An end-to-end strategy for hybrid quantum-classical computations of Green's functions in many-body systems is presented and applied to the pairing model. The scheme makes explicit use of the spectral representation of the Green's function, which entails the calculation of the $N$-body ground state as well as eigenstates and associated energies of the $(N\pm 1)$-body neighbors. While the former is accessed via variational techniques, the latter are constructed by means of the quantum subspace expansion method. Different ansatzes for the ground-state wave function, originating from either classical or quantum approaches, are tested and compared to exact calculations. The resulting one-body Green's functions prove to be accurate approximations of the exact one for a large range of parameters, including across the normal-to-superfluid transition. As a by-product, this approach yields a good description of odd systems provided that the starting even system is well reproduced by the variational ansatz.

Low-energy dipole excitations in ${}^{166}\mathrm{Er}$ were investigated via nuclear resonance fluorescence using a quasimonoenergetic, linearly polarized photon beam produced at the High Intensity $\gamma$-ray Source ($\mathrm{HI}\gamma \mathrm{S}$) facility at Duke University. The parity of the excited states was determined from the azimuthal asymmetry in the intensities of resonantly scattered $\gamma$ rays with respect to the polarization plane of the incident beam. Electric and magnetic dipole strengths were extracted for excitation energies between 2.2 and 3.5 MeV. The results are interpreted in terms of the nuclear scissors mode by comparing with large-scale shell-model calculations based on the Quasiparticle Vacua Shell Model. In addition, the characteristics of the $E1$ excitations are examined in comparison with those of neighboring rare-earth nuclei to explore their relations to collective two-phonon excitations of octupole and $\gamma$ modes.

High-precision lifetime measurements of the $4_1^{+}$ and $6_1^{+}$ states in ${}^{92}\mathrm{Mo}$ and ${}^{94}\mathrm{Ru}$ are performed following the ${}^{36}\mathrm{Ar} + {}^{64}\mathrm{Zn}$ fusion-evaporation reaction, employing a novel delayed-gated ${\mathrm{LaBr}}_3$ triple-$\gamma$ coincidence method. The lifetime of $4_1^{+}$ is determined to be 33(5) ps for ${}^{92}\mathrm{Mo}$ and 70(4) ps for ${}^{94}\mathrm{Ru}$, respectively. Our data confirm the anomalous enhancement of $B(E2;4^{+}\to 2^{+})$ in ${}^{94}\mathrm{Ru}$ versus previously known suppression in ${}^{96}\mathrm{Pd}$. Shell-model calculation in the $f_{5}p{g}_9$ model space with the monopole-based universal interaction demonstrates that rescaling off-diagonal two-body matrix elements reproduces all the $B(E2;4^{+}\to 2^{+})$ strengths without perturbing the others such as $B(E2;6^{+}\to 4^{+})$ and $B(E2;8^{+}\to 6^{+})$, identifying the significant influence of cross-orbital off-diagonal matrix elements on $B\left(E2\right)$ strengths as well as the underlying partial seniority symmetry breaking.

Isomer depletion via the process of nuclear excitation by inelastic electron scattering is investigated theoretically. A comprehensive study on low-energy nuclear excitations by inelastic electron scattering is performed to analyze the impact of the nuclear and ion charge, the nuclear transition energy, and the nuclear transition multipolarity on the cross section of the process. We apply the analysis to the case of isomer depletion, in which an excitation from the isomeric state to a nuclear level above the isomeric state can lead to decay to a nuclear level below the isomer itself and hence lead to the release of the energy stored in the isomer. For this purpose, the isomer depletion of ${}^{93\mathrm{m}}\mathrm{Mo}$, ${}^{152\mathrm{m}}\mathrm{Eu}$, and ${}^{178\mathrm{m}}\mathrm{Hf}$, which represent the most important scenarios of isomer depletion, are studied. Our results demonstrate the capability of the process of nuclear excitation by inelastic electron scattering for isomer depletion.

The level structure of ${}^{209}\mathrm{Po}$ has been studied by in-beam $\gamma$-ray spectroscopy with the ${}^{209}\mathrm{Bi}\left({}^6\mathrm{Li},\alpha 2n\right){}^{209}\mathrm{Po}$ reaction at beam energies of 28, 30, 34 MeV. The level scheme of ${}^{209}\mathrm{Po}$ is expanded by the $\gamma \text{−}\gamma$ coincidence measurement, where 27 new transitions and 23 new levels are observed. The lifetimes of $13/2^{-}$, $17/2^{-}$, and $23/2^{+}$ states are obtained and are consistent with the previous work, while the one of the $13/2^{+}$ state is measured for the first time. A configuration-interaction-shell-model calculation is performed, and its results are compared with the experimental results for ${}^{209}\mathrm{Po}$, with an emphasis on the coupling between the single valence neutron hole and the even-even core of ${}^{210}\mathrm{Po}$. A systematic comparison of the $13/2^{+}$ state in N = 125 chain is also studied in the current work.

Recent experiments on $\alpha$ decay of odd-odd superheavy nuclei give important information on the structure of the low-lying states of these nuclei. For this reason it is interesting to calculate the excitation spectra of these superheavy nuclei and compare the results with the experimental data. The aim of this work is to calculate the excitation energies of the two-quasiparticle states of nuclei belonging to the $\alpha$-decay chain of ${}^{288}\mathrm{Mc}$. The approximation of the noninteracting quasiparticles based on the Woods-Saxon single-particle potentials is used. Different sets of deformation parameters are considered. The spectra of the low-lying two-quasiparticle states are calculated. The $\alpha$-decay spectra of nuclei belonging to the $\alpha$-decay chain of ${}^{288}\mathrm{Mc}$ are obtained and compared with the experimental data. A possibility of the $E1$ transitions in ${}^{276}\mathrm{Mt}$ and ${}^{272}\mathrm{Bh}$ following $\alpha$ decay of ${}^{288}\mathrm{Mc}$ is considered. It is shown that the $E1$ transitions in ${}^{276}\mathrm{Mt}$ can be related to the transition $\pi \left[505\right]9/2\to \pi \left[615\right]11/2$. In ${}^{272}\mathrm{Bh}$ the $E1$ transition can be related to the neutron single-quasiparticle states.

We extract Compton form factors (CFFs) from deeply virtual Compton scattering measurements at the Thomas Jefferson National Accelerator Facility (JLab) using quantum-inspired deep neural networks (QDNNs). The analysis implements the twist-2 Belitsky-Kirchner-Müller formalism and employs a fitting strategy that emulates standard local fits. Using pseudodata, we benchmark QDNNs against classical deep neural networks (CDNNs) and find that QDNNs often deliver higher predictive accuracy and tighter uncertainties at comparable model complexity. Guided by these results, we introduce a quantitative selection metric that indicates when QDNNs or CDNNs are optimal for a given experimental fit. After obtaining local extractions from the JLab data, we perform a standard neural-network global CFF fit and compare with previous global analyses. The results support QDNNs as an efficient and complementary tool to CDNNs for CFF determination and for future multidimensional studies of parton distributions and hadronic structure.

The parity-violating spin asymmetry $A_{\mathrm{pv}}$ for elastic electron scattering from spin-zero nuclei, together with its QED corrections, is evaluated nonperturbatively within the phase-shift analysis. Dispersion corrections, taking into account low-lying transient nuclear excitations, are estimated with the help of the lowest-order $\gamma Z$ box diagrams. Collision energies in the range $5–500$ MeV are considered, and results are provided for the ${}^{12}\mathrm{C}$ and ${}^{208}\mathrm{Pb}$ target nuclei. In addition, we have evaluated $A_{\mathrm{pv}}$ at GeV energies and small scattering angles—relevant for the Pb Radius Experiment (PREx)—revealing that the low-lying nuclear excited states give no measurable dispersive contribution. However, they are important at lower energies and backward angles.

Background: The rapid cooling observed in the Cassiopeia A neutron star (Cas A NS) provides one of the most stringent tests for neutron star cooling theory. While the Cooper-pair breaking and formation (PBF) neutrino emission process is a leading candidate, significant theoretical uncertainties remain regarding both the PBF efficiency factor $q$ and the neutron ${}^{3}P_2$ pairing gap.

Purpose: This work aims to explore, in a data-driven manner, how the optimized shape of the neutron ${}^{3}P_2$ pairing gap responds to variations of the phenomenological PBF emissivity parameter $q$ within a fixed and controlled cooling setup.

Methods: We introduce a novel parametrization of the neutron ${}^{3}P_2$ pairing gap, in which each parameter carries direct physical meaning, allowing independent control of the gap amplitude, peak location, width, and asymmetry. Using a newly developed Fortran-based neutron star cooling code and the BSk24 equation of state, we perform systematic parameter-space exploration guided by the Cas A NS observational data. Global optimization is carried out with Optuna's tree-structured Parzen estimator, followed by local refinement using the Nelder-Mead simplex method. Both single-objective optimizations based solely on ${\chi }^2$ and multiobjective optimizations that combine ${\chi }^2$ with a slope-difference metric are examined under identical conditions.

Results: The optimized solutions yield physically reasonable neutron ${}^{3}P_2$ pairing gaps with peak amplitudes ${\mathrm{\Delta }}_{max}\approx 0.5–0.6\mathrm{MeV}$. While the multiobjective formulation explores the parameter space more broadly, the single-objective (${\chi }^2$-only) optimization finally achieves the lowest ${\chi }^2$, reflecting the intrinsically curved nature of neutron star cooling trajectories and the fact that minimizing a slope difference at a single epoch does not necessarily guarantee the best global agreement with the full Cas A NS dataset. Adopting the canonical neutron star mass $M_{\mathrm{NS}}=1.4M_{\odot }$, we find that increasing $q$ drives the optimized gap and critical-temperature profiles toward smoother and more localized shapes and improves consistency with the observed cooling trend. In particular, models with $q\gtrsim 0.4$ reproduce the Cas A NS decline rate within the $1\sigma$ confidence interval, whereas smaller values of $q$ lead to progressively shallower cooling slopes, with the baseline case $q\simeq 0.19$ lying near the $3\sigma$ level within the present setup.

Conclusions: Within this restricted and controlled modeling framework, our results suggest larger effective PBF emissivities than the baseline estimate. However, a statistically robust and less assumption-dependent constraint on $q$ requires a dedicated Bayesian inference that simultaneously accounts for uncertainties in neutron star mass, envelope composition, equation of state, pairing microphysics, and the age offset of Cas A NS. The physically interpretable gap parametrization and hybrid optimization strategy developed here provide a natural foundation for such future Bayesian and machine-learning-based studies of neutron star cooling.

I derive bounds on the equation of state of cold, dense matter by extending the causal, model-agnostic interpolation between chiral effective field theory and perturbative calculations with a microscopic constraint from relativistic kinetic theory. The additional condition restricts the stiffest admissible behavior of the equation of state and systematically reduces the range of allowed equations of state with the strongest effect at high densities. The resulting bounds remain consistent with known low- and high-density limits, while the strength of the constraint depends on the density above which the kinetic-theory condition is applied. These bounds can be readily incorporated into future studies of cold, dense matter and used to assess the impact of microscopic stability conditions on equation-of-state inference.

The systematics of energies and the contribution of the pygmy dipole resonance (PDR) to the energy-weighted sum rule of dipole gamma transitions in medium-heavy and heavy nuclei with an excess of neutrons are considered. The modified macroscopic model of Isacker-Nagarajan-Warner was used for calculating PDR energies with the number of surface neutrons proportional to the thickness of the neutron skin according to the Pethick-Ravenhall expression (PR INW approach). Such modification of the macroscopic approach by Isacker-Nagarajan-Warner enables taking into account microscopic evidence of a direct relationship between skin thickness and low-energy dipole response. The results are compared with the microscopic calculations for the chains of Ni, Sn, and Pb isotopes. It was demonstrated that the dependence of the magnitudes of the energies within the PR INW approach on neutron excess is in rather good agreement with experimental data and microscopic calculations if the absolute value of the strength of the neutron-proton interaction is nearly three times as large as that obtained by Isacker-Nagarajan-Warner by the volume integral of the nucleon-nucleon interaction. While the macroscopic INW PR model can describe the main features of the PDR, the above-mentioned discrepancy of the strength values does not not provide reason enough for the conclusion that PDR is a pure collective state. The analytical expressions for the PDR fraction of the energy-weighted sum rule for electric dipole transitions (E1 EWSR) are used. They are based on the “molecular” energy-weighted E1 sum rule, considering the number of surface neutrons as a function of the neutron thickness (PR MSR approach). Systematics for the PDR fraction of E1 EWSR are proposed with parameters obtained by fitting the experimental data and microscopic calculations.

Based on the kinetic theory with relaxation time approximation, we investigate the bulk viscosity $\left(\zeta \right)$ and its ratio to shear viscosity $(\zeta /\eta )$ of quark matter at finite temperature and chemical potential with the in-medium particle masses derived in the $2+1$ flavor Polyakov-loop improved Nambu–Jona-Lasinio model. We explore the behaviors of specific bulk viscosity $(\zeta /s)$ and $\zeta /\eta$ across different QCD phase transitions, including the Mott phase transition, the chiral crossover, and the first-order transition with the associated metastable phase. The calculation shows that both $\zeta /s$ and $\zeta /\eta$ are extremely small at high temperatures, approaching the nature of a conformal theory. Larger $\zeta /s$ and $\zeta /\eta$ are derived near the chiral phase transition at finite temperature. Along the chiral crossover line, $\zeta /s$ and $\zeta /\eta$ generally increase with decreasing temperature, though $\zeta /\eta$ exhibits a slight decline near the critical end point. On the boundary of the first-order transition, $\zeta /s$ shows a nonmonotonic variation with temperature. Furthermore, an additional peak structure emerges beyond the chiral phase boundary for both $\zeta /s$ and $\zeta /\eta$, with magnitudes even exceeding those near the chiral crossover of $u,d$ quarks. Our analysis indicates this peak originates from the chiral crossover transformation of strange quark.

Background: The fission character changes along the mercury isotopic chain, from asymmetric (${}^{180}\mathrm{Hg}$) through slightly asymmetric (${}^{190}\mathrm{Hg}$) to symmetric (${}^{198}\mathrm{Hg}$). Mercury isotopes have been studied using various techniques including $\beta$-delayed fission, Coulomb-induced fission, and fusion-fission, but the isotope ${}^{194}\mathrm{Hg}$ has not been investigated until now.

Purpose: To experimentally study the fusion-fission reaction of ${}^{194}\mathrm{Hg}$ at moderate excitation energy and to determine previously unknown independent fission yields and properties of emitted neutrons and $\gamma$ rays.

Method: The compound nucleus was formed in the reaction ${}^{12}\mathrm{C} +{}^{182}\mathrm{W}$. Prompt gamma rays emitted during the reaction were measured with the $\nu$-ball2 spectrometer. Independent fission yields of even-even nuclei were determined by detecting gamma-gamma cascades in the fission fragments and performing a maximum-likelihood analysis. The number of emitted neutrons was determined from the fragment distribution, as well as from the study of fission partners. Average momentum carried by the $\gamma$ rays was determined by the Manchester method. Additionally, the long-term $\beta$ activity of fragment residues was measured as a complementary method.

Results: The measured fission-fragment mass distribution is consistent with that of neighboring mercury isotopes, confirming the gradual change along the isotopic chain and influence of the $Z=36$ deformed proton shell in the light fragment. The independent fragment yield and distribution of fission partners is well described by the GEF model. However, there are discrepancies concerning the angular momentum of the fragments and the width of the mass distribution, confirmed by the independent residual activity measurements.

Conclusions: Our results demonstrate that the method based on fusion-fission and $\gamma$ spectroscopy is a valuable alternative to direct mass or charge measurements. Independent fission yields, correlation of fission partners, and the study of angular momentum of fragments open the possibility of a comprehensive description of the process. This is important both from a theoretical and experimental point of view and is needed to achieve further refinement of our understanding of the fission process.

One-neutron transfer reactions serve as a powerful tool to investigate nuclear structure and reaction dynamics, particularly for revealing how projectile and target properties influence the transfer probability and the population of specific nuclear states at energies near and below the Coulomb barrier. In this study, we examine the influence of projectile structure in one-neutron transfer reactions using an ${}^{18}\mathrm{O}$ beam incident on a ${}^{197}\mathrm{Au}$ target. These investigations are extended to a systematic analysis of existing data in the literature, encompassing a range of projectiles (${}^{4,6}\mathrm{He}, {}^{6,7}\mathrm{Li}, {}^9\mathrm{Be}, {}^{10}\mathrm{B}, {}^{12}\mathrm{C}, {}^{16}\mathrm{O}$, etc.) on ${}^{197}\mathrm{Au}$ at energies both above and below the Coulomb barrier. The measured cross sections are compared with theoretical predictions obtained through the grazing program based on Winther's semiclassical model of transfer reactions. The findings underscore the significance of one-neutron separation energies of the projectile and positive $Q\text{value}$ of neutron transfer channel, providing deeper insights into the underlying mechanisms of heavy-ion collisions.