Recent developments of the relativistic nuclear field theory on the finite-temperature response will be presented. The general non-perturbative framework, which advances the nuclear response theory beyond the random phase approximation (RPA), is formulated in terms of a closed system of non-linear equations for the two-body Green’s functions. This provides a direct link to ab initio theories and allows for controlled approximate solutions.
The response theory beyond RPA is extended to the case of finite temperature. For this purpose, the time blocking approximation to the time-dependent part of the in-medium nucleon-nucleon interaction amplitude is adopted for the thermal Green’s function formalism. The method is implemented in a parameter-free way on the base of Quantum Hadrodynamics with effective meson-nucleon coupling adjusted on the mean-field level. In this framework, we investigate the temperature dependence of dipole spectra in the even-even medium-heavy nuclei with a special focus on the giant dipole resonance’s width problem and on the low-energy dipole strength distribution. Its behavior, together with the temperature dependence of the charge-exchange resonances, are studied for their potential impact on the r-process nucleosynthesis.