Integrating quantum key distribution (QKD) with classical data transmission over the same fiber is crucial for scalable quantum-secured communication. However, noise from classical channels limits QKD distance. We demonstrate the longest-distance continuous-variable QKD (CV-QKD) over 120 km (20 dB loss) in the asymptotic regime, and over 100 km (17 dB loss) in the finite-size regime, both coexisting with a fully populated coarse wavelength division multiplexing system. Natural mode filtering of the local oscillator and phase noise mitigation enabled this without additional filtering or wavelength reallocation. Benchmarking against a commercial discrete-variable QKD system and considering finite-size effects confirms the feasibility of CV-QKD as a plug-and-play solution for typical 80–100 km long-haul optical networks. Our results set a record fiber distance for CV-QKD, showing its potential for cost-effective, large-scale deployment in existing network infrastructure.

We show for the first time that warm inflation is feasible with standard model (SM) gauge interactions alone. Our model consists of a minimal extension of the SM by a single scalar inflaton field with an axionlike coupling to gluons and a monomial potential. The effects of light fermions, which were previously argued to render warm inflation with the SM impossible, are alleviated by Hubble dilution of their chiral chemical potentials. Our model features only one adjustable combination of parameters and accommodates all inflationary observables. We briefly discuss implications for axion experiments, dark matter, and the strong $CP$ problem.

Machine-learning interatomic potentials have emerged as a revolutionary class of force-field models in molecular simulations, delivering quantum-mechanical accuracy at a fraction of the computational cost and enabling the simulation of large-scale systems over extended timescales. However, they often focus on modeling local environments, neglecting crucial long-range interactions. We propose a sum-of-Gaussians neural network (SOG-Net), a lightweight and versatile framework for integrating long-range interactions into a machine-learning force field. The SOG-Net employs a latent-variable learning network that seamlessly bridges short-range and long-range components, coupled with an efficient Fourier convolution layer that incorporates long-range effects. By learning sum-of-Gaussians multipliers across different convolution layers, the SOG-Net adaptively captures diverse long-range decay behaviors while maintaining close-to-linear computational complexity during training and simulation via nonuniform fast Fourier transforms. The method is demonstrated effective for a broad range of long-range systems.

We present a classical algorithm based on Pauli propagation for estimating expectation values of arbitrary observables on random unstructured quantum circuits across all circuit architectures and depths, including those with all-to-all connectivity. We prove that, for any architecture where each circuit layer is randomly sampled from a distribution invariant under single-qubit rotations, our algorithm achieves a small error $ϵ$ on all circuits except for a small fraction $\delta$. The computational time is polynomial in qubit count and circuit depth for any small constant $ϵ$, $\delta$ and quasipolynomial for inverse-polynomially small $ϵ$, $\delta$. Our results show that estimating observables of quantum circuits exhibiting chaotic and locally scrambling behavior is classically tractable across all geometries.

We study the exchange of energy between gravitational and electromagnetic waves in an extended Mach-Zehnder or Sagnac type geometry that is analogous to an “optical Weber bar.” In the presence of a gravitational wave (such as the ones measured by the Laser Interferometer Gravitational Wave Observatory), we find that it should be possible to observe (via interference or beating effects after a delay line) signatures of stimulated emission or absorption of gravitons with present-day technology. Apart from marking the transition from passively observing to actively manipulating such a natural phenomenon, this could also be used as a complementary detection scheme. Nonclassical photon states may improve the sensitivity and might even allow us to test certain quantum aspects of the gravitational field.

We introduce tile codes, a simple yet powerful way of constructing quantum codes that are local on a planar 2D lattice. Tile codes generalize the usual surface code by allowing for a bit more flexibility in terms of locality and stabilizer weight. Our construction does not compromise on the fact that the codes are local on a lattice with open boundary conditions. Despite its simplicity, we use our construction to find codes with parameters $[[288,8,12]]$ using weight-6 stabilizers and $[[288,8,14]]$ using weight-8 stabilizers, outperforming all previously known constructions in this direction. Allowing for a slightly higher nonlocality, we find a $[[512,18,19]]$ code using weight-8 stabilizers, which outperforms the rotated surface code by a factor of more than 12. Our approach provides a unified framework for understanding the structure of codes that are local on a 2D planar lattice and offers a systematic way to explore the space of possible code parameters. In particular, due to its simplicity, the construction naturally accommodates various types of boundary conditions and stabilizer configurations, making it a versatile tool for quantum error-correction code design.

Quantum memory, a pivotal hub in quantum information processing, is expected to achieve temporal storage and coherent manipulation of quantum states with memory efficiency exceeding 90% and quantum fidelity surpassing the noncloning limit. However, the current performance falls short of these requirements due to the inherent trade-off between memory efficiency enhancement and noise amplification, which not only imposes significant demands on quantum purification but also fundamentally impedes continuous-variable quantum information processing. In this Letter, we break through these constraints by unveiling a Hankel transform spatiotemporal mapping for light-spin-wave conversion in quantum memory and proposing an intelligently light-manipulated strategy for spin wave compaction, which maximizes memory efficiency while suppressing excess noise. This strategy is experimentally demonstrated for a Raman quantum memory in warm ${}^{87}\mathrm{Rb}$ atomic vapor with an efficiency up to $94.6\pm 1\%$ and a low noise level of only $0.026\pm 0.012$ photon per pulse. The unconditional fidelity reaches $98.91\pm 0.1\%$ with an average of 1.0 photon per pulse for a 17 ns input signal. Our results successfully demonstrate a practical benchmark for broadband quantum memory that may facilitate advancements in high-speed quantum networks, quantum state manipulation, and scalable quantum computation.

By coupling newly developed triparticle charged particle radiography with radiography reconstruction algorithms and novel reconstruction postprocessing techniques, the spatial structure and time evolution of self-generated electric and magnetic fields in laser-driven vacuum hohlraums have been quantitatively revealed. Through high-fidelity data from a series of experiments, it is shown that late in the hohlraum evolution (after the end of laser drive) these fields are strongly correlated in both space and time, providing evidence that their evolution is primarily dominated by advection with the plasma flow. At these late times, plasma flow velocities inferred from both gross radiography analysis and field reconstructions (and corroborated with Thomson scattering measurements) indicate that the plasma is approaching stagnation near the hohlraum axis. These experiments provide not only new physical insight into spontaneously generated hohlraum fields, but also provide important spatially and temporally resolved information for future benchmarking of numerical codes.

Flat bands, characterized by zero group velocity and strong energy localization, enable interaction-enhanced phenomena across both quantum and classical systems. Existing photonic flat-band implementations were limited to evanescent-wave systems, specific lattice symmetries, or complex supercell modulations. A simple, universal, and efficient approach to realizing flat bands without dedicated source excitation is yet to be explored. Here, inspired by geometrically frustrated configurations, we theoretically proposed and experimentally demonstrated threefold-degenerate flat bands by integrating orbital and rotational degrees of freedom in a photonic dipolar kagome lattice. By rotating the dipole orientation, the system exhibits a band flip transition at which point all bands achieve complete flatness and degeneracy across the entire Brillouin zone. In contrast to conventional $s$-orbital kagome lattices with only a single flat band, our approach flattens the entire band structure, eliminating dispersive modes and enabling compatibility with arbitrary excitations. These results establish a new mechanism for flat-band engineering, offering a tunable strategy for enhancing light-matter interactions and may have applications in compact photonic devices and energy-efficient information processing.

The first dedicated $Z$-boson mass measurement at the LHC with $Z\to {\mu }^{+}{\mu }^{-}$ decays is reported. The dataset uses proton-proton collisions at a center-of-mass energy of 13 TeV, recorded in 2016 by the LHCb experiment, and corresponds to an integrated luminosity of $1.7{\mathrm{fb}}^{-1}$. A template fit to the ${\mu }^{+}{\mu }^{-}$ mass distribution yields the following result for the $Z$-boson mass: $m_Z=91,185.7\pm 8.3\pm 3.9\mathrm{MeV}$, where the first uncertainty is statistical and the second systematic. This result is consistent with previous measurements and predictions from global electroweak fits.

Quasicrystals are aperiodic solids with exotic physical properties. The mechanisms driving their growth are far from understood, particularly in the presence of rigid obstacles. Using in situ synchrotron x-ray tomography and molecular dynamics simulations, we investigate the interaction between decagonal quasicrystals and obstacles (shrinkage pores) during solidification of an ${\mathrm{Al}}_{79}{\mathrm{Co}}_6{\mathrm{Ni}}_{15}$ alloy. The results reveal defect-free quasicrystal growth around the pores, independent of pore size and geometry. Our findings point to a universal feature of aperiodic solids: their ability to accommodate structural disruptions due to additional (phasonic) degrees of freedom. This Letter opens new possibilities for synthesizing large-scale, single quasicrystals from a liquid metal precursor.

In devices based on two-dimensional electron gases (2DEGs), gate electrodes can be used to tune the electronic properties by controlling the electron density. Despite the prevalence of such gated systems, the properties of 2DEGs in these environments remain poorly understood quantitatively. To address this, we have studied the 2DEG in a dual-gate geometry using quantum Monte Carlo simulations alongside simpler approximate methods, and we have mapped out the phase diagram of the gated 2DEG as a function of electron density and gate distance. We find that the Wigner crystal is unstable at all densities when the gates are sufficiently close to the 2DEG, and we identify the critical gate distance at which the Wigner crystal phase appears. For larger gate separations, we determine the phase boundary for the reentrant crystal to liquid transition that occurs with decreasing density. Our Letter is particularly relevant to Wigner crystal phases recently observed in a variety of gated two-dimensional materials.

We realize a driven-dissipative Ising spin glass using cavity QED in a novel “4/7” multimode geometry. Gases of ultracold atoms trapped within the cavity by optical tweezers serve as effective spins. They are coupled via randomly signed, all-to-all Ising cavity-mediated interactions. Networks of up to $n=25$ spins are holographically imaged via cavity emission. The system is driven through a frustrated transverse-field Ising transition, and we show that the entropy of the spin glass states depends on the rate at which the transition is crossed. Despite being intrinsically nonequilibrium, the system exhibits phenomena associated with Parisi’s theory of equilibrium spin glasses, namely, replica symmetry breaking (RSB) and ultrametric structure. For system sizes up to $n=16$, we measure the Parisi function $q(x)$, Edwards-Anderson overlap $q_{\mathrm{EA}}$, and ultrametricity $K$ correlator; all indicate a deeply ordered spin glass under RSB. The system can serve as an associative memory and enable aging and rejuvenation studies in driven-dissipative spin glasses at the microscopic level.

Temporal correlations in pulsed electron beams reflect the microscopic dynamics of emission and interparticle interaction. In femtosecond electron emission from nanoscale field emitters, Coulomb interactions result in structured few-electron states with strong correlations in energy, time, and transverse momentum. Interactions with external fields may be used to both probe and further manipulate these correlated states. Here, we combine femtosecond-gated, event-based detection with inelastic electron-light scattering to directly map the photoelectron phase-space distribution of two-electron states. Our experiments demonstrate a bimodal structure in longitudinal phase space, with distinct contributions from interparticle interaction and dispersion. Moreover, we imprint a global phase modulation onto two-electron states and theoretically show that coherent shaping of few-electron phase-space distributions enables attosecond temporal correlations. This controlled phasing of few-electron states can be harnessed to produce tailored excitations and superradiance via two-electron energy postselection.

We investigate the secondary low-energy electron emission induced by inelastic electron scattering from graphene and layered materials thereof. By applying a coincidence detection of the primary scattered and the emitted secondary electron we unravel pronounced resonance features otherwise overshadowed by the largely structureless secondary electron energy distribution. Supported by density functional theory calculations we show that these structures are the signature of prominent resonances above the vacuum threshold which originate from interlayer states acting as a doorway state for electron emission. Remarkably, some of these doorway states open up only for samples with more than five layers.

High harmonic generation (HHG) in crystals could enable attosecond and ultraviolet light sources with high compactness, great controllability, and rich functions. However, the HHG process is accompanied by a quite large wave vector mismatch that is uncompensated by any traditional phase-matching method, directly limiting its energy conversion efficiency. Here, we propose an effective strategy for phase matching of HHG with arbitrary harmonic orders in crystals. Two flakes of twisted van der Waals crystals induce a nonlinear optical phase that depends on the crystal symmetry, twist angle, and harmonic order, which can be accurately designed to compensate for the phase mismatch in HHG. Guided by the twist-phase-matching theory, we achieved a record-high conversion efficiency of $\sim 4\times {10}^{-5}$ for the fifth HHG in twisted hexagonal boron nitride crystals within thickness of $\sim 1\mathrm{\mu }\mathrm{m}$. Moreover, the designed crystal has the polarization controllability that can emit a pure circularly polarized HHG light. Our Letter establishes a foundation for developing ultrashort-wavelength and ultrafast-pulse laser sources in compact solid-state tabletop systems for fundamental and applied sciences.

Conditional mutual information (CMI) is a widely studied multipartite correlation measure with a connection to the Markov property. Intriguingly, CMI can be generated by local dissipation, a phenomenon closely related to teleportation. The onset of long-range CMI corresponds to an information-theoretic mixed-state phase transition, with far-ranging implications for phase transitions, decoding, and state compressions. Little is known, however, about the conditions under which dissipation can generate long-range CMI. In this Letter, we provide the first rigorous results in this direction. We establish that CMI in high-temperature commuting Gibbs states subject to local dissipation decays exponentially under certain mild restrictions. Conversely, we show that the same setup can sustain long-range CMI at low temperatures. Our results establish the existence of finite-temperature information-theoretic phase transitions even in models that have no finite-temperature thermodynamic phase transitions.

Coherent spin-photon coupling is believed to play a significant role in silicon-based quantum computation. The resonant exchange (RX) qubit, formed in a triple quantum dot, is a promising platform for spin-photon coupling and qubit scaling due to the large electric dipole moment and full electrical control without auxiliary micromagnets. However, there has been no experimental demonstration of silicon RX qubits and their strong coupling to microwave photons to date. In this work, we report the strong coupling between an RX qubit and a high-impedance resonator on a Si/SiGe heterostructure with coupling strength $g_{\mathrm{s}}/(2\pi )=65.8\mathrm{MHz}$ and decoherence rate ${\gamma }_{\mathrm{s}}/(2\pi )=21.4\mathrm{MHz}$. Furthermore, the dependence of decoherence rate on detuning is measured and analyzed using a phenomenological model, indicating that the charge noise is the main source of decoherence. Our results demonstrate the viability of RX qubits in silicon, highlighting their crucial role of large-scale qubit integration for silicon quantum computation and opening new possibilities for quantum network.

${\text{Ta}}_2{\mathrm{NiSe}}_5$ undergoes a phase transition characterized by the opening of an energy gap and a reduction in its crystal symmetry below $T_c=326\mathrm{K}$. The primary cause of this transition is debated to be either electron-hole correlations, in line with the excitonic insulator hypothesis, or structural instability. The chain structure of ${\mathrm{Ta}}_2{\mathrm{NiSe}}_5$ enables effective control over its electronic and lattice properties by applying uniaxial strain. In this study, we utilize polarization-resolved Raman spectroscopy to demonstrate that the electronic and structural order parameters respond differently to uniaxial pressure applied along the Ta-Ni chains. Compressive strain reduces monoclinic distortions while enhancing excitonic fluctuations. Such disparate behavior suggests that many-body effects may significantly amplify exciton fluctuations even when monoclinic distortions are minimized, thereby supporting the excitonic nature of the phase transition.

Physical aging in polymers is a fundamental yet poorly understood phenomenon, as diverse macromolecular systems exhibit remarkably similar slow dynamics. Through molecular dynamics simulations of physically cross-linked networks composed of semiflexible polymers, we identify a previously unexplored class of self-similar aging. The network undergoes ultraslow coarsening characterized by a logarithmically growing mesh size, $L(t)\sim \ln t$, which governs the spatial organization, cohesive and bending energies, and the aging dynamics of the system. This single time-dependent length scale defines an internal clock, giving rise to spatiotemporal self-similarity of both structure and dynamics—offering a perspective on aging in soft and disordered materials.