Abstract
Mixing of the shell model (SM) eigenstates due to the coupling via the common decay channel influences leads in many cases to the formation of a collective eigenstate which carries many features of the nearby decay channel. This generic mechanism in open quantum systems explains the phenomenological Ikeda diagram and generalizes it for various clusters/correlations in the vicinity of the respective cluster decay thresholds. The near-threshold collectivization of the SM states may also influence their electromagnetic decays. We discuss this phenomenon on the example of B(Eλ) decays of near-threshold 2+ states in 14C.
Highlights
Since the beginning of century, the low-energy nuclear theory evolves rapidly
This work has led, for example, to the no-core shell model coupled with the resonating-group method [1, 2] and the no-core Gamow shell model [3, 4, 5] for calculating continuum properties, such as resonances and scattering configurations
May lead to the coalescence of two eigenvalues, i.e., to the formation of double poles of the scattering matrix, the so-called exceptional points (EPs) [27], which are the key ingredient of the configuration mixing mechanism in open quantum system (OQS)
Summary
Since the beginning of century, the low-energy nuclear theory evolves rapidly. New innovative strategies of solving nuclear many-body problem have been proposed. At the limit of nuclear stability with respect to the particle emission, i.e. in the vicinity of driplines or near the particle emission threshold in well-bound stable nuclei, nuclear states belong to the multidimensional network of states interconnected via the coupling to decay channels and scattering states This network of open quantum system (OQS) eigenstates spans the 3Dlattice in the space of proton numbers, neutron numbers, and excitation energy. GSM studies [18] have shown that one-nucleon spectroscopic factor shows an anomalous behaviour near neutral particle emission threshold with a characteristic dependence (−Sn)l−1/2 below the threshold and (−Sn)l+1/2 above the threshold, in a complete analogy with the Wigner threshold phenomenon for reaction cross-sections This unusual dependence of spectroscopic factors is a result of an interplay between discrete resonant states and non-resonant continuum in the many-body wave function. We will show that the collectivization of the SM eigenstates may have a noticeable effect on electromagnetic transitions and nuclear moments in weakly bound and unbound states
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
