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Nuclear Theory·nucl-th

Wednesday·July 14, 2021

5 papers—3 primary·2 cross-listed

All5Primary3Cross-lists2
  1. 01

    Angular momentum projection in the deformed relativistic Hartree-Bogoliubov theory in continuum

    Xiang-Xiang Sun · Shan-Gui Zhou

    The angular momentum projection (AMP) method is implemented in the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) with the point-coupling density functional. The wave functions of angular momentum projected states are expanded in terms of the Dirac Woods-Saxon (WS) basis, providing a proper description of the asymptotic behavior of the wave functions for weakly bound nuclei. The contribution of continuum induced by the pairing is considered by treating the pairing correlation with the Bogoliubov transformation. We present the formulae and numerical checks for the DRHBc+AMP approach and use it to study low-lying excited states of weakly bound deformed nuclei. Our calculations show that neutron-rich magnesium isotopes Mg are all well deformed nuclei. The low-lying excited states of these three nuclei are obtained by performing the AMP on the mean-field ground-states. The ground-state rotational bands of Mg are reproduced reasonably well by using this new DRHBc+AMP approach with the density functional PC-F1.

    nucl-thPRC(2021)·40 citations
  2. 02

    Many-body theory for quasiparticle states in superfluid fermionic systems

    Elena Litvinova · Yinu Zhang

    We present a formalism for the fermionic quasiparticle propagator in a superfluid fermionic system. Starting from a general many-body hamiltonian confined by the two-body instantaneous interaction, the equation of motion for the fermionic propagator is obtained in the Dyson form. Before making any approximation, the interaction kernel is found to be decomposed into the static and dynamical (time-dependent) contributions, while the latter translates to the energy-dependent and the former maps to the energy-independent terms in the energy domain. The three-fermion correlation function being the heart of the dynamical part of the kernel is factorized into the two-fermion and one-fermion ones. With the relaxed particle number constraint, the normal propagator is coupled to the abnormal one via both the static and dynamical kernels, that is formalized by introducing the generalized quasiparticle propagator of the Gor'kov type. The dynamical kernel in the factorized form is associated with the quasiparticle-vibration coupling (QVC) with the vibrations unifying both the normal and pairing phonons. The QVC vertices are related to the variations of the Hamiltonian of the Bogoliubov quasiparticles, which can be obtained by the finite amplitude method.

    nucl-thPRC(2021)·10 citations
  3. 03

    Constraining Neutron-Star Matter with Microscopic and Macroscopic Collisions

    S. Huth · P. T. H. Pang · I. Tews · T. Dietrich · A. Le Fèvre · A. Schwenk · W. Trautmann · K. Agarwal · M. Bulla · M. W. Coughlin · C. Van Den Broeck

    Interpreting high-energy, astrophysical phenomena, such as supernova explosions or neutron-star collisions, requires a robust understanding of matter at supranuclear densities. However, our knowledge about dense matter explored in the cores of neutron stars remains limited. Fortunately, dense matter is not only probed in astrophysical observations, but also in terrestrial heavy-ion collision experiments. In this work, we use Bayesian inference to combine data from astrophysical multi-messenger observations of neutron stars and from heavy-ion collisions of gold nuclei at relativistic energies with microscopic nuclear theory calculations to improve our understanding of dense matter. We find that the inclusion of heavy-ion collision data indicates an increase in the pressure in dense matter relative to previous analyses, shifting neutron-star radii towards larger values, consistent with recent NICER observations. Our findings show that constraints from heavy-ion collision experiments show a remarkable consistency with multi-messenger observations and provide complementary information on nuclear matter at intermediate densities. This work combines nuclear theory, nuclear experiment, and astrophysical observations, and shows how joint analyses can shed light on the properties of neutron-rich supranuclear matter over the density range probed in neutron stars.

    nucl-thastro-ph.HEastro-ph.SRgr-qc+1Nature(2022)·388 citations

Affiliations

first authorsco-authorsvia INSPIRE