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Nuclear Theory·nucl-th

Friday·October 16, 2020

10 papers—5 primary·5 cross-listed

All10Primary5Cross-lists5
  1. 06

    Spectra of quark-antiquark bound states via two derived QCD potential

    M. S. Ali🇪🇬 · A. M. Yasser🇪🇬

    In the current paper, we propose two types of quark-antiquark interactions, which may be tailored to describe various meson sectors. The interactions contain Quantum Chromodynamics (QCD) inspired components, such as the Coulomb-like interaction, the confinement linear potential, and the spin-spin interaction. Our scheme relies on the non-relativistic quark model through the introduction of two derived QCD potential models. The application of the two proposed potentials resulted in spectra for quark-antiquark bound states, which are compared with published experimental data. We found that one of the two potentials is favored over the other in terms of high precision comparisons.

    ↳ hep-phcs.NAhep-thmath.NA+23 citations
  2. 07

    Rotating quantum turbulence in the unitary Fermi gas

    Khalid Hossain🇺🇸 · Konrad Kobuszewski🇵🇱 · Michael McNeil Forbes🇺🇸 · Piotr Magierski🇺🇸 · Kazuyuki Sekizawa🇯🇵 · Gabriel Wlazłowski🇺🇸

    Quantized vortices carry the angular momentum in rotating superfluids, and are key to the phenomenon of quantum turbulence. Advances in ultra-cold atom technology enable quantum turbulence to be studied in regimes with both experimental and theoretical control, unlike the original contexts of superfluid helium experiments. While much work has been performed with bosonic systems, detailed studies of fermionic quantum turbulence are nascent, despite wide applicability to other contexts such as rotating neutron stars. In this paper, we present the first large-scale study of quantum turbulence in rotating fermionic superfluids using an accurate orbital based time-dependent density functional theory (DFT) called the superfluid local density approximation (SLDA). We identify two different modes of turbulent decay in the dynamical equilibration of a rotating fermionic superfluid, and contrast these results with a computationally simpler orbital-free DFT, which we find can qualitatively reproduce these decay mechanisms if dissipation is explicitly included. These results demonstrate that one-body dissipation mechanisms intrinsic to fermionic superfluids play a key role differentiating fermionic from bosonic turbulence, but also suggest that simpler orbital-free theories may be corrected so that these more efficient techniques can be used to model extended physical systems such as neutron superfluids in neutron stars.

    ↳ cond-mat.quant-gasnucl-thquant-phPRA(2022)·17 citations
  3. 08

    QCD and the Strange Baryon Spectrum

    Tetsuo Hyodo🇯🇵 · Masayuki Niiyama🇯🇵

    The strange quark plays a unique role in QCD, reflecting its intermediate mass between the light and heavy quarks. In recent years, remarkable progress has been made in the spectroscopy of baryons with strangeness. Many new features of the strange baryon spectrum have been revealed by accurate experimental data with novel techniques, as well as systematic developments of theoretical framework to describe hadron resonances. The basic properties of strange baryons, namely, the pole positions, spin and parity, and decay branching ratios, are being determined accurately. As a consequence, the Particle Data Group have added new entries in the particle listings, such as the and the . The developments of the spectroscopy stimulate intensive discussion on the exotic internal structure of strange baryons beyond the ordinary three-quark configuration. In this review, we introduce the basics of QCD, the scattering theory, and the exotic internal structure of hadrons, emphasizing the importance of the pole positions of the scattering amplitude for the characterization of hadron resonances. We then summarize the current status of selected strange baryon resonances; , , , , and , from theoretical and experimental viewpoints.

    ↳ hep-phhep-exnucl-exnucl-thPPNP(2021)·86 citations
  4. 09

    Setting the string shoving picture in a new frame

    Christian Bierlich🇸🇪 · Smita Chakraborty🇸🇪 · Gösta Gustafson🇸🇪 · Leif Lönnblad🇸🇪

    Based on the recent success of the \angantyr model in describing multiplicity distributions of the hadronic final state in high energy heavy ion collisions, we investigate how far one can go with a such a string-based scenario to describe also flow effects measured in such collisions. For this purpose we improve our previous so-called \textit{shoving} model, where strings that are close in space--time tend to repel each other in a way that could generate anisotropic flow, and we find that this model can indeed generate such flows in Å\ collisions. The flow generated is not quite enough to reproduce measurements, but we identify some short-comings in the presented implementation of the model that, when fixed, could plausibly give a more realistic amount of flow.

    ↳ hep-phnucl-thJHEP(2021)·59 citations
  5. 10

    Hydrogen molecule spectrum by many-body GW and Bethe-Salpeter equation

    Jing Li🇫🇷 · Valerio Olevano🇫🇷

    We check the ab initio GW approximation and Bethe-Salpeter equation (BSE) many-body methodology against the exact solution benchmark of the hydrogen molecule H ground state and excitation spectrum, and in comparison with the configuration interaction (CI) and time-dependent Hartree-Fock methods. The comparison is made on all the states we could unambiguously identify from the excitonic wave functions' symmetry. At the equilibrium distance , the GW+BSE energy levels are in good agreement with the exact results, with an accuracy of 0.1~0.2 eV. GW+BSE potential-energy curves are also in good agreement with the CI and the exact result up to . The solution no longer exists beyond for triplets ( for singlets) due to instability of the ground state. We tried to improve the GW reference ground state by a renormalized random-phase approximation (r-RPA), but this did not solve the problem.

    ↳ physics.chem-phcond-mat.othercond-mat.str-elnucl-thPRA(2021)·3 citations

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first authorsco-authorsvia INSPIRE