Papers

The quantum anomalous Hall effect carries dissipationless chiral edge currents without an external magnetic field, yet raising its operating temperature and controlling the number of edge channels remain difficult. Using first-principles calculations, we identify the two-dimensional metal-organic kagome ferromagnet Eu$_2$(C$_6$H$_4$)$_3$ as an intrinsic Chern insulator whose topological gap can be enlarged by mechanical strain. The monolayer has a spin-orbit-coupling-induced gap of 72.7 meV that widens to 124.7 meV under -8% biaxial strain, realizing a quantum anomalous Hall phase with Chern number $\mathcal{C}=-1$ and a single chiral edge state. The local moments come from the half-filled Eu $4f^{7}$ shell, while the gap-opening spin-orbit coupling is carried by Eu $5d$ states hybridized into the carbon kagome bands. The AB-stacked bilayer couples ferromagnetically and accumulates the per-layer Chern numbers, giving $\mathcal{C}=-2$ with two co-propagating chiral channels. An out-of-plane electric field then drives the bilayer through a sequence of topological transitions among $\mathcal{C}=-2$, $-3$, and $-1$, switching the number of edge channels. Together, strain, stacking, and gating give three distinct handles on the gap and the Chern number within a single stoichiometric material.

We investigated the upper critical field of a large single grain of the Nb-substituted van der Waals layered quasicrystal (Ta$_{0.7}$Nb$_{0.3}$)$_{1.6}$Te. The sample exhibits a sharp superconducting transition at $T_{\mathrm{c}}$ = 1.35 K, the highest value reported to date among quasicrystal superconductors. The angular dependence of the critical field exhibits a pronounced criterion dependence: the field determined using the 10% $R_{\mathrm{N}}$ ($R_{\mathrm{N}}$: normal-state resistance) criterion is well described by the anisotropic Ginzburg-Landau model, whereas those determined using the 65% and 90% $R_{\mathrm{N}}$ criteria exhibit Tinkham-like angular dependence characteristic of two-dimensional superconductivity. The high-field part of the resistive transition is well described by a surface-superconductivity model and exhibits a pronounced excitation-current dependence for magnetic fields close to the $ab$ plane, supporting the presence of surface superconductivity on the quasiperiodic $ab$-plane surfaces. The bulk $H_{\mathrm{c2}}$ is strongly anisotropic, with the in-plane $H_{\mathrm{c2}}$ exceeding the weak-coupling Pauli limit by a factor of approximately 2.5. For both field orientations, $H_{\mathrm{c2}}(T)$ deviates upward from the conventional dirty-limit Werthamer-Helfand-Hohenberg prediction at low temperatures. A phenomenologically modified Ginzburg-Landau-Abrikosov-Gorkov model incorporating a spatial distribution of the electronic diffusivity substantially improves the description of $H_{\mathrm{c2}}(T)$, suggesting that spatial variations in electronic transport properties may contribute to its anomalous temperature dependence.

Magnetic moments carried by rotating ionic motion in crystals are becoming recognized as an important contribution to magnetism, angular momentum transport, and optical activity. However, efficient approaches to their dynamical control are lacking. Here, we report THz-driven generation and optical detection of quantum ionic magnetism in quantum paraelectric SrTiO3. We observe an oscillatory ionic magnetization without a corresponding oscillatory polarization, contradicting from the classical relation M~PXdP/dt while its suppression above the quantum paraelectric regime points to a quantum ionic origin. Analysis shows that this effect results from the beating between quantum ionic eigenstates whose degeneracy is lifted due to the directional symmetry breaking by the THz pulse. The presented approach provides a pathway for the ultrafast control of ionic magnetization in quantum materials for spintronic and thermotronic applications.

We show that the noncommutative second Chern number of a $(3+1)$D disordered axion pump remains quantized beyond global spectral gap closure at $W_g \approx 14.5$. Large-scale computation of the second Chern number and finite-size scaling demonstrate convergence of $\mathrm{Ch}_2$ toward $-1$ well into the mobility-gap regime ($W \lesssim 16.5$), while the Středa-Hall response $\partial_\phi \mathrm{Ch}_{0,3}$ departs rapidly after global spectral gap closure, serving as an internal control that distinguishes bulk mobility-gap protection from finite-size artifacts. Level statistics identify a 3D unitary Anderson transition at each pump slice and locate the mobility-edge bottleneck at $\tau=0$, with critical disorder $W_c \approx 18$.

Conventional score-based diffusion models learn scores without representing normalized densities, whereas tractable normalized models support both sampling and direct likelihood evaluation. A recent tensor-network approach provides such a representation but is largely restricted to low-dimensional lattices. Here we introduce a discrete diffusion model that parameterizes normalized probability distributions using variational autoregressive networks. Explicit Markov jump operators govern the forward noising and reverse denoising dynamics, extending discrete diffusion models with normalized distributions to spin systems on higher-dimensional lattices. We apply this framework to the two- and three-dimensional Ising models across ordered, critical, and disordered regimes, accurately computing thermodynamic quantities including free energy, energy, and magnetization. We further integrate the framework with Monte Carlo sampling, using adaptive diffusion steps to maintain high acceptance rates even at low temperatures while enhancing sample diversity. These results establish a neural-network framework for the discrete diffusion model with normalized probability distributions.

In physical experiments, interventions can alter hidden experimental states in ways that cannot be predicted in advance. Autonomous scientific agents must therefore interpret the consequences of their interventions while operating with incomplete knowledge of the experimental state. Here we investigate this problem using scanning tunneling microscopy (STM) tip conditioning, traditionally a human-expert-intensive task governed by inaccessible tip apex conditions and uncertain action outcomes. We introduce quailbot, an agent harness that places the LLM inside the instrument feedback loop by linking physical interventions with experimental readbacks. After a brief apprenticeship with a human expert, frontier LLM agents autonomously completed end-to-end tip conditioning on an STM and passed an independent verification. The contingencies that arose during the experiments further exposed the limits of LLM agentic autonomy when relevant experimental states or dynamics were hidden or unmodeled. Our results show that future autonomous physical experimentation requires agents to infer hidden and unmodeled experimental states, track the outcomes of their actions, and operate within the observability and action limits of real instruments.

Electric-field control of magnetic order and valley polarization holds great promise for spintronic and valleytronic applications. However, achieving such electrical modulation remains a fundamental challenge in two-dimensional (2D) van der Waals (vdW) magnets. Herein, via first-principles calculations, we verify that electrically tunable interlayer magnetic order and valley polarization can be realized in Janus VSSe bilayers with different interfaces. Although the magnitudes of dipole moments within each constituent Janus monolayer are identical, the vertical built-in electrostatic potential difference $\Delta\phi$ across the bilayer depends strongly on the orientations of these dipoles, which originates from the distinct interfacial configurations. As a consequence, the VSSe bilayers with different interfaces possess distinct interlayer magnetic couplings and show dramatically varied responses to external electric fields. For Se-S interface, reversible electric-field switching between antiferromagnetic (AFM) and ferromagnetic (FM) states can be achieved due to the competition between itinerant-electron-mediated FM exchange coupling and interlayer $\Delta\phi$-dependent AFM/FM super-superexchange interactions mediated by interfacial Se and S atoms. For Se-Se interface, both the valley polarization and spin splitting can be effectively reversed by the out-of-plane electric field, realizing an all-electric-field controlled anomalous valley Hall effect. Our results demonstrate that the interface of the magnetic Janus bilayer could act as an additional degree of freedom to tune the electronic, magnetic, and valley properties in 2D vdW materials. The Janus VSSe bilayers are identified as a promising platform for the design of low-power spintronic and valleytronic devices.

Kinetic models of protein aggregation describe populations by size, not by spatial organization or morphology. We extend Lumry-Eyring nucleated polymerization to a model in which the monomer is a density field and each aggregate is a region bounded by a level set. Growth is a flux condition on the available sites of a surface. Condensation is a reaction between the bonding sites of two surfaces in contact, at a rate set by the bond rate and the contact geometry. The availability of those sites is a field on the interface, and its equilibrium value follows from Wertheim's perturbation theory. The collision efficiency and the Fuchs stability ratio are therefore computed, not fitted. In a well-mixed limit the model's spatial averages satisfy the rate equations term by term; the monomer fraction agrees to eight parts in ten thousand, a difference that arises from equating aggregate size with volume. The condensation kernel's exponent is $0.5806\pm0.0013$ against the $0.600\pm0.010$ fitted to a monoclonal antibody. The computed stability ratio reproduces thirteen of fourteen published conditions at twelve $k_BT$, but only with the bond rate at the top of its range. In a many-body box, aggregates merge at $2.2$ to $3.8$ times the two-body rate.

Several researchers have reported an atypical inversion of the lowest singlet ($S_{1}$) and triplet ($T_{1}$) excited states in nitrogen-substituted planar hydrocarbons. Contrary to Hund's rule of maximum multiplicity, poly-aza derivatives of phenalenyl, such as cyclazine and heptazine, have long been known to possess a negative singlet-triplet gap, $\Delta E_{ST}=E(S_{1})-E(T_{1})$. Using the well-known Pariser-Parr-Pople (PPP) model, a semi-empirical, wave-function-based Hamiltonian for correlated $\pi$-electrons, we investigate the singlet-triplet gap in ten N-substituted phenalenyl motifs. Two schemes of long-range Coulomb interactions are considered, and key parameters, including the on-site orbital energy, Hubbard U, and hopping integrals, are systematically tuned to benchmark the model for reliably estimating negative singlet-triplet gaps. Full configuration-interaction (FCI) method is employed to incorporate electron-correlation effects. Ground-state and $T_{1}$ absorption spectra are subsequently calculated using the optimized PPP parameters that best reproduce the available experimental data. For validation, first-principles TDDFT calculations using various exchange–correlation functionals are also performed. Conventional adiabatic TDDFT fails to reproduce the inverted ($S_{1}-T_{1}$) ordering, indicating that the inclusion of the correlation driven multiconfigurational effects are essential for describing it. We find that the singlet TDDFT ground-state absorption spectra reproduce several qualitative features of the PPP-FCI spectra, although the TDDFT excitation energies are systematically higher. Detailed analysis of the ground-state and $T_{1}$ absorption spectra reveals significant configuration mixing, providing a comprehensive characterization of the optical response of the N-substituted phenalenyl derivatives studied.

We extend the spherical-integral approach to $\mathcal{R}$-transforms of non-Hermitian random matrices to random matrices with a fixed $K \times K$ block structure. We introduce a rank-$K$ spherical integral defining a scalar $H$-transform on $2K \times 2K$ overlap matrices and an associated matrix-valued $\mathcal{R}$-transform encoding the joint block structure. Using the replica method, we derive a conjectural subordination relation for sums of independent block matrices. This framework provides a method for determining the spectral boundaries of large non-Hermitian random matrices with a fixed block structure.

The stochastic block model is a paradigmatic model of networks with community structure. Yet percolation in the model has been studied primarily in cases with a fixed block structure, even though in real networks, the community structure may evolve as the network grows. Here we study percolation in sequences of stochastic block models in which the numbers and sizes of communities, as well as the intra- and intercommunity connection probabilities may all change with the network size. We analyze five such sequences using two methods: linearized self-consistent equations for the locally tree-like models and a branching process at the community scale for the models with nonvanishing clustering. We find that the critical average degree is not generally equal to $1$, even in locally tree-like sequences, because the transition depends on how connections are distributed across the evolving community structure. We also show that the community-scale branching process accurately predicts the transition when intercommunity connections are sufficiently sparse, even in the presence of nonvanishing clustering, while a geometric stochastic block model sequence demonstrates the limitations of this method when correlations between intercommunity connections cannot be neglected. These results extend percolation studies in the stochastic block model to more realistic scenarios with evolving community structure, and may provide new methods to derive the upper and lower bounds for the percolation threshold in geometric long-range percolation.

Large-scale simulations of correlated electron systems require repeated evaluations of the electronic forces and transition energies driving collective dynamics. Machine-learning surrogates alleviate this bottleneck, but incorporating symmetry often involves carefully designed descriptors or specialized network architectures. We show that ordinary multilayer perceptrons equipped with finite-group averaging provide exactly equivariant surrogates directly from microscopic configurations. The construction separates symmetry enforcement from the internal network architecture and applies to both discrete and continuous lattice degrees of freedom. In the Falicov–Kimball model, it predicts directional hopping free-energy differences; in the Holstein model, its invariant limit generates conservative lattice forces. Benchmarks against exact diagonalization establish microscopic accuracy and agreement of dynamical correlations, while large-scale simulations recover multiscale charge ordering and charge-density-wave coarsening. These results demonstrate an accessible, reusable route to symmetry-preserving many-body dynamics for systems with finite lattice point groups.

For the purpose of modelling ferroelectric switching in wurtzite-structured materials, four cost-effective density-functional theory (DFT) methods (PBE, PBEsol, r2SCAN, and r2SCAN-rVV10) are considered and compared to various ab initio approaches based on the random-phase approximation (RPA), including RPA with singles corrections (RPAR+S), as well as second-order Møller-Plesset perturbation theory (MP2). The purpose is to determine whether an ab initio approach could act as a 'gold standard' for estimating the reliability of DFT, thus determining an optimal DFT method for use in exhaustive tasks such as the training of machine-learning interatomic potentials (MLIP) for large-scale simulations of materials of arbitrary composition and structure such as Al1-xScxN and Zn1-xMgxO, using AlN, Al0.5Sc0.5N, ZnO, and Zn0.5Mg0.5O as model materials. Applications of active learning (AL) are now common, in which results from MLIP simulations are used to enhance the DFT training data set, but future extended active learning (EAL) methods will also need to systematically assess the DFT methodology against a gold standard. Herein, the variability of the ab initio results is found to exceed that required for a robust gold standard, but the DFT and ab initio approaches appear to converge on RPAR+S and r2SCAN-rVV10 as optimal method choices to initiate EAL. The electron correlation energy is found to be dominated by covalent binding effects associated with the high-electron-density anions involved, but the van der Waals dispersion force is seen to be too significant to ignore in ferroelectric modelling.

Here, magneto-optical magnetometry measurements on Py/NiO bilayers reveal a pronounced magnetic-field-induced wavelength shift, demonstrating strong magneto-optical coupling in this antiferromagnetic system. A systematic and monotonic spectral shift of up to ~ 400 nm is observed as the applied magnetic field increases, saturating at higher fields. Quantitative analysis shows that the associated magneto-optical energy variation is on the order of 107 eV, comparable to the magnon energy scale in NiO. Owing to the large NiO thickness, the observed effect originates from magnons intrinsic to the antiferromagnetic NiO layer rather than from spin currents injected by the Py underlayer. These results provide direct experimental evidence for magnetic-field control of antiferromagnetic magnon energies via magneto-optical interactions, establishing Py/NiO bilayers as a promising platform for optically probing and manipulating antiferromagnetic spin dynamics.

We report the first experimental observation of resonantly enhanced propagating phonon transport induced by magnon pumping in a ferromagnetic/piezoelectric bilayer. Surface acoustic waves (SAWs) generated in a 128$^{\circ}$ Y-cut LiNbO$_3$ delay-line device resonantly excite magnetization dynamics in an adjacent Co film through magnetoelastic coupling. The enhancement of the transmitted acoustic signal occurs exclusively when the SAW frequency satisfies the ferromagnetic resonance condition predicted by the Kittel dispersion, providing a direct experimental fingerprint of resonant magnon-phonon coupling. A systematic comparison between the Co/LiNbO$_3$ bilayer and the bare LiNbO$_3$ substrate demonstrates that the observed transmission enhancement originates solely from the dynamic interaction between propagating phonons and coherent magnetization precession. Furthermore, measurements performed at different SAW harmonics reveal that only the harmonic satisfying the FMR condition produces a measurable enhancement, confirming the frequency-selective nature of the phenomenon. These findings establish an efficient mechanism for transferring energy from magnons to propagating phonons and provide a new strategy for actively controlling coherent acoustic transport in hybrid spintronic, straintronic, and quantum phononic platforms.

Exciton condensates are long-sought correlated quantum states arising from macroscopic coherence of bound electron-hole pairs. Although equilibrium and transient excitonic states have been reported in several material platforms, direct evidence for a light-induced exciton condensate state has been challenging to achieve as an intrinsic property of a bulk quantum material. Here, we use time- and angle-resolved photoemission spectroscopy to investigate long-lived photoexcited carriers in the intrinsic magnetic topological insulator MnBi$_2$Te$_4$ with the chemical potential tuned to the topological surface state by Sb substitution. Following optical excitation, we observe the delayed emergence of a transient state whose formation coincides with depopulation of the bulk conduction band and whose lifetime extends to the microsecond timescale. The quasiparticle dispersion exhibits a pronounced flattening and develops a Mexican-hat-like profile. These spectral signatures are consistent with the formation of a metastable excitonic condensate state. Our results establish magnetic topological insulators as a promising platform for investigating long-lived photoinduced many-body states and their interplay with topology and magnetism.

We investigate how particle-hole symmetry, quantum interference, and tunnel barriers shape thermodynamic uncertainty relations in chaotic Andreev billiards. Using random-matrix theory and the Mahaux-Weidenmüller scattering approach, we study charge conductance and shot noise across the four Altland-Zirnbauer symmetry classes, from the single-channel extreme quantum limit to the multichannel semiclassical regime and from ideal to opaque contacts. We characterize thermodynamic precision through two complementary ensemble observables: either by averaging the sample-resolved noise-to-conductance ratio, or from the separately averaging noise and conductance. Their pronounced discrepancy in the extreme quantum regime reveals the non-self-averaging character of mesoscopic transport and persists over a broad range of barrier transparencies. For ideal contacts, the first provides a sensitive fingerprint of the Altland-Zirnbauer symmetry class. In the opaque regime, this hierarchy changes. Despite these strong symmetry- and barrier-dependent effects, the standard thermodynamic uncertainty relation remains satisfied throughout all regimes investigated. Our results establish thermodynamic uncertainty as a symmetry-sensitive probe of universal transport in chaotic normal-superconducting systems.

Usually in semiconductor heterostructures, such as quantum wells, the quantum confinement is realized by means of heterobarriers, which are simply the band offsets in adjacent materials. Here the arguments are provided, that the energy dispersions in materials (in simple case determined by effective masses) are important as well. Using a simple model system, such as quantum well with an additional heterojunction, it is shown the predominant localization of the carrier density in the regions with higher effective mass. The possibility of different spatial localization of wave function for different subbands is predicted. This can be applied in semiconductor structures such as quantum cascade lasers.

Polymer property prediction lacks open, standardized benchmarks that enable rigorous comparison of machine-learning methods, with existing resources covering only a narrow fraction of polymer architectures, such as homopolymers. We introduce Polymer Benchmark 2026 (PolyBench26), an open dataset comprising nearly 250,000 polymer-property datapoints across eight physical properties, including data from experimental measurements, density functional theory, and molecular dynamics. The benchmark supports four evaluation tasks across homopolymers and alternating, random, and block copolymers: in-distribution property prediction, dataset-size scaling, repeat-unit complexity, and transfer to held-out polymer architectures. We compare language model, graph-based, and descriptor-based approaches and find graph-based models provide the lowest errors in property prediction, retain their advantage across the evaluated training-set sizes, and remain robust to increasing repeat-unit complexity. PolyBench26 provides a reproducible foundation for developing models for the increasingly complex polymer design space. The PolyBench26 benchmark is available open-source at https://github.com/rlearsch/PolymerBenchmark2026.

Quantisation is considered as an action of classical point operators on field states at the Planck scale of the phase space. Emphasis is placed on the sequence of physical variables. A "state language/Dirac notation" for classical mechanics is introduced; in many cases, it replaces the principle of stationary action for conservative systems. Observed classical and quantum dynamics are considered as different vectorisations of the free semigroup contribution of time. There is a dream of describing classical dynamics as complex transformations of state vectors over such a free semigroup, rather than solving differential equations. The transition from the alphabet to states, from states to state functions, and from state functions to measurable quantities is managed by projectors. An attempt is made to provide a derivation of the Legendre transformation. The trivial multiplication of the potential energy by the wave function in the coordinate representation and its non-trivial operator action in the momentum representation are obtained without a Fourier transform nor the Planck scale. The quantisation procedure is divided into two stages: first, the action of point-like classical operators on field functions; and second, accounting for the physically finite scale of the Planck length against the backdrop of the possible infinitesimality in the classical phase space. The concept of an angle between states is introduced, defining the measure of "quantumness". The free semigroup time contribution is studied in the context of the Born rule.

We develop a first-principles theory for nonadiabatic surface dynamics, providing a fit-free connection between density functional theory (DFT) calculations and the effective multi-orbital Anderson-Newns (AN) theory. Our theory contains two main advances. First, we outline the multi-orbital AN theory with orbital overlap and derive closed-form expressions for the hybridization energy, electronic dynamics, and electronic friction. Second, we describe a procedure to map the DFT Hamiltonian into the effective AN Hamiltonian with nuclear-position dependence. We obtain the electronic part of the AN Hamiltonian solely from the adsorbate-projected density-of-states matrix. We then define the bare nuclear potential as the difference between the total energy and the hybridization energy. The theory is applied to H and CO on the Cu surface, where widely used assumptions about the hybridization function, including the wide-band limit, semi-elliptical forms, and separability in energy and nuclear coordinate, are found to fail, and the single-orbital description breaks down qualitatively for CO. We expect this work to be broadly useful for first-principles modeling of coupled nuclear-electronic dynamics and chemical reactions at metallic surfaces.

We have examined the nature of elementary excitations in particular, their spin polarization, in recently discovered zero-field fractional Chern insulator in twisted bilayer MoTe$_2$. We have found that the finite-size bilayer system, in close proximity to a planar parabolic quantum dot containing a single electron (or a hole), forms an incompressible spin-unpolarized fractional Chern insulator at 1/3 filling factor. The corresponding energy gap is found to be large and weakly dependent on the separation between the quantum dot and the bilayer. We predict that in this fractional Chern insulator coupled to a quantum dot, spin-unpolarized quasiparticles and quasiholes are expected to appear as low-energy elementary excitations. The charge density results indicate that, for the spin-unpolarized quasiparticles, the positive charge is strongly localized near the negatively charged QD within the spin-flipped component, whereas for the spin-polarized quasiparticles, such localization is much less pronounced.

The interplay between non-trivial background geometries and quantum dynamics has emerged as a powerful tool to tailor the electronic properties of 2D materials. In this work, we investigate the effective quantum dynamics of massless Dirac fermions confined to a twisted graphene structure called a catenoid bridge, which connects two single-layer sheets. By adopting a continuum approach, where the electron dynamics is governed by a purely covariant curved Dirac equation, we obtain the effective Hamiltonian containing both curvature and twist interactions. We found that the torsion modifies the electronic states by producing a geometric phase on the wave function. In addition, the twist also deforms the surface geometry, which leads to a new geometric term in the effective Hamiltonian. This twist potential enhances the barrier around the catenoid throat, which increases the suppression of the inter-layer transmission coefficient. Like the spin-curvature interaction, the spin-twist term has a chiral dependence which is invariant under a combined parity and spin flip transformation. As a result, the electronic states can be restricted to the upper or lower layer. These findings provide valuable insights into how mechanical deformations can be harnessed to control quantum transport in graphene-based wormhole architectures.

Understanding how liquid-liquid phase separation impacts the mechanics of filament networks is a fundamental physical problem at the heart of biological cellular processes and soft material design. While a few theoretical mechanisms have been proposed, a clear demonstration of the direct coupling of phase separation to the overall network stiffness is missing. We report experiments that reveal a universal mechanism by which the condensation of macromolecular crowders induces a rigidity transition in a model filament network. We reconstituted stiff sterically interacting helical filaments and polymeric crowders. Initially, the macromolecules were uniformly dissolved and the filaments formed bundles that assembled a rigid entangled network. Once the crowders condensed into droplets, the network structure lost its rigidity and its mechanical response weakened by an order-of-magnitude. The subsequent dissolution of the condensates was accompanied by the re-establishment of rigidity. Our results show that crowder phase separation modulates the mechanics of filament networks by tuning the osmotic pressure holding the network together. This principle may serve as a paradigm for devising dynamically tunable filamentous materials.

Using determinant quantum Monte Carlo simulations, we compare charge transport in the two-dimensional attractive and repulsive Hubbard models at strong coupling, $|U|/t=6$. Although the interaction with opposite signs generates qualitatively different low-energy spin, charge, and pairing correlations, both exhibit approximately linear-in-temperature resistivity over a broad intermediate- and high-temperature regime. At asymptotically high temperature this common behavior follows from the moment expansion of the conductivity, whose leading contribution is even in $U$. More strikingly, the similarity persists to temperatures well below $|U|$, where strong interaction-dependent correlations have already developed, and also irrespective of whether resistivity crosses the MIR limit. Using the Nernst–Einstein relation, we find that the common linear-in-temperature resistivity is primarily associated with an approximately Curie-like charge compressibility and weakly temperature-dependent diffusivity. The two models separate only at lower temperatures, where the attractive model develops a pronounced feature in the charge diffusivity correlated with signatures of pair formation. These results show that linear-in-temperature incoherent transport in the Hubbard model can be remarkably insensitive to the microscopic nature of the low-energy correlations. Our results suggest that transport in the incoherent regime appears insensitive to what the system will ultimately become at low temperature; the distinction between competing low-energy states becomes visible only when their characteristic correlations acquire sufficiently long spatial or temporal coherence.

Biochemical systems such as protein complexes often occupy configuration spaces whose dimensionality grows with the number of molecular components. Although usually viewed as an obstacle to coherent dynamics, here we show that high dimensionality can enhance topologically protected oscillations. In the topological regime, a stochastic system with a $D$-dimensional configuration space develops a steady-state current confined to a one-dimensional edge cycle. The intervening boundary faces between the $D$-dimensional bulk and the one-dimensional cycle form an interdimensional funnel, sequentially pushing the system towards lower dimensional faces, down to the one-dimensional cycle. As a consequence, increasing $D$ enhances the funnel, leading to improved one-dimensional localization and oscillatory coherence. A quantized biorthogonal Zak phase identifies the transition to the topological regime, which additionally exhibits a highly structured non-Hermitian skin effect. In contrast with previous realizations of topological states in stochastic systems, the phenomena we uncover have no counterpart in quantum condensed matter or active matter systems.

A conventional interaction-driven Weyl density wave is a complex scalar and supports vortex lines, but no topologically stable point defects. We show that two Weyl flavors do not merely duplicate this order. Starting from the matrix-valued internode coherence, a local flavor-symmetric repulsion selects a traceless adjoint condensate within the density-wave sector, while the fermionic ground-state energy locks its complex components into the collinear form $\mathbf{\Delta}=\Phi_0\mathbf{n} e^{i\theta}$. The resulting order-parameter manifold, $(S^2\times S^1)/\mathbb Z_2$, supports both unit hedgehogs and half-quantum Alice strings of the same electronic mass that gaps the Weyl fermions. An elementary hedgehog binds a single normalizable zero mode whose empty and occupied sectors carry charges $-e/2$ and $+e/2$ at neutrality. An elementary Alice string carries a single chiral electronic mode despite its $\pi$ phase winding, and transporting a hedgehog around it reverses the hedgehog winding, $N\rightarrow-N$. Flavor therefore converts spontaneous translation breaking into a route to point-defect fractionalization and intertwines the point- and line-defect sectors of an interaction-generated electronic mass.

Cavitation, the growth of bubbles in fluids and soft matter, plays a central role in tissue damage, ultrasound therapies, and material failure, yet the influence of viscoelastic dissipation on bubble dynamics remains unclear. Here, we investigate cavitation in polyacrylamide hydrogels with identical elastic moduli but different viscous dissipation. We observe a striking symmetry breaking transition: elastic gels rapidly develop ellipsoidal cavities before rupture, whereas viscoelastic gels sustain large, nearly spherical bubbles. A modified Rayleigh Plesset framework shows that viscous stresses suppress shape instabilities and delay symmetry breaking, whereas elastic stresses accelerate cavity deformation. Finite element simulations independently validate these findings. The Deborah number (De) further captures the competition between material relaxation and cavity growth, with higher De associated with predominantly elastic growth and lower De with greater relaxation. Together, our results establish viscous dissipation as a key stabilizing mechanism that governs bubble morphology and failure in soft materials. These results have direct implications for understanding cavitation-mediated damage in biological tissues, optimizing therapeutic ultrasound, and advancing mechanical characterization of hydrogels for engineering and food processing applications.

A simple symmetric random walk on a one-dimensional lattice is guaranteed to reach any target site, yet its mean first-passage time diverges. Here, we show that stochastic fluctuations in the jump rate can fundamentally alter this classic result. We find a phase transition in the mean first-passage time: sufficiently broad rate fluctuations render it finite, whereas weaker fluctuations leave it infinite. Our results demonstrate that temporal fluctuations in the jump rate—and hence in the diffusivity—can overcome spatial wandering and regularize otherwise divergent first-passage times.

In multilayer quantum Hall systems, when the layer separation is sufficiently small, the interplay between intralayer and interlayer Coulomb interactions can lead to exotic, multi-component, many-body states. A particular example is the even-denominator fractional quantum Hall state (FQHS) at total filling factor $\nu=1/2$ in bilayer systems with negligible interlayer tunneling. This state can be understood as a generalized Laughlin state described by the Halperin-Laughlin $\Psi_{331}$ wavefunction. While such correlated states have been extensively explored in bilayers, little is known about their counterparts in systems with more than two layers. Here, we investigate a trilayer two-dimensional electron system confined to ultrahigh-quality GaAs triple quantum wells. We observe an exotic FQHS at total filling factor $\nu=5/7$, evinced by a deep longitudinal resistance minimum and a quantized Hall plateau, when the side layers have a density larger than the middle layer and $d/l_B \simeq 2.2$ ($d$ is the interlayer distance and $l_B$ the magnetic length). This state is naturally interpreted as the long-predicted trilayer, generalized Laughlin ($\Psi_{33311}$) state, characterized by $\nu=1/3$-like intralayer correlation within each layer and $\nu=1$-like interlayer correlation between neighboring layers. Our observation establishes a new member of the Halperin-Laughlin many-body states that extends interlayer coherence to three coupled layers.