Entanglement distribution is the overarching purpose of quantum networks. While communication over long distances can use deployed fiber infrastructure, it requires photons in the telecom band. However, advanced quantum network nodes do not operate at such wavelengths. Here we overcome this limitation with two tailor-made low-noise quantum-frequency converters to distribute entanglement between a single atom and a resonant photon over 14 km line of sight via 24 km of a deployed commercial fiber. The photon at wavelength 780 nm is first entangled with the atom, then converted to the telecom S-band, and finally back-converted after propagation through the fiber. This link enables a photon transfer efficiency of 1.7% while affecting the atom-photon entanglement fidelity by less than 1%. This brings integration of atomic quantum nodes with existing long-distance fiber networks into reach, enabling novel applications in quantum information processing.

Using $20.3{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we report the first observation of the semileptonic decays $D^0\to K^{-}\omega e^{+}{\nu }_e$ and $D^{+}\to K_S^0\omega e^{+}{\nu }_e$ with significances of $8.0\sigma$ and $5.8\sigma$, respectively. Their decay branching fractions are measured to be $\mathcal{B}(D^0\to K^{-}\omega e^{+}{\nu }_e)=({9.4}_{-1.8}^{+2.0}\pm 0.6)\times {10}^{-5}$ and $\mathcal{B}(D^{+}\to K_S^0\omega e^{+}{\nu }_e)=({8.0}_{-2.1}^{+2.4}\pm 0.7)\times {10}^{-5}$. Combining these with the latest measurements of $D^{0(+)}\to K^{-}{\pi }^{+}{\pi }^{-(0)}{e}^{+}{\nu }_e$ and assuming ${\overline{K}}_1(1270)$ to be the sole mediating resonance in all processes, the branching ratios are determined to be $\{[\mathrm{\Gamma }(K_1(1270{)}^{-}\to K^{-}{\pi }^{+}{\pi }^{-})]/[\mathrm{\Gamma }(K_1(1270{)}^{-}\to K^{-}\omega )]\}={3.4}_{-0.7}^{+0.8}\pm 0.3$ and $\{[\mathrm{\Gamma }({\overline{K}}_1(1270{)}^0\to K^{-}{\pi }^{+}{\pi }^0)]/[\mathrm{\Gamma }({\overline{K}}_1(1270{)}^0\to {\overline{K}}^0\omega )]\}={7.9}_{-2.1}^{+2.4}\pm 0.7$. The combined branching fraction is determined to be $\mathcal{B}({\overline{K}}_1(1270)\to \overline{K}\omega )=(8.4\pm 1.4\pm 0.5)\%$, which is the most precise measurement from a collider experiment. Furthermore, for the first time based on a single vector-pseudoscalar decay channel, the ${\overline{K}}_1(1270)$ mass is measured to be $(1336\pm 9\pm 2)\mathrm{MeV}/c^2$, providing unique experimental support for the two-pole structure of the ${\overline{K}}_1(1270)$ resonance. The first uncertainties are statistical, and the second are systematic.

The first measurement of the polarization of charm baryons by the LHCb experiment recorded in fixed-target mode is presented. The polarization of ${\mathrm{\Lambda }}_c$ baryons is studied in collisions of protons, at an energy of 2.51 TeV, incident on a gaseous target of neon, at a nucleon-nucleon center-of-mass energy of 68.6 GeV. The world’s first measurement of separate-charge polarizations for ${\mathrm{\Lambda }}_c^{+}$ and ${\overline{\mathrm{\Lambda }}}_c^{-}$ baryons is performed, determining $P_{{\mathrm{\Lambda }}_c^{+}}=(24\pm 9\pm 2)\%$, $P_{{\overline{\mathrm{\Lambda }}}_c^{-}}=(-8\pm 12\pm 3)\%$, where the first uncertainty is statistical and the second systematic. The polarization is also measured in intervals of baryon transverse momentum and the Feynman-$x$ variable.

We present converged ab initio calculations of short-range neutrinoless double-beta ($0\nu \beta \beta$)-decay nuclear matrix elements for the key experimental isotopes ${}^{76}\mathrm{Ge}$, ${}^{82}\mathrm{Se}$, ${}^{130}\mathrm{Te}$, and ${}^{136}\mathrm{Xe}$. Starting from different nuclear forces derived from chiral effective field theory, we apply the in-medium similarity renormalization group to obtain an effective valence-space Hamiltonian along with consistently transformed $0\nu \beta \beta$-decay operators. We then obtain a range of values for the matrix elements that is consistent with, but generally smaller than, those from phenomenology. Finally, we combine our results with current limits from $0\nu \beta \beta$-decay searches to obtain constraints for the sterile-neutrino mixing-mass parameter space when considering the inclusion of a fourth, sterile neutrino.

We report the first creation of a bulk sample of ultracold heteronuclear $p$-wave Feshbach molecules in an optically trapped Bose-Bose mixture of ${}^{23}\mathrm{Na}$ and ${}^{87}\mathrm{Rb}$ atoms. Using loss spectroscopy and binding energy measurements, we systematically characterize the interspecies $p$-wave Feshbach resonances near 284 G. Leveraging this understanding, we use magnetoassociation to form $p$-wave NaRb Feshbach molecules, producing both pure samples and mixtures of molecules in different $p$-wave orbitals. We further measure the molecular lifetime and identify atom-molecule and molecule-molecule collisions as the dominant loss mechanisms. This Letter establishes a previously unavailable ultracold molecule platform that combines orbital anisotropy with heteronuclear constituents, represents a significant step toward realizing tunable $p$-wave interactions in Bose-Bose mixtures, and provides a foundation for exploring nonzero angular momentum molecules.

The integration of nitrogen-vacancy color centers into diamond anvil cells has opened the door to quantum sensing at megabar pressures. Despite a multitude of experimental demonstrations and applications ranging from quantum materials to geophysics, a detailed microscopic understanding of how stress affects the NV center remains lacking. In this work, using a combination of first principles calculations as well as high-pressure NV experiments, we develop a complete description of the NV’s optical properties under general stress conditions. In particular, our ab initio calculations reveal the complex behavior of the NV’s intersystem crossing rates under stresses that both preserve and break the defect’s symmetry. Crucially, our proposed framework immediately resolves a number of open questions in the field, including (i) the microscopic origin of the observed contrast enhancement in (111)-oriented anvils, and (ii) the surprising observation of NV contrast inversion in certain high-pressure regimes. Our work lays the foundation for optimizing the performance of NV high-pressure sensors by controlling the local stress environment, and more generally, suggests that symmetry-breaking stresses can be utilized as a novel tuning knob for generic solid-state spin defects.

We demonstrate a magnetic quantum critical point embedded within the superconducting state of Zn-doped ${\mathrm{CeCoIn}}_5$, revealed by a pronounced peak in the magnetic penetration depth at zero temperature $\lambda (0)$. Using scanning superconducting quantum interference device microscopy, we determine the local superconducting transition temperature $T_{\mathrm{c}}$ and $\lambda (0)$. By parametrizing $\lambda (0)$ in terms of the local $T_{\mathrm{c}}$ rather than nominal Zn substitution, we circumvent the ambiguity caused by doping inhomogeneity and enable a more precise extraction of the critical exponent. The extracted effective exponent exceeds the clean spin-density-wave value, consistent with a disorder-modified quantum critical regime. The enhancement of $\lambda (0)$ reflects the suppression of the superfluid stiffness and is consistent with critical scaling. Our approach provides a route to uncover underlying quantum critical behavior obscured by inhomogeneity in unconventional superconductors.

We investigate the electronic structure at the surface of the correlated oxide ${\mathrm{Ca}}_3{\mathrm{Ru}}_2{\mathrm{O}}_7$, a low-symmetry ruthenate oxide which hosts an unconventional polar-metal phase. From a combination of angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy measurements, we demonstrate that the surface hosts an insulating phase, a distinct departure from metallicity within the bulk. Utilizing quantitative low-energy electron diffraction in conjunction with electronic structure calculations, we show how this results from a combined surface structure relaxation and the impact of marked electronic correlations in this system. Our findings highlight the proximity of ${\mathrm{Ca}}_3{\mathrm{Ru}}_2{\mathrm{O}}_7$ to an insulating metallic state, and illustrate how subtle structural distortions can control its emergent electronic phases.

Realization of a three-dimensional (3D) analog of graphene has been a central challenge in topological materials science. Graphene is stabilized by covalent bonding, unlike conventional spin-orbit-type 3D Dirac semimetals (DSMs). In this study, we demonstrate the material realization of covalent-type 3D DSMs $R_8\mathrm{Co}{X}_3$ stabilized by covalent bonding. We confirm the clean Dirac semimetal state in ${\mathrm{Y}}_8{\mathrm{CoIn}}_3$ by combined thermodynamic and transport experiments. We also realize high carrier mobility exceeding $3000{\mathrm{cm}}^2/\mathrm{Vs}$ even in polycrystalline samples of $R_8\mathrm{Co}{X}_3$. Our research provides a material platform for exploration of Dirac electrons in three dimensions with wide chemical tunability.

Mechanical metamaterials composed of bistable elements have recently emerged as promising platforms for mechanical memory. Traditional approaches to writing information in these systems typically rely on localized actuation or predefined coupling schemes, which are often labor-intensive or lack adaptability. In this Letter, we introduce a one-dimensional metamaterial consisting of mass-in-mass bistable units that are statically decoupled yet dynamically switchable, allowing arbitrary mechanical information to be encoded through nonlinear waves applied at the boundary of the system. Through a combination of experiments and simulations, we demonstrate that tailored input signals can selectively trigger state transitions deep within the structure, enabling remote and programmable bit writing. This approach opens a new avenue for mechanical memory, harnessing the robustness of bistable elements and the tunability of nonlinear wave-driven actuation.

Theoretical descriptions of the stepping-stone model, a cornerstone of spatial population genetics, have long overlooked diffusive noise arising from migration dynamics. We derive a fluctuating hydrodynamic description of this model from microscopic rules, which we then use to demonstrate that diffusive noise significantly alters early-time genetic demixing, which we characterize through heterozygosity, a key measure of diversity. Combining macroscopic fluctuation theory and microscopic simulations, we demonstrate that the scaling of allele-number fluctuations in a spatial domain displays an early-time behavior dominated by diffusive noise. Our results underscore the need for additional terms in existing continuum theories and highlight the necessity of including diffusive noise in models of spatially structured populations.

Understanding how animals move as collectives requires knowledge of movement and interaction rules implemented by individuals within such groups. We report that micro glassfish Danionella cerebrum exhibit highly dynamic schooling that is explained by a stochastic model with pairwise copying of swimming direction. We identify discrete time points that correspond directly to these copying interactions, and confirm the model’s predictions by examining the behavior of fish as they school with virtual conspecifics. The model’s success in quantitatively recapitulating group behaviors opens a door to future investigations into models of collective motion where emergent group behaviors are highly dynamic and depend strongly on group size. Furthermore, the interactions in the model serve as candidate computations implemented in the brains of individuals, facilitating future studies into the neuronal mechanisms underlying complex group behaviors.

Proper characterization of quantum correlations in multimode optical quantum states is critical for applications in quantum information science. However, standard entanglement measurements can lead to incomplete state reconstruction and characterization. Here, we implement a resonator-based detection system that reveals entanglement between sideband modes of twin beams, achieving full tomography and retrieving often ignored quantum correlations. Unlike standard spectral measurements such as homodyne detection, resonator detection can independently address the sidebands of each beam, thereby accessing these hidden correlations. Additionally, we show how phase shifts between the carrier and the sideband modes of the involved fields redistribute information and modify the observation of entanglement for different witnesses. The ability of the resonant detection to independently address sideband modes of entangled states can contribute to enhancing the capacity for secure communication and quantum networking protocols.

Recovering properties of correlation functions is typically challenging. On the one hand, experimentally, it requires measurements with a temporal resolution finer than the system’s dynamics. On the other hand, analytical or numerical analysis requires solving the system evolution. Here, we use recent results of quantum metrology with continuous measurements to derive general lower bounds on the relaxation and second-order correlation times that are both easy to calculate and measure. These bounds are based solely on steady-state expectation values and their derivatives with respect to a system parameter, and can be readily extended to the autocorrelation of arbitrary observables. We validate our method on two examples of critical quantum systems: a critical driven-dissipative resonator, where the bound matches analytical results for the dynamics, and the infinite-range Ising model, where only the steady state is solvable, and thus the bound provides information beyond the reach of existing analytical approaches. Our results can be applied to the experimental characterization of ultrafast systems and to the theoretical analysis of many-body models whose dynamics are hard to compute.

The storage of large-scale quantum information at finite temperature requires an autonomous and reliable quantum hard drive, also known as a self-correcting quantum memory. It is a long-standing open problem to find a self-correcting quantum memory in three dimensions. The recently introduced layer codes achieve the best possible scaling of code parameters and logical energy barrier in three dimensions; these are tantalizing features for the purposes of self-correction. In this Letter, we show that a family of layer codes based on good quantum Tanner codes exhibit partial self-correction. Their memory time grows exponentially with linear system size, up to a length scale that is exponential in the inverse temperature. At this length scale, the memory time scales as a double exponential of inverse temperature. To establish this result, we introduce a concatenated matching decoder that combines three rounds of parallelized minimum-weight perfect matching with a decoder for good quantum Tanner codes. We show that our decoder corrects errors up to a constant fraction of the energy barrier, and a constant fraction of the code distance, for a family of layer codes. Our results position layer codes as the leading candidate for a partially self-correcting memory in three dimensions in the asymptotically large system size regime. While they fall short of achieving strict self-correction in the thermodynamic limit, our Letter highlights the potential of these local codes in three dimensions, with fast distance and logical qubit growth, fast decoders, and a long memory time over a wide range of parameters. In particular, recent work by Gu et al. reports promising numerical results for the memory time of small explicit instances of layer codes based on random input codes.

Mapping the $S$ matrix of a generic theory of flat-space gravity coupled to matter to correlation functions of a putative Carrollian dual, we show that bulk interactions imply boundary nonlocality.

The ultrafast nonlinear optical response of molecular ensembles is fundamentally altered under strong light-matter coupling. To rigorously isolate the genuine many-body contributions, an exact time-domain field-subtraction protocol is developed within a fully nonperturbative Maxwell-Liouville framework explicitly incorporating the two-exciton manifold in real space and time. This approach reveals that while collective cavity delocalization drives the macroscopic nonlinear signal toward a severe harmonic cancellation (an effect termed “spectral starvation”), intrinsic many-body molecular interactions robustly resurrect genuine polaritonic double-quantum coherences. This many-body resurrection is governed by a universal two-photon matching rule, ${\mathrm{\Delta }}_B+4J={\mathrm{\Omega }}_R$, linking molecular anharmonicity (${\mathrm{\Delta }}_B$) to the macroscopic Rabi splitting (${\mathrm{\Omega }}_R$) and excitonic coupling ($J$). Crucially, this resonance exploits the spatial mismatch between macroscopic polaritons and localized two-exciton pairs to break harmonic cancellation. For $J$ aggregates ($J<0$), this condition uniquely isolates the resonant many-body state below the dense manifold of localized dark states, protecting the macroscopic coherence from spatial fragmentation. This predictive framework establishes a direct phase diagram to engineer and protect optical nonlinearities across diverse strongly coupled platforms.

Instabilities driven by energetic particles normally reduce fusion power, but recent studies find Alfvén eigenmode instabilities can drive “zonal” flows and currents that reduce thermal transport, improving overall performance. Motional Stark effect data from the DIII-D tokamak reveal changes in magnetic pitch angle during the phase when Alfvén-eigenmode nonlinearity drives zonal flows, suppresses microturbulence, and increases the electron and ion temperatures. Measured changes in the safety factor of $\mathrm{\Delta }q/\overline{q}\simeq 5\%$ occur in roughly 20 ms, consistent with a rough estimate based on the measured zonal flow.