Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physics Education

Antihydrogen in a bottle

M. Charlton, S. Eriksson, Christopher Aled Isaac, N. Madsen, Dirk Peter van der Werf

Published Feb 22, 2013• 1 citation
Publisher

Abstract

We describe recent experiments at CERN in which antihydrogen, an atom made entirely of antimatter, has been held in a magnetic minimum neutral atom trap and subjected to microwave radiation to induce a resonant quantum transition in the anti-atom. We discuss how this, the first experiment to observe an interaction between an antihydrogen atom and a photon, was achieved. We provide some background to antimatter physics and cover aspects of the current motivation for our experiments.

DOI
10.1088/0031-9120/48/2/212

Related papers

Physics with antihydrogen

William Alan Bertsche, Eoin Butler, M. Charlton +1 more

Performing measurements of the properties of antihydrogen, the bound state of an antiproton and a positron, and comparing the results with those for ordinary hydrogen, has long been seen as a route to test some of the fundamental principles of physics. There has been much experimental progress in this direction in recent years, and antihydrogen is now routinely created and trapped and a range of exciting measurements probing the foundations of modern physics are planned or underway. In this contribution we review the techniques developed to facilitate the capture and manipulation of positrons and antiprotons, along with procedures to bring them together to create antihydrogen. Once formed, the antihydrogen has been detected by its destruction via annihilation or field ionization, and aspects of the methodologies involved are summarized. Magnetic minimum neutral atom traps have been employed to allow some of the antihydrogen created to be held for considerable periods. We describe such devices, and their implementation, along with the cusp magnetic trap used to produce the first evidence for a low-energy beam of antihydrogen. The experiments performed to date on antihydrogen are discussed, including the first observation of a resonant quantum transition and the analyses that have yielded a limit on the electrical neutrality of the anti-atom and placed crude bounds on its gravitational behaviour. Our review concludes with an outlook, including the new ELENA extension to the antiproton decelerator facility at CERN, together with summaries of how we envisage the major threads of antihydrogen physics will progress in the coming years.

Journal of Physics B Atomic Molecular and Optical Physics•Oct 6, 2015•44 citations

Advances in Antihydrogen Physics

M. Charlton, Dirk Peter van der Werf

The creation of cold antihydrogen atoms by the controlled combination of positrons and antiprotons has opened up a new window on fundamental physics. More recently, techniques have been developed that allow some antihydrogen atoms to be created at low enough kinetic energies that they can be held inside magnetic minimum neutral atom traps. With confinement times of many minutes possible, it has become feasible to perform experiments to probe the properties of the antiatom for the first time. We review the experimental progress in this area, outline some of the motivation for studying basic aspects of antimatter physics and provide an outlook of where we might expect this field to go in the coming years.

Science Progress•Mar 1, 2015•18 citations

Antimatter

P. Thornton Greenland

Antihydrogen has recently been produced in CERN. I discuss the original motivation for the study of antimatter, and describe the large, but as yet unsuccessful attempt to produce cold antihydrogen confined to a trap, where it can be studied spectroscopically, and compared with ordinary hydrogen. I also describe the experiment at CERN, which produced ∼ 11 atoms of antihydrogen moving at 90% of the speed of light, circumstances that make precision spectroscopy difficult.

Contemporary Physics•May 1, 1997•10 citations

The ALPHA antihydrogen trapping apparatus

C. Amole, Gorm Bruun Andresen, M. D. Ashkezari +53 more

The ALPHA collaboration, based at CERN, has recently succeeded in confining cold antihydrogen atoms in a magnetic minimum neutral atom trap and has performed the first study of a resonant transition of the anti-atoms. The ALPHA apparatus will be described herein, with emphasis on the structural aspects, diagnostic methods and techniques that have enabled antihydrogen trapping and experimentation to be achieved.

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment•Oct 1, 2013•67 citations

Antimatter Research with Cold Antihydrogen and Cold Antiproton

Y. Yamazaki

Antihydrogen, the opposite number of hydrogen, is the simplest antimatter, and stable in vacuum, which guarantees a long observation time for high precision spectroscopy. This review discusses a short history of antimatter followed by the motivation of the cold antihydrogen research, and then a couple of latest results, which open a new era of antihydrogen research enabling high precision spectroscopy for the first time. A comparison of the spectroscopic properties of antihydrogen with those of hydrogen constitutes a stringent test of the CPT symmetry, the most fundamental law of physics. One of the important achievements of cold antihydrogen study in the last couple of years is the trapping of antihydrogen atoms in an octupole magnetic bottle. Considering the bottle depth, the trapped antihydrogen atoms were really cold, less than 0.5K in their temperature. High precision laser spectroscopy of 1S-2S transition is foreseen once antihydrogen atoms can be laser-cooled. The other milestone development was a successful synthesis of antihydrogen atoms in a so-called cusp trap, where an anti-Helmholtz coil configuration is adopted. The cusp trap enables extraction of antihydrogen atoms in a field-free region as an intensified spin-polarized beam,which realizes high resolution microwave spectroscopy of ground state hyperfine transitions.

Molecular Science•Jan 1, 2012•0 citations

Probing Trapped Antihydrogen. In Situ Diagnostics and Observations of Quantum Transitions

Tim Friesen

Antihydrogen, the bound state of a positron and an antiproton, is the simplest pure anti-atomic system and an excellent candidate to test the symmetry between matter and antimatter. This thesis focuses on the magnetic confinement of antihydrogen and the first ever resonant interaction with trapped antihydrogen, as performed by the ALPHA collaboration. The ALPHA apparatus and the techniques that have been developed to form, trap, probe, and detect antihydrogen atoms will be described in detail. The first successful demonstration of trapped antihydrogen will then be described. In the initial demonstrations, 38 trapped antihydrogen atoms were detected after being confined for at least 172 ms. Since then, over 400 antihydrogen atoms have been trapped and confinement times of 1000 s (over 15 minutes) have been demonstrated. Spectroscopy of these trapped antihydrogen atoms is the next major step forward. As an initial proof-of-principle demonstration, ALPHA induced and observed reso- nant positron spin flip (PSR) transitions between the ground states of antihydrogen. Because of the strong magnetic field dependence of these transition frequencies, the success of this experiment relied heavily on the ability to measure the magnetic field seen by the antihydrogen atoms. A novel method to measure the magnetic field in situ by detecting the cyclotron resonance of a trapped electron plasma is presented. This method allowed ALPHA to measure the magnetic field strength at the minimum of the magnetic antihydrogen trap to within 1.4 parts in 103. Hardware improvements and further study should allow this resolution to be improved by several orders of magnitude. The cyclotron resonance measurements can also be applied as a roughdiagnostic of a microwave field within the ALPHA apparatus. This allowed for important diagnostics of the microwave field used to excite the PSR transitions. Finally, the experimental results demonstrating resonant PSR transitions in antihydrogen are presented. This experiment is the first ever spectroscopic measurement of antihydrogen and an important step towards future precision spectroscopy.

•Jan 31, 2014•1 citation
We describe recent experiments at CERN in which antihydrogen, an atom made entirely of antimatter, has been held in a magnetic minimum neutral atom trap and subjected to microwave radiation to induce a resonant quantum transition in the anti-atom. We discuss how this, the first experiment to observe an interaction between an antihydrogen atom and a photon, was achieved. We provide some background to antimatter physics and cover aspects of the current motivation for our experiments.
Performing measurements of the properties of antihydrogen, the bound state of an antiproton and a positron, and comparing the results with those for ordinary hydrogen, has long been seen as a route to test some of the fundamental principles of physics. There has been much experimental progress in this direction in recent years, and antihydrogen is now routinely created and trapped and a range of exciting measurements probing the foundations of modern physics are planned or underway. In this contribution we review the techniques developed to facilitate the capture and manipulation of positrons and antiprotons, along with procedures to bring them together to create antihydrogen. Once formed, the antihydrogen has been detected by its destruction via annihilation or field ionization, and aspects of the methodologies involved are summarized. Magnetic minimum neutral atom traps have been employed to allow some of the antihydrogen created to be held for considerable periods. We describe such devices, and their implementation, along with the cusp magnetic trap used to produce the first evidence for a low-energy beam of antihydrogen. The experiments performed to date on antihydrogen are discussed, including the first observation of a resonant quantum transition and the analyses that have yielded a limit on the electrical neutrality of the anti-atom and placed crude bounds on its gravitational behaviour. Our review concludes with an outlook, including the new ELENA extension to the antiproton decelerator facility at CERN, together with summaries of how we envisage the major threads of antihydrogen physics will progress in the coming years.
The creation of cold antihydrogen atoms by the controlled combination of positrons and antiprotons has opened up a new window on fundamental physics. More recently, techniques have been developed that allow some antihydrogen atoms to be created at low enough kinetic energies that they can be held inside magnetic minimum neutral atom traps. With confinement times of many minutes possible, it has become feasible to perform experiments to probe the properties of the antiatom for the first time. We review the experimental progress in this area, outline some of the motivation for studying basic aspects of antimatter physics and provide an outlook of where we might expect this field to go in the coming years.
Antihydrogen, the opposite number of hydrogen, is the simplest antimatter, and stable in vacuum, which guarantees a long observation time for high precision spectroscopy. This review discusses a short history of antimatter followed by the motivation of the cold antihydrogen research, and then a couple of latest results, which open a new era of antihydrogen research enabling high precision spectroscopy for the first time. A comparison of the spectroscopic properties of antihydrogen with those of hydrogen constitutes a stringent test of the CPT symmetry, the most fundamental law of physics. One of the important achievements of cold antihydrogen study in the last couple of years is the trapping of antihydrogen atoms in an octupole magnetic bottle. Considering the bottle depth, the trapped antihydrogen atoms were really cold, less than 0.5K in their temperature. High precision laser spectroscopy of 1S-2S transition is foreseen once antihydrogen atoms can be laser-cooled. The other milestone development was a successful synthesis of antihydrogen atoms in a so-called cusp trap, where an anti-Helmholtz coil configuration is adopted. The cusp trap enables extraction of antihydrogen atoms in a field-free region as an intensified spin-polarized beam,which realizes high resolution microwave spectroscopy of ground state hyperfine transitions.
Antihydrogen, the bound state of a positron and an antiproton, is the simplest pure anti-atomic system and an excellent candidate to test the symmetry between matter and antimatter. This thesis focuses on the magnetic confinement of antihydrogen and the first ever resonant interaction with trapped antihydrogen, as performed by the ALPHA collaboration. The ALPHA apparatus and the techniques that have been developed to form, trap, probe, and detect antihydrogen atoms will be described in detail. The first successful demonstration of trapped antihydrogen will then be described. In the initial demonstrations, 38 trapped antihydrogen atoms were detected after being confined for at least 172 ms. Since then, over 400 antihydrogen atoms have been trapped and confinement times of 1000 s (over 15 minutes) have been demonstrated. Spectroscopy of these trapped antihydrogen atoms is the next major step forward. As an initial proof-of-principle demonstration, ALPHA induced and observed reso- nant positron spin flip (PSR) transitions between the ground states of antihydrogen. Because of the strong magnetic field dependence of these transition frequencies, the success of this experiment relied heavily on the ability to measure the magnetic field seen by the antihydrogen atoms. A novel method to measure the magnetic field in situ by detecting the cyclotron resonance of a trapped electron plasma is presented. This method allowed ALPHA to measure the magnetic field strength at the minimum of the magnetic antihydrogen trap to within 1.4 parts in 103. Hardware improvements and further study should allow this resolution to be improved by several orders of magnitude. The cyclotron resonance measurements can also be applied as a roughdiagnostic of a microwave field within the ALPHA apparatus. This allowed for important diagnostics of the microwave field used to excite the PSR transitions. Finally, the experimental results demonstrating resonant PSR transitions in antihydrogen are presented. This experiment is the first ever spectroscopic measurement of antihydrogen and an important step towards future precision spectroscopy.