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Nuclear Theory·nucl-th

Monday·November 11, 2024

4 papers—2 primary·2 cross-listed

All4Primary2Cross-lists2
  1. 01

    Configuration interaction relativistic Hartree-Fock model

    Jia Liu · Yi Fei Niu · Wen Hui Long

    The configuration interaction relativistic Hartree-Fock (CI-RHF) model is developed in this work. Compared to the conventional configuration interaction shell model (CISM), the CI-RHF model can be applied to study the structural properties of a wide range of nuclei without readjusting any parameters, as the effective Hamiltonian for different model space can be deduced consistently from a universal density-dependent Lagrangian based on the Hartree-Fock single-particle basis. The convergence of intermediate-state excitations has been examined in evaluating the effective interactions, and the core-polarization effects are illustrated, by using O as an example. Employing the CI-RHF model, both the bulk properties and low-lying spectra of even-even nuclei Ne have been well reproduced with the model space restricted to the shell. Studies of the isotopic evolution concerning charge radii and low-lying spectra highlight the shell closure at for neon isotopes. Furthermore, the cross-shell calculations extending from the to shell successfully reproduced the low-lying spectra of Ne and Ne. Notably, remarkably low excitation energies of Ne suggest the disappearance of the conventional magicity .

    nucl-thCPC(2025)·7 citations
  2. 02

    Radiative and exchange corrections for two-neutrino double-beta decay

    Ovidiu Niţescu🇸🇰 · Fedor Šimkovic🇸🇰

    We investigate the impact of radiative and atomic exchange corrections in the two-neutrino double-beta ()-decay of Mo. In the calculation of the exchange correction, the electron wave functions are obtained from a modified Dirac-Hartree-Fock-Slater self-consistent framework that ensures orthogonality between continuum and bound states. The atomic exchange correction causes a steep increase in the low-energy region of the single-electron spectrum, consistent with previous studies on -decay, while the radiative correction primarily accounts for a 5\% increase in the decay rate of Mo. When combined, the radiative and exchange effects cause a leftward shift of approximately 10 keV in the maximum of the summed electron spectrum. This shift may impact current constraints on parameters governing potential new physics scenarios in -decay. The exchange and radiative corrections are introduced on top of our previous description of -decay, where we used a Taylor expansion for the lepton energy parameters within the nuclear matrix elements denominators. This approach results in multiple components for each observable, controlled by the measurable and parameters. We explore the effects of different and values, including their experimental measurements, on the total corrected spectra. These refined theoretical predictions can serve as precise inputs for double-beta decay experiments investigating standard and new physics scenarios within -decay.

    nucl-thhep-thPRC(2025)·12 citations
  3. 03

    Exploring entanglement and spectral split correlations in three-flavor collective neutrino oscillations

    Pooja Siwach🇺🇸 · A. Baha Balantekin🇺🇸 · Amol V. Patwardhan🇺🇸 · Anna M. Suliga🇺🇸

    In environments with prodigious numbers of neutrinos, such as core-collapse supernovae, neutron star mergers, or the early universe, neutrino-neutrino interactions are dynamically significant. They can dominate neutrino flavor evolution and force it to be nonlinear, causing collective neutrino oscillations. Such collective oscillations have been studied numerically, for systems with up to millions of neutrinos, using mean-field or one-particle effective approximations. However, such a system of interacting neutrinos is a quantum many-body system, wherein quantum correlations could play a significant in the flavor evolution-thereby motivating the exploration of many-body treatments which follow the time evolution of these correlations. In many-body flavor evolution calculations with two neutrino flavors, the emergence of spectral splits in the neutrino energy distributions has been found to be correlated with the degree of quantum entanglement across the spectrum. In this work, for the first time, we investigate the emergence of spectral-splits in the three-flavor many-body collective neutrino oscillations. We find that the emergence of spectral splits resembles the number and location found in the mean-field approximation but not in the width. Moreover, unlike in the two-flavor many-body calculations, we find that additional degrees of freedom make it more difficult to establish a correlation between the location of the spectral splits and the degree of quantum entanglement across the neutrino energy spectrum.

    ↳ hep-thhep-phnucl-thquant-phPRD(2025)·13 citations
  4. 04

    Condensation and prescaling in spatial Polyakov loop correlations far from equilibrium

    Daniel Spitz🇩🇪 · Kirill Boguslavski🇦🇹 · Thimo Preis🇩🇪

    The far-from-equilibrium dynamics of spatial Polyakov loop correlations, which provide gauge-invariant observables akin to effective particle numbers for gluon plasmas, are investigated within real-time lattice gauge theory at weak couplings and large gluon occupations. The momentum zero mode of these correlations reveals the dynamic formation of a condensate, while at nonzero momenta, energy is transported toward the ultraviolet. We demonstrate that the non-zero momentum dynamics is well described by a direct cascade in terms of gauge-invariant Polyakov loop excitations, exhibiting self-similar prescaling indicative of a nonthermal attractor. This behavior can be analytically understood through perturbation theory for the Polyakov loop correlations and the established dynamics of gauge field correlations. We perform simulations for both and gauge groups, providing further consistency checks on the -dependence of perturbative expectations. No evidence of an inverse cascade toward lower momenta is found for momenta above the electric screening scale.

    ↳ hep-phcond-mat.quant-gashep-latnucl-thPRD(2025)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE