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We propose a simple quartet condensation model (QCM) which describes with very high accuracy the isovector pairing correlations in self-conjugate nuclei. The quartets have an alpha-like structure and are formed by collective isovector…

Nuclear Theory · Physics 2015-06-04 N. Sandulescu , D. Negrea , J. Dukelsky , C. W. Johnson

Some results for two distinct but complementary exactly solvable algebraic models for pairing in atomic nuclei are presented: 1) binding energy predictions for isotopic chains of nuclei based on an extended pairing model that includes…

Nuclear Theory · Physics 2018-02-20 J. P. Draayer , V. G. Gueorguiev , K. D. Sviratcheva , C. Bahri , Feng Pan , A. I. Georgieva

We discuss the treatment of isovector pairing by an alpha-like quartet condensate which conserves exactly the particle number, the spin and the isospin. The results show that the quartet condensate describes accurately the isovector pairing…

Nuclear Theory · Physics 2011-09-23 N. Sandulescu , J. Dukelsky , D. Negrea

Pair vibrations are studied for a Hamiltonian with neutron-neutron, proton-proton and neutron-proton pairing. The spectrum is found to be rich in strongly correlated, low-lying excited states. Changing theratio of diagonal to off-diagonal…

Nuclear Theory · Physics 2010-02-09 R. R. Chasman , P. Van Isacker

Finite nuclei such as those found in the chain of even tin isotopes from ^{102}Sn to ^{130}Sn, exhibit a near constancy of the 2^+_1-0^+_1 excitation energy, a constancy which can be related to strong pairing correlations and the near…

Nuclear Theory · Physics 2007-05-23 Oe. Elgaroey , T. Engeland , M. Hjorth-Jensen , E. Osnes

In the present study, the effect of the pairing interaction and the isovector correlation between nucleons on the properties of the isobar analog resonances (IAR) in $^{112-124}$Sb isotopes and the isospin admixture in $^{100-124}$Sn…

Nuclear Theory · Physics 2008-11-26 T. Babacan , D. Salamov , A. Kucukbursa , H. Babacan , I. Maras , H. A. Aygor , A. Unal

The self-energy of nucleons in asymmetric nuclear matter is evaluated employing different realistic models for the nucleon-nucleon interaction. Starting from the Brueckner Hartree Fock approximation without the usual angle-average in the…

Nuclear Theory · Physics 2009-11-10 Kh. S. A. Hassaneen , H. Müther

We perform \textit{ab initio} nuclear lattice calculations of the neutron-rich carbon and oxygen isotopes using high-fidelity chiral interactions. We find good agreement with the observed binding energies and compute correlations associated…

A closed expression is derived for the pair vibrational correlation energy generated in the random phase approximation by the isovector pairing force in the case when Kramers and charge degenerate single-nucleon levels are uniformly…

Nuclear Theory · Physics 2018-09-24 K. Neergård

The quartet condensation model (QCM) is extended for the treatment of isovector and isoscalar pairing in odd-odd N=Z nuclei. In the extended QCM approach the lowest states of isospin T=1 and T=0 in odd-odd nuclei are described variationally…

Nuclear Theory · Physics 2017-03-03 D. Negrea , N. Sandulescu , D. Gambacurta

The subtle interplay between the two nuclear superfluids, isovector T=1 and isoscalar T=0 phases, are investigated in an exactly soluble model. It is shown that T=1 and T=0 pair-modes decouple in the exact calculations with the T=1…

Nuclear Theory · Physics 2009-11-06 J. A. Sheikh , R. Wyss

The complex eigenvalues of some non-Hermitian Hamiltonians, e.g. parity-time symmetric Hamiltonians, come in complex-conjugate pairs. We show that for non-Hermitian scattering Hamiltonians (of a structureless particle in one dimension)…

Quantum Physics · Physics 2019-05-22 M. A. Simón , A. Buendía , A. Kiely , Ali Mostafazadeh , J. G. Muga

A shell-model study of proton-neutron pairing in f - p shell nuclei using a parametrized hamiltonian that includes deformation and spin-orbit effects as well as isoscalar and isovector pairing is reported. By working in a shell-model…

Nuclear Theory · Physics 2015-05-18 Lei Yang , S. Pittel , B. Thakur , N. Sandulescu , A. Poves , Yu-Min Zhao

Pairing gaps for fermionic atoms in harmonic oscillator traps are calculated for a wide range of interaction strengths and particle number, and compared to pairing in nuclei. Especially systems, where the pairing gap exceeds the level…

Atomic Physics · Physics 2009-11-10 H. Heiselberg

The role of neutron-proton pairing correlations on the structure of nuclei along the $N=Z$ line is reviewed. Particular emphasis is placed on the competition between isovector ($T=1$) and isoscalar $(T=0$) pair fields. The expected…

Nuclear Theory · Physics 2014-09-19 Stefan Frauendorf , Augusto O. Macchiavelli

The charge-dependent realistic nuclear Hamiltonian for a nucleus, composed of neutrons and protons, can be successfully approximated by a charge-independent one. The parameters of such a Hamiltonian, i.e., the nucleon mass and the NN…

Nuclear Theory · Physics 2009-10-31 G. P. Kamuntavicius , P. Navratil , B. R. Barrett , G. Sapragonaite , R. K. Kalinauskas

In this contribution, we review some works related with the extraction of the symmetry energy parameters from isovector nuclear excitations, like the giant resonances. Then, we move to the general issue of how to assess whether correlations…

Nuclear Theory · Physics 2023-07-19 G. Colo' , X. Roca-Maza , N. Paar

We consider quantum systems consisting of a linear chain of n harmonic oscillators coupled by a nearest neighbour interaction of the form $-q_r q_{r+1}$ ($q_r$ refers to the position of the $r$th oscillator). In principle, such systems are…

Mathematical Physics · Physics 2009-02-27 G. Regniers , J. Van der Jeugt

Simple generic aspects of nuclear pairing in homogeneous medium as well as in finite nuclei are discussed. It is argued that low-energy nuclear structure is not sensitive enough to resolve fine details of nuclear nucleon-nucleon (NN)…

Nuclear Theory · Physics 2009-11-11 Wojciech Satula

We study the couplings between collective vibrations such as the isovector giant dipole and isoscalar giant quadrupole resonances in tin isotopes in the framework of the time-dependent Hartree-Fock theory with a Skyrme energy density…

Nuclear Theory · Physics 2009-12-30 Cédric Simenel , Philippe Chomaz