Nuclear many-body problem at zero and finite temperature
Seminar “Nuclear Theory”
Date and Time: Monday, 2 November 2020, at 3:30 PM
Venue: Online conference in Zoom, Bogoliubov Laboratory of Theoretical Physics
Seminar topic: «Nuclear many-body problem at zero and finite temperature»
Speaker: Elena Litvinova (Department of Physics, Western Michigan University, Kalamazoo, USA; NSCL, Michigan State University, East Lansing, USA; GANIL, CEA/DRF-CNRS/IN2P3, Caen, France_)
Recent developments of the relativistic nuclear field theory (NFT) on the fermionic correlation functions (propagators) will be presented. In this talk, the general non- perturbative equation of motion framework is formulated in terms of a closed system of non-linear equations for one-body and two-body propagators, which serve as building blocks for higher-rank correlation functions. The present formulation provides a direct link to ab-initio theories and extends the explicit treatment of many-body correlations beyond the conventional NFT. The novel approach to the nuclear response, which includes self-consistently up to three-particle-three-hole (3p3h) correlated configurations is discussed in detail. The latter developments are implemented numerically on the basis of the relativistic effective meson-nucleon Lagrangian and compared to the models confined by lower-rank configurations. The results obtained for the response of medium-heavy nuclei in comparison to available experimental data show that the higher-complexity configurations are necessary for a successful description of both gross and fine details of the spectra in both highenergy and low-energy sectors.
The relativistic response theory confined by the 2q⊗phonon configurations was extended recently to finite temperature for both neutral and charge-exchange nuclear response. Within this approach, we investigate the temperature dependence of nuclear spectra in various channels, such as the monopole, dipole, quadrupole and spin-isospin ones, for even-even medium-heavy nuclei. Consequences for the giant dipole resonance’s width problem, the low-energy strength distributions and the influence of temperature on the equation of state are outlined. The temperature dependence of the Gamow-Teller and spin dipole excitations are discussed in the context of its potential impact on the astrophysical modeling of supernovae and neutron-star mergers.