Nuclear Theory·nucl-th

Monday·June 8, 2026

12 papers—6 primary·6 cross-listed

01
Microscopic formulation of the interacting boson-fermion model using the nuclear energy density functional
M. Homma · K. Nomura
Microscopic modeling of low-energy spectroscopy in medium-heavy and heavy odd- $A$ nuclei is an outstanding open problem in nuclear physics. We propose a novel spectra-generating collective model for odd- $A$ nuclei constructed by means of the nuclear energy density functional theory and the interacting boson-fermion model. The bosonic Hamiltonian for an even-even nucleus, which is treated as a core, and the strength parameters for the interactions between the core and an odd nucleon are completely determined by using as microscopic inputs the potential energy curves and deformed single-particle spectra obtained from the self-consistent mean-field calculations. In applications to odd- $A$ Eu, Sm, La, and Ba isotopes, we demonstrate the validity of the proposed method in reproducing reasonably the observed low-energy spectra and shape phase transitions in the general cases of the quadrupole collective states, that is, nearly spherical, strongly deformed, and $γ$ -soft shapes, in the presence of an odd nucleon in a single- $j$ orbit.
nucl-thnucl-exPRC(2026)·0 citations
02
Solution of the Equation-of-Motion Phonon Method eigenvalue problems on the D-Wave quantum annealer
C. De Lucia🇮🇹 · A. Martone🇮🇹 · F.A. D'Aniello🇮🇹 · A. Mastroianni🇮🇹 · G. Nunziata🇮🇹 · G. De Gregorio🇮🇹 · R. Folprecht🇨🇿 · F. Knapp🇨🇿 · N. Lo Iudice🇲🇽 · P. Vesely🇨🇿
The solution of large-scale eigenvalue problems is crucial in nuclear many-body theory, where Hamiltonian matrices often reach extremely large dimensions. Quantum computing opens new perspectives for addressing such demanding problems. Although the Quantum Phase Estimation algorithm offers, in principle, a systematic route to matrix diagonalization, its practical deployment demands levels of coherence and error correction that current quantum hardware cannot yet support. A viable near-term strategy is instead to exploit quantum annealing, which enables the recasting of eigenvalue problems into quadratic unconstrained binary optimization formulations that can be addressed by existing annealing-based processors. Here, we propose a hybrid quantum-classical algorithm that combines quantum annealing and classical deflation to iteratively extract the full eigenspectrum of both standard and generalized eigenvalue problems. We benchmark this method on eigenvalue problems arising from the Equation of Motion Phonon Method performing calculations on real quantum hardware. Our approach illustrates the capabilities and limitations of near-term quantum devices in addressing nuclear eigenvalue problems.
nucl-thquant-phPRC(2026)·0 citations
03
External-Field-Assisted Muon Reactivation in Muon-Catalyzed Fusion: A Rate-Network Criterion for Reducing Alpha Sticking
Wei Kou · Xurong Chen
Alpha sticking is a major loss channel in deuterium--tritium muon-catalyzed fusion. We study whether an additional external-field-assisted stripping channel can reduce the residual sticking loss after conventional collisional reactivation. The external contribution is written as $R_{X} = f_{X} P_{X} η_{X}$ , where $f_{X}$ is the space--time overlap between the external field and the residual stuck $(α μ)^{+}$ population, $P_{X}$ is the microscopic stripping probability, and $η_{X}$ is the probability that the stripped $μ^{-}$ is returned to the $d μ / t μ \to d t μ$ fusion cycle before escape or decay. This gives $ω_{S}^{eff} = ω_{S}^{0} (1 - R_{col}) (1 - R_{X})$ and leads directly to a probability-level no-go condition, $η_{X}^{crit} > 1$ , for any target improvement requiring more recycling than is probabilistically available. We construct an energy-resolved post-stripping rate network including slowing down, atomic capture, free escape, muon decay, atomic-stage loss, ordinary molecular formation, and an effective resonant $d t μ$ channel. Benchmark scans show that the useful regime is a transport window: the stripped muon must be confined and recycled efficiently. With the reference inputs used here, the best-performing scenario increases the cycle yield from $N_{fus, μ} = 112.6$ in the collision-only case to $N_{fus, μ} = 156.5$ . Resonant molecular formation suppresses atomic-stage loss and broadens the high-recycling region, but it cannot compensate for prompt escape or poor field--population overlap. The rate network therefore identifies the transport and overlap conditions required for external-field-assisted reactivation to reduce residual alpha sticking.
nucl-th1 citation
04
Impact of Shape Coexistence on Nuclear Stability
G. Saxena · H. Sikhwal · N. Chandnani · Pranali Parab · Siddharth Parashari · Gabriela Llosá · Mamta Aggarwal
Nuclear decay properties are conventionally predicted assuming nuclei decay from their ground-state configurations. However, this often neglects a fundamental structural complexity which is the phenomenon of shape coexistence, where nuclei possess multiple competing configurations at nearly degenerate energies. When both parent and daughter nuclei can exist in different energy minima, multiple decay pathways become possible. We systematically investigate how shape coexistence influences nuclear decay for approximately 1500 even-even nuclei ( $8 \leq Z \leq 118$ , $8 \leq N \leq 184$ ) using the Nilsson-Strutinsky method and relativistic mean-field calculations with NL3 $^{*}$ , DD-ME2, and DD-PC1 functionals. We identify around 400 nuclei exhibiting competing energy minima separated by less than 1 MeV. For these shape-coexisting nuclei, we calculate $α$ , $β^{+}$ and $β^{-}$ decay half-lives considering all possible transition pathways between the competing minima. Our results demonstrate that shape coexistence substantially impacts decay predictions, with half-lives showing variations up to nearly one logarithmic unit depending on which configurations participate in the transition. Comparison with experimental data from NUBASE2020 shows that pathways involving the second minimum sometimes reproduce measured lifetimes more closely than conventional ground-state to ground-state assumptions. Branching ratios exhibit even stronger sensitivity, with certain nuclei displaying complete inversions of the dominant decay mode depending on configuration choice. These pathway-dependent variations are not due to model uncertainties but reflect inherent structural effects. The correlation between the shape dynamics and nuclear stability establishes the shape coexistence as an essential component in predictive nuclear structure and astrophysics studies.
nucl-thPLB(2026)·0 citations
05
Probing exotic multi-proton emitters: A Gamow shell model study of proton-rich fluorine and neon isotopes beyond the drip line
N. Chen · J. G. Li · M. R. Xie · P. Y. Wang · K. H. Li · Q. Yuan · N. Michel
We investigate proton-rich systems beyond the proton drip line, focusing on the notably poorly known 13F and 15Ne and the yet unobserved 14Ne, whose structure properties remain weakly constrained. Using the Gamow shell model (GSM), which consistently incorporates both inter-nucleon correlations and couplings to the particle continuum, we study oxygen, fluorine, and neon isotopes with mass A=12-16. Taking 8C as an inert core, the GSM Hamiltonian based on an effective field theory nucleon-nucleon interaction is optimized for this proton-rich region. The constructed Hamiltonian reproduces the low-lying spectra and decay properties of fluorine and neon isotopes beyond the proton drip line. We quantify many-body configuration and average partial-wave occupancies to elucidate the structural evolution of the drip line nuclei 12-14O, 13-15F, and 14-16Ne. In particular, multi-proton separation energies and spectroscopic factors are analyzed in detail, leading to a prediction for the unresolved ground state of 13F. Furthermore, the candidate 4p emitter 14Ne is theoretically predicted for the first time, providing valuable guidance for future experimental investigations.
nucl-thPLB(2026)·1 citation
06
Proton and Neutron Elastic Scattering on He Targets from $Ab Initio$ SA-NCSM Optical Potentials
Darin C. Mumma · Matthew B. Burrows · Kristina D. Launey · Daniel Langr · Tomas Dytrych
We construct and discuss $ab initio$ nucleon-nucleus optical potentials at low energies for $^{3, 4, 6}$ He targets. In this work, we use the $ab initio$ SA-NCSM/GF approach that combines the $ab initio$ symmetry-adapted no-core shell model with the Green's function technique to construct optical potentials, and extend this formulation to proton scattering and targets with nonzero spin. We show that these optical potentials reproduce experimental differential cross sections and phase shifts for proton and neutron elastic scattering remarkably well. The $ab initio$ SA-NCSM/GF approach provides nonlocal, energy dependent and dispersive optical potentials, suitable for the astrophysically relevant regime of low energies and for exotic nuclei, where experiments are difficult and data is often unavailable.
nucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Microscopic formulation of the interacting boson-fermion model using the nuclear energy density functional

Solution of the Equation-of-Motion Phonon Method eigenvalue problems on the D-Wave quantum annealer

External-Field-Assisted Muon Reactivation in Muon-Catalyzed Fusion: A Rate-Network Criterion for Reducing Alpha Sticking

Impact of Shape Coexistence on Nuclear Stability

Probing exotic multi-proton emitters: A Gamow shell model study of proton-rich fluorine and neon isotopes beyond the drip line

Proton and Neutron Elastic Scattering on He Targets from Ab Initio SA-NCSM Optical Potentials

Affiliations

Proton and Neutron Elastic Scattering on He Targets from $Ab Initio$ SA-NCSM Optical Potentials