Nuclear Theory·nucl-th

Tuesday·October 31, 2023

26 papers—12 primary·14 cross-listed

01
[Submitted on 28 Oct 2023]
Uncertainty Quantification-Enabled Inversion of Nuclear Euclidean Responses
K. Raghavan · A. Lovato
Nuclear quantum many-body methods rely on integral transform techniques to infer properties of electroweak response functions from ground-state expectation values. Retrieving the energy dependence of these responses is highly non-trivial, especially for quantum Monte Carlo methods, as it requires inverting the Laplace transform -- a notoriously ill-posed problem. In this work, we propose an artificial neural network architecture suitable for accurate response function reconstruction with precise estimation of the uncertainty of the inversion. We demonstrate the capabilities of this new architecture benchmarking it against Maximum Entropy and previously developed neural network methods designed for a similar task, paying particular attention to its robustness against increasing noise in the input Euclidean responses.
Comments:
11 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2310.18756 [pdf]
PRC(2024)·5 citations
02
[Submitted on 29 Oct 2023]
Large-scale shell-model study of two-neutrino double-beta decay of $^{82}$ Se, $^{94}$ Zr, $^{108}$ Cd, $^{124}$ Sn, $^{128}$ Te, $^{130}$ Te, $^{136}$ Xe, and $^{150}$ Nd
Deepak Patel🇮🇳 · Praveen C. Srivastava🇮🇳 · V.K.B. Kota🇮🇳 · R. Sahu🇮🇳
Large-scale shell-model calculations have been performed for the study of two neutrino double-beta ( $2 ν β β$ ) decay in $^{82}$ Se, $^{94}$ Zr, $^{108}$ Cd, $^{124}$ Sn, $^{128}$ Te, $^{130}$ Te, $^{136}$ Xe, and $^{150}$ Nd. We have employed JUN45 interaction to calculate the nuclear matrix element (NME) for $2 ν β β$ decay in $^{82}$ Se. In the case of $^{94}$ Zr, the glekpn effective interaction is used. For $^{108}$ Cd, we have used a realistic effective interaction derived through the G-matrix approach. In the case of $^{124}$ Sn, $^{128, 130}$ Te and $^{136}$ Xe, the sn100pn effective interaction is employed. For $^{150}$ Nd, we have used KHHE effective interaction based on holes in a $^{208}$ Pb core. We have extracted the half-lives of these nuclei for the $2 ν β β$ decay with the help of calculated NME. Our results are consistent with the available experimental half-lives. The variation of cumulative $2 ν β β$ NME with respect to the excitation energy of the intermediate $1^{+}$ states is also shown, and in all cases, it is ensured that their values are almost saturated. In the present work we have calculated more intermediate $1^{+}$ states as much as possible in comparison to results available in the literature.
Comments:
17 pages, 2 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2310.19015 [pdf]
NPA(2024)·9 citations
03
[Submitted on 30 Oct 2023]
Electromagnetic current operators for phenomenological relativistic models
Wayne Polyzou🇺🇸
Background: Phenomenological Poincaré invariant quantum mechanical models can provide an efficient description of the dynamics of strongly interacting particles that is consistent with spectral and scattering observables. These models are representation dependent and in order to apply them to reactions with electromagnetic probes it is necessary to have a consistent electromagnetic current operator. Purpose: The purpose of this work is to use local gauge invariance to construct consistent strong current operators. Method: Current operators are constructed from a model Hamiltonian by replacing momentum operators in the Weyl representation by gauge covariant derivatives. Results: The construction provides a systematic method to construct explicit expressions for current operators that are consistent with relativistic models of strong interaction dynamics.
Comments:
31 pages, contribution to 25-th European Conference on Few Body Problems Physics, Mainz
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2310.19243 [pdf]
Few Body Syst.(2024)·2 citations
04
[Submitted on 30 Oct 2023]
Hartree-Fock Formulation of the QMC Model at Finite Temperature
P A M Guichon🇫🇷 · J R Stone🇺🇸 · A W Thomas🇦🇺
We present, for the first time, a detailed theory of high density matter including the entire baryon octet at finite temperature, based on a fully relativistic mean field model with a consistent treatment of exchange (Fock) terms, using the quark-meson-coupling model (QMC). It has been already demonstrated that the QMC equation of state is applicable in thermodynamic scenarios in stationary and rotating isentropic proto-neutron stars, producing results in agreement with recent observation. It is also suitable for the simulation of the behavior following a binary neutron star merger [1]; https://compose.obspm.fr/eos/205. We develop a comprehensive demonstration of the impact of the Fock terms in the QMC energy density functional on properties of neutrinoless proto-neutron stars with cores containing the full hyperon octet with constant entropy, S/A=2kB. Given the interest in the properties of the proto-neutron star remaining after either a supernova explosion or the merger of two neutron stars, it is vital to develop modern equations of state at finite temperature. While much attention has been paid to relativistic mean-field calculations at finite temperature, it is crucial to explore the consequences of a consistent treatment of the Fock terms.
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2310.19262 [pdf]
PRD(2024)·6 citations
05
[Submitted on 30 Oct 2023]
Eigenvector Continuation and Projection-Based Emulators
Thomas Duguet🇫🇷 · Andreas Ekström🇸🇪 · Richard J. Furnstahl🇺🇸 · Sebastian König🇺🇸 · Dean Lee🇺🇸
Eigenvector continuation is a computational method for parametric eigenvalue problems that uses subspace projection with a basis derived from eigenvector snapshots from different parameter sets. It is part of a broader class of subspace-projection techniques called reduced-basis methods. In this colloquium article, we present the development, theory, and applications of eigenvector continuation and projection-based emulators. We introduce the basic concepts, discuss the underlying theory and convergence properties, and present recent applications for quantum systems and future prospects.
Comments:
Final version to appear as colloquium article in Rev. Mod. Phys., 22 pages, 17 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); cs.NA (cs.NA); math.NA (math.NA); Nuclear Experiment (nucl-ex); Quantum Physics (quant-ph)
arXiv:
2310.19419 [pdf]
RMP(2024)·84 citations
06
[Submitted on 30 Oct 2023]
Revision of Analytical Properties of Reaction Amplitude near Thresholds Using the Example of Muon-Induced Prompt Fission
F.F. Karpeshin
Experimental data on the muon-induced prompt fission are analyzed and compared to theory. Good agreement is observed for the 2p to 1s and 3d to 1s transitions. Anomalously big nonradiative width in the case of 3d to 1s transition is surprised. Ways of resolving this puzzle are discussed.
Comments:
6 pages. To be published in ISINN-29 Proceedings
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2310.19421 [pdf]
1 citation
07
[Submitted on 30 Oct 2023]
Intersections of ultracold atomic polarons and nuclear clusters: How is a chart of nuclides modified in dilute neutron matter?
Hiroyuki Tajima · Hajime Moriya · Wataru Horiuchi · Eiji Nakano · Kei Iida
Neutron star observations, as well as experiments on neutron-rich nuclei, used to motivate one to look at degenerate nuclear matter from its extreme, namely, pure neutron matter. As an important next step, impurities and clusters in dilute neutron matter have attracted special attention. In this paper, we review in-medium properties of these objects on the basis of the physics of polarons, which have been recently realized in ultracold atomic experiments. We discuss how such atomic and nuclear systems are related to each other in terms of polarons. In addition to the interdisciplinary understanding of in-medium nuclear clusters, it is shown that the quasiparticle energy of a single proton in neutron matter is associated with the symmetry energy, implying a novel route toward the nuclear equation of state from the neutron-rich side.
Comments:
28 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Quantum Gases (cond-mat.quant-gas)
arXiv:
2310.19422 [pdf]
AAPPS Bull.(2025)·10 citations
08
[Submitted on 30 Oct 2023]
At the edge of shape coexistence in the Z=40 region
Esperanza Maya-Barbecho · Samira Baid · José-Manuel Arias · José-Enrique García-Ramos
In this contribution, the shape coexistence phenomenon near the proton sub-shell closure at Z=40 is analyzed. Particular emphasis is placed on extracting the nuclear deformation values by examining experimental B(E2) transition rates and observing how the kinematic moment of inertia evolves in these nuclei. Based on the analysis of these two observables, we arrive at the conclusion that the notable effects of shape coexistence at approximately Z=40 are largely diminished in Mo isotopes and are scarcely detectable in Ru isotopes.
Comments:
To appear in the CGS-17 2023 proceedings, 3 pages
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2310.19458 [pdf]
EPJ Web Conf.(2025)·0 citations
09
[Submitted on 30 Oct 2023]
The 5-dimensional Langevin approach to fission of atomic nuclei
F.A.Ivanyuk · C.Ishizuka · S.Chiba
We have generalized the four-dimensional Langevin approach used in our previous works for the description of fission process to the five-dimensional by considering the neck parameter $\eps$ in the two-center shell model shape parametrization as an independent dynamical variable. The calculated results for the mass distribution of fission fragments are in better agreement with the available experimental data. In particular, the transition from the mass-symmetric to mass-asymmetric fission via the triple-humped distribution in fission of Thorium isotopes is well reproduced.
Comments:
9 pages, 11 figures, submitted to PRC
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2310.19466 [pdf]
PRC(2024)·15 citations
10
[Submitted on 30 Oct 2023]
First-forbidden transition of nuclear $β$ decay by projected shell model
Bin-Lei Wang · Long-Jun Wang
The first-forbidden transition of nuclear $β$ decay is expected to play crucial roles in many aspects in nuclear physics, nuclear astrophysics and particle physics such as the stellar $β$ -decay rates and the reactor anti-neutrino spectra. In this work we develop the projected shell model (PSM) for description of first-forbidden transition of nuclear $β$ decay for the first time. Detailed theoretical framework and logics are provided, and 35 dominant first-forbidden transitions that are expected to be important for the reactor anti-neutrino spectra problems are calculated and compared systematically with the data to test the new development of the PSM. The corresponding experimental Log $f_{0} t$ values are described reasonably, and the quenching factors of nuclear matrix elements are found to affect the Log $f_{0} t$ values as well as the related shape factors, which may be helpful for better understanding of the reactor anti-neutrino spectra problems.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2310.19523 [pdf]
PLB(2024)·16 citations
11
[Submitted on 30 Oct 2023]
Scalar field, nucleon structure and relativistic chiral theory for nuclear matter
Guy Chanfray🇫🇷
The work that Peter Schuck and I carried out during the nineties in collaboration with the Lyon and Darmstadt theory groups is summarized. I retrace how our theoretical developments combined with experimental results concerning the in-medium modification of the pion-pion interaction allowed a clarification of the chiral status of the sigma meson introduced in relativistic theories of nuclear matter. This enabled us to build a relativistic chiral theory, now called the chiral confining model of nuclear matter, which includes the effect of the nucleon substructure, namely the response of the nucleon to the nuclear scalar field generating an efficient and natural contribution to the saturation mechanism. Using parameters from a QCD-connected version of the chiral confining model, I describe the relative roles of the chiral scalar field and two-pion (or two-rho) exchange for the in-medium $N N$ attractive interaction and the associated sources of three-body interactions needed for the saturation mechanism.
Comments:
16 pages, 8 figures. arXiv admin note: text overlap with arXiv:2307.03484
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2310.19532 [pdf]
EPJA(2024)·10 citations
12
[Submitted on 30 Oct 2023]
Expansion of one-, two- and three-body matrix elements on a generic spherical basis for nuclear ab initio calculations
Alberto Scalesi🇫🇷 · Carlo Barbieri🇮🇹 · Enrico Vigezzi🇮🇹
Ab initio studies of atomic nuclei are based on Hamiltonians including one-, two- and three-body operators with very complicated structures. Traditionally, matrix elements of such operators are expanded on a Harmonic Oscillator single-particle basis, which allows for a simple separation of the center-of-mass motion from the intrinsic one. A few recent investigations have showed that the use of different single-particle bases can bring significant advantages to numerical nuclear structure computations. In this work, the complete analytical expression of the Hamiltonian matrix elements expanded on a generic spherical basis is presented for the first time. This will allow systematic studies aimed at the determination of optimal nuclear bases.
Comments:
42 pages, 1 figure
Subjects:
Nuclear Theory (nucl-th); Mathematical Physics (math-ph); math.MP (math.MP); Quantum Physics (quant-ph)
arXiv:
2310.19547 [pdf]
Annals Phys.(2024)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE