8Nuclear shape transition has been actively studied in the past decade. In particular, the 9 understanding of this phenomenon from a microscopic point of view is of great 10 importance. Because of this reason, many works have been employed to investigate shape 11 phase transition in nuclei within the relativistic and non-relativistic mean field models by 12 examining potential energy curves (PECs). In this paper, by using layered feed-forward 13 neural networks (LFNNs), we have constructed consistent empirical physical formulas 14 (EPFs) for the PECs of Ti calculated in Hartree-Fock-Bogoliubov (HFB) method 15 with SLy4 Skyrme forces. It has been seen that the PECs obtained by neural network 16 method are compatible with those of HFB calculations.
18The study of the structural evolution in atomic nuclei with changing numbers of their 2 neutron and proton constituents dates back to the early days of the nuclear physics. In the 3 last decade, a number of theoretical developments have given insights into, and ways to 4 model, this structural evolution, particularly in transitional regions of rapid change [1, 2].
5These breakthroughs involve the concepts of quantum phase transitions (QPTs) and the 6 critical-point symmetries. A new class of symmetries E(5) and X(5) have been suggested 7 to describe shape phase transitions in atomic nuclei by Iachello [3, 4]. The E(5) critical-8 point symmetry has been found to correspond to the second order transition between U(5) 9 and O(6), while the X(5) critical-point symmetry has been found to correspond to the first 10 order transition between U(5) and SU(3). These symmetries was experimentally 11 identified in the spectrum of 134 Ba [5] and 152 Sm [6]. 12 From theoretical point of view, QPTs have been studied within the Interacting Boson 13 Model (IBM) and the solutions of Bohr-Mottelson differential equations. They are useful 14 representations for describing QPTs in nuclei. Also, phenomenological mean field 15 models (e.g, Hartree-Fock-Bogoliubov (HFB) method [7, 8] and relativistic mean field 16 (RMF) model [9, 10, 11]) have been used to investigate the critical-point nuclei with E(5) energy curves (PECs) obtained from quadrupole constrained calculations have been used 19 for describing the possible critical-point nuclei. Relatively flat PECs are obtained for 20 critical-point nuclei with E(5) symmetry, while in nuclei with X(5) symmetry, PECs with 21 a bump are obtained. It should be noted, however, that one should go beyond a simple 22mean field level for a quantitative analysis of QPT in nuclei. For this purpose, some 23 methods have been utilized in Ref. [21, 22, 23, 24]. The application of these methods for 24 a systematic study of QPT in nuclei is at present still very time-consuming. Therefore, the 25 evolution of the PECs along the isotopic or isotonic chains is important and can be used 26 for qualitative understanding of QPTs in nuclei.
27In Ref. [19], HFB method with SLy4 Skyrme forces have been employed to 28 investigate ground-state properties of even-even 3...