35 citations · 250 across the 23 of their papers we have counts for
23 papers
Excited states of zero seniority based on a pair condensate
Th. Popa, N. Sandulescu, M. Sambataro
We study the excited states of zero seniority for various like-particle systems interacting by pairing forces and by general two-body interactions. We consider two types of excitat…
Coexistence of quartets and pairs in even-even nuclei
M. Sambataro, N. Sandulescu, D. Gambacurta
We analyse the structure of the ground states of even-even nuclei with nucleons moving in the same major shell and interacting via realistic two-body forces of shell-model ty…
Intrinsic states of deformed N=Z nuclei in a quartet formalism
M. Sambataro, N. Sandulescu
The band structure of N=Z nuclei is constructed from intrinsic states defined in terms of quartets. The simplest of these states is a condensate of collective quartets with isospin…
Band-like structures and quartets in deformed N=Z nuclei
M. Sambataro, N. Sandulescu
We provide a description of deformed nuclei in a formalism of -like quartets. Quartets are constructed variationally by resorting to the use of proper intrinsic states. Va…
-like quartetting in the excited states of proton-neutron pairing Hamiltonians
M. Sambataro, N. Sandulescu
Previous studies have shown that the ground state of systems of nucleons composed by an equal number of protons and neutrons interacting via proton-neutron pairing forces can be de…
Quartet condensation induced by the isovector pairing force
M. Sambataro, N. Sandulescu
The phenomenon of quartet condensation in the ground state of an isovector pairing Hamiltonian for an even-even system is investigated. For this purpose we follow the evoluti…
Exact T=0 Eigenstates of the Isovector Pairing Hamiltonian
M. Sambataro, N. Sandulescu
We derive the exact seniority-zero eigenstates of the isovector pairing Hamiltonian for an even number of protons and neutrons. Nucleons are supposed to be distributed over a…
Pairing correlations and eigenvalues of two-body density matrix in atomic nuclei
Michelangelo Sambataro, Nicolae Sandulescu
The quantum phases of superconductivity and superfluidity are characterised mathematically by the Yang concept of Off-Diagonal Long Range Order (ODLRO), related to the existence of…
Quartet structure of nuclei in a boson formalism: the case of Si
M. Sambataro, N. Sandulescu
The structure of the nucleus Si is studied by resorting to an IBM-type formalism with and bosons representing isospin and angular momentum and $J=2…
Quartet correlations in N=Z nuclei induced by realistic two-body interactions
M. Sambataro, N. Sandulescu
Two variational quartet models previously employed in a treatment of pairing forces are extended to the case of a general two-body interaction. One model approximates the nuclear s…
Quartetting in odd-odd self-conjugate nuclei
M. Sambataro, N. Sandulescu
We provide a description of odd-odd self-conjugate nuclei in the sd shell in a formalism of collective quartets and pairs. Quartets are four-body structures carrying isospin T=0 wh…
Isoscalar-isovector proton-neutron pairing and quartet condensation in N=Z nuclei
M. Sambataro, N. Sandulescu
We show that the correlations generated in the ground state of nuclei by the isovector and isoscalar pairing forces can be treated with high precision as a condensate of alph…
Nuclear excitations as coupled one and two random--phase--approximation modes
D. Gambacurta, F. Catara, M. Grasso +3
We present an extension of the random--phase approximation (RPA) where the RPA phonons are used as building blocks to construct the excited states. In our model, that we call doubl…
Quarteting and spin-aligned proton-neutron pairs in heavy N=Z nuclei
M. Sambataro, N. Sandulescu
We analyze the role of maximally aligned isoscalar pairs in heavy nuclei by employing a formalism of quartets. Quartets are superpositions of two neutrons and two protons cou…
Four-body correlations in nuclei
M. Sambataro, N. Sandulescu
Low-energy spectra of 4 nuclei are described with high accuracy in terms of four-body correlated structures ("quartets"). The states of all nuclei belonging to the $A=…
Isoscalar and isovector pairing in a formalism of quartets
M. Sambataro, N. Sandulescu, C. W. Johnson
Isoscalar (T=0,J=1) and isovector (T=1,J=0) pairing correlations in the ground state of self-conjugate nuclei are treated in terms of alpha-like quartets built by two protons and t…
Isovector pairing in a formalism of quartets for N=Z nuclei
M. Sambataro, N. Sandulescu
We describe the ground state of the isovector pairing Hamiltonian in self-conjugate nuclei by a product of collective quartets of different structure built from two neutrons and tw…
Treatment of like-particle pairing with quartets
M. Sambataro, N. Sandulescu
The ground state correlations induced by a general pairing Hamiltonian in a finite system of like fermions are described in terms of four-body correlated structures (quartets). The…
Multipair approach to pairing in nuclei
M. Sambataro
The ground state of a general pairing Hamiltonian for a finite nuclear system is constructed as a product of collective, real, distinct pairs. These are determined sequentially via…
Configuration interaction study of single and double dipole plasmon excitations in Na_8
F. Catara, D. Gambacurta, M. Grasso +1
We carry out a microscopic analysis of the ground and excited states of the Na_8 metal cluster within the jellium model. We perform a series of configuration interaction calculatio…
Extended RPA within a solvable 3 level model
F. Catara, M. Grasso, M. Sambataro
Working within an exactly solvable 3 level model, we discuss am extension of the Random Phase Approximation (RPA) based on a boson formalism. A boson Hamiltonian is defined via a m…
Many-body correlations in a multistep variational approach
M. Sambataro
We discuss a multistep variational approach for the study of many-body correlations. The approach is developed in a boson formalism (bosons representing particle-hole excitations)…
Baryon Mapping of Quark Systems
M. Sambataro
We discuss a mapping procedure from a space of colorless three-quark clusters into a space of elementary baryons and illustrate it in the context of a three-color extension of the…