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Nuclear Theory·nucl-th

Thursday·June 22, 2023

10 papers—6 primary·4 cross-listed

All10Primary6Cross-lists4
  1. 07

    Superfluid Rivers in Spinning-down Neutron Stars

    Yuri Levin · Bennett Link

    We study the motion of neutron superfluid vortices in a spinning-down neutron star, assuming axisymmetry of the flow and ignoring motion of vortices about the rotation axis. We find that the vortex array, if initially rectilinear, is soon substantially deformed as the star spins down; vortices are swept outward by the Magnus force, accumulating in regions of the inner crust where they pin, accompanied by significant bending of the vortex array. As the star spins down to below a spin rate of ~20 Hz (twice the spin rate of the Vela pulsar), the Magnus and pinning forces gradually compress the vortex array into dense sheets that follow spherical shells. In some cases, the vortex array bends on itself and reconnects, forming one or more tori of vortex rings that contain superfluid ``rivers" with significant angular momentum. Vortex sheets are likely to form near the base of the inner crust, in the regime of nuclear pasta.

    ↳ astro-ph.HEnucl-thApJ(2023)·6 citations
  2. 08

    The Jost function and Siegert pseudostates from R-matrix calculations at complex wavenumbers

    Paul Vaandrager · Jérémy Dohet-Eraly · Jean-Marc Sparenberg

    The single-channel Jost function is calculated with the computational R-matrix on a Lagrange-Jacobi mesh, in order to study its behaviour at complex wavenumbers. Three potentials derived from supersymmetric transformations are used to test the accuracy of the method. Each of these potentials, with s-wave or p-wave bound, resonance or virtual states, has a simple analytical expression for the Jost function, which is compared with the calculated Jost function. Siegert states and Siegert pseudostates are determined by finding the zeros of the calculated Jost function. Poles of the exact Jost function are not present in the calculated Jost function due to the truncation of the potential in the R-matrix method. Instead, Siegert pseudostates arise in the vicinity of the missing poles.

    ↳ quant-phnucl-thEPJA(2024)·1 citation
  3. 09

    What is the nature of the HESS J1731-347 compact object?

    Violetta Sagun · Edoardo Giangrandi · Tim Dietrich · Oleksii Ivanytskyi · Rodrigo Negreiros · Constança Providência

    Once further confirmed in future analyses, the radius and mass measurement of HESS J1731-347 with and will be among the lightest and smallest compact objects ever detected. This raises many questions about its nature and opens up the window for different theories to explain such a measurement. In this article, we use the information from Doroshenko et al. (2022) on the mass, radius, and surface temperature together with the multimessenger observations of neutron stars to investigate the possibility that HESS J1731-347 is one of the lightest observed neutron star, a strange quark star, a hybrid star with an early deconfinement phase transition, or a dark matter-admixed neutron star. The nucleonic and quark matter are modeled within realistic equation of states (EOSs) with a self-consistent calculation of the pairing gaps in quark matter. By performing the joint analysis of the thermal evolution and mass-radius constraint, we find evidence that within a 1 confidence level, HESS J1731-347 is consistent with the neutron star scenario with the soft EOS as well as with a strange and hybrid star with the early deconfinement phase transition with a strong quark pairing and neutron star admixed with dark matter.

    ↳ astro-ph.HEgr-qcnucl-thApJ(2023)·96 citations
  4. 10

    Phase structure of the on-shell parametrized 2+1 flavor Polyakov quark-meson model

    Suraj Kumar Rai🇮🇳 · Vivek Kumar Tiwari🇮🇳

    Augmenting the improved chiral effective potential of the on-shell renormalized 2+1 flavour quark-meson (RQM) model with the Polyakov-loop potential that accounts for the deconfinement transition,~we get the Quantum Chromodynamics (QCD) like framework of the renormalized Polyakov quark-meson (RPQM) model.~When the divergent quark one-loop vacuum term is included in the effective potential of the quark-meson (QM) model,~its tree level parameters or the parameters fixed by the use of meson curvature masses,~become inconsistent as the curvature masses involve the self energy evaluations at zero momentum.~Using the modified minimal subtraction method,~the consistent chiral effective potential for the RQM model has been calculated after relating the counterterms in the on-shell (OS) scheme to those in the scheme and finding the relations between the renormalized parameters of both the schemes where the physical (pole) masses of the and pseudo-scalar mesons and the scalar meson,~the pion and kaon decay constants,~have been put into the relation of the running couplings and mass parameter.~Using the RPQM model and the PQM Model with different forms for the Polyakov-loop potentials in the presence or the absence of the quark back-reaction,~we have computed and compared the effect of the consistent quark one-loop correction and the quark back-reaction on the scaled chiral order parameter,~the QCD phase diagrams and the different thermodynamic quantities.~The results have been compared with the 2+1 flavor lattice QCD data from the Wuppertal-Budapest collaboration \{JHEP 09,73(2010); PLB 730,99(2014)\} and the HotQCD collaboration \{PRD 90,094503(2014)\}.

    ↳ hep-phnucl-thPRD(2024)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE