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Nuclear Theory·nucl-th

Friday·March 7, 2025

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 04

    [Submitted on 18 Feb 2025] (cross-list from nlin.CD)

    Classical periodic orbits in extended phase space for spherical harmonic oscillator with spin-orbit coupling

    Kenichiro Arita

    A complete analysis of classical periodic orbits (POs) and their bifurcations was conducted in spherical harmonic oscillator system with spin-orbit coupling. The motion of the spin is explicitly considered using the spin canonical variables derived by semiclassical approximation to the spin coherent state path integral representation. In addition to the diametric and two circular PO families with frozen spin, solutions that bridge two circular POs are found in which orbital motion is coupled to spin precession. In addition, each bridge encounters a secondary bifurcation on the way from one circular PO to the other and generates a new PO, that survives at higher energies while maintaining a constant period. The generic expressions for those POs are obtained explicitly, and all the above peculiar bifurcation scenarios are described fully analytically.

    Comments:
    10 pages, 9 figures, published version
    Subjects:
    nlin.CD (nlin.CD); Nuclear Theory (nucl-th)
    arXiv:
    2503.03758 [pdf]
    PRE(2025)·0 citations
  2. 05

    [Submitted on 5 Mar 2025] (cross-list from cond-mat.quant-gas)

    Constrained many-body phases in a -Higgs lattice gauge theory

    Alexander Schuckert🇺🇸 · Stefan Kühn🇩🇪 · Kevin C. Smith🇺🇸 · Eleanor Crane🇺🇸 · Steven M. Girvin🇺🇸

    We study the ground-state phase diagram of a one-dimensional lattice gauge theory coupled to soft-core bosonic matter at unit filling, inspired by the Higgs sector of the standard model. Through a combination of analytical perturbative approaches, exact diagonalization, and density-matrix-renormalization-group simulations, we uncover a rich phase diagram driven by gauge-field-mediated resonant pair hopping and the confinement of single particles. The pair hopping results in a bunching state with superextensive energy and macroscopic particle number fluctuations at strong electric field strengths and weak on-site interactions. The bunching state crosses over into a pair superfluid phase as the on-site interaction increases, characterized by a finite superfluid density and powerlaw-decaying pair correlations. At large on-site interaction strengths and driven by effective interactions induced by the gauge constraint, the superfluid transitions into an incompressible pair Mott insulator phase. At weak field strengths and on-site interactions, we find a plasma-like region, where single bosons exhibit large short-range correlations and the ground state is composed almost equally of states with even and odd local boson occupation. The presence of a bunching state with large number fluctuations, which is difficult to study using classical numerics, motivates experimental realizations in hybrid boson-qubit quantum simulation platforms such as circuit QED, neutral atoms, and trapped ions. Our findings highlight the rich interplay between gauge fields and soft-core bosonic matter.

    Comments:
    4+2 pages, 5+1 figures
    Subjects:
    Quantum Gases (cond-mat.quant-gas); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2503.03828 [pdf]
    2 citations
  3. 06

    [Submitted on 6 Mar 2025] (cross-list from astro-ph.HE)

    Precise constraint on properties of neutron stars through new universal relations and astronomical observations

    Zehan Wu · Dehua Wen

    In view of the great uncertainty of the equation of state (EOS) of high-density nuclear matter, establishing EOS-independent universal relations between global properties of neutron stars provides a practical way to constrain the unobservable or difficult-to-observe properties through astronomical observations. It is common to construct universal relations between EOS-dependent properties (e.g., moment of inertia, tidal deformation, etc.) or combined properties (e.g., compactness). Improving the precision of the universal relations may provide stricter constraint on the properties of neutron star. We find that in 3-dimensional space with mass and radius as the base coordinates, the points corresponding to a certain property of neutron star described by different EOSs are almost located in the same surface. Thus the universal relation between the property and the stellar mass-radius can be expressed through describing the surface. It is shown that the resulting universal relations have higher precisions. As an example, we construct high-precision universal relations for the moment of inertia, the -mode frequency, and the dimensionless tidal deformation respect to the mass-radius. As the observational data of neutron star mass and radius from NICER grows in data and accuracy, these universal relations allow for more precise constraints on the unobservable or difficult-to-observe properties.

    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    2503.03981 [pdf]
    CPC(2025)·2 citations
  4. 07

    [Submitted on 6 Mar 2025] (cross-list from hep-ph)

    Towards modeling the short-range interactions of hidden/open charm pentaquark molecular states

    Ru Xu🇨🇳 · Lu Meng🇩🇪 · Hai-Xiang Zhu🇨🇳 · Ning Li🇨🇳 · Wei Chen🇨🇳

    The hadronic and interactions are revisited, with a focus on their short-range parts, motivated by a tension between the interpretations of , , and in effective field theory (EFT) frameworks and the one-boson-exchange (OBE) model. While the three states can be interpreted as molecular states within EFT frameworks, this is not feasible in the single-channel OBE model with consistent cutoff. In this work, the possibility to reconcile OBE model with EFTs by refitting the -, - and -exchange interaction is explored and ruled out. It is pointed out that the problem in OBE arises from the strong short-range spin-dependent one-pion-exchange (OPE) interaction and the fixed signs of other short-range interactions in OBE model also prevent the cancellation. To address this issue, the short-range subtraction strategies within the OBE model are revisited. Two subtraction schemes are explored: removing the delta-function from all interactions and eliminating it only from the pseudoscalar-meson-exchange component. These schemes favor different spin assignments for and . Though solving the problem, there is no clear dynamical picture to support the subtraction schemes. We propose a new quark-exchange mechanism motivated by the Pauli principle. Different from the two subtraction schemes in OBE, the quark-exchange mechanism offers an explanation grounded in microscopic dynamics. It is shown that the spin-dependent quark-exchange interaction cancels those from OPE. The differences in the predictions for the spin, isospin, and open-charm partner states of the experimental states offer a way to distinguish between the subtracted OBE model and the OBE model with quark-exchange contributions.

    Comments:
    18 pages, 12 figures. Accepted version by PRD
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2503.04264 [pdf]
    PRD(2025)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE