Superoperator approach to theory of hot nuclei and astrophysical applications
Seminars
Bogoliubov Laboratory of Theoretical Physics
Seminar on Nuclear Theory
Date and Time: Monday, 25 October 2021, at 3:30 PM
Venue: Blokhintsev lecture hall (4th floor), Bogoliubov Laboratory of Theoretical Physics, online seminar on Zoom
Seminar topic: “Superoperator approach to the theory of hot nuclei and astrophysical applications”
Speaker: Alan A. Dzhioev
Abstract:
The method of superoperators in Liouville space was applied to study equilibrium and excited states of hot nuclei. It is shown for the first time that properly
defined fermionic superoperators allow us to generalize the equation of motion method to hot nuclei. Within the developed approach and using the Skyrme
energy density functional, we derived the equations of thermal quasiparticle random phase approximation. From these equations one can calculate the strength
functions of charge-exchange and charge-neutral excitations of hot nuclei in a thermodynamically consistent way, avoiding the use of the Axel-Brink hypothesis
and violation of the detailed balance principle. Based on the quasiparticle phonon nuclear model a method for accounting the coupling of simple and complex
configurations in hot nuclei is proposed. By the example of selected iron group nuclei and neutron-rich nuclei with N∼50, the temperature effects on the rates and
cross sections of various weak-interaction mediated reactions (electron capture, inelastic neutrino scattering, etc.) playing an important role at the late stages of massive star evolution, were studied. It is shown that thermodynamically consistent incorporation of thermal effects leads to a stronger temperature dependence of the rates and cross sections than predicted by the shell model calculations.
(based on the doctoral thesis)