Papers

Thermal control is one of the important technologies for fundamental science and thermal management. Among them, thermal oscillators have been in demands in the field of materials science and device application. In general, flexible frequency, amplitude, and waveform are needed for useful thermal oscillator, and the stability of the average temperature is also highly required. However, thermal oscillators based on an AC-current-driven heater require complicated control of input power to achieve the above-mentioned flexibility and stability of the outputs. Here, we demonstrate that magnetically-driven thermal oscillators fabricated using a metal-superconductor (Cu-Pb) joint achieve those requirements easily by tuning the applied magnetic field (H). A DC-current-driven heater is attached on the metal (Cu) side, and the superconductor (Pb) edge is attached to thermal bath. We use a sharp and huge change in thermal conductivity at the superconducting transition of the Pb wire to generate thermal oscillation at the Cu-wire side. A sine-shaped thermal oscillation with an amplitude of 180 mK and a frequency of 0.17 Hz is observed with highly stable average temperature. Furthermore, a larger amplitude is achieved in a square-shaped oscillation with a larger H amplitude. Our thermal oscillator with temperature stability, large amplitude, and relatively high frequency will work as a flexible AC heat source at cryogenic temperatures.

First principles molecular dynamics simulations of germanium reveal a reversible liquid-glass transition below the equilibrium melting point with a wide hysteresis loop. Direct calculation of the liquid and amorphous state free energies, enabled by absolute entropy calculations, verify that the transition is first order in character between two metastable phases. These results lend credence to models of explosive recrystallization from amorphous Ge thin films, through a metastable liquid state and finally reaching the low temperature crystalline structure.

In 1966, Hohenberg, Mermin and Wagner proved that long-wavelength fluctuations destabilize the long-range order of continuous symmetry in two-dimensional (2D) systems. Later in the 1970s, Berezinskii, Kosterlitz and Thouless developed the BKT theory describing an unconventional phase transition between quasi-long-range and short-range order in 2D systems driven by the binding-unbinding of topological defects, which has become a fundamental topic in statistical mechanics, condensed matter physics, and soft matter physics. One of the most important applications of the BKT theory is the melting of 2D crystals, whose mechanisms are not yet fully understood. Recently, this topic has been extended to the area of active matter, where the non-equilibrium nature leads to novel phenomena that deviate from the Hohenberg-Mermin-Wagner theorem. In this review, we first focus on the recent theoretical and computational progress in the 2D melting problem in passive systems, and then summarize the inspiring results obtained from non-equilibrium systems. The review closes with comments on several promising directions for predicting 2D melting scenarios and for understanding the non-equilibrium nature in 2D active matter systems.

We report end-to-end inference of Qwen3.6-35B-A3B – a 35-billion-parameter, $\sim$3B-active Mixture-of-Experts (MoE) model with a hybrid gated-delta-net / full-attention backbone – on a 2011 NVIDIA Tesla C2075 (Fermi, compute capability \smtwenty, 6\,GB), a GPU that predates tensor cores, native FP16 arithmetic, the DP4A integer dot-product instruction, and support in every modern CUDA toolchain. Because the 4-bit model ($\approx$10.5\,GB) is roughly twice the device memory, we adopt a hybrid execution strategy: the GPU performs batched prompt prefill with expert weights streamed layer-by-layer from host RAM, while decode runs on the host CPU using a hand-written W4A8 integer GEMV built on the SSSE3 pmaddubsw instruction. The entire engine – GEMM, hybrid-attention recurrence, MoE routing, and a from-scratch vision tower – is written by hand for \smtwenty{} and compiled with the legacy CUDA 8.0 toolchain. On a 947-token prompt we reduce prefill latency from 57.2\,s to 37.5\,s ($-34\%$) through expert pinning, single-pass prefill, and NUMA interleaving, and we raise decode throughput from 2.8 to 8.6\,\tps{} ($\approx 3\times$) with the integer-SIMD kernel. A position-indexed snapshot cache for the recurrent (gated-delta-net) state restores prefix reuse on a recurrent architecture, cutting a repeated 78\,s prefill to 0.5\,s. We also report a set of negative results – offloading the language-model head to the idle GPU, hyper-threading, and three GPU-kernel rewrites all fail to help – % which together pin down the practical floor of this hardware. Our aim is not a speed record but a careful account of what it takes, and where the walls are, to run a contemporary frontier-class MoE on fourteen-year-old silicon.

Conventional Fabry–Perot interferometry accesses only full braids of anyons and therefore cannot directly probe the elementary \(\pi\)-rotation exchange. Motivated by the recent quantum-antidot proposal for the Abelian anyons, we propose an interferometry for probing the elementary exchanges of non-abelian anyons using two gate-controlled quantum antidots. By tuning two antidots independently, the device realizes distinct cooperative tunnelling processes, which correspond to different braids of non-abelian anyons. For the unresolved local fusion channels, the difference between the interference signals of the single and double cooperative processes allows us to measure the elementary exchange of the non-abelian anyons, providing a direct probe of their non-abelian statistics and topological spins. For the resolved local fusion channels, the double-cooperative process is further distinguished by a reduced interference amplitude. Our work provides a promising and practical route for manipulating and detecting non-abelian braiding with the fundamental fractional statistics.

We introduce cyclic denoising – repeated forward and reverse diffusion at controlled noise amplitudes – as an extraction attack for image diffusion models. Inspired by random organization in disordered solids, cyclic denoising exposes regions of the learned distribution that are largely inaccessible to standard sampling. The dynamics drive samples toward attractors with a broad stability spectrum. The deepest attractors are ultrastable: they regenerate after near-total corruption and persist through thousands of noising-denoising cycles. Many of these attractors correspond to memorized training images, including stock photographs, brand watermarks, and web-crawl artifacts. The attack requires only sampler-level control, with no gradients, weight inspection, prompts, captions, or prior knowledge of the training data. Unlike generate-and-filter attacks, which rely on large-scale prompted generation and post-hoc similarity or membership-inference filtering, our main protocol is fully unconditioned. We demonstrate the phenomenon in Stable Diffusion v1.4 and in a pixel-space DDPM, showing consistent behavior across latent- and pixel-space diffusion models. Across noise amplitudes, we observe a yielding-like transition: low-amplitude cycling produces trivial absorbing fixed points or limit cycles, while larger amplitudes induce rearrangements, basin hopping, and long-lived trapping in structured memorized attractor basins. We also observe hierarchical partial absorption, prompt-stabilized basins, and cross-initial-condition universality of the recovered attractor set. Our results therefore show that cyclic denoising is both a physics-inspired probe of generative landscapes and a practical tool for memorization auditing, with implications for privacy, copyright compliance, and model fingerprinting.

The pairing symmetry of magic-angle moiré graphene is a fundamental question that remains unresolved. Combining experimental and theoretical inputs, we constrain the superconducting order parameters that can emerge from the incommensurate Kekulé spiral (IKS) normal state on the hole-doped side of $\nu = -2$. Imposing the additional experimental constraint of nodal superconductivity, we are left with the task of distinguishing between singlet or triplet pairing, and of determining the d-vector in the latter case. We propose definitive tests to identify the pairing symmetry based on two classes of experiments using the response of the superconducting state to Zeeman field orientation. The first set of predictions is for spectroscopic and thermodynamic measurements sensitive to low-energy excitations near the nodes. The second set is for phase-sensitive measurements of topologically protected Andreev bound states near boundaries, whose spectroscopy is shown to provide a smoking gun signature of the pairing symmetry.

Two-dimensional electron systems (2DESs) confined to wide GaAs quantum wells provide a unique platform to study exotic fractional quantum Hall states (FQHSs) because the 2DES has a bilayer charge distribution with significant interlayer tunneling. Precise control over the 2DES density allows the tuning of the interlayer tunneling over a wide range. Here, we present our discovery of new even-denominator FQHSs in the lowest Landau level (orbital index N = 0) at filling factors $\nu = 3/4$ and 5/4 in an ultrahigh-quality 2DES confined to a 72.5-nm-wide GaAs quantum well. The ground states at $\nu = 3/4$ and 5/4 both evolve from composite fermion Fermi seas to FQHSs as the density is raised so that interlayer tunneling is sufficiently reduced and the 2DES becomes two-component, signaled by the behavior of the FQHSs flanking $\nu = 3/4$ and 5/4. The two-component nature of the $\nu=3/4$ and 5/4 FQHSs is also evident from their extreme sensitivity to the bilayer charge distribution symmetry: both states disappear quickly when the charge distribution is made asymmetric by only $\simeq 2\%$. We find a natural explanation for the 3/4 and 5/4 FQHSs in terms of two states linked by particle-hole symmetry, and using the Scarola-Jain bilayer composite fermion framework which is a generalization of the well-known, two-component, Halperin state ($\Psi_{331}$ state). Our observations elucidate the crucial role of competing energy and length scales in wide quantum wells in stabilizing new ground states.

We report on the characterization of a narrow-line magneto-optical trap (MOT), where two different isotopes of the dysprosium (Dy) atom can be simultaneously loaded and trapped. We rely on phase modulation via high-power, free-space electro-optic modulators (EOMs) to generate optical sidebands at the correct detuning for two different isotopes. This technique is applied on the slowing transition at 421 nm and the MOT transition at 626 nm. Using modular resonant electronic circuits, we match the sideband separation to the isotope shift among the two target isotopes, realizing mixtures of the bosonic isotopes 164Dy -162Dy and 162Dy -160Dy. We exploit the interplay between radiation forces and gravity in the narrow-line MOT to control the spatial position of the two isotopes with the EOM drive frequency. We demonstrate full control of the isotopic mixture with the EOM drive, offering new and cost-effective capabilities for controlling mixtures of atomic species that can be trapped in a narrow-line MOT.

We consider Josephson junctions formed by two minimal Kitaev chains and investigate how the interplay between non-Hermiticity and superconducting phase difference enables the realization of stable topological states that do not exist in the Hermitian realm. In particular, we focus on non-Hermiticity produced by coupling the minimal Kitaev chain Josephson junction to normal reservoirs, which renders the system open and characterized by a complex Andreev spectrum. Interestingly, we find that this complex spectrum hosts second order exceptional points, where a pair of eigenvalues and their respective eigenvectors coalesce, and are fully controlled by the superconducting phase difference. Depending on the spatial unequal distribution of non-Hermiticity, these Andreev exceptional points can appear at zero or finite energies connecting stable energy lines protected by non-Hermitian topology. Moreover, tuning the system parameters, such as onsite energies, non-Hermiticity, or electron cotunneling, the Andreev exceptional points give rise to Andreev exceptional lines enclosing protected two-dimensional zero real energy areas. We also discuss potential detection schemes of Andreev exceptional points by using local and nonlocal conductance signatures. Our results demonstrate the utility of non-Hermiticity from normal reservoirs as a useful resource for engineering non-Hermitian topological phases in minimal Kitaev chain Josephson junctions.

Imaginary-time evolution (ITE) underpins a broad family of algorithms for ground-state preparation in quantum simulation and quantum many-body physics. In these methods, convergence is governed by the energy variance of the instantaneous state, causing the flow to approach the ground state only asymptotically. We introduce an augmented imaginary-time evolution (AITE) framework that replaces the standard gradient flow on the energy landscape with a geometrically informed descent along locally optimal directions, which are identified by exploiting the higher-order statistical structure of the instantaneous energy distribution. The resulting flow strictly outperforms standard ITE throughout the entire evolution and exhibits two qualitatively distinct regimes: a superlinear convergence regime, followed by an extinction regime in which the energy error vanishes exactly at a finite value of the imaginary-time flow parameter, in contrast to the asymptotic exponential decay of ITE. Standard ITE is recovered in the zero-skewness limit of AITE, implying that the acceleration extends naturally across the broader ITE algorithmic family.

We computationally investigate how environmental sensitivity of active matter interacts with soft confinement to shape collective dynamics. In our model, the active constituents are represented as self-propelled particles (SPPs), implemented as nematic, disjoint ring polymers whose direction of motion can reverse without tumbling. Coarse-grained molecular dynamics simulations reveal that collective dynamics arise from a three-way feedback between active stresses, boundary elasticity, and particle-level memory. With increasing driving force, FD, this feedback generates a sequence of collective dynamical regimes. At low FD, SPP motion is dominated by thermal fluctuations. At intermediate FD, coherent vortical motion emerges with intermittent, noise-driven reversals. With further increase in FD, reversals are suppressed, yielding sustained unidirectional vortical motion. At sufficiently high FD, the system transitions to a polar state characterized by strong nematic ordering of the SPPs, symmetry breaking of the enclosure shape, and persistent polar collective motion. In this regime, the SPPs accumulate at the leading edge of the enclosure, driving sustained ballistic propulsion. These results demonstrate how environmental sensitivity and soft confinement jointly regulate emergent collective states and identify boundary elasticity as a control parameter governing the balance between vortical and ballistic dynamics.

Active filaments, ranging from motor-driven biopolymers to elongated bacteria and worms, are paradigmatic examples of deformable active matter. How filament flexibility interacts with environmental heterogeneity to control their transport in crowded environments, however, remains poorly understood. Here, we perform large-scale Brownian dynamics simulations of tangentially driven active polymers moving through ordered and disordered obstacle arrays to map the long-time diffusion as a function of obstacle density and filament flexibility. We find that flexibility can either enhance or hinder transport depending on the structure of the medium. In disordered environments, transport is optimized at intermediate filament flexibility, whereas both highly flexible and semiflexible filaments diffuse more slowly. In contrast, dense ordered arrays enhance the mobility of semiflexible filaments by promoting directed motion along periodic channels. We identify three distinct transport regimes: (i) tortuosity-controlled diffusion of highly flexible filaments, characterized by trapping-and-hopping dynamics; (ii) confinement-assisted transport of moderately flexible filaments, which enhances diffusion in dense media; and (iii) persistence-controlled transport of semiflexible filaments, which facilitates diffusion in dense ordered media, but suppresses it in disordered media. Combining theory and simulations, we show that long-time diffusion is governed by confinement-induced changes in filament conformation and reorientation dynamics. Our work uncovers general transport principles for deformable active agents in heterogeneous environments and provides a predictive framework for active-filament navigation in complex porous landscapes.

We compare two different soft matter models, a generalized Random Organization Model (ROM) describing the stroboscopic dynamics of cyclically sheared suspensions, and an elastoplastic model describing the mesoscale dynamics of a yield-stress fluid under imposed stress. Both show absorbing phase transitions, sharing a peculiar mechanism: activity induces an internal noise which is transmitted over large distances by long-ranged mediated interactions, either hydrodynamic or elastic, which results in non-local creation of activity. They also both show convex transitions (i.e., the exponent $\beta >1$), in stark contrast with usual absorbing phase transitions, like (Conserved) Directed Percolation, which are concave ($\beta <1$). We further compare the dependence of the critical properties (activity mean value and fluctuations, avalanche statistics, low-wavenumber structure factor) on the decay exponent $\alpha$ of long-range interactions in both models, finding a qualitatively similar scenario. A smooth crossover is observed as a function of $\alpha$ between a concave transition regime for short-range interactions, with diverging fluctuations and compact avalanches, and a convex transition regime, with vanishing fluctuations and non-compact avalanches, for longer-range interactions. Although for a given range exponent $\alpha$, the values of critical exponents for both models differ, a good agreement between the models is found by parametrically plotting the different critical exponents as a function of the exponent $\beta$ of the mean activity. In this parametric representation, the concave regime is consistent with the behavior of the Long-Range Conserved Directed Percolation class, while the convex regime can be accounted for by a mean-field-type scenario with anomalous diffusion close to an absorbing boundary, inspired by the Hébraud-Lequeux model for the yielding transition.

Fourier's law fails when the mean free path of the energy carriers becomes comparable to the length and time scales over which the temperature field varies. We derive a thermodynamically consistent generalization in which the conductivity is promoted to a nonlocal memory operator $\bm{\kappa}_{\mathrm{eff}}(\mathbf{k},\omega)$, obtained by combining mesoscopic nonequilibrium thermodynamics with the Mori–Kubo–Zwanzig projection-operator formalism. The Onsager kernel decomposes exactly into a tensor sum over vibrational normal modes weighted by their Bose heat capacities and relaxation functions, and satisfies the second law by construction. Two consequences follow. First, because the modal weights carry the directional group velocity, the kernel is anisotropic, so a nominally isotropic crystal exhibits direction-dependent apparent conductivities $\Lambda_z\neq\Lambda_r$. Second, in a pump–probe experiment the modulation frequency does not introduce temporal memory but sets the probed wavevector through the thermal penetration depth, so the suppression of the apparent conductivity measured by time-domain thermoreflectance on Si, Ge and Si$_{1-x}$Ge$_x$ is a spatial-nonlocality effect set by a sub-micron carrier mean free path. Fitting the data of Wilson and Cahill yields nonlocality lengths of $0.25$–$0.4~\mu$m consistent with the mean-free-path spectra of these crystals. The framework supplies a thermodynamic foundation for the two-channel ballistic/diffusive picture of nondiffusive heat transport.

A monolayer graphene and its Dirac electrons can be equipped with an enhanced spin-orbit coupling (SOC) when proximitized by other van der Waals (vdW) materials, such as transition metal dichalcogenides (TMDs). In this work we analyze the cyclotron resonance (CR) absorption of such heterobilayers at quantizing magnetic fields in the presence of proximity-induced spin interactions, including the spin-pseudospin Rashba coupling. We evaluate the spin-textured wave functions of the Landau levels and calculate the absorption spectrum paying special attention to its spin proximity induced modifications. We reveal the formation of a fine double-peak structure of the main interband CR transitions, as well as the presence of additional spin-flip absorption, the combined cyclotron resonance (CCR), centered at different resonant frequencies. The selection rules for CCRs are identified and complemented by the perturbation theory analysis. We also discuss the polarization dependence of the absorption and the proximity-induced emerging magneto-optical responses. Our theory explains the effect of proximity-induced spin interactions for Dirac electrons cyclotron resonance and points out at its experimental verifications.

We investigate ferrimagnetic domain-wall dynamics under linearly oscillating in-plane magnetic fields. Starting from a ferrimagnetic Lagrangian that retains the field-dependent contribution to the kinetic energy, we derive collective-coordinate equations for the domain-wall position and azimuthal angle. This formulation makes explicit the field-induced inertial terms, including Coriolis-, Euler-, and centrifugal-like contributions, and clarifies how they couple translational and azimuthal dynamics. For an oscillating in-plane field supplemented by a weak static out-of-plane bias field, we show that periodic switching of the wall angle can be rectified into a finite average domain-wall velocity. At low drive frequencies, where the wall angle follows the oscillating field, the induced drift is proportional to the drive frequency rather than the field amplitude, while above a cutoff frequency the wall angle can no longer follow the drive and the average motion is suppressed. Micromagnetic simulations confirm the analytical predictions and demonstrate that the magnitude and direction of the drift can be tuned by the net spin density. These results identify linearly oscillating fields as a mechanism for frequency-controlled domain-wall motion in ferrimagnets and highlight the role of inertial spin dynamics near magnetic compensation.

Thermodynamic control is typically formulated as the optimisation of a single objective, yet competing costs rarely admit a common optimum, so single-objective control captures only one corner of the achievable performance space. We develop a general framework for multi-objective thermodynamic control of intrinsically nonequilibrium systems that maps out the full Pareto front of optimal control strategies. We show that Pareto-optimal protocols generically consist of smooth branches connected by boundary jumps, and that the relative weights of the objectives combine with the physical parameters into a single intrinsic scale that alone governs the trade-off. Remarkably, this scale plays a double role: it parametrizes a single functional form that generates the entire front, and it defines control equivalence classes, in which systems with different parameters but the same scale share identical optimal strategies. We illustrate the framework for two paradigmatic systems that are experimentally accessible: transport of an active particle in a harmonic trap, and a cyclic quantum-dot engine. For both, we obtain the Pareto front and optimal strategies in closed form.

We introduce a variational method to solve continuum quantum models with discrete tensor network techniques. The method leverages wavelet matrix product states (wMPS): matrix product states built on top of sufficiently regular ($N\geq 6$) Daubechies scaling functions. These states live in the continuum field theory Fock space, have finite energy density, and can be optimized with standard algorithms, without restriction to free theories. Further, exploiting the multi-resolution analysis built into wavelets, and its quantum circuit description, we can iteratively refine wMPS to obtain accurate approximations at arbitrarily fine length-scales. We showcase the efficiency of the method on the Lieb-Liniger model, computing energy density and correlation functions.

We discuss phenomenology associated with turbulent hydrodynamics in quantum fluids from a condensed-matter perspective. We begin with weakly-interacting superfluids, often modeled by a mean-field theory governed by the Gross-Pitaevskii equation. Considering the effect of quantum fluctuations beyond the mean-field approximation, we propose a study of many-body quantum effects in turbulent hydrodynamics, especially near zero temperature. We motivate examples of quantum many-body systems where such effects may be uncovered. These include bosons confined in a periodic potential in low spatial dimensions (one and two), and the associated quantum critical point of the superfluid-insulator transition, realized in present-day ultracold-atom and quantum computing platforms. We conclude by listing a set of (open) questions that may be answered using modern quantum many-body techniques. This article is part of the theme issue 'Frontiers of turbulence and statistical physics'.

We propose a unified perspective on classical and quantum chaos based on the sensitivity of a system's stationary states to slow driving. We probe this sensitivity via the system's susceptibility to the average protocol speed, which we call the “speed-Fisher information," and relate it to irreversible entropy production in the system. We show that chaotic dynamics manifests as a divergence of the speed-Fisher information with the protocol time, and that this response is controlled by the perturbation's low-frequency spectral weight. This approach to chaos applies to both classical and quantum Hamiltonian systems, and naturally extends to non-Hamiltonian classical flows. We illustrate this framework with simple classical and quantum examples, along with a non-Hamiltonian flow that qualitatively exhibits analogous low-frequency spectral behavior.

Spin-orbit coupling (SOC) is a relativistic effect that underpins a broad spectrum of phenomena in condensed matter physics, from topological phases of matter to spintronic functionality. Its relativistic origin, however, restricts strong SOC to heavy-element materials and locks spin-momentum texture into a fixed, material-specific pattern. Here we show that odd-parity coplanar magnets offer a nonrelativistic pathway to highly tunable SOC effects. We construct a bilayer coplanar magnet via symmetry-guided stacking of two monolayer odd-parity altermagnets and demonstrate that Rashba, Weyl, and Dresselhaus spin textures can all be realized, and that the spin texture can be switched between these forms simply by tuning the layer Neel vector. Through the spin Edelstein effect and the realization of fully gapped chiral topological superconducting phases, we demonstrate that this nonrelativistic SOC achieves physical equivalence to its relativistic counterpart. Our findings identify a new class of odd-parity coplanar magnets as a versatile platform for engineering SOC effects.

The 2025 Iberian blackout has renewed concerns about the resilience of power grids with high shares of renewable generation. This commentary argues that renewable generation can not only advance decarbonization but also strengthen grid stability through synthetic inertia, advanced inverter-based control, and coordinated transmission planning. Rapid advances in energy storage and power electronics make this transition increasingly viable.

Dual-unitary circuits have emerged as a paradigm of exactly solvable yet non-integrable quantum dynamics. Recently, a generalization of dual unitarity attempting to extend the phenomenology of exactly solvable circuits has been introduced through a hierarchy of conditions, with dual unitarity as the first level. However, beyond the second level the proposed generalized dual-unitary hierarchy ceases to be solvable in the whole spacetime. We present an infinite hierarchy of solvability conditions remedying this problem. These new conditions can be combined with the generalized dual-unitary hierarchy to obtain circuits for which correlation functions and entanglement dynamics can be analyzed exactly in the whole spacetime. We show that this novel hierarchy possesses non-trivial solutions at every level. Our results demonstrate that dual unitarity can be systematically extended while preserving solvability, opening up investigations of exactly solvable non-integrable systems with more general properties.

We study the two-dimensional Kondo-Heisenberg model on a square lattice, with the conduction electrons away from half-filling, using neural network quantum states. Mapping the ground-state phase diagram as a function of the Kondo and Heisenberg couplings, we identify (i) at weak Kondo coupling, antiferromagnetic Néel order with a Fermi surface whose enclosed area counts only the conduction electrons and is insensitive to the Néel order, and (ii) at strong coupling, a heavy Fermi liquid with a Fermi surface whose enclosed area counts both the conduction electrons and the spins. In the crossover between these regimes, we find $d_{x^2-y^2}$ superconductivity, evidenced by off-diagonal long-range order in the pair-pair correlations and a pairing-amplitude dome that coexists with the underlying magnetic phase. Our results establish Fermi volume change and unconventional superconductivity as intrinsic features of the two-dimensional Kondo-Heisenberg model.

In the presence of a magnetic field, electronic states of moiré quantum materials develop a Hofstadter spectrum that provides a unique setting for studying the interplay between band topology and strong electron-electron interaction. Using scanning tunneling microscopy, we study Hofstadter's states in bilayer graphene aligned with hexagonal BN and directly visualize the formation of interaction-driven symmetry breaking Chern insulators. Our measurements reveal the formation of phases that double, triple or quadruple the moiré unit cell at fractional filling of the Hofstadter bands, as well as states with complex intra-unit-cell wave functions. We visualize two distinct quantum phenomena in different Chern states, including quantum melting driven by the appearance and proliferation of topological defects, and a quantum transition co-occurring with phase competition and separation.

Chaotic dynamics play an important role in a number of physical systems. One of the qualitative hallmarks of this behavior is the appearance of a sufficiently "complex" spectrum of energy levels. This also makes it challenging to directly verify the onset of chaos in interacting quantum field theories. We present a class of 4D superconformal field theories (SCFTs) given by orbifolds of 4D $\mathcal{N} = 4$ Super Yang–Mills theory in which operator mixing in a controlled subsector is described by an effective spin chain in one spatial dimension with nearest neighbor interactions tuned by the marginal couplings of the SCFT. Tuning the marginal couplings results in a chaotic spectrum, while generically the spin chain exhibits Anderson localization. We diagnose the onset of chaos by analyzing the statistical distribution of eigenvalues of the dilatation operator, in particular properties such as eigenvalue level repulsion, spectral rigidity, and the spectral form factor. We also show that other diagnostics such as Krylov complexity sometimes do not faithfully capture this information. This structure defines a chaotic billiard in the target space of the stringy realization. We also comment on the large $N$ holographic dual description, where the controlled single spin chain approximation must be supplemented by multi-trace dynamics, i.e., the splitting and joining of multiple spin chains.

Andreev reflection converts an incoming fermion into an outgoing hole and is usually tied to a superconducting interface. We show that an analogous charge-conjugating boundary condition emerges from a purely lattice duality defect. Starting from a Majorana representation of the transverse-field Ising chain, we construct a folded lattice model in which a boundary Majorana impurity implements a one-site translation of a staggered Majorana chain. In the continuum, this translation becomes a chiral fermion-parity defect: it flips the sign of the only left-moving Majorana mode while leaving the right-moving mode unchanged. When the two Majorana modes are recombined into a complex fermion in the folded geometry, this sign flip becomes the Andreev-like boundary condition. Our lattice formulation gives a microscopic interpretation of the Emery–Kivelson boundary of the two-channel Kondo problem and of Maldacena–Ludwig monopole scattering, while identifying the boundary as the interface between a Kitaev-chain SPT phase and a gapless chain. The same Majorana translation defect also provides a lattice realization of an axial $U(1)_A$-symmetric charge-flip boundary.

Demographic noise generates stochastic Turing patterns even when reaction-diffusion systems are deterministically stable. We show analytically and verify numerically in the Levin-Segel model that temporal integration of configurations reveals emergent large-scale organization. The intensive number variance in a window of size $R \gg 1$ approaches a finite reaction-kinetic floor as $1/R$, over a spatial range growing by orders of magnitude near the Turing instability. This yields an effectively hyperuniform, fine-tuning-free regime previously unidentified in non-conserved multispecies stochastic systems.

Real-time dynamics after a local quench by a charged operator encodes the response functions measured in spectroscopic experiments, yet they have long posed a challenge for variational Monte Carlo calculations. The obstacle is a support mismatch: the projective action by a charged local operator forces an exponentially large number of configurations to vanish, but these configurations may still contribute to the dynamics, biasing the estimators and freezing the evolution at the very first step. This difficulty is an artifact of the chosen sampling basis, and the support mismatch generated by a charged local operator is itself local. We demonstrate that the missing support can be restored by a local rotation of the sampling basis, without changing the underlying variational dynamics. We propose a local basis-rotation sampling scheme that resolves the support-mismatch problem and can be readily incorporated into existing variational Monte Carlo algorithms. Benchmarks show that rotation sampling accurately captures long-time quantum dynamics, enabling variational Monte Carlo calculations of dynamical structure factors in one dimension and unbiased local-operator quench dynamics in two dimensions. We also show that this resolution of the support-mismatch problem extends beyond real-time dynamics, and may also be helpful for ground state variational Monte Carlo calculations.