Nuclear Theory·nucl-th

Friday·June 13, 2025

10 papers—4 primary·6 cross-listed

01
[Submitted on 12 Jun 2025]
Gapless superfluidity in neutron stars: Normal-fluid fraction
Valentin Allard · Nicolas Chamel
Our previous investigation within the time-dependent nuclear energy-density functional theory showed that the nuclear superfluids contained inside cold neutron stars could become gapless under certain circumstances. The absence of a gap in the energy spectrum of quasiparticle excitations leads to a specific heat that is comparable to that in the normal phase in sharp contrast with the exponential suppression in the BCS phase of type $^{1} S_{0}$ pairing. Here, we further study gapless superfluidity within the same microscopic framework focusing on hydrodynamic properties. In particular, we calculate the mass fraction transported by the normal fluid of quasiparticle excitations, and we find that it can be finite even at zero temperature. We derive an approximate analytical formula for arbitrary neutron-proton superfluid mixtures. We also present numerical results for neutron stars. Our study suggests that the dynamics of neutron stars may be much more complicated than previously thought. The realization of gapless superfluidity in neutron stars and its implications are discussed.
Comments:
28 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2506.10649 [pdf]
PRC(2023)·9 citations
02
[Submitted on 12 Jun 2025]
Geometry of Configuration Mixing in Bose-Fermi Systems
A. Leviatan · N. Gavrielov
A geometric interpretation for an algebraic interacting boson-fermion model with configuration mixing is presented. The formalism is based on an extended Bose-Fermi matrix coherent states and is applied to gain insight on intertwined quantum shape-phase transitions and shape coexistence in odd-mass Nb nuclei.
Comments:
5 pages, 3 figures, 1 Table, Physics Letters B, in press
Subjects:
Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2506.10659 [pdf]
PLB(2025)·5 citations
03
[Submitted on 12 Jun 2025]
HFB3: an axial HFB solver with Gogny forces using a 2-center HO basis (C++/Python)
N. Dubray🇫🇷 · J. P. Ebran🇫🇷 · P. Carpentier🇫🇷 · M. Frosini🇫🇷 · A. Zdeb🇫🇷 · N. Pillet🇫🇷 · J. Newsome🇫🇷 · M. Verrière🇫🇷 · G. Accorto🇫🇷 · D. Regnier🇫🇷
The HFB3 program solves the axial nuclear Hartree-Fock-Bogoliubov (HFB) equations using bases formed by either one or two sets of deformed Harmonic Oscillator (HO) solutions with D1-type and D2-type Gogny effective nucleon-nucleon interactions. Using two sets of HO solutions shifted along the z-axis (2-center basis) allows to accurately describe highly elongated nuclear systems while keeping a moderate basis size, making this type of basis very convenient for the description of the nuclear fission process. For the description of odd-even and odd-odd systems, the equal-filling-approximation is used. Several observables can be calculated by the program, including the mean values of the multipole moments, nuclear radii, inertia tensors following Adiabatic Time-Dependent Hartree-Fock-Bogoliubov (ATDHFB) or Generator Coordinate Method (GCM) prescriptions, local and non-local one-body densities, local and non-local pairing densities, some fission fragment properties, etc. The program can ensure that the mean values associated with some specific operators take pre-defined values (constraints). Such constraints can be set on the usual multipole moments (for protons, neutrons or total mass). This program can be used as a monoprocess and monothreaded CLI executable, or through full-featured Python bindings (available through the Python Package Index PyPI).
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2506.10745 [pdf]
EPJA(2025)·3 citations
04
[Submitted on 12 Jun 2025]
Microscopic theory of angular momentum distributions across the full range of fission fragments
Petar Marević🇭🇷 · Nicolas Schunck🇺🇸 · Marc Verriere🇺🇸
Modern nuclear theory provides qualitative insights into the fundamental mechanisms of nuclear fission and is increasingly capable of making reliable quantitative predictions. Most quantities of interest pertain to the primary fission fragments, whose subsequent decay is typically modeled using statistical reaction models. Consequently, a key objective of fission theory is to inform these models by predicting the initial conditions of the primary fragments. In this work, we employ a framework that combines joint angular momentum and particle number projection with time-dependent configuration mixing to calculate the angular momentum distributions of primary fragments. Focusing on the benchmark cases of neutron-induced fission of $^{235}$ U and $^{239}$ Pu, we predict - for the first time - microscopic angular momentum distributions for all fragments observed in experiments. Our results reveal a pronounced sawtooth pattern in the average angular momentum as a function of fragment mass, consistent with recent measurements. Additionally, we observe substantial variations in angular momentum distributions along isobaric chains, indicating that commonly used empirical formulas lack sufficient accuracy. We also quantify a strong correlation between the angular momentum and the deformation of the fragments at scission, and a weak correlation in the magnitude of the angular momentum between fragment partners. The generated data will enable estimation of the impact of microscopic distributions on fission spectra, paving the way toward fission modeling based on microscopic inputs.
Comments:
20 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2506.10777 [pdf]
PRC(2026)·5 citations
05
[Submitted on 11 Jun 2025] (cross-list from astro-ph.HE)
Locating the QCD critical point with neutron-star observations
Christian Ecker🇩🇪 · Niko Jokela🇫🇮 · Matti Järvinen🇰🇷
We present a probabilistic model for the QCD critical endpoint (CEP) and the equation of state (EOS) at $β$ -equilibrium, constrained by neutron-star observations. Using a hybrid framework that combines the holographic V-QCD model with an effective van der Waals description of nuclear matter, we generate a large ensemble of EOSs incorporating nuclear theory uncertainties. Constraining this ensemble with neutron-star mass-radius data and tidal deformability measurements from gravitational waves, we identify a strong first-order deconfinement transition at zero temperature, with a transition strength of $Δ n_{PT} / n_{0} = 3.7 5_{- 0.53}^{+ 0.70}$ and onset density $n_{PT} / n_{0} = 4. 9_{- 1.17}^{+ 1.33}$ . The resulting posterior yields $95%$ credible intervals for the CEP location: $μ_{crit} = 62 6_{- 179}^{+ 90} MeV$ , $T_{crit} = 11 9_{- 6}^{+ 14} MeV$ .
Comments:
9 pages, 5 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2506.10065 [pdf]
PRD(2026)·23 citations
06
[Submitted on 12 Jun 2025] (cross-list from hep-ph)
Baryon and Meson Excited States
L. David Roper (VTech)🇺🇸 · Igor Strakovsky (GWU)🇺🇸
The masses of fifteen baryon sets and twenty-four meson sets of three or more equal-quantum excited states are fitted by a simple two-parameter logarithm function, $M_{n} = α L n (n) + β$ , where $n$ is the level of radial excitation. The conjecture is made that accurately measured masses using Breat-Wigner PDG2024 data at fixed $J^{P}$ for baryons and $J^{P C}$ for mesons of all equal-quantum baryons (including LHCb exotic $P_{c c ˉ}^{+}$ s) and meson (including $s s ˉ$ , $s c ˉ$ , $c c ˉ$ , $c b ˉ$ , and $b b ˉ$ ) excited states are related by the logarithm function used here; at least for the mass range of currently known excited states. Thus, a universal mass equation for equal-quantum excited-states sets is presented. The masses of twelve baryon sets and sixteen meson sets, with only two equal-quantum excited states in each set, using Breit-Wigner PDG2024 masses and their uncertainties, are fitted by thr universal mass equation.
Comments:
7 pages, 11 figures, contribution to the HADRON2025 Proceedings
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2506.10646 [pdf]
PoS(2026)·0 citations
07
[Submitted on 12 Jun 2025] (cross-list from hep-ph)
Unraveling the neutron skin thickness through jet charge in deep inelastic scattering
Shan-Liang Zhang🇨🇳 · Enke Wang🇨🇳 · Xin-Nian Wang🇨🇳 · Hongxi Xing🇨🇳
The neutron skin thickness in neutron-rich nuclei has traditionally been measured using elastic fixed target electron-nucleus scattering since the 1970s. In this paper, we propose a novel probe of the neutron skin thickness through deep inelastic scattering in electron-ion collisions, leveraging the intrinsic correlation between final-state jet charge distribution and initial-state partonic distributions in nucleons. Specifically, we demonstrate the sensitivity of jet charge distribution to the neutron skin thickness in $e$ +Pb collisions with varying centralities, and in isobar collisions of $e$ +Ru and $e$ +Zr. We predict a strong suppression of positive jet charge distribution and an enhancement for negative jet charge distribution in peripheral electron-ion collisions, revealing the neutron skin effect. This proposal can also be extended to photon and Z-boson tagged jet charge distribution in proton-nucleus collisions at the Large Hadron Collider, providing an alternative access to neutron skin thickness.
Comments:
6 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2506.10694 [pdf]
4 citations
08
[Submitted on 12 Jun 2025] (cross-list from hep-ph)
Extraction of Effective Parameters from Transverse Momentum Spectra of Heavy Quarkonia in Proton-Proton Collisions at the LHC
Peng-Cheng Zhang🇨🇳 · Hailong Zhu🇨🇳 · Fu-Hu Liu🇨🇳 · Khusniddin K. Olimov🇺🇿
The effective string tension ( $κ$ ) in the Schwinger mechanism and the effective temperature ( $T$ ) in Bose-Einstein statistics are extracted from the transverse momentum ( $p_{T}$ ) spectra of heavy quarkonia produced in proton-proton (p+p) collisions at the Large Hadron Collider (LHC). Here, $T$ derived from the heavy quarkonium $p_{T}$ spectra also serves as the initial effective temperature (effective temperature at the initial stage) of small collision systems. This is because, despite the absence of quark-gluon plasma (QGP) formation during the collisions, which leaves $T$ largely unaffected by QGP-related effects, the initial geometric asymmetry and local partonic thermalization still induce radial and transverse flows, thereby contributing to an increase in $T$ . The effective parameters ( $κ$ and $T$ ) are obtained by fitting the experimental $p_{T}$ spectra of $J / ψ$ and $Υ (n S)$ ( $n = 1$ , 2, and 3) within various rapidity intervals, produced in p+p collisions at center-of-mass energies of $s = 13$ and 8 TeV, as measured by the LHCb Collaboration. It is found that the multi-component distribution structured within the framework of the Schwinger mechanism or Bose-Einstein statistics can effectively describe the heavy quarkonium $p_{T}$ spectra in small collision systems. With decreasing rapidity in the forward region, both $κ$ and $T$ increase, indicating a directly proportional relationship between them. Based on $κ$ , the average minimum strong force radius of participant quarks is determined.
Comments:
21 pages, 6 figures. The title has been changed. Advances in High Energy Physics, accepted
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2506.10702 [pdf]
Adv.High Energy Phys.(2026)·0 citations
09
[Submitted on 12 Jun 2025] (cross-list from hep-ph)
Electric conductivity and flavor diffusion in a viscous, resistive quark-gluon plasma for weak and strong magnetic fields
Ferdinando Frascà🇮🇹 · Andrea Beraudo🇮🇹 · Luca Del Zanna🇮🇹
We present a microscopic calculation of the electric conductivity and net-particle diffusion coefficients for a viscous and resistive ultra-relativistic plasma. Our results might be of interest for several astrophysical and cosmological problems, but the main physical application we have in mind is the hot deconfined matter produced in relativistic heavy-ion collisions. Accordingly, as charged particles of the medium we take three species (flavors) of light (massless for the sake of simplicity) quarks -- $u$ , $d$ and $s$ -- and antiquarks, entailing the existence of three macroscopic conserved charges: baryon number $B$ , electric charge $Q$ and strangeness $S$ . Our results are valid both in a weakly and in a strongly-magnetized plasma, where the energy stored in the magnetic field is comparable to the one carried by the medium particles. Actually, for a conformal fluid, the behavior of the system only depends on the ratio between the thermal and the magnetic pressure, the so-called plasma beta-parameter, acting as a scaling variable. Our calculation, starting from a relativistic Boltzmann-Vlasov equation, is based on a generalized Chapman-Enskog approach in which space-time gradients and the local electric field are treated as first-order quantities in a perturbative expansion, while terms containing magnetic corrections are considered of zeroth order and hence self-consistently resummed. We find that, also in the strong-field limit, for each conserved charge a generalized Wiedemann-Franz law, connecting charge conductivity and diffusion coefficient, exists. However these transport coefficients acquire a non-trivial tensor structure, reflecting the development of a longitudinal, a transverse and a Hall current as a response to electric fields or density gradients.
Comments:
27 pages, 75 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2506.10783 [pdf]
EPJC(2025)·1 citation
10
[Submitted on 12 Jun 2025] (cross-list from quant-ph)
Non-Abelian dynamics on a cube: improving quantum compilation through qudit-based simulations
Jacky Jiang🇨🇦 · Natalie Klco🇺🇸 · Olivia Di Matteo🇨🇦
Recent developments in mapping lattice gauge theories relevant to the Standard Model onto digital quantum computers identify scalable paths with well-defined quantum compilation challenges toward the continuum. As an entry point to these challenges, we address the simulation of SU(2) lattice gauge theory. Using qudit registers to encode the digitized gauge field, we provide quantum resource estimates, in terms of elementary qudit gates, for arbitrarily high local gauge field truncations. We then demonstrate an end-to-end simulation of real-time, qutrit-digitized SU(2) dynamics on a cube. Through optimizing the simulation, we improved circuit decompositions for uniformly-controlled qudit rotations, an algorithmic primitive for general applications of quantum computing. The decompositions also apply to mixed-dimensional qudit systems, which we found advantageous for compiling lattice gauge theory simulations. Furthermore, we parallelize the evolution of opposite faces in anticipation of similar opportunities arising in three-dimensional lattice volumes. This work details an ambitious executable for future qudit hardware and attests to the value of codesign strategies between lattice gauge theory simulation and quantum compilation.
Comments:
22 pages, 22 figures, code available
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2506.10945 [pdf]
PRD(2025)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE