Nuclear Theory·nucl-th

Tuesday·June 24, 2025

15 papers—8 primary·7 cross-listed

01
Causality of polarizeable dissipative fluids from Lagrangian hydrodynamics
David Montenegro🇷🇺 · Giorgio Torrieri🇧🇷
We perform a causality analysis on the dispersion relation of hydrodynamics with spin well as shear and bulk viscosity, including the relaxation times for all these quantities. We find that the interplay of the three relaxational scales, for shear and bulk viscosity as well as polarization, leads to non-trivial effects on the dispersion relation. Unexpectedly, the presence of polarization leads to lower effective viscosity and a longer relaxation time, and the presence of viscosity leads to lower limits as well as upper ones on the group velocity and constraints relating polarization to viscosity relaxation times. We conclude with a qualitative discussion on how these results impact phenomenology, specifically the low effective viscosity in strongly interacting matter as well as shear-vorticity coupling.
nucl-thhep-phhep-thPRD(2025)·3 citations
02
Exploring the neutron-star matter properties via the deformed nuclear reactions
Yuan-Qing Guo🇨🇳 · Ya-Peng Zhang🇨🇳 · Zhao-Qing Feng🇨🇳
Within the framework of Lanzhou quantum molecular dynamics transport model, the correlation of initial deformation and isospin diffusion is systematically investigated in collisions of $^{238}$ U + $^{238}$ U. The impacts of the collision centrality, symmetry energy and initial configuration on the collective flows, neutron/proton and $π^{-} / π^{+}$ ratios have been systematically investigated. It is found that the broader neutron-rich region is formed in the body-body collisions in comparison with the ones in the tip-tip collisions. The neutron-star matter might be created in the density region of 0.2-0.5 $ρ_{0}$ (the normal nuclear density $ρ_{0}$ =0.165 fm $^{- 3}$ ) formed in the $^{238}$ U + $^{238}$ U reaction at the incident energy of 500 MeV/nucleon. The elliptic flows of protons are related to the incident energy, collision centrality, symmetry energy and collision orientation. The hard symmetry energy enables the larger free neutron/proton ratio at the beam energy of 500 MeV/nucleon. However, the neutron/proton and $π^{-} / π^{+}$ ratios in the density regime of $1.2 \leq ρ / ρ_{0} \leq 1.8$ are enhanced by the soft symmetry energy with the slope parameter of L=42 MeV.
nucl-thPRC(2026)·0 citations
03
Relations between spin observables of the reactions $dd \to n p d$ and $p d \to p d$ in impulse approximation
Yu.N. Uzikov🇷🇺
It is shown that the vector and tensor analyzing powers $A_{y}$ , $A_{y y}$ and also double spin correlation coefficients $C_{y, y}$ , $C_{y y, y}$ of the reaction $dd \to n + p + d$ in impulse approximation are linearly connected to corresponding observables of the $p d$ - elastic scattering. Obtained relations are necessary for motivation of the polarization experiments for the first phase of the SPD NICA project and for analysis of expected data.
nucl-thPhys.Part.Nucl.Lett.(2025)·2 citations
04
Investigation of the neutron-proton effective mass splitting via heavy ion collisions: Constraints and Implications
Junping Yang · Meiqi Sun · Ying Cui · Yangyang Liu · Zhuxia Li · Kai Zhao · Yingxun Zhang
The neutron-proton effective mass splitting ( $Δ m_{n p}^{*}$ ) is investigated through analyses of heavy-ion collisions using the improved quantum molecular dynamics (ImQMD) model with both standard and extended Skyrme interactions. By uncovering the strong correlation between the slope of the neutron-to-proton yield ratio with respect to the kinetic energy (i.e., $S_{n / p}$ ) and $Δ m_{n p}^{*}$ , we reveal that the constraints of the neutron-proton effective mass splitting via heavy ion collisions depend on the kinetic energy region of the emitted nucleons. At low kinetic energies, the data favor $m_{n}^{*} > m_{p}^{*}$ which is consistent with the nucleon-nucleus scattering analysis, while at high kinetic energies, they favor $m_{n}^{*} < m_{p}^{*}$ . Our findings partly resolve the longstanding discrepancy in the constraints of neutron-proton effective mass splitting with heavy ion collisions and nucleon-nucleus scattering, and significantly advance the understanding of nucleon effective mass splitting through heavy ion collisions.
nucl-thnucl-exPRC(2025)·4 citations
05
Towards Quantum Simulation of Rotating Nuclei using Quantum Variational Algorithms
Dhritimalya Roy🇮🇳 · Somnath Nag🇮🇳
Quantum variational algorithms (QVAs) are increasingly potent tools for simulating quantum many-body systems on noisy intermediate-scale quantum (NISQ) devices. This work examines the application of the Variational Quantum Eigensolver (VQE) to four progressively complex models based on the cranked Nilsson-Strutinsky (CNS) framework. By incorporating single-particle spacings, pairing correlations, and rotational cranking terms, we evaluate VQE performance against exact diagonalization (ED) benchmarks. We provide a systematic benchmarking of VQE across a hierarchy of CNS-inspired Hamiltonians, explicitly identifying where hardware-efficient ansatz succeed and fail, and introducing quantum information diagnostics, the entanglement spectrum and Quantum Fisher Information, as novel probes of the pairing-rotation. Our results demonstrate that with a properly optimised multi-restart warm-starting strategy, VQE achieves near-machine-precision convergence ( $∣Δ E ∣ < 1 0^{- 4}$ ) across the full cranking frequency range $ω \in [0, 1.2]$ and we confirm that the same strategy reproduces an established $^{6}$ He shell-model pairing benchmark, demonstrating that the RealAmplitudes ansatz is expressively sufficient for this problem class. The entanglement spectrum confirms the product-state character of the exact ground state throughout the pairing-rotation transition, while the Quantum Fisher Information identifies a finite-size precursor to the critical pair-breaking frequency. These results establish a systematic methodological baseline and provide a reproducible framework for the nuclear physics community.
nucl-thhep-phnucl-exquant-phEur.Phys.J.Plus(2026)·0 citations
06
Nuclear and neutron matter in the relativistic Brueckner-Hartree-Fock theory with next-to-leading order covariant chiral nuclear force
Wei-Jiang Zou🇨🇳 · Yi-Long Yang🇨🇳 · Jun-Xu Lu🇨🇳 · Peng-Wei Zhao🇨🇳 · Li-Sheng Geng🇨🇳 · Jie Meng🇨🇳
The symmetric nuclear matter and pure neutron matter are investigated by the relativistic Brueckner-Hartree-Fock (RBHF) theory with the covariant chiral nuclear forces up to the next-to-leading order~(NLO). A fitting scheme to ensure the naturalness of the low-energy constants is proposed, which plays a crucial role in the proper description of nuclear matter. With a momentum cutoff $Λ = 590$ MeV, the empirical saturation energy and density, as well as the incompressibility coefficient at the saturation density are reproduced well. The EoSs show less dependence on the momentum cutoff and become softer at densities above saturation density, in comparison with the previous leading order results. Given the good description for the saturation properties of nuclear matter, the present work encourages future studies of the finite nuclei in the framework of the RBHF theory with the NLO covariant chiral nuclear forces.
nucl-thhep-phnucl-exPRC(2026)·5 citations
07
Correlation between particle spectra and elliptic flow
Tribhuban Parida🇮🇳 · Rupam Samanta🇵🇱 · Jean-Yves Ollitrault🇫🇷
We introduce a new observable to probe the collective nature of the radial expansion of the quark-gluon plasma. This observable, dubbed $v_{02} (p_{T})$ , represents the correlation of the spectrum with elliptic flow, in the same way as the recently measured $v_{0} (p_{T})$ represents the correlation of the spectrum with the transverse momentum per particle. The advantage of $v_{02} (p_{T})$ over $v_{0} (p_{T})$ is that it is measured using a three-particle cumulant, as opposed to a pair correlation, which significantly reduces the sensitivity to nonflow effects. We predict non-trivial differences between $v_{02} (p_{T})$ and $v_{0} (p_{T})$ in semi-central Pb+Pb collisions at the Large Hadron Collider (LHC) on the basis of hydrodynamic simulations. A hint of these differences can be seen in the modification of $p_{T}$ spectra observed by ALICE in event-shape-engineered events.
nucl-thhep-exhep-phnucl-exPLB(2025)·5 citations
08
Nuclear $β$ -decay half-lives within the subtracted second random-phase approximation
Danilo Gambacurta🇮🇹 · Marcella Grasso🇫🇷
We employ, within the framework of Skyrme energy-density functional theory, the subtracted second random-phase approximation, recently developed for charge-exchange excitations, to compute $β$ -decay half-lives in four nuclei, $^{24}$ O, $^{34}$ Si, $^{78}$ Ni, and $^{132}$ Sn. Following our recent results on the description of the Gamow-Teller strength, we proceed coherently in the present work by computing $β$ -decay half-lives using the bare value of the axial-vector coupling constant $g_{A}$ . Half-lives are thus obtained, within the allowed Gamow-Teller approximation, without the use of any ad hoc quenching factors. A genuine quenching is indeed microscopically introduced in our model owing to the correlations induced by the coupling of one-particle one-hole configurations with two-particle two-hole ones. The role of the so-called $J^{2}$ terms is also studied. By comparing our results with experimental data, we show a general improvement of $β$ -decay half-lives with respect to results obtained within the commonly used Random Phase Approximation (RPA). The inclusion of the two-particle two-hole configurations produces a more fragmented and richer spectrum within the $β$ -window, resulting in lower $β$ half-lives with respect to the RPA ones.
nucl-thEPJA(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE