Nuclear Theory·nucl-th

Friday·October 11, 2024

11 papers—6 primary·5 cross-listed

01
Isospin composition of fission barriers
K. Godbey · C. Ross · A.S. Umar
We employ a microscopic method to study how isospin affect the fission potential of $^{240}$ Pu. Our approach uses constrained Hartree-Fock theory (CHF) which allows us to separately investigate the isoscalar and isovector properties of the nuclear energy density functional (EDF). By analyzing the isoscalar and isovector components of the EDF along the fission path we can assess the isovector contribution to fission barriers. We study this effect for the fully adiabatic path to scission. The isovector component of the fission potential is found to increase in magnitude as the nucleus evolves towards scission, exemplifying the importance of stringent constraints on the isovector sector of the nuclear EDF for reliable predictions of fission properties.
nucl-thPRC(2024)·2 citations
02
Re-investigation of neutron capture by 84Kr and 86Kr in the s-process nucleosynthesis
Abdul Kabir · Zain Ul Abideen · Jameel-Un Nabi
The thermonuclear reaction rates and Maxwellian averaged cross sections (MACS) for the 84Kr(n,{\gamma}) 85Kr and 86Kr(n,{\gamma}) 87Kr processes were examined using the statistical model code Talys v1.96. The effects of nuclear level densities (NLDs) on Maxwellian averaged cross sections and neutron capture rates are examined both quantitatively and qualitatively. The present Talys based MACS and radiative capture rates for 84Kr(n,{\gamma}) 85Kr and 86Kr(n,{\gamma}) 87Kr processes agree well with the earlier reported findings. The statistical models nuclear properties (level density and gamma ray strength) were fine tuned to reproduce the existing experimental nuclear data.
nucl-thastro-ph.SRnucl-exBraz.J.Phys.(2024)·4 citations
03
Investigation of Nuclear Structure and $β$ -decay Properties of As Isotopes
Jameel-Un Nabi · Abdul Kabir · Wajeeha Khalid · Syeda Anmol Rida · Izzah Anwaar
The nuclear ground state properties of 67 80As nuclei have been investigated within the framework of relativistic mean field (RMF) approach. The RMF model with density dependent (DDME2) interaction is utilized for the calculation of potential energy curves and the nuclear ground state deformation parameters $β_{2}$ of selected As isotopes. Later, the $β$ decay properties of As isotopes were studied using the proton neutron quasi particle random phase approximation pnQRPA model. These include Gamow Tellar (GT) strength distributions, log ft values, $β$ decay half lives, stellar $β$ plus minus decays and stellar electron positron capture rates. The $β_{2}$ values computed from RMF model were employed in the on QRPA model as an input parameter for the calculations of $β$ -decay properties for 67 80As. The calculated log ft values were in decent agreement with the measured data. The predicted $β$ -decay half lives matched the experimental values within a factor of 10. The stellar rates were compared with the shell model results. Only at high temperature and density values, the sum of $β$ plus and electron capture rates had a finite contribution. On the other hand, the sum of $β$ negative and positron capture rates were sizeable only at low density and high temperature values. For all such cases, the pn QRPA rates were found to be bigger than the shell model rates up to a factor of 33 or more. The findings reported in the current investigation could prove valuable for simulating the late stage stellar evolution of massive stars.
nucl-thastro-ph.SRChin.J.Phys.(2024)·4 citations
04
Relativistic spin hydrodynamics revisited with general rotation by entropy-current analysis
Lixin Yang🇨🇳 · Li Yan🇨🇳
We revisit the canonical formulation of spin hydrodynamics for Dirac fermions with a general thermal vorticity. The orders of the general thermal vorticity and the corresponding spin variables are considered independently from those of the conventional hydrodynamic variables and their perturbative gradients. Assuming a totally antisymmetric spin current of Dirac fermions, the entropy-current analysis with a general spin potential indicates that the constitutive relations of the stress-energy tensor have to involve spin variables, particularly those linked to boost symmetry, to adhere to the entropy principle. In the presence of the degree of freedom associated with boost symmetry, we choose the constitutive relations of the canonical formulation to be connected to those of the phenomenological formulation through pseudogauge transformation. Subsequently, a linear-mode analysis is conducted using the resulting spin hydrodynamic equations. It is observed that the spin and hydrodynamic modes in this canonical formulation display different characteristics compared to those in the phenomenological formulation up to the second order of gradient.
nucl-thhep-phhep-th3 citations
05
Frozen and $β$ -equilibrated $f$ and $p$ modes of cold neutron stars: nuclear metamodel predictions
Gabriele Montefusco🇫🇷 · Marco Antonelli🇫🇷 · Francesca Gulminelli🇫🇷
When the chemical re-equilibration timescale is sufficiently long, the normal and quasi-normal mode frequencies of neutron stars should be calculated in the idealized limit that the internal composition of each fluid element is fixed over the oscillation period. However, many studies rely on a barotropic equation of state, which implicitly overlooks potential out-of- $β$ -equilibrium effects. To investigate possible biases arising from this assumption, we calculate the non-radial fundamental ( $f$ ) and first pressure ( $p_{1}$ ) modes for a wide range of neutron star structures, each governed by different nucleonic equations of state. This ensemble is generated using the metamodel technique, a phenomenological framework that incorporates constraints from experimental nuclear physics and chiral effective field theory. The metamodel also provides the internal composition of $β$ -equilibrated $n p e μ$ matter, allowing us to calculate oscillation modes beyond those supported by a purely barotropic fluid. Thus, we systematically assess the impact of assuming a barotropic equation of state across various equations of state and provide a distribution of expected $f$ and $p_{1}$ mode frequencies that may be detectable by next-generation gravitational wave interferometers.
nucl-thastro-ph.HEAstron.Astrophys.(2025)·18 citations
06
Towards a fluid-dynamic description of an entire heavy-ion collision: from the colliding nuclei to the quark-gluon plasma phase
Andreas Kirchner🇩🇪 · Federica Capellino🇩🇪 · Eduardo Grossi🇮🇹 · Stefan Floerchinger🇩🇪
The fluid-dynamical modeling of a nuclear collision at high energy usually starts shortly after the collision. A major source of uncertainty comes from the detailed modeling of the initial state. While the collision itself likely involves far-from-equilibrium dynamics, it is not excluded that a fluid theory of second order can reasonably well describe its soft features. Here we explore this possibility and discuss how the state before the collision can be described in that setup, what are the requirements from relativistic causality to the form of the equations of motion, how much entropy production can result from shear and bulk viscous dissipation during the initial longitudinal dynamics, and how one can thus obtain sensible initial conditions for the subsequent transverse expansion. While we do here only first steps, we outline a larger program. If the latter could be successfully completed it could lead to a dynamical description of heavy-ion collisions where the only uncertainty lies in the thermodynamic and transport properties of quantum chromodynamics.
nucl-thPRC(2025)·2 citations
07
Toward hybrid quantum simulations with qubits and qumodes on trapped-ion platforms
Jack Y. Araz🇺🇸 · Matt Grau🇺🇸 · Jake Montgomery🇺🇸 · Felix Ringer🇺🇸
We explore the feasibility of gate-based hybrid quantum computing using both discrete (qubit) and continuous (qumode) variables on trapped-ion platforms. Trapped-ion systems have demonstrated record one- and two-qubit gate fidelities and long qubit coherence times, while qumodes, which can be represented by the collective vibrational modes of the ion chain, have remained relatively unexplored for their use in computing. Using numerical simulations, we show that high-fidelity hybrid gates and measurement operations can be achieved for existing trapped-ion quantum platforms. As an exemplary application, we consider quantum simulations of the Jaynes-Cummings-Hubbard model, which is given by a one-dimensional chain of interacting spin and boson degrees of freedom. Using classical simulations, we study its real-time evolution and develop a suitable variational quantum algorithm for ground state preparation. Our results motivate further studies of hybrid quantum computing in this context, which may lead to direct applications in condensed matter and fundamental particle and nuclear physics.
↳ quant-phhep-latnucl-thphysics.atom-phPRA(2025)·37 citations
08
Quantum Hall liquids in high-density QCD
Kentaro Nishimura🇯🇵 · Naoki Yamamoto🇯🇵 · Ryo Yokokura🇯🇵
There exist metastable domain walls of the flavor-singlet meson $η$ for the $U (1)$ axial symmetry in two-flavor color superconductivity (2SC) in QCD at large baryon density. We show that, due to the coupling of $η$ to confined $SU (2)$ gluons in the 2SC phase, the effective theory on the domain wall is described by the $SU (2)_{- 1}$ Chern-Simons theory, which is dual to the $U (1)_{2}$ Chern-Simons theory. This theory has a spin-1 droplet excitation that does not carry a baryon number, which we identify as a vector meson. We also discuss the effective theories and baryonic droplet excitations on the domain walls of the flavor-singlet mesons in the superfluid phases of QCD at large isospin density and two-color QCD at large baryon density.
↳ hep-thcond-mat.mes-hallhep-phnucl-thPRD(2025)·0 citations
09
Quantifying the Jet Energy Loss in Pb+Pb collisions at LHC
Vineet Kumar🇮🇳 · Prashant Shukla🇮🇳
In this work, we give a method to study the energy loss of jets in the medium using a variety of jet energy loss observables such as nuclear modification factor and transverse momentum asymmetry in dijets and $γ$ -jets in heavy ion collisions. The energy loss of jets in the medium depends mainly on the size and the properties of medium viz. temperature and is a function of energy of the jets as predicted by various models. A Monte Carlo (MC) method is employed to generate the transverse momentum and path-lengths of the initial jets that undergo energy loss. Using different scenarios of energy loss, the transverse momentum and system size dependence of nuclear modification factors and different measures of dijet momentum imbalance at energies $s q r t s_{NN}$ = 2.76 TeV and 5.02 TeV and $γ$ -jet asymmetry at $s_{NN}$ =2.76 TeV in Pb+Pb collisions are simulated. The results are compared with the measurements by ATLAS and CMS experiments as a function of transverse momentum and centrality. The study demonstrates how the system size and energy dependence of jet energy loss can be quantified using various experimental observables.
↳ hep-phhep-exnucl-thEPJA(2024)·1 citation
10
Three-point functions from a Schwinger-Keldysh effective action, resummed in derivatives
Navid Abbasi🇨🇳 · Dirk H. Rischke🇩🇪
The search for the conjectured QCD critical point in heavy-ion collisions requires to account for far-from equilibrium effects as well as fluctuations, and in particular non-Gaussian fluctuations, in the modeling of the dynamics of the hot and dense matter created in such collisions. In order to study far-from equilibrium effects as well as fluctuations, in this work we construct a Schwinger-Keldysh effective field theory (EFT) for the diffusion of the density to all orders in derivatives. The dissipation in the free part of our EFT follows the Boltzmann equation in the relaxation-time approximation (RTA). The interaction part of the EFT is constructed based on the self-interaction of the density field. We analytically find the quadratic and cubic parts of the KMS-invariant EFT in closed form, resummed in derivatives. We then explicitly compute the symmetrized three-point function at tree level, and investigate its analytical structure in detail. We also analytically calculate the branch-point singularity that appears in the structure of the two-point response function due to loop effects. Our results are important for future studies of the real-time dynamics of the correlation functions and the possible relation to thermalization when the system is far from equilibrium.
↳ hep-thcond-mat.str-elnucl-thJHEP(2025)·13 citations
11
Anomalous $U (1)_{A}$ couplings and the Columbia plot
Francesco Giacosa🇵🇱 · Győző Kovács🇭🇺 · Péter Kovács🇭🇺 · Robert D. Pisarski🇭🇺 · Fabian Rennecke🇩🇪
When the quark masses are lighter than those in QCD, the standard lore is that a chiral transition of first order must emerge for three, light flavors. Recently, however, numerical simulations on the lattice suggest that the chiral transition is of second order in the chiral limit. Using an extended linear sigma model in the mean field approximation, we study the relation between terms which break the anomalous, $U (1)_{A}$ symmetry and the order of the chiral phase transition, especially how a chiral transition of second order can arise for three, massless flavors. We note that in an (unphysical) region of the "Columbia" phase diagram, when the strange quark mass is light and negative, corresponding to topological angle $θ = π$ , the $C P$ symmetry is spontaneously broken.
↳ hep-phhep-latnucl-thPRD(2025)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE