Pseudopsin has been shown to be approximately conserved in nuclei. We investigate whether or not there is an advantage in using the pseudospin operators as well as the spin operators in the description of the nucleon-nucleon interaction. We conclude that, indeed, there is an advantage.
Pseudospin symmetry has been useful in understanding atomic nuclei. We review the arguments that this symmetry is a relativistic symmetry. The condition for this symmetry is that the sum of the vector and scalar potentials in the Dirac Hamiltonian is a constant. We give the generators of pseudospin symmetry. We review some of the predictions that follow from this insight into the relativistic origins of pseudospin symmetry. Since in nuclei the sum of the scalar and vector potentials is not zero but is small, we discuss preliminary investigations into the conditions on the potentials to produce…
The nearly degenerate triplet bands with the $πg_{9/2}^{-1}\otimes νh_{11/2} (g_{7/2},d_{5/2})$ configuration in $^{105}$Ag are studied via the relativistic mean-field (RMF) theory and the multiparticle plus rotor model (MPRM), which indicates that these bands are associated with chiral symmetry and pseudospin symmetry. The configuration-fixed constrained triaxial RMF calculations exhibit the pseudospin symmetry in single particle spectra and the triaxial shape coexistence. The experimental excitation energies and the electromagnetic transition probabilities for the triplet bands are reproduce…
The Dirac Equation is solved approximately for relativistic generalized Woods-Saxon potential including Coulomb-like tensor potential in exact pseudospin and spin symmetry limits. The bound states energy eigenvalues are found by using wavefunction boundary conditions, and corresponding radial wavefunctions are obtained in terms of hypergeometric function. Some numerical examples are given for the dependence of bound states energy eigenvalues on quantum numbers and potential parameters.
A reflection-asymmetric triaxial particle rotor model with three quasiparticles and a reflection-asymmetric triaxial rotor is developed, and applied to investigate the observed multiple chiral doublets (M\c{hi}D) candidates with octupole correlations in 131Ba, i.e., two pairs of positive-parity bands D3-D4 and D5-D6, as well as one pair of negative-parity bands D7-D8. The energy spectra, the energy staggering parameters, the B(M1)/B(E2) ratios, and the B(E1)/B(E2) ratios are reproduced well. The chiral geometries for these M\c{hi}D candidates are examined by the azimuthal plots, and the evolut…
We present finite temperature Dirac-Hartree-Bogoliubov (FTDHB) calculations for the tin isotope chain to study the dependence of pseudospin on the nuclear temperature. In the FTDHB calculation, the density dependence of the self-consistent relativistic mean fields, the pairing, and the vapor phase that takes into account the unbound nucleon states are considered self-consistently. The mean field potentials obtained in the FTDHB calculations are fit by Woods-Saxon (WS) potentials to examine how the WS parameters are related to the energy splitting of the pseudospin pairs as the temperature incr…
In this study, approximate bound state solutions of the Dirac equation with the newly proposed shifted Tietz-Wei (sTW) potential were obtained for any arbitrary quantum number. Using Generalized Parametric Nikiforov Methods, the eigenenergy equations as well as the upper and lower spinors of the wave function corresponding to spin and pseudospin symmetric solutions were obtained by solving the radial equation. The Pekeris approximation scheme in terms of the parameters of the shifted Tietz-Wei potential was used to deal with the spin-orbit coupling potential term k(k+1)/r^2. The solutions obta…
Exact conservation and breaking of pseudospin symmetry in single particle resonant states
本文介绍了单粒子共振态赝自旋对称性的研究结果。PSS是与核子狄拉克波函数的小分量相联系的相对论动力学对称性。人们做了许多努力来研究束缚态中的这种对称性。最近,我们通过检查对应于径向狄拉克波函数的小分量的Jost函数的零点和连续态的相移[1,Phys. Rev. Lett. 109(2012)072501]。我们证明了当吸引标量势和排斥矢量势大小相同但符号相反时,核中单粒子共振态的PSS是守恒的。在单粒子共振的精确守恒和这种对称性的破坏的例子给出了球形方井和伍兹-撒克逊潜力。
From spin to pseudospin symmetry: The origin of magic numbers in nuclear structure
School of Physics and Astronomy, Sun Yat-sen University(中山大学物理学院);Guangdong Provincial Key Laboratory of Quantum Metrology and Sensing, Sun Yat-Sen University(中山大学广东省量子计量与传感重点实验室);Graduate School of China Academy of Engineering Physics(中国工程物理研究院研究生院);Facility for Rare Isotope Beams, Michigan State University(密歇根州立大学稀有同位素束设施);Department of Physics & Astronomy, Michigan State University(密歇根州立大学物理与天文学系);Department of Physics, Graduate School of Science, The University of Tokyo(东京大学理学研究科物理学专业)
The quasi-degeneracy between the single-particle states $(n,\,l,\,j=l+1/2)$ and $(n-1,\,l+2,\,j=l+3/2)$ indicates a special and hidden symmetry in atomic nuclei---the so-called pseudospin symmetry (PSS)---which is an important concept in both spherical and deformed nuclei. A number of phenomena in nuclear structure have been successfully interpreted directly or implicitly by this symmetry, including nuclear superdeformed configurations, identical bands, quantized alignment, pseudospin partner bands, and so on. Since the PSS was recognized as a relativistic symmetry in 1990s, there have been co…
Symmetry plays a fundamental role in physics. The quasi-degeneracy between single-particle orbitals $(n, l, j = l + 1/2)$ and $(n-1, l + 2, j = l + 3/2)$ indicates a hidden symmetry in atomic nuclei, the so-called pseudospin symmetry (PSS). Since the introduction of the concept of PSS in atomic nuclei, there have been comprehensive efforts to understand its origin. Both splittings of spin doublets and pseudospin doublets play critical roles in the evolution of magic numbers in exotic nuclei discovered by modern spectroscopic studies with radioactive ion beam facilities. Since the PSS was recog…