Bound states in the continuum (BICs) are a fascinating class of eigenstates that trap energy within the continuum, enabling breakthroughs in ultra-low-threshold lasing, high-$Q$ sensing, and advanced wave-matter interactions. However, their stringent symmetry requirements hinder practical integration, especially in acoustic and electromechanical systems where efficient mode excitation is challenging. Here, we demonstrate deployable nanoelectromechanical quasi-BICs on suspended lithium niobate thin films, enabled by nanoscale Lamb wave phononic crystals operating at gigahertz frequencies. By exploiting the decoupling of symmetric ($S$) and antisymmetric ($A$) Lamb wave modes, we create a robust framework for BICs. Controlled mirror symmetry breaking induces targeted coupling between the $S$ and $A$ modes, resulting in quasi-BICs that preserve high-$Q$ characteristics and can be excited by traveling waves, eliminating the need for specialized excitation schemes. Our approach enables the multiplexing of quasi-BIC resonators along a single transmission line, each corresponding to a unique frequency and spatial position. This Letter presents a scalable route for the on-chip integration of BICs, bridging the gap between theoretical concepts and practical nanoelectromechanical devices, and opening new avenues in advanced signal processing, high-precision sensing, and quantum acoustics.

Electron hydrodynamics encompasses the exotic fluidlike behavior of electrons in two-dimensional materials such as graphene. It accounts for superballistic conduction, also known as the Gurzhi effect, where increasing temperature reduces the electrical resistance. In analogy with conventional fluids, the Gurzhi effect is only expected in the hydrodynamic regime, with the decrease in the resistance occurring at intermediate temperatures. Nonetheless, experiments on electron fluids consistently show that superballistic conduction starts at close-to-zero temperature. To address this paradox, we study hydrodynamic flow, and we find that replacing the conventional dynamics with tomographic dynamics gives rise to an accurate low-temperature description. The latter strengthens superballistic conduction, with potential applications in low-dissipation devices, and explains its differences with the Molenkamp effect and conventional fluid dynamics. Our study reveals that the superballistic paradox is resolved by considering the peculiarities of electron-electron collisions at the Fermi surface.

Controlling exciton transport in van der Waals heterostructures opens new pathways for exploring quantum phenomena and advancing optoelectronic devices. Previous studies have primarily focused on bilayer structures, where exciton transport is governed by limited electronic hybridization between layers. Extending to trilayers promises greater freedom in tuning electronic hybridization and enabling richer exciton transport phenomena, yet this area remains largely unexplored. Here, we demonstrate tunable and robust exciton transport in fully hybridized ${\mathrm{WS}}_2/{\mathrm{MoSe}}_2/{\mathrm{WS}}_2$ trilayers. Unlike the monotonic behavior observed in bilayer systems, trilayers exhibit symmetry-driven exciton transport that can be modulated using external electric fields and remains stable up to 165 K. This distinctive transport mechanism originates from hybridization-driven transitions among different excitonic phases—quadrupolar, hybrid dipolar, and interlayer excitons. These transitions can also be triggered by adjusting the exciton density, resulting in abrupt changes in both transport characteristics and exciton lifetimes. Our findings provide essential insights into exciton transport mechanisms in multilayer heterostructures and highlight electronic hybridization as a key design principle for next-generation quantum optoelectronics.

We present a detailed experimental study of the effect of Landau level mixing on various fractional quantum Hall states (FQHs) about half filling in a multiband system, namely, Bernal stacked trilayer graphene (TLG). In pristine TLG, the excitation energy gaps, Landé $g$ factor, effective mass, and disorder broadening of the odd-denominator FQHs are identical to their hole-conjugate counterpart. This precise particle-hole symmetry (PHS) stems from the lattice mirror symmetry that precludes Landau level mixing. Introducing a nonzero displacement field $D$ disrupts this mirror symmetry, facilitating the hybridization between the monolayerlike and bilayerlike Landau levels. This interband coupling enhances the Landau level mixing factor $\eta$ and activates three-body interactions—both of which explicitly break the PHS of FQHs. As a result, various conventional FQHs are completely destabilized, offering a route to explore such mixing effects on FQHs in a controlled way. We establish that the PHS breaking in TLG is of extrinsic origin and is fundamentally distinct from the intrinsic, interaction-driven symmetry breaking observed in the lowest Landau levels of single-layer and bilayer graphene.

Non-Hermitian (NH) Hamiltonians describe open quantum systems, nonequilibrium dynamics, and dissipative processes. Although a rich range of single-particle NH physics has been uncovered, many-body phenomena in strongly correlated NH systems have been far less well studied. The Kondo effect, an important paradigm for strong correlation physics, has recently been considered in the NH setting. Here, we develop an NH generalization of the numerical renormalization group and use it to solve the NH Kondo model. Our nonperturbative solution applies beyond weak coupling, and we uncover a nontrivial phase diagram. The method is showcased by application to the NH pseudogap Kondo model, which we show supports a completely novel phase with a genuine NH stable fixed point and complex eigenspectrum. Our NH numerical renormalization group code, which can be used in regimes and for models inaccessible to, e.g., perturbative scaling and Bethe ansatz, is provided open source.

Reversible, all-electric control of symmetry-protected zero-dimensional modes has been a long-standing goal. In buckled honeycomb lattices, a perpendicular field couples to the staggered sublattice potential providing the required handle. We combine scanning tunneling microscopy and tight-binding theory to switch zero-dimensional topological end states reversibly on and off in ultranarrow germanene nanoribbons by tuning the electric field in the tunnel junction. Increasing the field switches off the end modes of topological two-hexagon-wide ribbons, while the same field switches on zero-dimensional states in initially trivial three- and four-hexagon-wide ribbons. This atomic scale platform realizes a proof of principle for a zero-dimensional topological field effect device, opening a path for ultrasmall memory, controllable qubits, and neuromorphic architectures.

Non-Hermitian physics has unveiled a realm of exotic phenomena absent in Hermitian systems, with the non-Hermitian skin effect (NHSE) showcasing boundary-localized eigenstates driven by non-reciprocal interactions. Here, we introduce a new class of non-Hermitian systems exhibiting pure decay modes—eigenstates with pure, smooth exponential decay, devoid of the oscillatory wave patterns typical of traditional NHSE. Modeled as directed graphs with nonreciprocal hopping, these systems reveal quantized decay charges, defined as the sum of decay constants along edges at each node, offering a novel topological invariant. We derive universal conditions for these modes, enabling versatile configurations from one-dimensional rings, directed graphs with complicated connectivity, to higher-dimensional lattices. Experimental validation using microwave resonant circuits confirms the predicted pure decay profiles. This discovery paves the way for potential applications in photonics, signal processing, and beyond, harnessing the unique topological properties of non-Hermitian networks.

Antiferromagnets have garnered significant attention due to their negligible stray field and ultrafast magnetic dynamics, which are promising for high-density and ultrafast spintronic applications. Their dual functionality as both spin sources and information carriers could enable all-electrical self-induced switching of antiferromagnetic order, offering great potential for ultracompact spintronic devices. However, related progress is still elusive. Here, we report the deterministic switching of chiral antiferromagnetic orders induced by charge current at zero external magnetic field in the van der Waals magnetically intercalated transition metal dichalcogenide ${\mathrm{CoTa}}_3{\mathrm{S}}_6$. This system exhibits strong interactions between cobalt atom magnetic moment lattice and itinerant electrons within the metallic layers, as demonstrated by temperature-dependent angle-resolved photoemission spectroscopy, scanning tunneling spectroscopy, and topological Nernst effect measurements. Notably, the itinerant-localization interactions lead to current-induced chiral spin-orbit torques as well as Ruderman-Kittel-Kasuya-Yosida exchange torques that interact with the localized magnetic moments, facilitating all-electrical switching of the chiral magnetic order in the ${\mathrm{CoTa}}_3{\mathrm{S}}_6$ flake. Our Letter opens a promising avenue for manipulating antiferromagnetic orders by delicately engineering the synergistic interactions between magnetic moments and itinerant electrons.

Exciton-exciton annihilation, in which two excitons interact to generate high-energy excitations, is an important nonradiative channel in light-induced excited-state relaxation. When efficient, this process offers an alternative route to exciton emission, potentially allowing extended energetically excited particle lifetime and coherence. These properties are significant in designing and understanding materials-based quantum devices, particularly for low-dimensional semiconductors. Here, we present a first-principles framework to compute exciton-exciton annihilation mechanisms and rates using many-body perturbation theory within the GW and Bethe-Salpeter equation formalism. Our method explicitly accounts for Coulomb-driven and phonon-assisted exciton-exciton scattering by explicitly evaluating the interaction channels between the constituent electrons and holes composing the Bethe-Salpeter equation excitons. We apply this framework to monolayer ${\mathrm{WSe}}_2$ and explore the $A$, $B$ excitation manifolds, finding picosecond-scale annihilation between bright and dark states, cross valleys, and cross peak manifolds. These channels become allowed due to scattering into free electron-hole pairs across the Brillouin zone. Our results supply new insights into nonradiative exciton relaxation mechanisms in two-dimensional materials, providing a predictive and general tool for modeling these interactions in excitonic materials.

Maximum entropy methods, rooted in the inverse Ising or Potts problem of statistical physics, have been fundamental in inferring pairwise interaction models of complex systems. These models have found impactful applications in fields such as bioinformatics, where they are used to infer protein structural contacts, and in neuroscience, for describing patterns of neural activity. Despite their considerable success, these approaches fail to capture higher-order interactions that could be crucial for a full description of collective behavior. In contrast, modern machine learning methods can model such interactions, but their interpretability usually comes at a prohibitive computational cost. Restricted Boltzmann machines (RBMs) provide a computationally efficient alternative by encoding statistical correlations through hidden units in a bipartite architecture. In this Letter, we introduce a method that maps RBMs onto generalized Potts models, enabling the systematic extraction of interactions up to arbitrary order. Leveraging large-$N$ approximations, made tractable by the RBM’s structure, we extract effective many-body couplings with minimal computational effort. We further propose a robust framework for recovering higher-order interactions in more complex generative models, and introduce a simple gauge-fixing scheme for the effective Potts representation. Validation on synthetic data demonstrates accurate recovery of two- and three-body interactions. Applied to protein sequence data, our method reconstructs contact maps with high fidelity and outperforms state-of-the-art inverse Potts models. These results establish RBMs as a powerful and efficient tool for modeling higher-order structure for high-dimensional categorical data.

We performed experiments to directionally freeze agar hydrogel drops on a copper substrate maintained at low temperature. Unlike the water droplets studied in the literature, where the liquid part can reorganize during freezing, these droplets present a strictly vertical expansion. This is due to the presence of the viscoelastic solid polymer matrix, which prevents deformation of the unfrozen part, leading mainly to an elongation in the direction of the temperature gradient. We can then derive two distinct models to describe the deformation upon freezing for 2D water droplets and hydrogels, respectively. They are both in good agreement with the experimental observations. The model is also predictive for different object shapes, as the hydrogel can be freely molded without a container.

The source count dipole from wide-area radio continuum surveys allows us to test the cosmological standard model. Many radio sources have multiple components, which can cause an overdispersion of the source counts distribution. We account for this effect via a new Bayesian estimator, based on the negative binomial distribution. Combining the two best understood wide-area surveys, NVSS and RACS-low, and the deepest wide-area survey, LoTSS-DR2, we find that the source count dipole exceeds its expected value as the kinematic dipole amplitude from standard cosmology by a factor of $3.67\pm 0.49$—a $5.4\sigma$ discrepancy.

We present the first measurements with a new collinear laser spectroscopy setup at the Argonne Tandem Linac Accelerator System, utilizing its unique capability to deliver neutron-rich refractory metal isotopes produced by the spontaneous fission of ${}^{252}\mathrm{Cf}$. We measured isotope shifts from optical spectra for nine radioactive ruthenium isotopes ${}^{106–114}\mathrm{Ru}$, reaching deep into the mid-shell region. The extracted charge radii are in excellent agreement with predictions from the Brussels-Skyrme-on-a-Grid models that account for the triaxial deformation of nuclear ground states. We show that triaxial deformation impacts charge radii in models that feature shell effects, in contrast to what could be concluded from a liquid drop analysis. This indicates that this exotic type of deformation should not be neglected in regions where it is known to occur, even if its presence cannot be unambiguously inferred through laser spectroscopy.

We introduce group-based compartmental modeling (GBCM), a mean-field framework for irreversible contagion in higher-order networks that captures structural heterogeneity and correlations across group sizes. Validated through numerical simulations, GBCM analytically disentangles the role of each interaction order to the global epidemic dynamics, revealing how heterogeneity and inter-order correlations jointly shape the onset of outbreaks and the emergence of explosive dynamics. Crucially, we show that inter-order correlations drive the system along distinct pathways to explosive contagion—emerging universally across both irreversible and reversible spreading processes.

Efficient absorption of molecules through receptors on cell surfaces is crucial for various biological processes. While ubiquitous patterns of receptor distributions, including polar localization in rod-shaped cells, have been widely observed, the underlying evolutionary advantage of these patterns is unclear. In this Letter, we investigate how the spatial distribution of receptors on the cell surface affects the total flux entering the cell. We develop a numerical method that allows for the calculation of fluxes through all receptors using linear equations. Our calculations show that the flux through each receptor is spatially dependent for uniformly distributed receptors: the fluxes are highest near the poles in rod-shaped cells and near the invagination in defective spherical cells. Surprisingly, we show that the optimal receptor distribution on an arbitrarily shaped cell, which maximizes the total flux, is precisely the charge density distribution on an ideal conductor of the same shape, in agreement with numerical simulations. Our Letter unveils the evolutionary origin of receptor localizations.

Chemotaxis allows single cells to self-organize at the population level, as classically described by Keller-Segel models. We show that chemotactic aggregation can be understood using a generalized Maxwell construction based on the balance of density fluxes and reactive turnover. This formulation implies that aggregates generically undergo coarsening, which is interrupted and reversed by cell growth and death. Together, both stable and spatiotemporally dynamic aggregates emerge. Our theory mechanistically links chemotactic self-organization to phase separation and reaction-diffusion patterns.

We investigate the dynamical spreading of correlations in many-body quantum systems with competing short- and global-range couplings. We monitor the nonequilibrium dynamics of the correlations following a quench, showing that for strong short-range couplings the propagation of correlations is dominated at short and intermediate distances by a causal, light-cone dynamics, resembling the purely short-range quantum systems. However, the interplay of short- and global-range couplings leads to a crossover between space-time regions in which the light cone persists to regions where a supersonic, distance-independent spreading of the correlations occurs. We identify the important ingredients needed for capturing the supersonic spreading and demonstrate our findings in systems of interacting bosonic atoms, in which the global-range coupling is realized by a coupling to a cavity light field or atomic long-range interactions, respectively. We show that our results hold in both one and two dimensions and in the presence of dissipation. Furthermore, we characterize the short-time power-law scaling of the distance-independent growth of the density-density correlations.