3,767 research outputs found
Relativistic effect of spin and pseudospin symmetries
Dirac Hamiltonian is scaled in the atomic units , which allows us
to take the non-relativistic limit by setting the Compton wavelength . The evolutions of the spin and pseudospin symmetries towards
the non-relativistic limit are investigated by solving the Dirac equation with
the parameter . With transformation from the original
Compton wavelength to 0, the spin splittings decrease monotonously in all spin
doublets, and the pseudospin splittings increase in several pseudospin
doublets, no change, or even reduce in several other pseudospin doublets. The
various energy splitting behaviors of both the spin and pseudospin doublets
with are well explained by the perturbation calculations of Dirac
Hamiltonian in the present units. It indicates that the origin of spin symmetry
is entirely due to the relativistic effect, while the origin of pseudospin
symmetry cannot be uniquely attributed to the relativistic effect.Comment: 15 pages, 7 figures, accepted by PR
Predication of novel effects in rotational nuclei at high speed
The study of high-speed rotating matter is a crucial research topic in
physics due to the emergence of novel phenomena. In this paper, we combined
cranking covariant density functional theory (CDFT) with a similar
renormalization group approach to decompose the Hamiltonian from the cranking
CDFT into different Hermit components, including the non-relativistic term, the
dynamical term, the spin-orbit coupling, and the Darwin term. Especially, we
obtained the rotational term, the term relating to Zeeman effect-like, and the
spin-rotation coupling due to consideration of rotation and spatial component
of vector potential. By exploring these operators, we aim to identify novel
phenomena that may occur in rotating nuclei. Signature splitting, Zeeman
effect-like, spin-rotation coupling, and spin current are among the potential
novelties that may arise in rotating nuclei. Additionally, we investigated the
observability of these phenomena and their dependence on various factors such
as nuclear deformation, rotational angular velocity, and strength of magnetic
field.Comment: 7pages, 5figure
Exploration of relativistic symmetry by the similarity renormalization group
The similarity renormalization group is used to transform Dirac Hamiltonian
into a diagonal form, which the upper (lower) diagonal element becomes an
operator describing Dirac (anti-)particle. The eigenvalues of the operator are
verfied to be in good agreement with that of the original Hamiltonian.
Furthermore, the pseudospin symmetry is investigated. It is shown that the
pseudospin splittings appearing in the nonrelativistic limit are reduced by the
contributions from these terms relating the spin-orbit interactions, added by
those relating the dynamical terms, and the quality of pseudospin symmetry
origins mainly from the competition of the dynamical effects and the spin-orbit
interactions. The spin symmetry of antiparticle spectrum is well reproduced in
the present calculations.Comment: 5pages, 2figure
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