Production and detection of cold antihydrogen atoms

Amoretti, M.; Amsler, C.; Bonomi, G.; Bouchta, A.; Bowe, P. D.; Carraro, C.; Cesar, C. L.; Charlton, M.; Collier, M. J. T.; Doser, M.; Filippini, V.; Fine, K. S.; Fontana, A.; Fujiwara, M.; Funakoshi, R.; Genova, P.; Hangst, J. S.; Hayano, R.; Holzscheiter, M. H.; Jørgensen, L. V.; Lagomarsino, V.; Landua, R.; Lindelöf, D.; Rizzini, E. Lodi; Macrı́, M.; Madsen, N.; Manuzio, G.; Marchesotti, M.; Montagna, P.; Pruys, H.; Regenfus, C.; Riedler, P.; Rochet, J.; Rotondi, A.; Rouleau, G.; Testera, G.; Variola, A.; Watson, T.L.; Werf, D. P. van der

doi:10.1038/nature01096

Cited by 756 publications

(477 citation statements)

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“…Neutrinos, as we well as Supersymmetry searches, which we did not discuss here, constitute topics where new physics would definitely come into play, and where astrophysics has already given important results and/or constraints [6,55]. One cannot also exclude the possibility of having pleasant surprises from antimatter factories, such as [33], which may prove to be important for precision tests of CPT symmetry in the not-so-distant future.…”

Section: Discussionmentioning

confidence: 99%

“…In view of the recent 'massive' production of antihydrogen (H ) at CERN [33], which implies that interesting direct tests of CPT invariance using H are to be expected in the near future, we consider for our purposes here the specific case of MDE for Hydrogen H (anti-hydrogen H), although the formalism is generic. Let the spinor ψ represent the electron (positron) with charge q = −|e|(q = |e|) around a proton (antiproton) of charge −q.…”

Section: Quantum Gravity Lorentz Violation and Cptmentioning

confidence: 99%

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On CPT Symmetry: Cosmological, Quantum-Gravitational and Other Possible Violations and Their Phenomenology

Mavromatos

2004

Springer Proceedings in Physics

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Abstract. I discuss various ways in which CPT symmetry may be violated, and their phenomenology in current or immediate future experimental facilities, both terrestrial and astrophysical. Specifically, I discuss first violations of CPT symmetry due to the impossibility of defining a scattering matrix as a consequence of the existence of microscopic or macroscopic space-time boundaries, such as Planck-scale Black-Hole (event) horizons, or cosmological horizons due to the presence of a (positive) cosmological constant in the Universe. Second, I discuss CPT violation due to breaking of Lorentz symmetry, which may characterize certain approaches to quantum gravity, and third, I describe models of CPT non invariance due to violations of locality of interactions. In each of the above categories I discuss experimental sensitivities. I argue that the majority of Lorentz-violating cases of CPT breaking, with minimal (linear) suppression by the Planck-mass scale, are already excluded by current experimental tests. There are however some (stringy) models which can evade these constraints. CPT Breaking and the Scattering MatrixThe symmetry under the successive operations (in any order) of charge conjugation, C, parity (reflexion), P, and time reversal, T, known as CPT, is a fundamental symmetry of any local quantum field theory in flat space time, under the following assumptions [1]:• (i) Unitarity and the proper definition of a scattering matrix, • (ii) Lorentz Invariance and • (iii) Locality of InteractionsIn the presence of gravity, i.e. non-Minkowski,non-flat space time backgrounds, CPT symmetry may be violated, at least in in its strong form. This is indeed the case of singular space-time gravitational backgrounds, such as black holes, or in general space times with boundaries. The reason is that in such cases the presence of these boundaries jeopardizes requirements (i) and (ii) of the CPT theorem. In a quantum context, a Black hole evaporates due to Hawking radiation, and as such it may 'capture' for ever information on matter states passing nearby, as depicted schematically in figure 1. In such a case, one may not be able to define properly asymptotic state vectors |ψ > in a quantum context, given that Planck size black hole horizons appear as fluctuations of the geometry, and hence an asymptotic observer will necessarily trace out the information captured by the horizons. This means that the out states will be necessarily described by density matrices, ρ = Tr unobs |ψ >< ψ|. One has therefore an evolution from pure states to mixed, and unitarity is lost. The problem in defining asymptotic state vectors also implies the impossibility of defining a proper scattering S-matrix, since the latter connects by definition "in" and "out" state vectors: |OU T >= S|IN >. Instead, one can only define a Hawking $-matrix [2], which connects IN and OUT mixed states described by density matrices:where $ = SS † , with S = e iHt the S-matrix, and H the Hamiltonian of the matter subsystem. The $-matrix has no inverse, as a consequence...

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Section: Discussionmentioning

confidence: 99%

Section: Quantum Gravity Lorentz Violation and Cptmentioning

confidence: 99%

On CPT Symmetry: Cosmological, Quantum-Gravitational and Other Possible Violations and Their Phenomenology

Mavromatos

2004

Springer Proceedings in Physics

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“…See Amoretti et al [190]. This followed on from several years preparatory work by the ATHENA project (ApparaTus for High precision Experiments on Neutral Antimatter), Charlton et al [191] and Holzscheiter et al [192,193], and the competing ATRAP (Antihydrogen TRAP) project of Gabrielse et al [194].…”

Section: Antihydrogen Atomsmentioning

confidence: 99%

Stability of few-charge systems in quantum mechanics

2005

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We consider non-relativistic systems in quantum mechanics interacting through the Coulomb potential, and discuss the existence of bound states which are stable against spontaneous dissociation into smaller atoms or ions. We review the studies that have been made of specific mass configurations and also the properties of the domain of stability in the space of masses or inverse masses. These rigorous results are supplemented by numerical investigations using accurate variational methods. A section is devoted to systems of three arbitrary charges and another to molecules in a world with two space-dimensions.

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“…The properties of Rydberg states also depend on the orbital and magnetic quantum numbers and m. The selective production of Rydberg states of well-defined quantum numbers enables one to generate atoms or molecules with specific physical properties. This advantage is exploited in an increasing number of scientific applications in several subfields of physics and chemistry, such as quantum optics (see, e.g., [4,5]), quantum-information science (see, e.g., [6,7]), metrology in atoms and molecules (see, e.g., [8][9][10]), high-resolution photoelectron spectroscopy [11], the sensing of electromagnetic fields [12][13][14], and in research on antihydrogen [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Radiative and collisional processes in translationally cold samples of hydrogen Rydberg atoms studied in an electrostatic trap

Seiler¹,

Agner²,

Pillet³

et al. 2016

J. Phys. B: At. Mol. Opt. Phys.

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Supersonic beams of hydrogen atoms, prepared selectively in Rydberg-Stark states of principal quantum number n in the range between 25 and 35, have been deflected by 90 ○ , decelerated and loaded into off-axis electric traps at initial densities of ≈ 10 6 atoms/cm −3 and translational temperatures of 150 mK. The ability to confine the atoms spatially was exploited to study their decay by radiative and collisional processes. The evolution of the population of trapped atoms was measured for several milliseconds in dependence of the principal quantum number of the initially prepared states, the initial Rydberg-atom density in the trap, and the temperature of the environment of the trap, which could be varied between 7.5 K and 300 K using a cryorefrigerator. At room temperature, the population of trapped Rydberg atoms was found to decay faster than expected on the basis of their natural lifetimes, primarily because of absorption and emission stimulated by the thermal radiation field. At the lowest temperatures investigated experimentally, the decay was found to be multiexponential, with an initial rate scaling as n −4 and corresponding closely to the natural lifetimes of the initially prepared Rydberg-Stark states. The decay rate was found to continually decrease over time and to reach an almost n-independent rate of more than (1 ms) −1 after 3 ms. To analyze the experimentally observed decay of the populations of trapped atoms, numerical simulations were performed which included all radiative processes, i.e., spontaneous emission as well as absorption and emission stimulated by the thermal radiation. These simulations, however, systematically underestimated the population of trapped atoms observed after several milliseconds by almost two orders of magnitude, although they reliably predicted the decay rates of the remaining atoms in the trap. The calculations revealed that the atoms that remain in the trap for the longest times have larger absolute values of the magnetic quantum number m than the optically prepared RydbergStark states, and this observation led to the conclusion that a much more efficient mechanism than a purely radiative one must exist to induce transitions to Rydberg-Stark states of higher m values. While searching for such a mechanism, we discovered that resonant dipole-dipole collisions between Rydberg atoms in the trap represent an extremely efficient way of inducing transitions to states of higher m values. The efficiency of the mechanism is a consequence of the almost perfectly linear nature of the Stark effect at the moderate field strengths used to trap the atoms, which permits cascades of transitions between entire networks of near-degenerate Rydberg-atom-pair states. To include such cascades of resonant dipole-dipole transitions in the numerical simulations, we have generalized the two-state Förster-type collision model used to describe resonant collisions in ultracold Rydberg gases to a multi-state situation. It is only when considering the combined effects of collisional and radiative pr...

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Production and detection of cold antihydrogen atoms

Cited by 756 publications

References 16 publications

On CPT Symmetry: Cosmological, Quantum-Gravitational and Other Possible Violations and Their Phenomenology

On CPT Symmetry: Cosmological, Quantum-Gravitational and Other Possible Violations and Their Phenomenology

Stability of few-charge systems in quantum mechanics

Radiative and collisional processes in translationally cold samples of hydrogen Rydberg atoms studied in an electrostatic trap

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