We present a novel emulation scheme for ab initio many-body nuclear calculations that integrates a hierarchical framework with a Bayesian neural network. This approach enables accurate and simultaneous predictions of nuclear properties across entire isotopic chains and is broadly applicable to different regions of the nuclear chart. We benchmark our developments using the oxygen isotopic chain, achieving accurate results for ground-state energies and nuclear charge radii, while providing robust uncertainty quantification. Our framework enables global sensitivity analysis of nuclear binding energies and charge radii with respect to the low-energy constants that describe the nuclear force.

The identification of the first multiphonon $\gamma$-vibrational bands in an odd-odd neutron-rich nucleus of the nuclear chart is presented. These high-spin structures of hard to access ${}_{41}{}^{104}{\mathrm{Nb}}_{63}$, produced in fission, were studied by combining a spectrometer with isotopic resolution coupled to a $\gamma$-ray tracking array and independently from high-fold $\gamma$ coincidence measurements. Triaxial projected shell model calculations for the high-spin states are in good agreement with the measured observables for the yrast, one-phonon, and two-phonon $\gamma$ bands. The possibility of an oblate shape of an isomeric state and coexistence of triaxial and oblate configurations is investigated from the decay of the 141 keV isomer. The present Letter illustrates the robustness of vibration excitations in the presence of an odd valence proton and neutron as well as the possibly coexisting shapes beyond the $N=60$ transitional region.

The Chern theorem is applied to intrinsically deformed atomic nuclei, leading to states exhibiting topological quantization of the rotation-aligned component of angular momentum averaged over Hilbert space. These topologically quantized alignment (TQA) states can emerge when collective rotation breaks intrinsic-frame time reversal symmetry, and differ fundamentally from traditional nuclear states. They exhibit formal analogies with the integer quantum Hall effect, and are a first suggestion that topological matter with novel properties might exist in nuclei. We discuss experimental signatures and speculate that TQA bulk-boundary correspondence could lead to a nuclear Chern insulator, where a rotating nucleus has an insulating bulk and unidirectional charged and uncharged currents at its surface, with detectable consequences for the energy spectrum.

We present the first ab initio lattice calculations of the proton-rich tin isotopes ${}^{99}\mathrm{Sn}$ to ${}^{102}\mathrm{Sn}$ using nuclear lattice effective field theory with high-fidelity two- and three-nucleon forces. For a given set of three-nucleon couplings, we reproduce binding energies with $\sim 1\%$ accuracy for the even–even systems and obtain energy splitting and two-nucleon separation energies in agreement with experiment. Our results confirm the $N=50$ shell closure and reveal that the binding energy of ${}^{99}\mathrm{Sn}$ lies below values extrapolated from heavier isotopes.

We report on a high-precision measurement of the $\mathrm{D}(\gamma ,n)p$ photodisintegration reaction at the newly commissioned Shanghai Laser Electron Gamma Source, employing a quasimonochromatic $\gamma$-ray beam from Laser Compton Scattering. The cross sections were determined over $E_{\gamma }=2.327–7.089\mathrm{MeV}$, achieving up to a factor of 2.2 improvement in precision near the neutron separation threshold. Combined with previous data in a global Markov chain Monte Carlo analysis using dibaryon effective field theory, we obtained the unprecedentedly precise $p(n,\gamma )\mathrm{D}$ cross sections and thermonuclear rate, with a precision up to $\approx 4$ times higher than previous evaluations. Implemented in a standard Big Bang nucleosynthesis framework, this new rate decreases uncertainty of the key cosmological parameter of baryon density ${\mathrm{\Omega }}_b{h}^2$ by up to $\approx 16\%$ relative to the Laboratory for Underground Nuclear Astrophysics (LUNA) result. A residual $\approx 1.2\sigma$ tension between ${\mathrm{\Omega }}_b{h}^2$ constrained from primordial $\mathrm{D}/\mathrm{H}$ observations and cosmic microwave background measurements persists, highlighting the need for improved $dd$ reaction rates and offering potential hints of new physics beyond the standard model of cosmology.

We introduce a variational Monte Carlo framework that combines neural-network quantum states with the Lorentz integral transform technique to compute the dynamical properties of self-bound quantum many-body systems in continuous Hilbert spaces. While broadly applicable to various quantum systems, including atoms and molecules, in this initial application we focus on the photoabsorption cross section of light nuclei, where benchmarks against numerically exact techniques are available. Our accurate theoretical predictions are complemented by robust uncertainty quantification, enabling meaningful comparisons with experiments. We demonstrate that a relatively simple nuclear Hamiltonian—based on a leading-order pionless EFT expansion and known to accurately reproduce ground-state energies of nuclei with $A\le 40$—also provides a reliable description of the photoabsorption cross section.

The LEGEND Collaboration is searching for neutrinoless double-beta ($0\nu \beta \beta$) decay by operating high-purity germanium detectors enriched in ${}^{76}\mathrm{Ge}$ in a low-background liquid argon environment. Building on key technological innovations from the GERmanium Detector Array (GERDA) experiment and the MAJORANA DEMONSTRATOR experiment, LEGEND-200 has performed a first $0\nu \beta \beta$ decay search based on 61.0 kg yr of data. Over half of this exposure comes from our highest performing detectors, including newly developed inverted-coaxial detectors, and is characterized by an estimated background level of ${0.5}_{-0.2}^{+0.3}\mathrm{cts}/(\mathrm{keV}\mathrm{ton}\mathrm{yr})$ in the $0\nu \beta \beta$ decay signal region. A combined analysis of data from GERDA, the MAJORANA DEMONSTRATOR, and LEGEND-200, characterized by a 90% confidence level exclusion sensitivity of $2.8\times {10}^{26}\mathrm{yr}$ on the half-life of $0\nu \beta \beta$ decay, reveals no evidence for a signal and sets a new observed lower limit at $T_{1/2}^{0\nu }>1.9\times {10}^{26}\mathrm{yr}$ (90% confidence level). Assuming the decay is mediated by Majorana neutrinos, this corresponds to an upper limit on the effective Majorana mass in the range $m_{\beta \beta }<75–200\mathrm{meV}$, depending on the adopted nuclear matrix element.

We discover a surprising relation between the collective motion of nucleons within atomic nuclei, traditionally understood to be driven by long-range correlations, and short-range nucleon-nucleon interactions. Specifically, we find that quadrupole collectivity in low-lying states of ${}^6\mathrm{Li}$ and ${}^{12}\mathrm{C}$, calculated with state-of-the-art ab initio techniques, is significantly influenced by two opposing $S$-wave contact couplings that subtly alter the surface oscillations of one largely deformed nuclear shape, without changing that shape’s overall contribution within the nucleus. The results offer new insights into the nature of emergent nuclear collectivity and its link to the underlying nucleon-nucleon interaction at short distances.

We present a search for neutrinoless double-beta ($0\nu \beta \beta$) decay of ${}^{136}\mathrm{Xe}$ using the full KamLAND-Zen 800 dataset with 745 kg of enriched xenon, corresponding to an exposure of 2.1 ton yr of ${}^{136}\mathrm{Xe}$. This updated search benefits from a more than twofold increase in exposure, recovery of photo-sensor gain, and reduced background from muon-induced spallation of xenon. Combining with the search in the previous KamLAND-Zen phase, we obtain a lower limit for the $0\nu \beta \beta$ decay halflife of $T_{1/2}^{0\nu }>3.8\times {10}^{26}\mathrm{yr}$ at 90% CL, a factor of 1.7 improvement over the previous limit. The corresponding upper limits on the effective Majorana neutrino mass are in the range 28–122 meV using phenomenological nuclear matrix element calculations.

The first observation of coherent $\varphi (1020)$ meson photoproduction off heavy nuclei is presented using ultraperipheral lead-lead collisions at a center-of-mass energy per nucleon pair of 5.36 TeV. The data were collected by the CMS experiment and correspond to an integrated luminosity of $1.62\mathrm{\mu }{b}^{-1}$. The $\varphi (1020)$ meson signals are reconstructed via the $K^{+}{K}^{-}$ decay channel. The production cross section is presented as a function of the $\varphi (1020)$ meson rapidity in the range $0.3<|y|<1.0$, probing gluons that carry a fraction of the nucleon momentum ($x$) around ${10}^{-4}$. The observed cross section exhibits little dependence on rapidity and is significantly suppressed, by a factor of $\sim 5$, compared to a baseline model that treats a nucleus as a collection of free nucleons. Theoretical models that incorporate the nuclear shadowing effect generally provide a better description of the $\varphi (1020)$ data than those incorporating gluon saturation. This study establishes a powerful new tool for exploring nuclear effects and nuclear gluonic structure in the small-$x$ regime at a unique energy scale bridging the perturbative and nonperturbative quantum chromodynamics domains.

Shape coexistence, a collective manifestation of nuclear structure, emerges from the underlying single-particle dynamics and is prominently observed in the region below ${}^{68}\mathrm{Ni}$. Theoretical studies have emphasized the key role of the $\nu d_{5/2}$ orbital, the quadrupole partner of $\nu g_{9/2}$, in driving deformation. However, experimental constraints on the location and properties of neutron orbitals in neutron-rich isotopes in this region remain scarce. In this Letter, the single-particle structure of ${}^{69}\mathrm{Ni}$ was investigated via the ${}^{68}\mathrm{Ni}(d,p)$ reaction in inverse kinematics, performed at the ISOLDE Solenoidal Spectrometer at CERN. Several new excited states were observed, and comparisons with adiabatic distorted wave approximation (ADWA) calculations enabled $\ell$-value assignments for the most strongly populated states. In particular, a state at 2.56 MeV is interpreted as the dominant fragment of the $\nu d_{5/2}$ strength. The experimental findings are well reproduced by Large-Scale Shell Model calculations using a modified LNPS interaction with an increased $\nu g_{9/2}–\nu d_{5/2}$ energy gap. These results provide new insight into the structure of ${}^{69}\mathrm{Ni}$ and underscore the crucial role of the $\nu d_{5/2}$ orbital in the onset of collectivity at the $N=40$ island of inversion.

Evidence for a (sub)-shell closure at $Z=14$ has been observed from the spectroscopy of ${}^{22}\mathrm{Si}$ and ${}^{21}\mathrm{Al}$. Using a fast ${}^{23}\mathrm{Si}$ beam on a ${}^9\mathrm{Be}$ target, several proton-decaying resonances have been populated in ${}^{21}\mathrm{Al}$ and ${}^{22}\mathrm{Si}$, including the first measurement of the $2_1^{+}$ state in ${}^{22}\mathrm{Si}$ with an excitation energy of 2.352(55) MeV. Relative to the known $N=14$ subshell closure in ${}^{22}\mathrm{O}$, the ${}^{22}\mathrm{Si}$ $2_1^{+}$ excitation energy indicates the existence of a weakened $Z=14$ subshell closure. To reproduce the new spectroscopic information and known ${}^{22}\mathrm{Al}$ levels, the energy of the $1s_{1/2}$ orbit must be substantially decreased, which imparts Thomas-Ehrman shifts to all excited states observed in the present Letter and explains the structure of nuclei in the $sd$ shell for this region of the proton drip line.

We discuss a universal nonequilibrium enhancement of long-wavelength Goldstone bosons induced by quenches to the broken phase in Model G—the dynamical universality class of an $O(4)$ antiferromagnet and the chiral phase transition in QCD. Scaling arguments for the coarsening dynamics describing the formation of the chiral condensate predict a parametric enhancement in the infrared spectra of Goldstone bosons, a prediction confirmed by stochastic simulations of the transition. The details of the enhancement are determined by the nonlinear dynamics of a superfluid effective theory, which is a limit of Model G reflecting the broken $O(4)$ symmetry. Our results translate to a parametric enhancement of low-momentum pions in heavy-ion collisions at the LHC, which are underpredicted in current hydrodynamic models without critical dynamics.

Recent studies have completed the $A=16$ isospin quintets for states with $J^{\pi }=0^{+}$ and $2^{+}$. The dependence of their masses as a function of isospin projection shows evidence for deviations from quadratic behavior indicating isospin violation beyond the expectation from two-body forces. The deviation is most pronounced for the $2^{+}$ states. Predictions from the shell model embedded in the continuum allow us to explain that this isospin violation is associated with a modification of the nuclear structure due to the open-quantum-system nature of the proton-rich members of the quintet. In particular, the $0^{+}$ and $2^{+}$ states in ${}^{16}\mathrm{Ne}$ and the $2^{+}$ state in ${}^{16}\mathrm{F}$ are threshold resonances located just above a proton-decay threshold where $s$-wave coupling to the continuum is expected. The measured deviations of these threshold states from the quadratic behavior of the remaining members of the multiplets makes it possible to obtain information on the magnitude and the energy dependence of the continuum-coupling energy correction. Continuum coupling is also indicated for the ground state of ${}^8\mathrm{C}$, but this time through $p$-wave coupling.

This Letter introduces a unified emulation framework for studying continuum physics in finite quantum systems. Using a reduced basis method, we construct powerful emulators for the inhomogeneous Schrödinger equation that operate in a combined parameter space of complex energy ($E$) and other inputs ($\mathit{\theta }$). Within the space, the emulators simultaneously perform analytical continuation in $E$—extracting continuum physics from numerically simpler bound-state-like calculations—and interpolate this entire process across $\mathit{\theta }$. This yields a small, non-Hermitian system whose properties (e.g., resonances and scattering observables) can be rapidly predicted for any $\mathit{\theta }$. Crucially, the complex-$E$ emulation provides a pathway to compute continuum observables for complex systems where advanced bound-state methods exist but direct continuum calculations are yet to be developed, while the $\mathit{\theta }$ emulation enables rapid parameter-space exploration and can be adapted to accelerate other existing continuum calculations. Demonstrations with two- and three-body systems highlight the method’s effectiveness and suggest its connection to (near-)optimal rational approximation. This Letter presents the key results, with further details reserved for a companion paper.

Kinetic equilibration at late times is physically required for heavy particles in a finite temperature medium. In Fokker-Planck dynamics, it is ensured by the Einstein relation between the drag and longitudinal momentum diffusion coefficients. However, in certain gauge field theories, this relation is violated at any nonzero heavy quark velocity. Recent work in strongly coupled $\mathcal{N}=4$ SYM gauge theory shows that the Kolmogorov equation for the heavy quark phase space distribution (that reduces to Fokker-Planck form upon truncating the momentum transfer probability distribution to second moments) does equilibrate even though the Fokker-Planck equation does not. Going beyond these (to date theory-specific) insights, we derive a universal equilibration condition for the kernel of the Kolmogorov equation and, consequently, for the momentum transfer probability distribution that holds in any quantum field theory with any coupling strength. This condition, which is the generalization of the Einstein relation to quantum field theories which feature non-Gaussian fluctuations, reveals that the asymmetry between energy loss and energy gain in the momentum transfer probability distribution takes a simple, theory-independent, form.