Article
Multidisciplinary Sciences
Qingzhen Chai, Hongxing Chen, Minghao Zha, Junchen Pei, Furong Xu
Summary: This study investigates the exotic nuclear structures of Na-39 and Mg-42, which are weakly bound but have deformed halo structures. The results also demonstrate the significant influences of various pairing interactions on halo shapes.
Article
Physics, Nuclear
Yu-Xuan Luo, Quan Liu, Jian-You Guo
Summary: The study of exotic nuclei is a significant frontier in nuclear physics, involving weakly bound states, resonant states, deformation, and pairings to understand exotic phenomena. In this study, a deformed relativistic mean field theory in complex momentum representations with BCS pairings was developed and applied to 44Mg as an illustration example. The results indicate that 44Mg is a weakly bound nucleus with several broad resonant states near the Fermi surface, responsible for its halo structure. The density distributions suggest that 44Mg is a deformed halo nucleus with a prolate core and oblate halo, consistent with the deformed relativistic Hartree-Bogoliubov in continuum calculations. The role of resonances in halo formation is clearly demonstrated, contributing to a better understanding of the physical mechanism of deformed exotic nuclei.
Article
Physics, Multidisciplinary
X. W. Xia, Z. Shi
Summary: A triaxially deformed relativistic Hartree-Bogoliubov theory in the Woods-Saxon basis is developed to treat triaxial deformation, pairing correlations, and continuum in a unified way. The theory considers triaxial deformation by expanding the deformed potentials using spherical harmonic functions. It includes pairing correlations and properly treats the continuum by using the Dirac Woods-Saxon basis. Numerical checks are performed using examples of axially and triaxially deformed nuclei, and the ground-state properties of even-even germanium isotopes are investigated. The comparison with calculations from the relativistic Hartree-Bogoliubov theory based on harmonic-oscillator basis is made.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2023)
Article
Physics, Nuclear
Jing Guo, C. F. Chen, Xian-Rong Zhou, Q. B. Chen, H-J Schulze
Summary: The AA pairing effects in spherical and deformed multi-A hyperisotopes have been investigated using the Skyrme-Hartree-Fock approach. The results show the presence of magic numbers -S = 2, 8, 18, 20, 34, 58, 68, and 70 in spherical hyperisotopes, and additional possible magic numbers -S = 4, 6, 10, 14, 26, 30, and 32 in deformed hyperisotopes, which are sensitive to quadrupole deformation.
Article
Physics, Nuclear
P. Guo, C. Pan, Y. C. Zhao, X. K. Du, S. Q. Zhang
Summary: Using the state-of-the-art deformed relativistic Hartree-Bogoliubov theory, this study provides a self-consistent and microscopic analysis on the dominance of prolate-shape in Te, Xe, and Ba isotopes with neutron number 82 N 126. The results show that most isotopes exhibit prolate shapes in the ground state, while oblate shapes mainly appear after the major shell is half filled. The dominance of prolate-shape enhances with increasing proton number, and is in agreement with the microscopic canonical single-particle energies obtained in the theory.
Article
Materials Science, Multidisciplinary
A. M. Grudinina, I. L. Kurbakov, Yu E. Lozovik, N. S. Voronova
Summary: The study discusses the nonequilibrium Bose condensation of microcavity exciton-polaritons at high critical temperatures and their formation of quantum degenerate Bose-Einstein distribution in thermal equilibrium with the surrounding medium. It is found that large positive detunings provide conditions for the total lifetime to reach nanosecond timescales, allowing for the realization of thermodynamically equilibrium polariton systems with Bose-Einstein condensate forming at temperatures as high as tens of Kelvin.
Article
Physics, Nuclear
Yu-Ting Rong, Zhong-Hao Tu, Shan-Gui Zhou
Summary: New effective Lambda N interactions for hypernuclei are proposed and the coupling constants ratios R-sigma and R-omega are determined by fitting experimental values. A good linear relation is found between the two ratios, and the statistical errors of the ratio parameters in these effective interactions are analyzed. These interactions are used to study single-Lambda excited states, hypernuclear matter equation of state, and neutron-star properties with hyperons.
Article
Nuclear Science & Technology
En-Bo Huo, Ke-Ran Li, Xiao-Ying Qu, Ying Zhang, Ting-Ting Sun
Summary: The possible exotic nuclear properties in neutron-rich Ca, Ni, Zr, and Sn isotopes were studied using the continuum Skyrme Hartree-Fock-Bogoliubov theory and the Green's function method. The effects of pairing correlation, couplings with continuum, and blocking effects were properly considered. The study found that the neutron-rich isotopes show different properties depending on the criteria used for neutron drip line prediction, and the presence of unpaired odd neutron leads to lower neutron pairing energies in odd-A nuclei compared to neighbor-ing even-even nuclei. Possible halo structures were predicted in neutron-rich Ca, Ni, and Sn isotopes, characterized by significant deviations from the traditional r ? A(1/3) rule and diffuse spatial density distributions. The contributions of various partial waves to the neutron density were analyzed, and it was found that orbitals near the Fermi surface, particularly those with small angular momenta, significantly affect the extended nuclear density and large rms radii. The evolution of the number of neutrons above the Fermi surface as a function of mass number A is consistent with the pairing energy, supporting the important role of pairing correlation in halo phenomena.
NUCLEAR SCIENCE AND TECHNIQUES
(2023)
Article
Physics, Nuclear
Xiao-Wei Wang, Jian-You Guo
Summary: A theoretical method combining the complex momentum representation (CMR) method with the relativistic mean field (RMF) theory for deformed exotic nuclei has been established, using Cr-75 as an example. The study found that Cr-75 is a deformed nucleus with a d-wave deformed halo, providing helpful predictions for experiments exploring deformation halos in the medium mass region.
Article
Physics, Nuclear
Shilpa Rana, M. Bhuyan, Raj Kumar
Summary: In this study, the fusion barrier characteristics of different target-projectile combinations were explored within the relativistic mean-field formalism. By comparing different interaction potentials and density distributions, some conclusions were drawn regarding the fusion cross sections. The results of this study are of significant importance for understanding heavy-ion fusion reactions in nuclear physics and astrophysics.
Article
Mathematics, Applied
Jacky Chong, Manoussos Grillakis, Matei Machedon, Zehua Zhao
Summary: This paper proves that a certain Sobolev-type norm, slightly stronger than those given by energy conservation, remains uniformly bounded in time and N, enabling the extension of local existence results globally in time. The proof is based on interaction Morawetz-type estimates and Strichartz estimates, introducing a new dispersive estimate in mixed coordinates which may have independent interest.
COMMUNICATIONS IN PARTIAL DIFFERENTIAL EQUATIONS
(2021)
Article
Physics, Nuclear
Shilpa Rana, Raj Kumar, M. Bhuyan
Summary: The synthesis of isotopes Z = 120 is a crucial and exciting area of research in nuclear physics. Theoretical investigations using the relativistic mean-field formalism have predicted potential projectile-target combinations for the synthesis of element Z = 120. The increase in fusion cross section in superheavy nuclei indicates nuclear shell effects and provides important information for future experiments.
Article
Physics, Nuclear
J. Peng, Q. B. Chen
Summary: Self-consistent solutions for chiral rotation in Rh102-107 rhodium isotopes are obtained using the three-dimensional tilted axis cranking covariant density functional theory. The direction of angular momenta is determined self-consistently by minimizing the total Routhian surface calculations. It is found that the critical rotational frequency for the appearance of chiral aplanar rotation decreases when neutrons are added.
Article
Physics, Multidisciplinary
Sameena Murtaza, G. Gangopadhyay
Summary: The role of pairing in neutron-deficient Yb isotopes has been studied using the Hartree-Fock-Bogoliubov (HFB) approach and the SLy6 energy functional. A reasonably good description of the observed ground-state properties was obtained. Cranking solutions were found for the rotational bands, and neutron pair breaking was shown to play a major role above spin J = 14.
PRAMANA-JOURNAL OF PHYSICS
(2023)
Article
Multidisciplinary Sciences
Inbar Seroussi, Gadi Naveh, Zohar Ringel
Summary: Deep neural networks (DNNs) have complex structures, making direct microscopic analysis difficult. However, by identifying slow variables that average the behavior of fast variables, the authors have found a similar scale separation in finite deep convolutional neural networks and fully connected networks. They show that DNN layers couple through the second cumulant of their activations and pre-activations, which fluctuate in a Gaussian manner. The resulting thermodynamic theory of deep learning provides accurate predictions and new ways to understand DNNs.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
F. Mercier, J. Zhao, J-P Ebran, E. Khan, T. Niksic, D. Vretenar
Summary: A microscopic calculation of half-lives for the alpha and 2 alpha decays of Po-212 and Ra-224 was performed using a self-consistent framework based on energy density functionals. The calculated half-lives for the alpha decay of Po-212 and Ra-224 are in good agreement with experimental data. A new decay mode, symmetric 2 alpha emission, with half-lives similar to cluster emission, was predicted.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Z. X. Ren, D. Vretenar, T. Niksic, P. W. Zhao, J. Zhao, J. Meng
Summary: This study examines the process of nuclear fission, focusing on the formation and scission mechanism of a neck between the nascent fragments. By using time-dependent density functional theory, it is found that the assembly of two α-like clusters coincides with the formation of the neck. During scission, the neck ruptures between the two α-like clusters, and light charged clusters are formed. The findings provide insights into the mechanism of nuclear fission and its potential connection to ternary fission.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Nuclear
B. Li, D. Vretenar, Z. X. Ren, T. Niksic, J. Zhao, P. W. Zhao, J. Meng
Summary: The saddle-to-scission dynamics of induced fission process is investigated using a microscopic finite temperature model based on time-dependent nuclear density functional theory (TDDFT), which allows the tracking of local temperature evolution along the fission trajectories. By starting from a temperature corresponding to the experimental excitation energy of the compound system, nucleons are propagated along isentropic paths towards scission. The study focuses on the energy partitioning at scission, including dissipated energy along the fission path and the prescission kinetic energy, for four illustrative cases of induced fission. The model is also applied to the dynamics of neck formation and rupture, characterized by the formation of few-nucleon clusters in the low-density region between the nascent fragments.
Article
Physics, Nuclear
Y. Beaujeault-Taudiere, M. Frosini, J. -p. Ebran, T. Duguet, R. Roth, V. Soma
Summary: Ab initio approaches to the nuclear many-body problem have been extended, and a numerically efficient method for calculating electromagnetic response functions in superfluid and deformed nuclei is presented. This work allows systematic ab initio calculations of nuclear responses to electroweak probes across a significant portion of the nuclear chart.
Article
Physics, Nuclear
Jie Zhao, Tamara Niksic, Dario Vretenar
Summary: This model calculates the total kinetic energy distribution of fission fragments using the time-dependent generator coordinate method extended to include dissipation effects. It computes the integrated flux of probability current and the kinetic energy at scission for a specific pair of fragments to determine the TKE distribution.
Article
Physics, Multidisciplinary
F. Mercier, J. Zhao, J-P Ebran, E. Khan, T. Niksic, D. Vretenar
Summary: In this study, half-lives calculations for alpha decay of Po-212 and Ra-224 were performed using a microscopic self-consistent framework. The results showed good agreement with experimental values. Additionally, a new decay mode consisting of symmetric 2 alpha emission was predicted.
NUOVO CIMENTO C-COLLOQUIA AND COMMUNICATIONS IN PHYSICS
(2022)
Article
Physics, Nuclear
Jie Zhao, Tamara Niksic, Dario Vretenar
Summary: This study combines quantum theory of dissipation and time-dependent generator coordinate method (TDGCM) to incorporate dissipation effects in the description of induced fission dynamics. By accounting for the dissipation of energy from collective motion into intrinsic degrees of freedom through the addition of an extra term in the Hamiltonian, the effectiveness of this approach is demonstrated through a calculation of induced fission in Th-228.
Article
Physics, Nuclear
Z. X. Ren, J. Zhao, D. Vretenar, T. Niksic, P. W. Zhao, J. Meng
Summary: The dynamics of low-energy-induced fission is studied using a consistent microscopic framework that combines the time-dependent generator coordinate method and time-dependent nuclear density functional theory. Two methods based on the same nuclear energy density functional and pairing interaction are employed in an illustrative study of 240Pu induced fission. Fission observables are calculated and compared with available data.
Article
Physics, Nuclear
F. Mercier, J-P Ebran, E. Khan
Summary: This paper presents a systematic analysis of the low-energy monopole strength in different isotopic chains. The results show that the nature of these excitations varies with neutron excess and deformation, resulting in different modes such as cluster vibrations, downshifted components of the giant resonance, and pair excitations.
Article
Physics, Nuclear
D. D. Zhang, Z. X. Ren, P. W. Zhao, D. Vretenar, T. Niksic, J. Meng
Summary: The effects of rotation and valence nucleons in molecular linear alpha-chain nuclei are analyzed using a three-dimensional lattice cranking model based on covariant density functional theory. The study reveals that with increasing rotational frequency, the valence nucleons transition from the pi molecular orbital to the sigma molecular orbital, thus stabilizing the 3 alpha linear chain structure. The research also shows that the transition frequencies for valence protons and neutrons differ in different nuclei.
Article
Physics, Nuclear
Jie Zhao, Tamara Niksic, Dario Vretenar
Summary: The role of dynamical pairing in induced fission dynamics was investigated using the time-dependent generator coordinate method, showing a pronounced effect on collective inertia and collective flux, leading to reduced asymmetric peaks and enhanced symmetric fission yields in better agreement with empirical trends.
Article
Physics, Nuclear
K. Nomura, D. Vretenar, Z. P. Li, J. Xiang
Summary: The study investigates the effect of coupling between pairing and quadrupole triaxial shape vibrations on low-energy collective states of gamma-soft nuclei. By simultaneously considering both the shape and pairing collective degrees of freedom, the EDF-based IBM successfully reproduces data on low-energy 0(+) states and gamma-vibrational bands.
Article
Physics, Nuclear
K. Nomura, D. Vretenar, Z. P. Li, J. Xiang
Summary: This study addresses the long-standing problem of the simultaneous description of shape oscillations and pairing vibrations in deformed nuclei, using self-consistent mean-field calculations and the framework of the interacting boson approximation. Explicit coupling to pairing vibrations is taken into account, showing the importance of dynamical pairing degrees of freedom in low-energy excited states of gamma-soft and triaxial nuclei, as illustrated for Xe-128 and Xe-130.
Article
Physics, Nuclear
K. Nomura, L. Lotina, T. Niksic, D. Vretenar
Summary: The study shows the presence of octupole-deformed equilibrium states in the potential energy surfaces of Ba and Ce isotopes with N approximately equal to 56 and 88. The evolution of spectroscopic properties indicates enhanced octupole correlations in regions corresponding to N approximately equal to Z approximately equal to 56, Z approximately equal to 88, and Z approximately equal to 56, and N approximately equal to 56 and Z approximately equal to 34.
Article
Physics, Nuclear
F. Mercier, A. Bjelcic, T. Niksic, J-P Ebran, E. Khan, D. Vretenar
Summary: This study investigates the isoscalar low-energy response of N = Z nuclei using the finite amplitude method based on the microscopic nuclear energy density functionals framework. The low-energy strength functions exhibit prominent peaks attributed to cluster mode structures in light nuclei with large deformation, depending on the multipolarity of the excitation and equilibrium deformation of specific isotopes.
