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Nuclear Theory·nucl-th

Tuesday·December 8, 2020

16 papers—7 primary·9 cross-listed

All16Primary7Cross-lists9
  1. 01

    Equivalence of generator coordinate Brink cluster model and nonlocalized cluster model and supersolidity of cluster structure in nuclei

    S. Ohkubo

    It is found that cluster structure has the apparently opposing dual property of crystallinity and condensation simultaneously. The mathematical equivalence of the spatially localized Brink cluster model in the generator coordinate method (GCM) and the nonlocalized cluster model (NCM), which is also called the THSR (Tohsaki-Horiuchi-Schuck-Rpke) wave function based on the condensation of clusters, is shown. The latter is found to be an equivalent representation of the localized cluster model and it is a natural consequence that the many NCM (THSR) calculations reproduce the proceeding cluster model calculations using the GCM and the resonating group method (RGM). Localized cluster models, which have been successfully used for more than half a century, will continue to be very powerful. The equivalence is a manifestation of the duality of incompatible aspects: crystallinity and coherent wave nature due to condensation of clusters, i.e. the dual properties of a supersolid. The Pauli principle causes the duality. The evidence for supersolidity, the emergence of a Nambu-Goldstone mode caused by the spontaneous symmetry breaking of the global phase, is discussed

    nucl-th0 citations
  2. 02

    Nonequilibrium kinetic freeze-out properties in relativistic heavy ion collisions from energies employed at the RHIC beam energy scan to those available at the LHC

    Jia Chen🇨🇳 · Jian Deng🇨🇳 · Zebo Tang🇨🇳 · Zhangbu Xu🇺🇸 · Li Yi🇨🇳

    In this paper, we investigate the kinetic freeze-out properties in relativistic heavy ion collisions at different collision energies. We present a study of standard Boltzmann-Gibbs Blast-Wave (BGBW) fits and Tsallis Blast-Wave (TBW) fits performed on the transverse momentum spectra of identified hadrons produced in Au + Au collisions at collision energies of 7.7 - 200 GeV at the Relativistic Heavy Ion Collider (RHIC), and in Pb + Pb collisions at collision energies of 2.76 and 5.02 TeV at the Large Hadron Collider (LHC). The behavior of strange and multi-strange particles is also investigated. We found that the TBW model describes data better than the BGBW one overall, and the contrast is more prominent as the collision energy increases as the degree of non-equilibrium of the produced system is found to increase. From TBW fits, the kinetic freeze-out temperature at the same centrality shows a weak dependence of collision energy between 7.7 and 39 GeV, while it decreases as collision energy continues to increase up to 5.02 TeV. The radial flow is found to be consistent with zero in peripheral collisions at RHIC energies but sizable at LHC energies and central collisions at all RHIC energies. We also observed that the strange hadrons, with higher temperature and similar radial flow, approach equilibrium more quickly from peripheral to central collisions than light hadrons. The dependence of temperature and flow velocity on non-equilibrium parameter () is characterized by two second-order polynomials. Both and from the polynomials fit, related to the influence of the system bulk viscosity, increase toward lower RHIC energies.

    nucl-thPRC(2021)·42 citations
  3. 03

    Quasinormal modes of scalar field coupled to Einstein's tensor in the non-commutative geometry inspired black hole

    Zening Yan🇨🇳 · Chen Wu🇨🇳 · Wenjun Guo🇨🇳

    We investigate the quasinormal modes (QNMs) of the scalar field coupled to the Einstein's tensor in the non-commutative geometry inspired black hole spacetime. It is found that the lapse function of the non-commutative black hole metric can be represented by a Kummer's confluent hypergeometric function, which can effectively solve the problem that the numerical results of the QNMs are sensitive to the model parameters and make the QNMs values more reliable. We make a careful analysis of the scalar QNM frequencies by using several numerical methods, and find that the numerical results obtained by the new WKB method (the Padé approximants) and the Mashhoon method (Pschl-Teller potential method) are quite different from those obtained by the asymptotic iterative method (AIM) and time-domain integration method when the non-commutative parameter and coupling parameter are large. The most obvious difference is that the numerical results obtained by the AIM and the time-domain integration method appear a critical value with an increase of , which leads to the dynamical instability. After carefully analyzing the numeral results, we conclude that the numerical results obtained by the AIM and the time-domain integration method are closer to the theoretical values than those obtained by the WKB method and the Mashhoon method, when the and are large. Moreover, through a numerical fitting, we obtain that the functional relationship between the threshold and the non-commutative parameter satisfies for a fixed approximately. We find that the stability of dynamics can be ensured in the region.

    nucl-thgr-qcNPB(2021)·17 citations
  4. 04

    Demonstration of the Universality of Molecular Structures in Prolate Deformed Nuclei

    R Canavan · M Freer

    The relationship between the deformed harmonic oscillator and the formation of molecular cluster structures, whereby valence neutrons are exchanged between cluster cores, is examined. It is found that there is a strong connection between the properties of the valence orbitals associated with deformed structures in the deformed harmonic oscillator and the molecular orbitals created by linear combinations of single-centre orbitals around nuclear clusters. The conclusion is that in addition to the appearance of clustering in the deformed harmonic oscillator that \emph{every} prolate deformed cluster structure should have molecular orbitals built on that structure. This is demonstrated through a series of examples that range from C to Ni.

    nucl-thJ.Phys.G(2020)·5 citations
  5. 05

    Interpretation of the quasiparticle plus triaxial rotor model

    Q. B. Chen · S. Frauendorf

    We discuss in depth the application of the classical concepts for interpreting the quantal results from the triaxial rotor core without and with odd-particle. The corresponding limitations caused by the discreteness and finiteness of the angular momentum Hilbert space and the extraction of the relevant features from the complex wave function and distributions of various angular momentum components are discussed in detail. New methods based on spin coherent states and spin squeezed states are introduced. It is demonstrated that the spin coherent state map is a powerful tool to visualize the angular momentum geometry of rotating nuclei. The topological nature of the concepts of transverse and longitudinal wobbling is clarified and the transitional axis-flipregime is analysed for the first time.

    nucl-thnucl-ex2 citations
  6. 06

    Microscopic equation of state of hot nuclear matter for numerical relativity simulations

    Domenico Logoteta · Albino Perego · Ignazio Bombaci

    A precise understanding of the equation of state (EOS) of dense and hot matter is key to modeling relativistic astrophysical environments, including core-collapse supernovae (CCSNe), protoneutron star (PNSs) evolution, and compact binary mergers. In this paper, we extend the microscopic zero-temperature BL (Bombaci and Logoteta) %nuclear equation of state nuclear EOS %derived by Bombaci and Logoteta to finite temperature and arbitrary nuclear composition. We employ this new EOS to describe hot -stable nuclear matter and to compute various structural properties of nonrotating PNS. %protoneutron stars. We also apply the EOS to perform dynamical simulations of a spherically symmetric CCSN. The EOS is derived using the finite temperature extension of the Brueckner--Bethe--Goldstone quantum many-body theory in the Brueckner--Hartree--Fock approximation. Neutron star properties are computed by solving the Tolman--Oppenheimer--Volkoff structure equations numerically. The sperically symmetric CCSN simulations are performed using the AGILE-IDSA code. Our EOS models are able to reproduce typical features of both PNS and spherically symmetric CCSN simulations. In addition, our EOS model is consistent with present measured neutron star masses and particularly with the masses: and of the neutron stars in PSR~J0348+0432 and PSR J0740+6620 respectively. Finally, we suggest a feasible mechanism to produce low-mass black holes () that could have far-reaching consequences for interpreting the gravitational wave event GW190814 as a BH--BH merger.

    nucl-thastro-ph.HEAstron.Astrophys.(2021)·61 citations
  7. 07

    Transverse expansion of (1 + 2) dimensional magneto-hydrodynamics flow with longitudinal boost invariance

    R.Emamian🇮🇷 · A. F. Kord🇮🇷 · A. Ghaani🇮🇷 · B.Azadegan🇮🇷

    In the present work, we investigate the effects of magnetic field on expanding hot and dense nuclear matter as an ideal fluid. We consider QGP, on the particular case of a (1 + 2) dimensional longitudinally boost-invariant fluid expansion, in the background of an inhomogeneous magnetic field that is generated by external sources. We assume the magnetic field points in the direction perpendicular to the reaction plane, follows the power-law decay in proper time, and has two components on the transverse plane. To simplify the calculation, we suppose the investigated fluid has azimuthal symmetry, and magneto-hydrodynamic equations are described in a polar coordinate system on the transverse plane of reaction. Our results depict the space-time evolution of the transverse expansion of the fluid in the presence of an inhomogeneous external magnetic field. Ultimately, we utilize transverse velocity and correction of energy density to estimate the transverse momentum spectrum of final particles that emerge from heavy-ion collisions based on experimental data.

    nucl-thhep-phhep-thPLB(2022)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE