Tag: Publication
-
Investigation of the fine structure of antihydrogen
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 states. The observation of this separation, now known as the Lamb shift, marked an important event in the evolution of modern
-
Design and Commissioning of Beamlines for the ALPHA Antihydrogen Experiment
One of the greatest problems facing modern physics is the apparent asymmetry between matter and antimatter. While the standard model of particle physics predicts that equal amounts of matter and antimatter were produced following the Big Bang, astronomical observations have revealed that our universe contains little or no primordial antimatter. Precision measurements of cold, trapped
-
Cavity and Microwave Experiments on Electron Plasma
A new technique for rapidly generating a sequence of target plasmas in a Penning-Malmberg trap is presented and applied in the first demonstration of cavity-resonant cooling in a plasma. This “reservoir” technique further enables the in situ magnetic field to be measured to high precision by microwave ECR spectroscopy. A precision antihydrogen gravity experiment being
-
Observation of the 1S–2P Lyman-α transition in antihydrogen
In 1906, Theodore Lyman discovered his eponymous series of transitions in the extreme-ultraviolet region of the atomic hydrogen spectrum. 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
-
Characterization of the 1S–2S transition in antihydrogen
In 1928, Dirac published an equation 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 (or anti-electron) by Anderson in 1932, but
-
Axial to transverse energy mixing dynamics in octupole-based magnetostatic antihydrogen traps
The nature of the trajectories of antihydrogen atoms confined in an octupole minimum-B trap is of great importance for upcoming spectroscopy, cooling, and gravity experiments. Of particular interest is the mixing time between the axial and transverse energies for the antiatoms. Here, using computer simulations, we establish that almost all trajectories are chaotic, and then
-
Machine learning for antihydrogen detection at ALPHA
The ALPHA experiment at CERN is designed to produce and trap antihydrogen to the purpose of making a precise comparison with hydrogen. The basic technique consists of driving an antihydrogen resonance which will cause the antiatom to leave the trap and annihilate. The main background to antihydrogen detection is due to cosmic rays. When an
-
Lyman-Alpha Transition observed in Antihydrogen
The ALPHA collaboration has for the first time observed single-photon excitation of antihydrogen atoms from the ground (1S) state to the 2P state using 121nm pulsed laser light – the so-called lyman-alpha line of the Lyman series. The results were published in Nature on August 22nd 2018 and also demonstrate how the pulsed laser-light can
-
Methods for plasma stabilization and control to improve antihydrogen production
The ALPHA (Antihydrogen Laser Physics Apparatus) collaboration creates and performs precise measurements on antihydrogen to test Charge-Parity-Time (CPT) symmetry. Prior to creating antihydrogen we must prepare the antiproton and positron plasmas to have optimal and repeatable parameters. This thesis presents the development of a new method to simultaneously control the number of particles and plasma
-
First 1S-2S Line Shape published in Nature
Our latest breakthrough, the first detailed study of one of the hyperfine components of the 1S-2S line in trapped antihydrogen has been published in Nature and is the most precise and most accurate measurement of antimatter to date. This builds on years of work, developing techniques to manipulate super-cold antiprotons and positrons, create trapped antihydrogen