Prerequisites for studying relativistic quantum dynamics in experiments at the GSI and FAIR facilities
Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
Final Report Abstract
The DFG-SPSU 2016 joint bilateral research project was aimed at advancement of theoretical approaches for quantum dynamics of electrons (including electron-positron pair creation) and radiation processes in presence of strong electromagnetic fields with a particular emphasis for planned experiments at GSI and upcoming FAIR facilities. For this, the scientists from Friedrich-Schiller-Universität Jena and GSI Helmholtzzentrum für Schwerionenforschung have teamed up with theoretical physics group from St. Petersburg State University within this project. In the framework of this undertaking, basically all the goals set at the time of the application have been achieved. Namely, theoretical methods to describe dynamics of slow heavy-ion collisions have been significantly advanced. Two-center non-perturbative approaches have been developed based on fully relativistic framework. The calculations have been performed to describe the data from first experiments in this direction carried out at the ESR storage ring at GSI. Moreover, electron-positron pair production has been addressed in subcritical and supercritical regimes. Comparison of the results obtained within different theoretical approaches (e.g. monopole approximation) has been made and important differences as well as similarities have been identified. Very importantly, a new theoretical proposal has been worked out with a promising scenario to clearly distinguish spontaneous pair production from the dynamical mechanism. This provides a challenging but realistic opportunity for experimental identification of the spontaneous electron-position pair production in supercritical ion-atom collisions. If realized, this would be a first clear identification of the decay of quantum vacuum in supercritical fields which would be a groundbreaking discovery of fundamental importance in many aspects. Furthermore, fully-relativistic nonperturbative calculations of fundamental atomic processes with twisted electrons have been performed. These include; the elastic (Mott) scattering, the radiative recombination, and the Bremsstrahlung. This method allows one to obtain reliable results for heavy ions where relativistic effects are of high importance. The influence of the “twistedness” of the incoming electron on the angular and polarization properties of the emitted particles has been investigated and strong signatures have been found. On the experimental side, pilot measurements have been successfully carried out at the ESR storage ring observing collisions of bare, H-like, He-like xenon ions with xenon gas atoms at low energies. The measurements have already demonstrated possibility of selecting collisions with small impact parameters which is of particular importance for the planned quasi-molecular studies. In addition, important insights into the collision dynamics have been gained from the observed x-ray spectra. These developments are complemented by successful commissioning of the CRYRING@ESR (the very first FAIR facility) with heavy highly-charged ions injected from the ESR. This represents a very important milestone towards future experimental studies of low-energy heavy-ion atom/ion collisions. Within this project we have certainly fostered our collaboration with the theoretical physics group of St. Petersburg State University, which is the leading theoretical physics group world-wide in this field of research. The studies performed in this framework constitute surely a very important prerequisite for the challenging experimental campaign at GSI/FAIR.
Publications
- “Impact parameter sensitive study of inner-shell atomic processes in the experimental storage ring”, Nuclear Instruments and Methods in Physics Research B 408 (2017) 27
A. Gumberidze et al.
(See online at https://doi.org/10.1016/j.nimb.2017.04.090) - “Intensities of K-X-ray satellite and hypersatellite target radiation in Bi 83+-Xe @70 MeV/u collisions”, Nuclear Instruments and Methods in Physics Research B 408 (2017) 31
Y. S. Kozhedub et al.
(See online at https://doi.org/10.1016/j.nimb.2017.04.045) - “Pair production in low-energy collisions of uranium nuclei beyond the monopole approximation” Nuclear Instruments and Methods in Physics Research B 408 (2017) 97
I. Maltsev et al.
(See online at https://doi.org/10.1016/j.nimb.2017.05.005) - “Electron-positron pair production in slow collisions of heavy nuclei beyond the monopole approximation” Phys. Rev. A 98 (2018) 062709
I. Maltsev et al.
(See online at https://doi.org/10.1103/PhysRevA.98.062709) - “One-center calculations of the electron-positron pair creation in low-energy collisions of heavy bare nuclei”, Eur. Phys. J. D 72 (2018) 115
R. V. Popov et al.
(See online at https://doi.org/10.1140/epjd/e2018-90056-4) - “How to Observe the Vacuum Decay in Low-Energy Heavy-Ion Collisions” Phys. Rev. Lett. 123 (2019) 113401
I. Maltsev et al.
(See online at https://doi.org/10.1103/PhysRevLett.123.113401) - “Atomic processes with twisted electrons” J. Phys.: Conf. Ser. 1412 (2020) 052013
V. A. Zaytsev et al.
(See online at https://doi.org/10.1088/1742-6596/1412/5/052013) - “How to access QED at a supercritical Coulomb field” Phys. Rev. D 102 (2020) 076005
R. V. Popov et al.
(See online at https://doi.org/10.1103/PhysRevD.102.076005)
