department of Chemistry and Chemical Biology
| | - David D. Grimes
- Department of Physics
- Harvard University
- Cambridge
- USA
- Department of Chemistry and Chemical Biology
| | - Ming-Guang Hu
- Department of Physics
- Harvard University
- Cambridge
- USA
- Department of Chemistry and Chemical Biology
| | - Kang-Kuen Ni
- Department of Physics
- Harvard University
- Cambridge
- USA
- Department of Chemistry and Chemical Biology
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8
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Vasiliev S, Ahokas J, Järvinen J, Nesvizhevsky V, Voronin A, Nez F, Reynaud S. Gravitational and matter-wave spectroscopy of atomic hydrogen at ultra-low energies. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/s10751-018-1551-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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9
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Shakirov AM, Shchadilova YE, Rubtsov AN. Quantum statistical ensemble for emissive correlated systems. Phys Rev E 2016; 93:062122. [PMID: 27415223 DOI: 10.1103/physreve.93.062122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Indexed: 11/07/2022]
Abstract
Relaxation dynamics of complex quantum systems with strong interactions towards the steady state is a fundamental problem in statistical mechanics. The steady state of subsystems weakly interacting with their environment is described by the canonical ensemble which assumes the probability distribution for energy to be of the Boltzmann form. The emergence of this probability distribution is ensured by the detailed balance of the transitions induced by the interaction with the environment. Here we consider relaxation of an open correlated quantum system brought into contact with a reservoir in the vacuum state. We refer to such a system as emissive since particles irreversibly evaporate into the vacuum. The steady state of the system is a statistical mixture of the stable eigenstates. We found that, despite the absence of the detailed balance, the stationary probability distribution over these eigenstates is of the Boltzmann form in each N-particle sector. A quantum statistical ensemble corresponding to the steady state is characterized by different temperatures in the different sectors, in contrast to the Gibbs ensemble. We investigate the transition rates between the eigenstates to understand the emergence of the Boltzmann distribution and find their exponential dependence on the transition energy. We argue that this property of transition rates is generic for a wide class of emissive quantum many-body systems.
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Affiliation(s)
- Alexey M Shakirov
- Russian Quantum Center, Novaya Street 100A, 143025 Skolkovo, Moscow Region, Russia.,Department of Physics, Lomonosov Moscow State University, Leninskie gory 1, 119992 Moscow, Russia
| | - Yulia E Shchadilova
- Russian Quantum Center, Novaya Street 100A, 143025 Skolkovo, Moscow Region, Russia
| | - Alexey N Rubtsov
- Russian Quantum Center, Novaya Street 100A, 143025 Skolkovo, Moscow Region, Russia.,Department of Physics, Lomonosov Moscow State University, Leninskie gory 1, 119992 Moscow, Russia
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10
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Rauer B, Grišins P, Mazets IE, Schweigler T, Rohringer W, Geiger R, Langen T, Schmiedmayer J. Cooling of a One-Dimensional Bose Gas. PHYSICAL REVIEW LETTERS 2016; 116:030402. [PMID: 26849577 DOI: 10.1103/physrevlett.116.030402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Indexed: 06/05/2023]
Abstract
We experimentally study the dynamics of a degenerate one-dimensional Bose gas that is subject to a continuous outcoupling of atoms. Although standard evaporative cooling is rendered ineffective by the absence of thermalizing collisions in this system, we observe substantial cooling. This cooling proceeds through homogeneous particle dissipation and many-body dephasing, enabling the preparation of otherwise unexpectedly low temperatures. Our observations establish a scaling relation between temperature and particle number, and provide insights into equilibration in the quantum world.
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Affiliation(s)
- B Rauer
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria
| | - P Grišins
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria
| | - I E Mazets
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria
- Wolfgang Pauli Institute, 1090 Vienna, Austria
| | - T Schweigler
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria
| | - W Rohringer
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria
| | - R Geiger
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria
| | - T Langen
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria
| | - J Schmiedmayer
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria
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11
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El-Sherbini TM. Advances in atomic physics: Four decades of contribution of the Cairo University - Atomic Physics Group. J Adv Res 2015; 6:643-61. [PMID: 26425356 PMCID: PMC4563599 DOI: 10.1016/j.jare.2013.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Revised: 08/19/2013] [Accepted: 08/19/2013] [Indexed: 11/24/2022] Open
Abstract
In this review article, important developments in the field of atomic physics are highlighted and linked to research works the author was involved in himself as a leader of the Cairo University - Atomic Physics Group. Starting from the late 1960s - when the author first engaged in research - an overview is provided of the milestones in the fascinating landscape of atomic physics.
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12
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Abstract
Here we introduce the ReliefF machine learning algorithm and some of its extensions for detecting and characterizing epistasis in genetic association studies. We provide a general overview of the method and then highlight some of the modifications that have greatly improved its power for genetic analysis. We end with a few examples of published studies of complex human diseases that have used ReliefF.
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13
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Celik Y, Tsankov TV, Aramaki M, Yoshimura S, Luggenhölscher D, Czarnetzki U. Electron cooling in decaying low-pressure plasmas. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:046407. [PMID: 22680586 DOI: 10.1103/physreve.85.046407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 02/17/2012] [Indexed: 06/01/2023]
Abstract
A simple analytical fluid dynamic model is developed for evaporative electron cooling in a low-pressure decaying plasma and compared to a two-dimensional simulation and experimental data for the particular case of argon. Measured electron temperature and density developments are fully reproduced by the ab initio model and the simulation. Further, it is shown that in the late afterglow thermalization of electrons occurs by coupling to the ion fluid via Coulomb collisions at sufficiently high electron densities and not by coupling to the neutral background.
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Affiliation(s)
- Yusuf Celik
- Institute for Plasma and Atomic Physics, Ruhr University Bochum, 44780 Bochum, Germany.
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14
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Oki NO, Motsinger-Reif AA. Multifactor dimensionality reduction as a filter-based approach for genome wide association studies. Front Genet 2011; 2:80. [PMID: 22303374 PMCID: PMC3268633 DOI: 10.3389/fgene.2011.00080] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Accepted: 10/26/2011] [Indexed: 11/13/2022] Open
Abstract
Advances in genotyping technology and the multitude of genetic data available now provide a vast amount of data that is proving to be useful in the quest for a better understanding of human genetic diseases through the study of genetic variation. This has led to the development of approaches such as genome wide association studies (GWAS) designed specifically for interrogating variants across the genome for association with disease, typically by testing single locus, univariate associations. More recently it has been accepted that epistatic (interaction) effects may also be great contributors to these genetic effects, and GWAS methods are now being applied to find epistatic effects. The challenge for these methods still remain in prioritization and interpretation of results, as it has also become standard for initial findings to be independently investigated in replication cohorts or functional studies. This is motivating the development and implementation of filter-based approaches to prioritize variants found to be significant in a discovery stage for follow-up for replication. Such filters must be able to detect both univariate and interactive effects. In the current study we present and evaluate the use of multifactor dimensionality reduction (MDR) as such a filter, with simulated data and a wide range of effect sizes. Additionally, we compare the performance of the MDR filter to a similar filter approach using logistic regression (LR), the more traditional approach used in GWAS analysis, as well as evaporative cooling (EC)-another prominent machine learning filtering method. The results of our simulation study show that MDR is an effective method for such prioritization, and that it can detect main effects, and interactions with or without marginal effects. Importantly, it performed as well as EC and LR for main effect models. It also significantly outperforms LR for various two-locus epistatic models, while it has equivalent results as EC for the epistatic models. The results of this study demonstrate the potential of MDR as a filter to detect gene-gene interactions in GWAS studies.
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Affiliation(s)
- Noffisat O. Oki
- Bioinformatics Research Center, North Carolina State UniversityRaleigh, NC, USA
| | - Alison A. Motsinger-Reif
- Bioinformatics Research Center, North Carolina State UniversityRaleigh, NC, USA
- Department of Statistics, North Carolina State UniversityRaleigh, NC, USA
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15
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Pérez-Ríos J, Campos-Martínez J, Hernández MI. Ultracold O2 + O2 collisions in a magnetic field: On the role of the potential energy surface. J Chem Phys 2011; 134:124310. [DOI: 10.1063/1.3573968] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 10/27/2010] [Indexed: 11/09/2022]
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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. PHYSICAL REVIEW LETTERS 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] [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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McKinney BA, Crowe JE, Guo J, Tian D. Capturing the spectrum of interaction effects in genetic association studies by simulated evaporative cooling network analysis. PLoS Genet 2009; 5:e1000432. [PMID: 19300503 PMCID: PMC2653647 DOI: 10.1371/journal.pgen.1000432] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 02/19/2009] [Indexed: 11/19/2022] Open
Abstract
Evidence from human genetic studies of several disorders suggests that interactions between alleles at multiple genes play an important role in influencing phenotypic expression. Analytical methods for identifying Mendelian disease genes are not appropriate when applied to common multigenic diseases, because such methods investigate association with the phenotype only one genetic locus at a time. New strategies are needed that can capture the spectrum of genetic effects, from Mendelian to multifactorial epistasis. Random Forests (RF) and Relief-F are two powerful machine-learning methods that have been studied as filters for genetic case-control data due to their ability to account for the context of alleles at multiple genes when scoring the relevance of individual genetic variants to the phenotype. However, when variants interact strongly, the independence assumption of RF in the tree node-splitting criterion leads to diminished importance scores for relevant variants. Relief-F, on the other hand, was designed to detect strong interactions but is sensitive to large backgrounds of variants that are irrelevant to classification of the phenotype, which is an acute problem in genome-wide association studies. To overcome the weaknesses of these data mining approaches, we develop Evaporative Cooling (EC) feature selection, a flexible machine learning method that can integrate multiple importance scores while removing irrelevant genetic variants. To characterize detailed interactions, we construct a genetic-association interaction network (GAIN), whose edges quantify the synergy between variants with respect to the phenotype. We use simulation analysis to show that EC is able to identify a wide range of interaction effects in genetic association data. We apply the EC filter to a smallpox vaccine cohort study of single nucleotide polymorphisms (SNPs) and infer a GAIN for a collection of SNPs associated with adverse events. Our results suggest an important role for hubs in SNP disease susceptibility networks. The software is available at http://sites.google.com/site/McKinneyLab/software. Susceptibility to many diseases and disorders is caused by breakdown at multiple points in the genetic network. Each of these points of breakdown by itself may have a very modest effect on disease risk but the points may have a much stronger effect through statistical interactions with each other. Genome-wide association studies provide the opportunity to identify alleles at multiple loci that interact to influence phenotypic variation in common diseases and disorders. However, if each SNP is tested for association as though it were independent of the rest of the genome, then the full advantage of the variation from markers across the genome will be unfulfilled. In this study, we illustrate the utility of a new approach to high-dimensional genetic association analysis that treats the collection of SNPs as interacting on a system level. This approach uses a machine-learning filter followed by an information theoretic and graph theoretic approach to infer a phenotype-specific network of interacting SNPs.
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Affiliation(s)
- Brett A McKinney
- Department of Genetics, University of Alabama School of Medicine, Birmingham, AL, USA.
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Abrahamsson E, Tscherbul TV, Krems RV. Inelastic collisions of cold polar molecules in nonparallel electric and magnetic fields. J Chem Phys 2007; 127:044302. [PMID: 17672685 DOI: 10.1063/1.2748770] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The authors present a detailed study of low-temperature collisions between CaD molecules and He atoms in superimposed electric and magnetic fields with arbitrary orientations. Electric fields do not interact with the electron spin of the molecules directly but modify their rotational structure and, consequently, the spin-rotation interactions. The authors examine molecular Stark and Zeeman energy levels as functions of the angle between the fields and show that rotating fields may induce and shift avoided crossings between the Zeeman levels of the rotationally ground and rotationally excited states of the molecule. The dynamics of molecular collisions are extremely sensitive to external fields near these avoided crossings and it is shown that molecular collisions may be controlled by varying both the strength and the relative orientation of the fields. The effects observed in this study are due to interactions of the isolated molecules with external fields so the conclusions should be relevant for collisions of molecules with other atoms or collisions of molecules with each other. This study demonstrates that electric fields may be used to enhance or suppress spin-rotation interactions in molecules. The spin-rotation interactions induce nonadiabatic couplings between states of different total spins in systems of two open-shell species and it is suggested that electric fields might be used for controlling nonadiabatic spin transitions and spin-forbidden chemical reactions of cold molecules in a magnetic trap.
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Affiliation(s)
- E Abrahamsson
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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McKinney BA, Reif DM, White BC, Crowe JE, Moore JH. Evaporative cooling feature selection for genotypic data involving interactions. Bioinformatics 2007; 23:2113-20. [PMID: 17586549 PMCID: PMC3988427 DOI: 10.1093/bioinformatics/btm317] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
MOTIVATION The development of genome-wide capabilities for genotyping has led to the practical problem of identifying the minimum subset of genetic variants relevant to the classification of a phenotype. This challenge is especially difficult in the presence of attribute interactions, noise and small sample size. METHODS Analogous to the physical mechanism of evaporation, we introduce an evaporative cooling (EC) feature selection algorithm that seeks to obtain a subset of attributes with the optimum information temperature (i.e. the least noise). EC uses an attribute quality measure analogous to thermodynamic free energy that combines Relief-F and mutual information to evaporate (i.e. remove) noise features, leaving behind a subset of attributes that contain DNA sequence variations associated with a given phenotype. RESULTS EC is able to identify functional sequence variations that involve interactions (epistasis) between other sequence variations that influence their association with the phenotype. This ability is demonstrated on simulated genotypic data with attribute interactions and on real genotypic data from individuals who experienced adverse events following smallpox vaccination. The EC formalism allows us to combine information entropy, energy and temperature into a single information free energy attribute quality measure that balances interaction and main effects. AVAILABILITY Open source software, written in Java, is freely available upon request.
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Affiliation(s)
- B A McKinney
- Department of Genetics, University of Alabama School of Medicine, Birmingham, AL 35294, USA.
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van der Stam KMR, van Ooijen ED, Meppelink R, Vogels JM, van der Straten P. Large atom number Bose-Einstein condensate of sodium. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:013102. [PMID: 17503902 DOI: 10.1063/1.2424439] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We describe the setup to create a large Bose-Einstein condensate containing more than 120 x 10(6) atoms. In the experiment a thermal beam is slowed by a Zeeman slower and captured in a dark-spot magneto-optical trap (MOT). A typical dark-spot MOT in our experiments contains 2.0 x 10(10) atoms with a temperature of 320 microK and a density of about 1.0 x 10(11) atoms/cm(3). The sample is spin polarized in a high magnetic field before the atoms are loaded in the magnetic trap. Spin polarizing in a high magnetic field results in an increase in the transfer efficiency by a factor of 2 compared to experiments without spin polarizing. In the magnetic trap the cloud is cooled to degeneracy in 50 s by evaporative cooling. To suppress the three-body losses at the end of the evaporation, the magnetic trap is decompressed in the axial direction.
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Affiliation(s)
- K M R van der Stam
- Atom Optics and Ultrafast Dynamics, Utrecht University, TA Utrecht, The Netherlands
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McNamara JM, Jeltes T, Tychkov AS, Hogervorst W, Vassen W. Degenerate Bose-Fermi mixture of metastable atoms. PHYSICAL REVIEW LETTERS 2006; 97:080404. [PMID: 17026284 DOI: 10.1103/physrevlett.97.080404] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2006] [Indexed: 05/12/2023]
Abstract
We report the observation of simultaneous quantum degeneracy in a dilute gaseous Bose-Fermi mixture of metastable atoms. Sympathetic cooling of helium-3 (fermion) by helium-4 (boson), both in the lowest triplet state, allows us to produce ensembles containing more than 10(6) atoms of each isotope at temperatures below 1 microK, and achieve a fermionic degeneracy parameter of T/TF = 0.45. Because of their high internal energy, the detection of individual metastable atoms with subnanosecond time resolution is possible, permitting the study of bosonic and fermionic quantum gases with unprecedented precision. This may lead to metastable helium becoming the mainstay of quantum atom optics.
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Affiliation(s)
- J M McNamara
- Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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Abstract
This overview prefaces a collection of Insight review articles on the physics and applications of laser-cooled atoms. I will cast this work into a historical perspective in which laser cooling and trapping is seen as one of several research directions aimed at controlling the internal and external degrees of freedom of atoms and molecules.
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Affiliation(s)
- Steven Chu
- Physics Department, Stanford University, Stanford, California 94305-4060, USA
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Abstract
An evaporative cooling strategy that uses a two-component Fermi gas was employed to cool a magnetically trapped gas of 7 x 10(5) (40)K atoms to 0.5 of the Fermi temperature T(F). In this temperature regime, where the state occupation at the lowest energies has increased from essentially zero at high temperatures to nearly 60 percent, quantum degeneracy was observed as a barrier to evaporative cooling and as a modification of the thermodynamics. Measurements of the momentum distribution and the total energy of the confined Fermi gas directly revealed the quantum statistics.
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Affiliation(s)
- B DeMarco
- JILA, National Institute of Standards and Technology, and Physics Department, University of Colorado, Boulder, CO 80309-0440, USA
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Hau LV, Harris SE, Dutton Z, Behroozi CH. Light speed reduction to 17 metres per second in an ultracold atomic gas. Nature 1999. [DOI: 10.1038/17561] [Citation(s) in RCA: 3155] [Impact Index Per Article: 126.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Weinstein JD, deCarvalho R, Guillet T, Friedrich B, Doyle JM. Magnetic trapping of calcium monohydride molecules at millikelvin temperatures. Nature 1998. [DOI: 10.1038/25949] [Citation(s) in RCA: 336] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Pendrill L, Robertsson L. Atomic Physics and the Laser Metrology of Time and Length. ADVANCES IN QUANTUM CHEMISTRY 1998. [DOI: 10.1016/s0065-3276(08)60522-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wilkowski D, Garreau JC, Hennequin D, Zehnlé V. Atomic-velocity class selection using quantum interference. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1996; 54:4249-4258. [PMID: 9913975 DOI: 10.1103/physreva.54.4249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Cesar CL, Fried DG, Killian TC, Polcyn AD, Sandberg JC, Yu IA, Greytak TJ, Kleppner D, Doyle JM. Two-Photon Spectroscopy of Trapped Atomic Hydrogen. PHYSICAL REVIEW LETTERS 1996; 77:255-258. [PMID: 10062405 DOI: 10.1103/physrevlett.77.255] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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van Druten NJ, Townsend CG, Andrews MR, Durfce DS, Kurn DM, Mewes MO, Ketterle W. Bose-Einstein condensates—a new form of quantum matter. ACTA ACUST UNITED AC 1996. [DOI: 10.1007/bf02548113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Surkov EL, Walraven JT, Shlyapnikov GV. Collisionless motion and evaporative cooling of atoms in magnetic traps. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1996; 53:3403-3408. [PMID: 9913283 DOI: 10.1103/physreva.53.3403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Luiten OJ, Reynolds MW, Walraven JT. Kinetic theory of the evaporative cooling of a trapped gas. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1996; 53:381-389. [PMID: 9912894 DOI: 10.1103/physreva.53.381] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Lawall J, Kulin S, Saubamea B, Bigelow N, Leduc M, Cohen-Tannoudji C. Three-Dimensional Laser Cooling of Helium Beyond the Single-Photon Recoil Limit. PHYSICAL REVIEW LETTERS 1995; 75:4194-4197. [PMID: 10059843 DOI: 10.1103/physrevlett.75.4194] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Doyle JM, Friedrich B, Kim J, Patterson D. Buffer-gas loading of atoms and molecules into a magnetic trap. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1995; 52:R2515-R2518. [PMID: 9912638 DOI: 10.1103/physreva.52.r2515] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Bradley CC, Sackett CA, Tollett JJ, Hulet RG. Evidence of Bose-Einstein Condensation in an Atomic Gas with Attractive Interactions. PHYSICAL REVIEW LETTERS 1995; 75:1687-1690. [PMID: 10060366 DOI: 10.1103/physrevlett.75.1687] [Citation(s) in RCA: 188] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Anderson MH, Ensher JR, Matthews MR, Wieman CE, Cornell EA. Observation of Bose-Einstein Condensation in a Dilute Atomic Vapor. Science 1995; 269:198-201. [PMID: 17789847 DOI: 10.1126/science.269.5221.198] [Citation(s) in RCA: 905] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A Bose-Einstein condensate was produced in a vapor of rubidium-87 atoms that was confined by magnetic fields and evaporatively cooled. The condensate fraction first appeared near a temperature of 170 nanokelvin and a number density of 2.5 x 10(12) per cubic centimeter and could be preserved for more than 15 seconds. Three primary signatures of Bose-Einstein condensation were seen. (i) On top of a broad thermal velocity distribution, a narrow peak appeared that was centered at zero velocity. (ii) The fraction of the atoms that were in this low-velocity peak increased abruptly as the sample temperature was lowered. (iii) The peak exhibited a nonthermal, anisotropic velocity distribution expected of the minimum-energy quantum state of the magnetic trap in contrast to the isotropic, thermal velocity distribution observed in the broad uncondensed fraction.
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Davis KB, Mewes MO, Joffe MA, Andrews MR, Ketterle W. Evaporative cooling of sodium atoms. PHYSICAL REVIEW LETTERS 1995; 74:5202-5205. [PMID: 10058708 DOI: 10.1103/physrevlett.74.5202] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Adams CS, Lee HJ, Davidson N, Kasevich M, Chu S. Evaporative cooling in a crossed dipole trap. PHYSICAL REVIEW LETTERS 1995; 74:3577-3580. [PMID: 10058240 DOI: 10.1103/physrevlett.74.3577] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Newbury NR, Myatt CJ, Cornell EA, Wieman CE. Gravitational sisyphus cooling of 87Rb in a magnetic trap. PHYSICAL REVIEW LETTERS 1995; 74:2196-2199. [PMID: 10057867 DOI: 10.1103/physrevlett.74.2196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Anderson MH, Petrich W, Ensher JR, Cornell EA. Reduction of light-assisted collisional loss rate from a low-pressure vapor-cell trap. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1994; 50:R3597-R3600. [PMID: 9911442 DOI: 10.1103/physreva.50.r3597] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Spreeuw RJ, Gerz C, Goldner LS, Phillips WD, Rolston SL, Westbrook CI, Reynolds MW, Silvera IF. Demonstration of neutral atom trapping with microwaves. PHYSICAL REVIEW LETTERS 1994; 72:3162-3165. [PMID: 10056123 DOI: 10.1103/physrevlett.72.3162] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Hijmans TW, Kagan Y, Shlyapnikov GV, Walraven JT. Bose condensation and relaxation explosion in magnetically trapped atomic hydrogen. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:12886-12892. [PMID: 10007662 DOI: 10.1103/physrevb.48.12886] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Berkhout JJ, Walraven JT. Scattering of hydrogen atoms from liquid-helium surfaces. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:8886-8904. [PMID: 10004935 DOI: 10.1103/physrevb.47.8886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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47
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Luiten OJ, Werij HG, Setija ID, Reynolds MW, Hijmans TW, Walraven JT. Lyman- alpha spectroscopy of magnetically trapped atomic hydrogen. PHYSICAL REVIEW LETTERS 1993; 70:544-547. [PMID: 10054141 DOI: 10.1103/physrevlett.70.544] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Ketterle W, Pritchard DE. Atom cooling by time-dependent potentials. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1992; 46:4051-4054. [PMID: 9908601 DOI: 10.1103/physreva.46.4051] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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49
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Doyle JM, Sandberg JC, Yu IA, Cesar CL, Kleppner D, Greytak TJ. Hydrogen in the submillikelvin regime: Sticking probability on superfluid 4He. PHYSICAL REVIEW LETTERS 1991; 67:603-606. [PMID: 10044940 DOI: 10.1103/physrevlett.67.603] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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50
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Davé RD, Clark JW, Panoff RM. Elementary excitations of spin-aligned deuterium. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 41:757-760. [PMID: 9992812 DOI: 10.1103/physrevb.41.757] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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