Progress on tilted axis cranking covariant density functional theory for nuclear magnetic and antimagnetic rotation

Magnetic rotation and antimagnetic rotation are exotic rotational phenomena observed in weakly deformed or near-spherical nuclei, which are respectively interpreted in terms of the shears mechanism and two shearslike mechanism. Since their observations, magnetic rotation and antimagnetic rotation phenomena have been mainly investigated in the framework of tilted axis cranking based on the pairing plus quadrupole model. For the last decades, the covariant density functional theory and its extension have been proved to be successful in describing series of nuclear ground-states and excited states properties, including the binding energies, radii, single-particle spectra, resonance states, halo phenomena, magnetic moments, magnetic rotation, low-lying excitations, shape phase transitions, collective rotation and vibrations, etc. This review will mainly focus on the tilted axis cranking covariant density functional theory and its application for the magnetic rotation and antimagnetic rotation phenomena.     

一场学习革命

<正>机器学习的基础工作早在上世纪中叶已经奠定。然而,正如Marric Stephens所发现的,越来越强大的计算机以及过去十年间不断改进的算法,正推动着机器学习在从医学物理到材料科学等诸多方面应用的爆发。     

Deformation Effect on the Center-of-Mass Correction Energy in Nuclei Ranging from Oxygen to Calcium

The microscopic c.m. correction energies for nuclei ranging from oxygen to calcium are systematically calculated by both spherical and axially deformed relativistic mean-field （RMF） models with the effective interaction PK1. The microscopic c.m. correction energies strongly depend on the isospin as well as deformation and deviate from the phenomenological ones. The deformation effect is discussed in detail by comparing the deformed with the spherical RMF calculation. It is found that the direct and exchange terms of the c.m. correction energies are strongly correlated with the density distribution of nuclei and are suppressed in the deformed case.     

α-cluster structure of 12C and 16O in the covariant density functional theory with a shell-model-like approach

The α-cluster structures for ¹²C and ¹⁶O are investigated in the framework of the covariant density functional theory, where the pairing correlation is treated with a particle number conserving shell-model-like approach. The ground states of ¹²C and ¹⁶O have been calculated and the density distributions demonstrate an equilateral triangle 3α clustering for ¹²C and a regular tetrahedron 4α clustering for ¹⁶O. The existence of linear nα chain structure of both ¹²C and ¹⁶O is revealed at high quadrupole deformation.     

Shape coexistence and <Emphasis Type="Italic">α</Emphasis>-decay chains of <Superscript>293</Superscript>Lv

Two recently observed ²⁹³Lv (Z = 116) α-decay chains [Eur. Phys. J. A 48, 62 (2012)] are investigated in the framework of covariant density functional theory with PC-PK1, where the pairing correlations are treated by the Bardeen-Cooper-Schrieffer method with a density-independent zerorange force. From the calculated potential energy curves, it is found that two minima always occur, with one having an almost spherical shape and the other exhibiting a large deformed prolate shape. Originating from the ground state and the shape-isomeric state of ²⁹³Lv, the two observed α-decay chains are constructed and the calculated Q _α values are found to be in good agreement with the data.