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Stegeby, Henrik
Publications (5 of 5) Show all publications
Stegeby, H. & Piszczatowski, K. (2016). Resonance states in the hydrogen-antihydrogen system from a nonadiabatic treatment. Journal of Physics B: Atomic, Molecular and Optical Physics, 49(1), Article ID 014002.
Open this publication in new window or tab >>Resonance states in the hydrogen-antihydrogen system from a nonadiabatic treatment
2016 (English)In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 49, no 1, article id 014002Article in journal (Refereed) Published
Abstract [en]

The quantum-mechanical four-body problem for the hydrogen-antihydrogen system has been solved by means of the variational implementation of the coupled-arrangement channel method. Wave functions have been formed using the Gaussian expansion method (GEM) in Jacobi coordinates; they explicitly include components corresponding to the rearrangement from hydrogen and antihydrogen (H + (H) over bar into protonium and positronium (Pn + Ps). We analyze the solutions belonging to the discretized spectrum of the four-body eigenvalue problem, searching for resonance states at energies just below the H-(H) over bar dissociation energy threshold by means of the stabilization method and complex scaling.

Keywords
antimatter, resonance, hydrogen-antihydrogen, few-body system, stability method, complex scaling
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-274895 (URN)10.1088/0953-4075/49/1/014002 (DOI)000367153800003 ()
Funder
Wenner-Gren FoundationsSwedish Research Council
Available from: 2016-02-02 Created: 2016-01-26 Last updated: 2018-04-22Bibliographically approved
Stegeby, H., Kowalewski, M., Piszczatowski, K. & Karlsson, H. O. (2015). Wave packet simulations of antiproton scattering on molecular hydrogen. Journal of Physics B: Atomic, Molecular and Optical Physics, 48(19), 195204:1-7, Article ID 195204.
Open this publication in new window or tab >>Wave packet simulations of antiproton scattering on molecular hydrogen
2015 (English)In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 48, no 19, p. 195204:1-7, article id 195204Article in journal (Refereed) Published
National Category
Theoretical Chemistry Computational Mathematics
Identifiers
urn:nbn:se:uu:diva-261547 (URN)10.1088/0953-4075/48/19/195204 (DOI)000361036700011 ()
Projects
eSSENCE
Available from: 2015-08-28 Created: 2015-09-01 Last updated: 2018-04-22Bibliographically approved
Stegeby, H. (2012). Four-Body Treatment of the Hydrogen-Antihydrogen System. (Licentiate dissertation). Uppsala: Uppsala universitet
Open this publication in new window or tab >>Four-Body Treatment of the Hydrogen-Antihydrogen System
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis presents a nonadiabatic (4-body) description of the hydrogen-antihydrogen system at a nonrelativistic level. The properties of the system, the rearrangement processes and the possible existence of resonance states are investigated by using a variational method for coupled arrangement channels, the Gaussian Expansion Method, and the stabilization method.

The 4-body basis set is optimized by means of prediagonalization of 2-body fragments. In paper I, a mass-scaling procedure of the Born-Oppenheimer potential is introduced for the description of the relative motion between hydrogen and antihydrogen. The nonadiabaticity of the system is investigated in paper II.

Place, publisher, year, edition, pages
Uppsala: Uppsala universitet, 2012. p. 104
Keywords
Antimatter, antihydrogen, four-body system, Adiabatic approximation, Born-Oppenheimer, elastic scattering, stabilization method, resonance states, coupled arrangement channels, coupled rearrangement channels, Gaussian Expansion Method, Antimateria, antiväte, fyrkroppars system, adiabatisk approximation, stabilisationsmetoden, resonanstillstånd, spridningstillstånd, kopplade arrangemangskanaler
National Category
Atom and Molecular Physics and Optics Atom and Molecular Physics and Optics
Research subject
Quantum Chemistry
Identifiers
urn:nbn:se:uu:diva-174015 (URN)
Presentation
2012-05-25, Å: 64119, Department of Chemistry - Ångström Laboratory Box 518, SE-751 20 UPPSALA, Sweden, UPPSALA, 13:00 (English)
Opponent
Supervisors
Available from: 2012-09-27 Created: 2012-05-09 Last updated: 2012-09-27Bibliographically approved
Stegeby, H., Piszczatowski, K., Karlsson, H. O., Lindh, R. & Froelich, P. (2012). Variational calculations for the hydrogen-antihydrogen system with a mass-scaled Born-Oppenheimer potential. CENTRAL EUROPEAN JOURNAL OF PHYSICS, 10(5), 1038-1053
Open this publication in new window or tab >>Variational calculations for the hydrogen-antihydrogen system with a mass-scaled Born-Oppenheimer potential
Show others...
2012 (English)In: CENTRAL EUROPEAN JOURNAL OF PHYSICS, ISSN 1895-1082, Vol. 10, no 5, p. 1038-1053Article in journal (Refereed) Published
Abstract [en]

The problem of proton-antiproton motion in the H- system is investigated by means of the variational method. We introduce a modified nuclear interaction through mass-scaling of the Born-Oppenheimer potential. This improved treatment of the interaction includes the nondivergent part of the otherwise divergent adiabatic correction and shows the correct threshold behaviour. Using this potential we calculate the vibrational energy levels with angular momentum 0 and 1 and the corresponding nuclear wave functions, as well as the S-wave scattering length. We obtain a full set of all bound states together with a large number of discretized continuum states that might be utilized in variational four-body calculations. The results of our calculations gives an indication of resonance states in the hydrogen-antihydrogen system.

Keywords
antihydrogen; Born-Oppenheimer approximation; adiabatic approximation; matter-antimatter interactions
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:uu:diva-188930 (URN)10.2478/s11534-012-0131-y (DOI)000311496400002 ()
Available from: 2012-12-21 Created: 2012-12-21 Last updated: 2018-04-22Bibliographically approved
Berggren, P., Stegeby, H., Voronin, A. & Froelich, P. (2008). Impact of the strong force on the Coulombic decay of a hydrogen-antihydrogen molecule. Journal of Physics B: Atomic, Molecular and Optical Physics, 41(15), 155202
Open this publication in new window or tab >>Impact of the strong force on the Coulombic decay of a hydrogen-antihydrogen molecule
2008 (English)In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 41, no 15, p. 155202-Article in journal (Refereed) Published
Abstract [en]

The lifetime of the meta-stable hydrogen-antihydrogen molecule in various vibrational states is calculated. The partial lifetime with respect to the proton-antiproton annihilation is obtained from complex eigenvalues which arise upon inclusion of the strong force in the adiabatic formulation of the molecular decay problem. We study the influence of the strong force, which causes annihilation, on the transition probability for decay via Coulombic rearrangement to protonium and positronium.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-109174 (URN)10.1088/0953-4075/41/15/155202 (DOI)000258020000008 ()
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2018-04-22
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