Abstract The main objective of the present paper is to discuss the consequences of matter-antimatter interaction at low energy. The production of large number of cooled antimatter in laboratory and the formation of exotic atoms composed of particles and antiparticles are reviewed. Particularly, the quantum mechanical treatment of Four-Body exotic molecules is shortly discussed. The main goal of the paper is to shed light on possible novel discoveries and applications based on the coexistence of matter and antimatter.
Abstract The main objective of the present paper is to discuss the consequences of matter-antimatter interaction at low energy. The production of large number of cooled antimatter in laboratory and the formation of exotic atoms composed of particles and antiparticles are reviewed. Particularly, the quantum mechanical treatment of Four-Body exotic molecules is shortly discussed. The main goal of the paper is to shed light on possible novel discoveries and applications based on the coexistence of matter and antimatter.
Positron,an antiparticle of electron,is much more easily obtained than other's antipartices,such as antiproton,antihydrogen,thus electron-positron system is the most suitable way for studying the combination of common matter and antimatter.In this article,we describe the history,current state and future prospect of antimatter(positron) research in combination with first laboratory synthesis of matter-antimatter molecule;and emphasizes on the experimental techniques based on positron trapping,confinement and accumulation,and the production of molecular positronium.
The stability of antimatter in contact with matter has been investigated. The interaction between hydrogen and antihydrogen is considered as the prototype reaction. We have focused interest on the rates for proton-antiproton and/or electron-positron annihilation during hydrogen-antihydrogen collisions at low energies. In particular, we have concentrated on the calculation of the rates for the rearrangement reaction leading to formation of protonium and positronium, ending inevitably in particle-antiparticle annihilation. The cross section for the rearrangement collision has been calculated in a fully quantum-mechanical treatment. Additionally, we have calculated cross sections for direct annihilation during the collision process, which was found to be comparable to the rearrangement cross section. The elastic cross section and its low-energy limit, given by the scattering length, have been calculated, allowing, by comparison to the inelastic processes, a prediction for the efficiency of cooling antihydrogen via collisions with ultracold hydrogen atoms.
An overview of the antiatom interactions with matter is given in the context of the ongoing efforts to trap and cool antihydrogen at CERN. We show how the atom‐antiatom scattering can, in addition to annihilation, result in a number of collisional reactions such as elastic scattering, rearrangement to protonium and positronium, and even radiative association leading to formation of unusual short‐lived atom‐antiatom molecules. We also show that sufficiently cold antiatoms can be reflected from material walls. The rates for these reactions are of interest for the experiments with antihydrogen atoms at CERN, they probe the feasibility of collisional cooling of antihydrogen and they contribute to the understanding of stability of matter in contact with antimatter in general.
Ever since antiparticles were discovered their nature has been something of a mystery. They were postulated to be identical to regular particles except for having opposite charge, but this would imply that an equal amount of antiparticles and particles should have been created at the beginning of time. However, everywhere we look the Universe seems to be constituted of regular particles, giving rise to the question whether there is something else that differentiates antiparticles from regular particles, or if there is something amiss in the Standard Model of particle physics. This thesis focuses on a central system of study in this field, the hydrogen-antihydrogen system and the theory surrounding it, as well as an expansion into systems with an antiproton interacting with small molecules, bridging the fields of quantum physics and quantum chemistry. Methods expanding on the Born-Oppenheimer approximation for the interaction between the two atoms are presented. The resulting 2-body interaction potential is then used for creating a part of the basis in a non-adiabatic 4-body method in order to look for resonance states whose existence could impact cross-sections of hydrogen-antihydrogen scattering. The eigenfunctions obtained from the non-adiabatic method are used by extracting the 2-body hadronic density function and comparing it to the adiabatic wave function, for measuring the adiabaticity of the hydrogen-antihydrogen system. The antiproton-matter interaction is first investigated by a quantum dynamical approach of an antiproton scattering on molecular hydrogen, common products in high-energy collision experiments, continued by a study of the potential energy surfaces of an antiproton interacting with a range of functional groups present in the human body.
Abstract The invention and development of laser methods for cooling and trapping atoms have led to the advent of the physics of ultracold matter. Low-temperature quantum physics has so far dealt with condensed media, wherein quantum phenomena (superfluidity and superconductivity) usually manifest themselves at temperatures of a few kelvin. Laser cooling and trapping of atoms have made it possible to successively attain millikelvin, microkelvin, and nanokelvin temperatures, at which the de Broglie wavelength of the atoms becomes commensurable with the interatomic separation, even in dilute gases. The interaction of atoms in ultracold dilute gases becomes essentially quantum mechanical. The physics of such quantum gases is more akin to the well-developed physics of condensed matter at low temperatures. It is in essence a boundary field between atomic, laser, and condensed-matter physics. Following the first, pioneering experiments on the Bose–Einstein condensation of alkali-metal atoms, this field has continued to develop at a very fast pace, which can be explained by the vast variety of particles (atoms, isotopes, and molecules) that can be laser cooled and trapped under degeneracy conditions. This is much more than physicists had at their disposal previously (3,4He). Moreover, laser radiation and magnetic fields additionally make it possible to control not only the intrinsic quantum state of the interacting ultracold particle species, but also the interaction of the particles. All this makes the research in the field of quantum gases a great breakthrough, both in atomic–molecular physics and in many-body-interaction physics, which heretofore was the prerogative of low-temperature condensed-matter physics.