Nuclear Theory·nucl-th

Wednesday·June 11, 2025

12 papers—5 primary·7 cross-listed

06
Dense Matter in Neutron Stars with eXTP
Ang Li🇨🇳 · Anna L. Watts🇳🇱 · Guobao Zhang🇨🇳 · Sebastien Guillot🇫🇷 · Yanjun Xu🇨🇳 · Andrea Santangelo🇩🇪 · Silvia Zane🇬🇧 · Hua Feng🇨🇳 · Shuang-Nan Zhang🇨🇳 · Mingyu Ge🇨🇳 · Liqiang Qi🇨🇳 · Tuomo Salmi🇫🇮 and 73 other authors
In this White Paper, we present the potential of the enhanced X-ray Timing and Polarimetry (eXTP) mission to constrain the equation of state of dense matter in neutron stars, exploring regimes not directly accessible to terrestrial experiments. By observing a diverse population of neutron stars - including isolated objects, X-ray bursters, and accreting systems - eXTP's unique combination of timing, spectroscopy, and polarimetry enables high-precision measurements of compactness, spin, surface temperature, polarimetric signals, and timing irregularity. These multifaceted observations, combined with advances in theoretical modeling, pave the way toward a comprehensive description of the properties and phases of dense matter from the crust to the core of neutron stars. Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences, the eXTP mission is planned to be launched in early 2030.
↳ astro-ph.HEastro-ph.SRhep-phnucl-thSCPMA(2025)·48 citations
07
Wave-function microscopy: Derivation and anatomy of exact algebraic spinful wave functions and full Wigner-molecular spectra of a few highly correlated rapidly rotating ultracold fermionic atoms
Constantine Yannouleas · Uzi Landman
Exploring strongly correlated spinful states of few fermionic ultracold atoms in a rapidly rotating trap, an example of which was recently realized for two fermionic $^{6}$ Li atoms in an optical tweezer, we derive analytical (algebraic) total-spin-eigenstate wavefunctions through the development and employment of a theoretical platform that integrates exact numerical diagonalization (full configuration interaction, FCI) with symbolic language processing. For such rapid rotations, where the atoms occupy the lowest Landau level (LLL), the obtained algebraic expressions can address the full LLL spectrum in all its complexity, demonstrating that their spatial, spectral, and spin characteristics manifest formation of collectively rotating and vibrating Wigner molecules. The explicitly exhibited analytic wavefunctions (for two and three spinful $^{6}$ Li atoms) reproduce precisely the corresponding numerical FCI results, and they are shown to reach beyond the limited range of applicability of previous Jastrow-type treatments. These results, and their extension to bosonic systems, provide the impetus and analysis tools for future experimental and theoretical simulations of larger mesoscopic systems
↳ cond-mat.quant-gasnucl-thquant-phPRA(2025)·0 citations
08
Revealing Dark Matter's Role in Neutron Stars Anisotropy: A Bayesian Approach Using Multi-messenger Observations
Xue-Zhi Liu🇨🇳 · Premachand Mahapatra🇮🇳 · Chun Huang🇺🇸 · Ayush Hazarika🇮🇳 · Chiranjeeb Singha🇮🇳 · Prasanta Kumar Das🇮🇳
Dark matter (DM) continues to evade direct detection, but neutron stars (NSs) serve as natural laboratories where even a modest DM component can alter their structure. While many studies have examined DM effects on NSs, they often rely on specific choices of equations of state (EOS) models, assume isotropy, and lack a Bayesian statistical framework, limiting their predictive power. In this work, we present a Bayesian framework that couples pressure-anisotropic nuclear EOS to a self-interacting fermionic DM component, constrained by NICER and GW170817 data. Our results show that DM mass fractions up to $\sim 10%$ remain consistent with current data, which softens the high-density EOS, leading to reduced stellar radii and tidal deformabilities while requiring negligible pressure anisotropy. Bayesian model comparison reveals no statistically significant preference between pure baryonic and DM-admixed NSs, indicating that DM inclusion enhances physical realism without complexity penalties. However, existing data cannot tightly constrain the DM parameters, and our empirical radius definition introduces a systematic bias toward the DM core configurations. To address this, we therefore introduce the DM radius span $Δ R_{χ} \equiv R_{χ, max} - R_{χ, min}$ as a unified diagnostic for DM distributions. This parameter simultaneously characterizes core-halo transition features while exhibiting strong linear correlations ( $Δ R_{χ} < 4 km$ ) with both DM and BM parameters, providing a clear avenue for future constraints. Our approach bridges current limitations and future potential in probing DM through compact star observations.
↳ astro-ph.HEgr-qcnucl-thPRD(2025)·12 citations
09
Crust (Unified) Tool for Equation-of-state Reconstruction (CUTER) v2
P. J. Davis🇫🇷 · H. Dinh Thi🇺🇸 · A. F. Fantina🇫🇷 · F. Gulminelli🇫🇷 · M. Oertel🇫🇷 · L. Suleiman🇺🇸
The equation of state (EoS) is a needed input to determine the neutron-star global properties and to relate them. It is thus important to provide consistent and unified EoSs to avoid possible biases in the analyses coming from the use of inconsistent EoSs. We propose a numerical tool, CUTER, allowing the user to consistently match a nuclear-physics informed crust to an arbitrary higher density EoS. We present here the second version of this tool, CUTER v2. Two functionalities are available with the CUTER v2 tool, allowing the user to reconstruct either the whole (outer and inner) crust, or the outer crust only. We show that the code, that has been tested and validated for use by the astrophysical community, is able to efficiently perform both tasks, allowing the computation of neutron-star global properties in a consistent way.
↳ astro-ph.HEnucl-thEPJA(2025)·8 citations
10
$D$ and $D^{*}$ mesons in isospin asymmetric nuclear medium
Anshu Gautam🇮🇳 · Dhananjay Singh🇮🇳 · Navpreet Kaur🇮🇳 · Satyajit Puhan🇮🇳 · Suneel Dutt🇮🇳 · Harleen Dahiya🇮🇳 · Arvind Kumar🇮🇳
We investigate the properties of pseudoscalar $D$ and vector $D^{*}$ mesons in an isospin asymmetric nuclear medium using a hybrid approach that integrates the light-front quark model with the chiral SU(3) quark mean field model. The influence of isospin asymmetric nuclear medium is examined by utilizing the in-medium quark masses derived from the chiral SU(3) quark mean field model as an input in the light-front quark model to study the medium modification of $D$ mesons. We examine the impact of isospin asymmetry and baryon density at zero and finite temperature on the effective masses, weak decay constants, and distribution amplitudes of the pseudoscalar mesons $D^{0}$ , $D^{+}$ , $D_{s}$ , and the vector mesons $D^{0 *}$ , $D^{+*}$ , and $D_{s}^{*}$ . Our results indicate significant medium-induced changes for pseudoscalar $D$ and vector $D^{*}$ mesons having $u / d$ as one of their constituent quarks, while a comparatively reduced effect is observed for mesons containing a strange quark. In contrast to temperature and isospin asymmetry, changes in the baryon density of the nuclear medium have a larger effect on different properties of $D$ and $D^{*}$ mesons.
↳ hep-phnucl-thPTEP(2025)·1 citation
11
Modern approach to muonic x-ray spectroscopy demonstrated through the measurement of stable Cl radii
K.A. Beyer🇩🇪 · T.E. Cocolios🇧🇪 · C. Costache🇷🇴 · M. Deseyn🇧🇪 · P. Demol🇧🇪 · A. Doinaki🇨🇭 · O. Eizenberg🇮🇱 · M. Gorshteyn🇩🇪 · M. Heines🇧🇪 · A. Herzáň🇸🇰 · P. Indelicato🇫🇷 · K. Kirch🇨🇭 and 16 other authors
Recent advances in muonic x-ray experiments have reinvigorated efforts in measurements of absolute nuclear charge radii. Here, a modern approach is presented, and demonstrated through determination of the charge radii of the two stable chlorine nuclides $^{35}$ Cl and $^{37}$ Cl. Knowledge of these radii has implications for fundamental studies in nuclear and atomic physics. For this purpose, a state-of-the-art experiment was performed at the $π$ E1 beamline in the Paul Scherrer Institute (Switzerland), using a large-scale HPGe detector array in order to extract precise energies of the muonic $^{35}$ Cl and $^{37}$ Cl $n p 1 s$ transitions. The nuclear charge radius extraction relies on modern calculations for QED effects and nuclear polarization with rigorous uncertainty quantification, including effects that were not accounted for in older studies. Additionally, we established a new method for applying the nuclear shape correction directly from energy density functionals, which are amenable to isotopes for which no high-quality electron scattering experiments are available. The resulting charge radii are $3.3335 (23) f m$ for $^{35}$ Cl and $3.3445 (23) f m$ for $^{37}$ Cl, thus improving the uncertainty of the available electron scattering values by a factor of seven. The correlation of several observables was evaluated between the different isotopes in order to produce a more precise value of the differential mean square charge radius $δ ⟨ r^{2} ⟩^{37, 35} = + 0.0771 (66) f m^{2}$ . In this case, improvement of the uncertainty by more than one order of magnitude was achieved compared to the literature value. This precision is sufficient to use this differential as input for isotope shift factor determination.
↳ nucl-exnucl-thphysics.atom-phphysics.data-an7 citations
12
Entanglement Suppression, Quantum Statistics and Symmetries in Spin-3/2 Baryon Scatterings
Tao-Ran Hu🇨🇳 · Katsuyoshi Sone🇯🇵 · Feng-Kun Guo🇨🇳 · Tetsuo Hyodo🇯🇵 · Ian Low🇺🇸
We explore the interplay among entanglement suppression, quantum statistics and enhanced symmetries in the non-relativistic $S$ -wave scattering involving the lowest-lying spin-3/2 baryons, which can be considered as four-dimensional qudits. These baryons form a ten-dimensional representation (decuplet) under the $SU (3)$ light-flavor symmetry and, in this limit, are considered indistinguishable under strong interactions. Treating the $S$ -matrix in the spin-3/2 baryon-baryon scattering as a quantum logic gate in the spin space, we study the consequence of entanglement suppression and compute the entanglement power of the $S$ -matrix. When the entanglement power vanishes, the $S$ -matrix is either an Identity or a SWAP gate and spin-flavor symmetries and/or non-relativistic conformal invariance emerge, as previously observed in spin-1/2 baryons. In the case of scattering identical particles, the entanglement power never vanishes due to constraints from spin statistics, which we interpret as projection-valued measurements onto symmetric or antisymmetric Hilbert space and define the entanglement power accordingly. When the entanglement power is non-vanishing but sits at a global or local minimum, enhanced symmetries still emerge and the $S$ -matrix can be interpreted as an Identity or a SWAP gate acting on the restricted Hilbert space allowed by quantum statistics. In general, when scattering identical spin- $s$ particles, we identify an enhanced $SU (2 s + 1)_{spin}$ symmetry for the Identity gate.
↳ hep-phhep-thnucl-thquant-phPRResearch(2025)·27 citations

Affiliations

first authorsco-authorsvia INSPIRE

Dense Matter in Neutron Stars with eXTP

Wave-function microscopy: Derivation and anatomy of exact algebraic spinful wave functions and full Wigner-molecular spectra of a few highly correlated rapidly rotating ultracold fermionic atoms

Revealing Dark Matter's Role in Neutron Stars Anisotropy: A Bayesian Approach Using Multi-messenger Observations

Crust (Unified) Tool for Equation-of-state Reconstruction (CUTER) v2

D and D∗ mesons in isospin asymmetric nuclear medium

Modern approach to muonic x-ray spectroscopy demonstrated through the measurement of stable Cl radii

Entanglement Suppression, Quantum Statistics and Symmetries in Spin-3/2 Baryon Scatterings

Affiliations

$D$ and $D^{*}$ mesons in isospin asymmetric nuclear medium