Related papers: The (2j-1) rule with other interactions
Random one plus two-body hamiltonians invariant with respect to $O({\cal N}_1) \oplus O({\cal N}_2)$ symmetry in the group-subgroup chains $U({\cal N}) \supset U({\cal N}_1) \oplus U({\cal N}_2) \supset O({\cal N}_1) \oplus O({\cal N}_2)$…
Using the local hidden gauge approach, we study the possibility of the existence of bottomed strange molecular states with isospin 0. We find three bound states with spin-parity $0^+$, $1^+$ and $2^+$ generated by the $\bar{K}^*B^*$ and…
In previous works we examined the spectra for systems of 2 protons and 2 neutrons, in a single j shell calculation, by obtaining matrix elements from experiment. More recently we considered schematic interactions in the same model space. We…
The atomic nucleus is a quantum many-body system whose constituent nucleons (protons and neutrons) are subject to complex nucleon-nucleon interactions that include spin- and isospin-dependent components. For stable nuclei, already several…
The role of pairing correlations for nucleon pairs with isospin $T=1$ and $T=0$ is investigated for nuclei in the mass region $12 \leq A \leq 42$. For that purpose the two-nucleon densities resulting from nuclear shell-model calculations in…
The unbound nucleus $^{12}$Li is evaluated by using the multistep shell model in the complex energy plane assuming that the spectrum is determined by the motion of three neutrons outside the $^9$Li core. It is found that the ground state of…
New experimental information has been recently obtained on the odd-odd nucleus 134-I. We interpret the five observed excited states up to the energy of ~3 MeV on the basis of a realistic shell-model calculation, and make spin-parity…
We study low-lying states of even carbon isotopes in the range A = 10 - 20 within the large- scale no-core shell model (NCSM). Using several accurate nucleon-nucleon (NN) as well as NN plus three-nucleon (NNN) interactions, we calculate…
The structure of few-fermion systems having $1/2$ spin-isospin symmetry is studied using potential models. The strength and range of the two-body potentials are fixed to describe low energy observables in the angular momentum $L=0$ state…
Collinear laser spectroscopy has been performed on the $^{79}_{30}$Zn$_{49}$ isotope at ISOLDE-CERN. The existence of a long-lived isomer with a few hundred milliseconds half-life was confirmed, and the nuclear spins and moments of the…
The effects of setting all T=0 two body interaction matrix elements equal to a constant (or zero) in shell model calculations (designated as $<T=0>=0$) are investigated. Despite the apparent severity of such a procedure, one gets fairly…
A set of interacting particles are coupled to a phenomenological core described using the generalized coherent state model. Among the particle-core states a finite set which have the property that the angular momenta carried by the proton…
Recent studies show that for systems with four identical fermions in the $j=9/2$ shell two special states, which have seniority $v=4$ and total spins I=4 and 6, are eigenstates of any two-body interaction. These states have good seniority…
A simple model based on the group SO(5) suggests that both the like-particle and neutron-proton components of isovector pairing correlations in odd-A nuclei are Pauli blocked. The same effect emerges from Monte Carlo Shell-model…
From the experimental data on odd-even staggering of masses, we have shown that variation of pairing as a function of neutron number plays an important role in many distinctive features like occurrence of new shell closures, shell erosion,…
We develop a no-go theorem for two-dimensional bosonic systems with crystal symmetries: if there is a half-integer spin at a rotation center, where the point-group symmetry is $\mathbb D_{2,4,6}$, such a system must have a ground-state…
In a system of interacting f=1 bosons (in the subspace where the total spin in the z-direction is vanishing), we prove inequalities for the ground state expectation value of the density of spin-0 bosons. The inequalities imply that the…
The formal equivalence between the quartetting picture and the symmetry restored BCS picture is established for the ground state correlations induced by the general isovector-isoscalar pairing interaction. Multiple ground state structures…
It is shown that in N \simeq Z nuclei the effects of isovector pairing and the symmetry energy are intimately related. In particular, in the odd-odd N = Z nuclei these two effect are essentially equal in magnitude, causing near degeneracy…
A huge number of independent true ground-state configurations is calculated for two-, three- and four-dimensional +- J spin-glass models. Using the genetic cluster-exact approximation method, system sizes up to N=20^2,8^3,6^4 spins are…