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Nuclear Theory·nucl-th

Tuesday·January 27, 2026

17 papers—7 primary·10 cross-listed

All17Primary7Cross-lists10
  1. 01

    Quarkyonic matter with strangeness in an extended relativistic mean-field model

    Wei Sun🇨🇳 · Cheng-Jun Xia🇨🇳 · Ting-Ting Sun🇨🇳

    Quarkyonic matter is expected to play a key role for the transition from hadronic matter to quark matter in compact stars. Within the framework of the relativistic mean-field (RMF) model and equivparticle model with density-dependent quark masses, we construct the ``quark Fermi sea" with a ``baryon Fermi surface" to characterize the properties of the quarkyonic matter. In particular, we develop a comprehensive framework to account for the strangeness degrees of freedom, incorporating , , and hyperons as well as strange quarks in a unified quarkyonic framework. Our calculations indicate that the inevitable emergence of hyperons softens the equations of state, leading to a reduction in the equilibrium sound velocity around , and consequently reducing the masses and radii of neutron stars. When the quark-hadron phase transition is taken into account, the equation of state at high densities exhibits additional softening consistent with current astronomical observational constraints. This softening leads to a maximum equilibrium sound velocity of , which is close to the ultrarelativistic limit of .

    nucl-thhep-phPRD(2026)·1 citation
  2. 02

    Two-body cluster entangled structure in the Hilbert space

    Fei-Long Xu · Xi-Guang Cao · Yu-Gang Ma

    This study introduces a quantum information perspective to analyze the internal structure of atomic nuclei, focusing on the quantum entanglement between clusters in the 0 state of Be. A wave function based on angular momentum coupling is developed to transform the two-cluster wave function from the conventional center of mass and relative coordinate basis () into the individual particle basis (), which is essential for a precise quantification of entanglement. Within this method, the von Neumann entropy is employed to quantify the entanglement arising from the mixing of angular momentum channels. Additionally, we introduce the concept of spatially resolved entropy, which measures entanglement as a function of the radial separation between clusters. Our analysis reveals that the entanglement is strongly correlated with the spatial configuration at the femtometer scale. As the inter cluster separation vanishes, the system approaches a separable -wave state, indicating that entanglement is dynamically generated during the spatial separation of the clusters. This research provides a new tool for investigating nonlocal quantum correlations in nuclear structure, complementing existing descriptions.

    nucl-thPRC(2026)·2 citations
  3. 03

    Basis Representation for Nuclear Densities from Principal Component Analysis

    Chen-Jun Lv · Tian-Yu Wu · Xin-Hui Wu · Gianluca Colò · Kouichi Hagino

    We develop an efficient method to represent nuclear densities using basis functions extracted via Principal Component Analysis (PCA). Applying PCA to densities of 75 nuclei calculated with the relativistic continuum Hartree-Bogoliubov (RCHB) theory yields an orthogonal set of components that efficiently capture the dominant features of nuclear density distributions, which can be used as basis functions for nuclear density representation. The first five basis functions account for more than 99.999\% of the total variance, demonstrating the efficiency of these PCA basis functions. The PCA basis achieves significantly higher accuracy and faster convergence than the Fourier-Bessel and Sum-of-Gaussians methods for reconstructing both theoretical and experimental densities. This approach provides an efficient and robust representation of nuclear densities, offering a practical tool for experimental density representation and for theories where densities play a central role, such as the orbital-free density functional theory, or the double folding model for nuclear reactions.

    nucl-thnucl-exPLB(2026)·4 citations
  4. 04

    The role of the surface energy in nuclear octupole excitations

    Khlood Alharthi · Paul Stevenson

    Octupole excitations of atomic nuclei can be viewed as fluctuations around an equilibrium shape. These fluctuations in turn can be seen as probes of nuclear matter properties to the extent that the shape changes explore changes in compression, surface to volume ratio, or isospin overlap. In the present work we use a series of Skyrme interactions, which were fitted to provide a systematic range of surface energies, to explore the surface energy dependence of octupole excitations in Pb. We find a strong positive linear corelation between the surface energy of a Skyrme interaction and its prediction of the first octupole excitation energy.

    nucl-thMod.Phys.Lett.A(2026)·0 citations
  5. 05

    Meson-exchange currents and nuclear correlations in neutrino and electron scattering with nuclei

    Paloma Rodríguez Casalé🇪🇸

    This thesis is dedicated to the study of electron and neutrino scattering on nuclei, with special emphasis on meson-exchange currents (MEC) and short-range correlations (SRC) between nucleon pairs in one-particle emission processes. In chapter 2, the SuSAM* model is improved by redefining the single nucleon hadronic tensor, averaging it over a Fermi distribution instead of using the previous extrapolation from the relativistic Fermi gas. This formulation removes the inconsistency associated with negative contributions in kinematics far from the QE peak. The new definition allows extending the SuSAM* formalism to include MEC, which is the focus of chapter 3. In chapter 3, a scaling analysis of 12C data is performed incorporating MEC explicitly at the single nucleon level, leading to a new phenomenological scaling function. Using this model, the effect of MEC on EM responses is studied and compared with the relativistic Fermi gas (RFG) and the relativistic mean field (RMF) models. Chapter 4 presents a detailed analysis of the interference between 1b2b in the RT. It is shown that this interference is always negative within the independent-particle approximation. Chapter 5 extends the study of MEC to the CCQE neutrino scattering within the RFG, RMF, and SuSAM* frameworks. It is found that OB-MEC interference reduces both the RT and the neutrino cross section. Chapter 6 addresses SRC in the wave function of a nucleon pair in nuclear matter. The BG equation is solved using the NN potential developed by the Granada group, allowing for the calculation of high-momentum components. Finally, chapter 7 combined the effect of MEC and SRC, which extends the FG by including the high-momentum components of nucleon pairs affected by MEC. It is found that SRC enhance the RT, in contrast with what is observed in uncorrelated models.

    nucl-th0 citations
  6. 06

    Probability distribution of observables from a Bogoliubov vacuum projected onto good particle number: application to scission configurations of an actinide

    Alice Bernard🇫🇷 · David Regnier🇫🇷 · Junah Newsome🇫🇷 · Paul Carpentier🇫🇷 · Noël Dubray🇫🇷 · Nathalie Pillet🇫🇷

    Nuclear fission dynamics described within nuclear energy density functional frameworks (EDF) have seen substantial advances in the last decade. Part of this success stems from projection techniques, which allow the computation f probability distribution functions (pdf) for selected observables such as particle number and angular momentum of the fragments. Predicting the pdf of other observables, such as the total kinetic energy of the fragments, remains undone. This work proposes a method to determine the complete pdf of a new category of observables from a Bogoliubov vacuum projected onto good particle number. It relies on sampling nucleonic configurations in coordinate and intrinsic-spin representation. We assess the feasibility and convergence properties of the method and apply it to states representative of the scission of an actinide. Fluctuations in fragment shapes, inter-fragment Coulomb and nuclear interaction as well as the corresponding torques are analyzed. We find that a significant fraction of the fluctuation of several measured fission observables is already present within the mean-field picture.

    nucl-thEPJA(2026)·0 citations
  7. 07

    Role of the symmetry energy on hybrid stars

    H. Güven🇫🇷 · K. Bozkurt🇹🇷 · E. Khan🇫🇷 · J. Margueron🇺🇸

    The impact of the symmetry energy on the properties of compact stars is analyzed considering constraints from nuclear physics and astrophysics. A compact star can be a neutron star composed only of nuclear matter or a hybrid star with a quark core. Two typical models (soft and stiff) are considered for the nuclear equation of state, and for the hybrid one, a parameterized first-order phase transition approach, completed with a linear quark matter equation of state, is implemented. We show that the phase transition reduces the tension between GW170817 and NICER observations, and we illustrate the impact of the symmetry energy for the understanding of the nature of the binary system in GW170817. We also confirm our previous findings that the GW170817 waveform is best described as a binary HS with a low-density onset of stiff quark matter. This could also be interpreted as a quarkyonic cross-over.

    nucl-thastro-ph.HEastro-ph.SRhep-ph1 citation

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first authorsco-authorsvia INSPIRE