The annual modulation signal, claimed to be consistent with dark matter as observed by DAMA/LIBRA in a sodium-iodide based detector, has persisted for over two decades. COSINE-100 and ANAIS-112 were designed to test the claim directly using the same target material. COSINE-100, located at Yangyang Underground Laboratory in South Korea, and ANAIS-112, located at Canfranc Underground Laboratory in Spain, have been taking data since 2016 and 2017, respectively. Each experiment published its respective results independently. In this Letter, we present the results of an annual modulation search as a test of the signal observed by DAMA/LIBRA with the first three respective years of data from COSINE-100 and ANAIS-112. Using a Markov Chain Monte Carlo method, we find best fit values for modulation amplitude of $-0.0002\pm 0.0026\mathrm{cpd}/\mathrm{kg}/\mathrm{keV}$ in the 1–6 keV and $0.0021\pm 0.0028\mathrm{cpd}/\mathrm{kg}/\mathrm{keV}$ in the 2–6 keV energy regions. These results are not compatible with DAMA/LIBRA’s assertion for their observation of annual modulation at $3.7\sigma$ and $2.6\sigma$, respectively. Performing a simple combination of the newly released 6-year datasets from both experiments finds values consistent with no modulation at $0.0005\pm 0.0019\mathrm{cpd}/\mathrm{kg}/\mathrm{keV}$ in the 1–6 keV and $0.0027\pm 0.0021\mathrm{cpd}/\mathrm{kg}/\mathrm{keV}$ in the 2–6 keV energy regions with $4.7\sigma$ and $3.5\sigma$ respective exclusions of the DAMA/LIBRA signal.

The Event Horizon Telescope (EHT) has significantly advanced our ability to study black holes, achieving unprecedented spatial resolution and revealing horizon-scale structures. Notably, these observations feature a distinctive dark shadow—primarily arising from faint jet emissions—surrounded by a bright photon ring. Anticipated upgrades of the EHT promise substantial improvements in dynamic range, enabling deeper exploration of low-background regions, particularly the inner shadow defined by the lensed equatorial horizon. Our analysis shows that observations of these regions transform supermassive black holes into powerful probes for annihilating dark matter, which is expected to accumulate densely in their vicinity. By analyzing the black hole image morphology and performing electron-positron propagation calculations in realistic plasma backgrounds derived from general relativistic magnetohydrodynamic simulations, we set stringent constraints on dark matter annihilation, requiring contributions below the astrophysical emission. These constraints, derived from both current EHT observations and projections for future upgraded arrays, exclude a substantial region of previously unexplored parameter space and remain robust against astrophysical uncertainties, including black hole spin and plasma temperature variations.

Magnetic dynamics at the nanoscale provide crucial insight into the behavior of superconductors. Using single-spin scanning quantum microscopy, we probe vortex dynamics in the two-dimensional superconductor ${\mathrm{NbSe}}_2$. Our measurements reveal a disordered vortex glass phase that melts near the critical temperature and displays cooling-rate-dependent configurations. Surprisingly, magnetic noise persists well below $T_c$, with a strength that increases at lower temperatures—contrary to expectations. This behavior, detected via spin decoherence, points to an intrinsic origin driven by competition between supercurrent density and thermal fluctuations. Our results establish single-spin microscopy as a powerful platform for investigating fluctuations in 2D superconductors.

Interlayer sliding, together with twist angle, is a crucial parameter that defines the atomic registry and thus determines the properties of two-dimensional (2D) material homobilayers. Here, we theoretically demonstrate that controlled interlayer sliding in bilayer graphene induces Berry curvature reversals, leading to topological states confined within a one-dimensional moiré channel. We experimentally realize interlayer sliding by bending the bilayer graphene geometry across a nanoridge. Systematic electronic transport measurements reveal topological valley transport when the Fermi energy resides within the band gap, consistent with theoretical predictions of eight topological channels. Our findings establish interlayer sliding as a powerful tool for tuning the electronic properties of bilayer graphene and underscore its potential for broad application across 2D material systems.

We present the results of a first-principles theoretical study of the inclusive semileptonic decays of the $D_s$ meson. We performed a state-of-the-art lattice QCD calculation by taking into account all sources of systematic errors. A detailed discussion of our lattice calculation, demonstrating that inclusive semileptonic decays can nowadays be studied on the lattice at a phenomenologically relevant level of accuracy, is the subject of a companion paper [A. De Santis et al., Inclusive semileptonic decays of the $D_s$ meson: A first-principles lattice QCD calculation, Phys. Rev. D 112, 054503 (2025)]. Here, we focus on the phenomenological implications of our results. Using the current best estimates of the relevant Cabibbo-Kobayashi-Maskawa (CKM) matrix elements, our theoretical predictions for the decay rate and for the first two lepton-energy moments are in very good agreement with the corresponding experimental measurements. We also argue that, while the inclusive $D_s$ channel is not yet competitive with the exclusive channels in the $|V_{cs}|$ determination, the situation can be significantly improved in the near future.

Recent advances in laser excitation of the low-energy nuclear isomer transition in ${}^{229}\mathrm{Th}$ have opened avenues for developing nuclear clocks, a novel quantum technology with exceptional performance and sensitivity to exotic physics. Here, we explore the host dependence of the nuclear clock frequency, focusing on the isomer shift induced by the difference in the nuclear charge distribution between the ground and excited nuclear states. We combine relativistic many-body methods of atomic structure with periodic density functional theory to evaluate the isomer shifts in solid-state hosts. We elucidate the critical importance of the “relaxation” effect in evaluating the isomer shifts. Our analysis predicts nuclear clock frequencies for various solid-state and trapped ion platforms: ${\omega }_{\mathrm{clk}}(\text{solid state})=2020407384(40)\mathrm{MHz}$, ${\omega }_{\mathrm{clk}}({{}^{229}\mathrm{Th}}^{4+})=2020407648(70)\mathrm{MHz}$, and ${\omega }_{\mathrm{clk}}({{}^{229}\mathrm{Th}}^{3+})=2020407114(70)\mathrm{MHz}$. We also determine the nuclear transition energy for the bare ${}^{229}\mathrm{Th}$ nucleus to be ${\omega }_{\mathrm{nuc}}=8.272(22)\mathrm{eV}$. Our calculated valence band isomer shifts for different host materials constrain the nuclear transition frequencies to an 80-MHz-wide frequency window, aiding experimental searches for the ${}^{229}\mathrm{Th}$ nuclear transition in novel materials.

Semiconducting transition metal dichalcogenides are promising platforms for exploring emergent two-dimensional (2D) exciton physics and constructing 2D optoelectronic devices. However, even in mechanically exfoliated and hexagonal boron nitride encapsulated samples that are expected to maintain the most intrinsic properties, shallow defect states are still unavoidable. Here, we reported a method for eliminating the defect states in monolayer ${\mathrm{WSe}}_2$ by coupling it with a c-plane sapphire surface. We found that the defect-relevant photoluminescence peaks at cryogenic temperatures can be completely suppressed in ${\mathrm{WSe}}_2$ on c-plane sapphire, resulting in intrinsic exciton radiation, prolonged lifetime, and increased diffusion length. Ab initio calculations revealed that the surface of c-plane sapphire is much more active than other planes, where oxygen atoms preferentially transfer to ${\mathrm{WSe}}_2$ to repair selenium vacancy defects. Our Letter provides a new platform for defect engineering, which will promote the development of high-performance electronic and optoelectronic devices based on 2D materials.

Activation volume is a crucial concept in mechanochemistry because it describes how the applied mechanical energy facilitates chemical reactions. The activation volume can be determined readily from the load dependence of a chemical reaction based on the stress-assisted thermal activation theory (also known as the Bell model), but it is still very challenging to fully understand what activation volume means physically and how to compute it. Here, by introducing a concept of inherent stress difference (${\sigma }_{\mathrm{T}}$) between the initial and transition states, which is associated with the displacement of reacting atoms, a universal formula of activation volume ($\mathrm{\Delta }{V}^{*}$) for the interfacial reactions is derived, that is, $\mathrm{\Delta }{V}^{*}=(V_{\mathrm{eff}}{\sigma }_{\mathrm{T}}/E)$, where $E$ and $V_{\mathrm{eff}}$ refer to the Young’s modulus and the volume influenced by reaction, respectively. This formula implicates that $\mathrm{\Delta }{V}^{*}$ is related to the volume change from the initial to transition states. Then, the first-principles calculation was used to confirm the validity of the proposed definition in diverse types of chemical reactions. This Letter provides clear physical insight into how a chemical reaction that is unlikely to occur under thermal conditions is facilitated by mechanical stress, explaining the core principle of mechanochemistry.

Quantum defects in solids have emerged as a transformative platform for advancing quantum technologies. A key requirement for these applications is achieving high-fidelity single-spin readout, particularly at room temperature for quantum biosensing. Here, we demonstrate through ab initio simulations of a primary quantum defect in 4H silicon carbide that strain is an effective control parameter for significantly enhancing readout contrast. We validate this principle experimentally by inducing local strain in silicon carbide-on-insulator membranes, achieving a readout contrast exceeding 60% while preserving the favorable coherence properties of single spins. Our findings establish strain engineering as a powerful strategy for optimizing coherent spin-photon interfaces in PL6 divacancy centers within silicon carbide membranes and potentially other similar defect systems.

Observation of gamma rays from an exploding black hole would provide strong evidence for primordial black holes, the first direct evidence of Hawking radiation, and definitive information on the particles present in nature. However, indirect constraints suggest that direct observation of an exploding Schwarzschild black hole at current or upcoming gamma ray observatories is implausible. We introduce a dark-QED toy model consisting of a dark photon and a heavy dark electron. In this scenario a population of light primordial black holes charged under the dark $u(1)$ symmetry can become quasiextremal, so they survive much longer than if they were uncharged, before discharging and exhibiting a Schwarzschild-like final explosion. We show that the answer is “yes,” in this scenario the probability of observing an exploding black hole over the next 10 years could potentially be over 90%.

The gravitational-wave signal GW250114 was observed by the two LIGO detectors with a network matched-filter signal-to-noise ratio of 80. The signal was emitted by the coalescence of two black holes with near-equal masses $m_1={33.6}_{-0.8}^{+1.2}{M}_{\odot }$ and $m_2={32.2}_{-1.3}^{+0.8}{M}_{\odot }$, and small spins ${\chi }_{1,2}\le 0.26$ (90% credibility) and negligible eccentricity $e\le 0.03$. Postmerger data excluding the peak region are consistent with the dominant quadrupolar $(\ell =|m|=2)$ mode of a Kerr black hole and its first overtone. We constrain the modes’ frequencies to $\pm 30\%$ of the Kerr spectrum, providing a test of the remnant’s Kerr nature. We also examine Hawking’s area law, also known as the second law of black hole mechanics, which states that the total area of the black hole event horizons cannot decrease with time. A range of analyses that exclude up to five of the strongest merger cycles confirm that the remnant area is larger than the sum of the initial areas to high credibility.

This Letter reports the first evidence of electroweak production of same-sign $W$ boson pairs where at least one of the $W$ bosons is longitudinally polarized and the most stringent constraint to date for the production of two longitudinally polarized same-sign $W$ bosons. The dataset used corresponds to an integrated luminosity of $140{\mathrm{fb}}^{-1}$ of proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the ATLAS detector during run 2 of the Large Hadron Collider. The study is performed in final states including two same-sign leptons (electrons or muons), missing transverse momentum, and at least two jets with a large invariant mass and a large rapidity difference. Two independent fits are performed targeting the production of same-sign $W$ bosons with at least one, or two longitudinally polarized $W$ bosons. The observed (expected) significance of the production with at least one longitudinally polarized $W$ boson is 3.3 (4.0) standard deviations. An observed (expected) 95% confidence level upper limit of 0.45 (0.70) fb is reported on the fiducial production cross section of two longitudinally polarized same-sign $W$ bosons.

The natural van der Waals heterostructure $4H_b\text{−}{\text{TaS}}_2$ composed of alternating $1T$- and $1H\text{−}{\text{TaS}}_2$ layers serves as a platform for investigating the electronic correlations and layer-dependent properties of novel quantum materials. The temperature evolution of the conductivity spectra $\sigma (\omega )$ obtained through infrared spectroscopy elucidates the influence of band modifications associated with the charge-density-wave (CDW) superlattice on the $1T$ layer, resulting in a room-temperature energy gap, ${\mathrm{\Delta }}_{\mathrm{CDW}}\approx 0.35\mathrm{eV}$. Supported by density functional theory calculations, we attribute the behavior of interband transitions to the convergence of the layers, which amplifies the charge transfer from the $1T$ to the $1H$ layers, progressing as the temperature decreases. This phenomenon leads to an enhanced carrier density. The presence of an energy gap and the temperature-tunable charge transfer within the bulk of $4H_b\text{−}{\text{TaS}}_2$—driven by layer-dependent CDW states—contribute to a more comprehensive understanding of other complex compounds of transition-metal dichalcogenides.

Incoherent $J/\psi$ photoproduction in heavy ion ultraperipheral collisions (UPCs) provides a sensitive probe of localized, fluctuating gluonic structures within heavy nuclei. This Letter reports the first measurement of the photon-nucleon center-of-mass energy ($W_{\gamma \mathrm{N}}$) dependence of this process in PbPb UPCs at a nucleon-nucleon center-of-mass energy of 5.02 TeV, using $1.52{\mathrm{nb}}^{-1}$ of data recorded by the CMS experiment. The measurement covers a wide $W_{\gamma \mathrm{N}}$ range of $\approx 40–400\mathrm{GeV}$, probing gluons carrying a fraction $x$ of nucleon momentum down to an unexplored regime of $6.5\times {10}^{-5}$. Compared to baseline predictions neglecting nuclear effects, the measured cross sections exhibit significantly greater suppression at lower $x$. Additionally, the ratio of incoherent to coherent photoproduction is found to be constant across the probed $W_{\gamma \mathrm{N}}$ and $x$ range, disfavoring the establishment of the black disk limit. This Letter provides critical insights into the $x$-dependent evolution of fluctuating gluonic structures within nuclei and calls for further advancements in theoretical models incorporating nuclear shadowing and gluon saturation.

Excitons are bosonic quasiparticles with a variety of applications in optoelectronics, photosynthesis, and dissipationless informatics, and their lifetime can become sufficiently long to form a quantum condensate. While exciton condensation has been predicted to occur as a ground state of a solid, so-called an excitonic insulator, whose material realization has been elusive. Here we report the observation of direct photoemission signals from excitons in a ground state of a very recent excitonic insulator candidate ${\mathrm{Ta}}_2{\mathrm{Pd}}_3{\mathrm{Te}}_5$ below its metal-insulator transition temperature using orbital-selective angle-resolved photoemission spectroscopy. It is confirmed that the excitons have a lower energy than the valence band maximum to possibly drive the phase transition. This measurement further discloses the size and the unusual odd parity of the exciton wave function. The present finding opens an avenue toward applications of coherent excitons in solid systems and searching for exotic quantum phases of exciton condensates.

Despite exhibiting a similar $d_{x^2-y^2}$ band character to cuprates, infinite-layer nickelates host additional electron pockets that distinguish them from single-band cuprates. The elusive orbital origin of these electron pockets has led to competing theoretical scenarios. Here, using polarization-dependent and resonant angle-resolved photoemission spectroscopy, we determine the orbital character of the Fermi surfaces in ${\mathrm{NdNiO}}_2$. Our data reveal that the electronlike pocket arises predominantly from interstitial $s$ states, with negligible contributions from rare-earth $5d$ and $4f$ orbitals near the Fermi level. The observation of well-defined quantum-well states indicates a uniform distribution of these interstitial electrons throughout the film thickness. By comparing with electronic structure of ${\mathrm{LaNiO}}_2$, we find that the rare-earth element modulates the Ni-derived bands and hopping integrals through a chemical pressure effect. These findings clarify the role of rare-earth elements in shaping the low-energy electronic structure and establish the presence of electridelike interstitial $s$ states in a correlated oxide system, where electrons occupy lattice voids rather than atomic orbitals. The electridelike character offers new insight into the self-doping and superconductivity in infinite-layer nickelates.

Superradiance emerges from collective spontaneous emission in optically pumped gases, and is characterized by photon emission enhancements of up to $\frac{1}{4}{N}^2$ in an $N$ atom system. The gain mechanism derives from correlations developed within the decay medium rather than from stimulated emission as in lasing, so an analog of this process should be possible for fermionic final states. We introduce here the concept of superradiant neutrino emission from a radioactive Bose Einstein condensate, which can form the basis for a superradiant neutrino laser. A plausible experimental realization based on a condensate of electron-capture isotope ${}^{83}\mathrm{Rb}$ could exhibit effective radioactive decay rates accelerated from 86.2 days to minutes in viably sized rubidium condensates of ${10}^6$ atoms.

The strength-toughness trade-off in polymer glasses presents a fundamental challenge, as enhancing one property typically compromises the other. Moreover, efforts to enhance mechanical performance often lead to increased melt viscosity, which in turn hinders processability. Here, we demonstrate that incorporating single-chain nanoparticles (SCNPs) breaks this trilemma by simultaneously enhancing strength, toughness, and processability. Through a combined experimental and molecular dynamics simulation approach, we reveal that SCNPs with higher glass transition temperature than the matrix not only increase yield strength but also delay and homogenize crazing, leading to dramatically improved toughness in the glassy state. Importantly, the SCNPs reduce melt viscosity in the molten state, countering the conventional trend of viscosity increase in nanocomposites. This triple enhancement establishes a universal framework for designing high-performance polymer glasses that transcend traditional material property limitations.

Sea ice is a key component of Earth’s climate system, making its aging process an essential focus of current research. The age of sea ice is closely linked to its thermal and mechanical properties, which govern its interactions with the surrounding environment. In this study, we combine experimental techniques and modeling to explore the full dynamical process of mushy ice growth and spontaneous aging in saline water, within a natural convective flow system. We show that the aging of newly formed mushy ice in the present system, characterized by a gradual long-term reduction in porosity, is controlled by diffusion-driven desalination. Moreover, we observe that the system eventually transits into a dense freshwater ice layer adjacent to a well-mixed saline water region. The shape of the ice layer in this asymptotic state is well captured by numerical simulations of nonporous ice. Our findings improve the understanding of the complex physics governing phase changes in aqueous systems and provide a framework for studying sea ice aging in laboratory settings, with implications spanning diverse natural and industrial applications.

We present the first experimental evidence of stimulated Raman rescattering of a laser in plasma: The scattered light produced by the Raman instability is intense enough to scatter again through the same instability. Although never observed, rescattering processes have been studied theoretically and numerically for many years in the context of inertial confinement fusion, since the plasma waves they generate could bootstrap thermal electrons to high energies [B. J. Winjum et al., Phys. Rev. Lett. 110, 165001 (2013)], preheating the fuel and degrading ignition conditions. Our experimental results are obtained with a spatially smoothed laser beam consisting of many speckles, with an average intensity around ${10}^{14}\mathrm{W}/{\mathrm{cm}}^2$ and close to ${10}^{15}\mathrm{W}/{\mathrm{cm}}^2$ in the speckles, such as those usually used in direct-drive inertial confinement fusion. Kinetic and hydrodynamic simulations show good agreement with the observations.