No Arabic abstract
The dominance (preponderance) of the 0+ ground state for random interactions is shown to be a consequence of certain random interactions with chaotic features. These random interactions, called chaotic random interactions, impart a symmetry property to the ground-state wave function: an isotropy under an appropriate transformation, such as zero angular momentum for rotation. Under this mechanism, the ground-state parity and isospin can also be predicted in such a manner that positive parity is favored over negative parity and the isospin T = 0 is favored over higher isospins. As chaotic random interaction is a limit with no particular dynamics at the level of two interacting particles, this realization of isotropic symmetry in the ground state can be considered as the ultimate case of many-body correlations. A possible relation to the isotropy of the early universe is mentioned.
Dirac Hamiltonian is scaled in the atomic units $hbar =m=1$, which allows us to take the non-relativistic limit by setting the Compton wavelength $% lambda rightarrow 0 $. The evolutions of the spin and pseudospin symmetries towards the non-relativistic limit are investigated by solving the Dirac equation with the parameter $lambda$. With $lambda$ 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 $lambda$ 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.
Entanglement suppression in the strong interaction $S$-matrix is shown to be correlated with approximate spin-flavor symmetries that are observed in low-energy baryon interactions, the Wigner $SU(4)$ symmetry for two flavors and an $SU(16)$ symmetry for three flavors. We conjecture that dynamical entanglement suppression is a property of the strong interactions in the infrared, giving rise to these emergent symmetries and providing powerful constraints on the nature of nuclear and hypernuclear forces in dense matter.
We examine critically how tightly the density dependence of nuclear symmetry energy esym is constrained by the universal equation of state (EOS) of the unitary Fermi gas $E_{rm{UG}}(rho)$ considering currently known uncertainties of higher order parameters describing the density dependence of the Equation of State of isospin-asymmetric nuclear matter. We found that $E_{rm{UG}}(rho)$ does provide a useful lower boundary for the esym. However, it does not tightly constrain the correlation between the magnitude $E_{rm{sym}}(rho_0)$ and slope $L$ unless the curvature $K_{rm{sym}}$ of the symmetry energy at saturation density $rho_0$ is more precisely known. The large uncertainty in the skewness parameters affects the $E_{rm{sym}}(rho_0)$ versus $L$ correlation by the same almost as significantly as the uncertainty in $K_{rm{sym}}$.
A coherent state technique is used to generate an Interacting Boson Model (IBM) Hamiltonian energy surface that simulates a mean field energy surface. The method presented here has some significant advantages over previous work. Specifically, that this can be a completely predictive requiring no a priori knowledge of the IBM parameters. The technique allows for the prediction of the low lying energy spectra and electromagnetic transition rates which are of astrophysical interest. Results and comparison with experiment are included for krypton, molybdenum, palladium, cadmium, gadolinium, dysprosium and erbium nuclei.
Following a recent rapid communications[Phys.Rev.C85,021302(R) (2012)], we present more details on the investigation of the relativistic symmetry by use of the similarity renormalization group. By comparing the contributions of the different components in the diagonal Dirac Hamiltonian to the pseudospin splitting, we have found that two components of the dynamical term make similar influence on the pseudospin symmetry. The same case also appears in the spin-orbit interactions. Further, we have checked the influences of every term on the pseudospin splitting and their correlations with the potential parameters for all the available pseudospin partners. The result shows that the spin-orbit interactions always play a role in favor of the pseudospin symmetry, and whether the pseudospin symmetry is improved or destroyed by the dynamical term relating the shape of the potential as well as the quantum numbers of the state. The cause why the pseudospin symmetry becomes better for the levels closer to the continuum is disclosed.