Related papers: A study of randomness, correlations and collectivi…
We conduct a systematic investigation of the nuclear collective dynamics that emerges in systems with random two-body interactions. We explore the development of the mean field and study its geometry. We investigate multipole collectivities…
High-energy nuclear collisions have opened a new experimental method to reveal collective behavior in nuclear ground states through the lens of many-body correlations of nucleons. Using ab initio lattice and variational calculations of…
We present systematic calculations on the spectroscopy and transition properties of even-even Te isotopes by using the large-scale configuration interaction shell model approach with a realistic interaction. These nuclei are of particular…
Low-lying collective states in nuclei are investigated in the framework of the interacting boson model using an ensemble of random many-body interactions. It is shown that whenever the number of bosons is sufficiently large compared to the…
A collective bands of positive and negative parity could be composed of the vibrations and rotations. The rotations of the octupole configurations can be based either on the axial or the non-axial octupole vibrations. A consistent approach…
Combining analytical and numerical methods, we investigate properties of the two-body random ensemble (TBRE). We compare the TBRE with the Gaussian orthogonal ensemble of random matrices. Using the geometric properties of the nuclear shell…
A collective Hamiltonian for the rotation-vibration motion of nuclei is considered, in which the axial quadrupole and octupole degrees of freedom are coupled through the centrifugal interaction. The potential of the system depends on the…
Exceptionally low values of the ratio of electric quadrupole transition rates, $B_{4/2}\equiv B(E2;4^+_1\rightarrow2^+_1)/B(E2;2^+_1\rightarrow0^+_{\mathrm{gs}})<1$, have been observed in neutron-deficient nuclei near $N\approx94$ (W, Os,…
We show and interpret three examples of nontrivial results obtained in numerical simulations of many-body systems: exponential convergence of low-lying energy eigenvalues in the process of progressive truncation of huge shell-model…
In order to provide a microscopic description of levels and E2 transitions in rapidly rotating nuclei with internal excitation energy up to a few MeV, use is made of a shell model which combines the cranked Nilsson mean-field and the…
Signatures of order and collectivity appear in a broad range of one and two level boson systems. Toy systems of $N$ particles on a single $j=3,\,4\dots 7$ level, and on 2 levels $(j_1,\,j_2)$ with $j_1+j_2 \leq 6$ were studied. Surprising…
I explore weakly-collective singly-closed shell nuclei with high-j shells where active valence neutrons and particle-particle correlations may be the dominant collective degree of freedom. The combination of large and close-lying proton and…
Recent investigations have looked at the many-body spectra of random two-body interactions. In fermion systems, such as the interacting shell model, one finds pairing-like spectra, while in boson systems, such as IBM-1, one finds rotational…
In this paper, we discuss the regularities of energy of each angular momentum $I$ averaged over all the states for a fixed angular momentum (denoted as $\bar{E}_I$'s) in many-body systems interacting via a two-body random ensemble. It is…
Low-lying states in nuclei are investigated using an ensemble of random interactions. Both in the nuclear shell model and in the interacting boson model we find a dominance of $J^P=0^+$ ground states. It is shown that this feature is not…
Due to the time reversal invariance of the angular momentum operator J^2, the average energies and variances at fixed J for random two-body Hamiltonians exhibit odd-even-J staggering, that may be especially strong for J=0. It is shown that…
The predictions of the IBM two-body random ensemble are compared to empirical results on nuclei from Z=8 to 100. Heretofore unrecognized but robust empirical trends are identified and related both to the distribution of valence nucleon…
The quadrupole collective Hamiltonian, based on relativistic energy density functionals, is extended to include a pairing collective coordinate. In addition to quadrupole shape vibrations and rotations, the model describes pairing…
The structure of exotic nuclei provides valuable tests for state-of-the-art nuclear theory. In particular electromagnetic transition rates are more sensitive to aspects of nuclear forces and many-body physics than excitation energies alone.…
The density functional theory of nuclear structure provides a many-particle wave function that is useful for static properties, but an extension of the theory is necessary to describe correlation effects or other dynamic properties. Here we…