Speaker
Description
In a series of papers [1], a generalization of the theory of finite fermi systems (TFFS) was developed within the framework of the Green's function method to consistently account for complex configurations with phonons. However, quantitative estimates of the effects obtained there were not carried out due to the large quantitative difficulties. It seems that these difficulties can be circumvented or greatly reduced if to use the separable forces approximation applied, for example, in the well-known quasiparticle-phonon model (QPM) [2]. In the non-self-consistent QPM, the parameters of separable multipole forces are usually adjusted according to experimental data, in particular, for the lowest-lying $2^+$ and $3^-$-phonons, and a good description of many other excited states of spherical and deformed nuclei is obtained, for more details see [2].
We used "our" separable forces adjusting their two parameters in the corresponding equation for the effective field (vertex) [3, 4] and proceeding from fixed effective quadrupole charges based on the general formula we derived for them. In particular, for $e^{n, p}_{eff}$ =1 and 2 at $\omega$ =0 in $^{208}Pb$, we obtained that two separable forces parameters are equal.
Within the framework of this approach, a simple and useful relationship between $e^{p, n}_{eff}$ and two parameters of separable forces, that approximate the full amplitude $\Gamma$ in the standard TFFS, is also obtained.
The results obtained are used to quantify new effects in the generalized TFFS: equations for the regular part $\Gamma^r$ of the amplitude $\Gamma$, the ratios of various phonon-exchange interactions, the equation for the two phonon creation amplitude, which is contained in the concept of tadpole, and other effects.
- S. P. Kamerdzhiev, M.I. Shitov, Phys. At. Nucl. 84 No.6, 804 (2021); 84 №5, 649 (2021); 85 №5, 425 (2022).
- V. G. Solovʹev, Theory of Atomic Nuclei, Quasi-particle and Phonons, Institute of Physics Pub., Bristol; Philadelphia, 1992.
- A. B. Migdal, The theory of finite Fermi systems and the properties of atomic nuclei (2nd revised and enlarged edition), Nauka, Moscow, 1983.
- S. P. Kamerdzhiev, Sov. J. Nucl. Phys. 5, 971 (1967).
| Section | Nuclear structure: theory and experiment |
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