Papers

Thermal transport in polymer chains is commonly attributed to ballistic propagation of long-wavelength acoustic phonons, which act as Goldstone modes protected by translational symmetry, whereas transport by higher-frequency phonons is suppressed by Anderson localization. Consistent with this picture, highly aligned polymers exhibit exceptionally high thermal conductivity, while poorly aligned polymers are orders of magnitude less conductive and serve as efficient thermal insulators. Here we show that this striking sensitivity to molecular alignment originates from acoustic-phonon scattering by molecular kinks. In the long-wavelength limit, longitudinal acoustic (LA) phonons are completely reflected by a single kink, whereas transverse acoustic (TA) phonons exhibit a universal transmission coefficient of one half. We show that the strong reflection results from the breaking of translational symmetry caused by the change in molecular-axis direction at the kink, while the universal TA transmission originates from virtual scattering through an evanescent transverse Bloch mode. The resulting strong suppression of long-wavelength phonon transport dramatically reduces the thermal conductivity of poorly aligned chains. These findings identify kink engineering as a promising strategy for controlling thermal transport in polymeric materials.

We report measurements of the thermopower of atomic-size gold contacts realized by the mechanically controllable break junction (MCBJ) technique over a temperature range from 18 K to 295 K. A thermometer included in the lithographic structure close to the constriction provides a direct measurement of the temperature increase generated by heating one side of the contact with a focused laser beam. While the conductance histograms confirm the quantum nature of the transport, we observe a nonmonotonic temperature dependence of the ensemble-averaged thermopower with a minimum of $-2\,\mu$VK$^{-1}$ at about 150 K. The values for the thermopower obtained at the lowest and the high temperature are compatible with values reported in the literature, but the nonmonotonic behavior in between disagrees with the expected linear dependence for quantum coherent conductors described by the Landauer formula. We develop a theoretical model based on an energy dependent transmission function that qualitatively reproduces the nonmonotonic behavior, but fails quantitatively. We therefore interpret our data as a result of phonon contributions to the thermopower beyond the Landauer model and with opposite sign than the classical phonon drag known from bulk systems. Our findings show that, firstly, the thermopower gives important insight into the transport properties of atomic-size structures and second that the linear approximation of the Landauer model has to be used with caution when studying more complex transport properties even for atomic contacts from free-electron metals.

La-doped bilayer iridates provide an important platform for studying the evolution of the spin-orbit-assisted Mott state under electron doping, but the La solubility achieved by conventional ambient-pressure synthesis is limited. Here, we report the synthesis and physical properties of nominally La-doped (Sr$_{1-x}$La$_x$)$_3$Ir$_2$O$_7$ (x = 0.05, 0.10, 0.15, and 0.20) prepared using high-pressure high-temperature techniques. Single-crystal X-ray diffraction refinements, supported by scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), reveal significantly enhanced La incorporation, with nominal x = 0.05 and 0.15 corresponding to actual compositions of approximately (Sr$_{0.89}$La$_{0.11}$)$_3$Ir$_2$O$_7$ and (Sr$_{0.77}$La$_{0.23}$)$_3$Ir$_2$O$_7$, respectively. At nominal x = 0.20, the bilayer phase is no longer stabilized and instead transforms into cubic perovskite Sr$_{1-x}$La$_x$IrO$_3$. (Sr$_{0.89}$La$_{0.11}$)$_3$Ir$_2$O$_7$ exhibits a ferromagnetic-like transition near 186 K accompanied by magnetic hysteresis and subtle lattice anomalies indicative of spin-lattice coupling. Despite its high electron-doping level, the compound remains strongly insulating, consistent with a heavily doped localized magnetic insulating state distinct from both parent Sr$_3$Ir$_2$O$_7$ and ambient-pressure La-doped samples. In contrast, (Sr$_{0.77}$La$_{0.23}$)$_3$Ir$_2$O$_7$ displays metal-like electronic behavior, weakened magnetic order, and enhanced carrier delocalization, although disorder-driven localization persists at low temperatures. These results demonstrate that high-pressure synthesis substantially extends the accessible doping range of bilayer iridates and reveals electronic and magnetic states inaccessible through conventional synthesis routes.

This work is motivated by the experimentally observed coherence of the supercurrent in semiconductor nanowires covered by a half-shell metallic superconductor, which leads to flux dependent supercurrent oscillations with period h/2e, as expected for a tubular superconductor, i.e. Little-Parks oscillations. We perform microscopic model calculations and compare the results for full and half metallic shells. We use an effective Hamiltonian derived from the Green's function of the proximitized semiconductor nanowire, where the presence of the superconductor is represented by a self energy. Furthermore, we incorporate the electrostatic band-bending at the metal-semiconductor interface as a rectangular narrow quantum well on the semiconductor side. The properties of the eigenstates of the effective Hamiltonian are determined by the spatial profile of the corresponding transverse modes in the normal state. For half-shell wires, transverse modes with high-enough energy expand outside the interface quantum well and generate eigenstates with mixed electron-hole character that surround the entire circumference of the nanowire, similar to eigenstates of the full-shell system. We identify these states as being responsible for the observed Little-Parks effect.

Lightly Cu-doped BiMn$_7$O$_{12}$ (x = 0.05, 0.10, and 0.15) was investigated using high-pressure synthesis, single-crystal X-ray diffraction, pair distribution function (PDF) analysis, STEM, magnetic measurements, and first-principles calculations. All compositions retain an average monoclinic $I$2/$m$ structure, while Cu substitution progressively suppresses the monoclinic distortion and drives the lattice toward a pseudo-cubic metric symmetry. PDF analysis reveals increasing local structural disorder and reduced medium-range coherence with increasing Cu concentration, despite preservation of the overall quadruple-perovskite framework. Single-crystal refinements indicate enhanced electron density at the octahedral Mn B sites, suggesting preferential Cu occupation within the MnO$_6$ network rather than the conventional square-planar sites expected for Cu$^{2+}$. Magnetic measurements reveal two characteristic anomalies near $T_1$ ~ 100-120 K and $T_2$ ~ 50-60 K, together with pronounced magnetic irreversibility, field-dependent hysteresis, and unsaturated magnetization. Increasing Cu concentration progressively suppresses the low-temperature magnetic state and weakens the field-induced moment. First-principles calculations favor Cu occupation at the square-planar sites, contrasting with the experimental refinements and highlighting strong competitions among local bonding, short-range disorder, and metastability in this highly frustrated quadruple perovskite system.

Adapting machine-learned interatomic potential (MLIP) foundation models to specialised tasks through fine-tuning is an increasingly important practice, yet systematic guidance on when and how to fine-tune is currently limited. We evaluate seven fine-tuning strategies – naive full-parameter updates, two layer-freezing variants, Low-Rank Adaptation (LoRA), multihead replay, pseudolabelled replay, and replay combined with LoRA – across five chemically diverse benchmarks (aqueous NaCl, ice polymorphs, S$_\mathrm{N}$2 reactions, SPICE biomolecules, and lithium electrolytes), three generations of foundation models, and training sets spanning five orders of magnitude. To support this evaluation we implement three capabilities in the MACE codebase: LoRA adapted for equivariant message-passing architectures, including both scalar and equivariant linear layers; pseudolabelled replay, which decouples the replay data source from the original pretraining corpus; and model-aware atomic reference energy (E0) reestimation for fine-tuning workflows. We find that foundation model quality, correct E0 initialisation, and well-chosen hyperparameters are prerequisites whose impact routinely exceeds that of the fine-tuning strategy itself. Once these prerequisites are met, most strategies achieve strong target-task accuracy, consistently surpassing models trained from scratch. The practical distinction depends on deployment scope: naive fine-tuning offers the best convergence for single-system applications, while multihead replay – with either original or pseudolabelled data – is the only approach tested that consistently preserves out-of-distribution robustness, maintaining both pretraining-distribution accuracy for broader deployment and many-body short-range repulsion.

We show that, under a short optical pulse, the quantum metric of Bloch states in the momentum-time (kx, ky , t) of graphene becomes dynamic and exhibits a wave-like behavior near Dirac points. This quantum metric wave reflects the Floquet-band structure caused by the pulse, as revealed by solving the time-dependent Schrödinger equation assuming that correlations and out-of-equilibrium effects can be ignored. The momentum and temporal components of the metric have very distinct time dependence that persists even after the pulse has passed. In addition, the pulse also generates a Berry curvature wave that is otherwise absent in static graphene. The time-dependent electron densities in conduction and valence bands also give arise to a Fisher information wave that constitutes part of the quantum metric wave, and is readily measurable by pump-probe experiments.

Symmetry-protected topological phases have attracted significant interest at the fundamental level and as a potential platform for quantum information processing, owing to their protected edge states and resilience to perturbations. Applying these features for practical and efficient quantum computation is highly desirable, but remains an open challenge. Here, we demonstrate the partitioning into multiple independent Haldane phase subsystems of a single spin-1/2 ladder system and propose this as a scalable architecture for gate-based quantum computation, which takes advantage of the symmetry-protected topological order. We encode qubits in the two topological states of the $S^{z}=0$ sector of each subsystem. Finite-size effects, typically viewed as detrimental, instead provide a controllable energy splitting that enables single-qubit rotations using only local magnetic fields. An Ising-type interaction between neighboring subsystem edges generates entangling gates, enabling universal quantum computation driven by two control parameters that are easily accessible experimentally. Our results demonstrate how symmetry-protected topological phases can be directly harnessed for circuit-model quantum computation in realistic systems.

Linear-in-temperature resistivity is a hallmark for strange metallic transport, and appears universally in many strongly correlated electron systems. However, the focus on the longitudinal channel often overshadows the profound microscopic insights contained within the transverse response. Here, we utilize numerically exact determinantal quantum Monte Carlo simulations of the doped Hubbard model in a magnetic field to calculate longitudinal and transverse transport. We demonstrate that while the resistivity is robustly $T$-linear across parameter sets, the Hall response is highly sensitive to particle-hole asymmetry, Fermi surface topology, and many-body correlation effects. Specifically, the combination of these effects determine a crossover scale in which the system becomes quantum-coherent, and is reflected in the Hall conductivity. Our results demonstrate that while the $T$-linearity in resistivity appears universal, the Hall response reveals a crossover from semi-classical to quantum-coherent transport otherwise masked in the longitudinal channel.

Photoelectrochemical (PEC) cells are a compelling route to solar-driven chemical energy storage and feedstock synthesis, yet their deployment is hindered by coupled losses spanning light absorption, carrier transport, interfacial charge transfer, and semiconductor-electrolyte matching. Existing models address these losses in an architecture-specific manner and fall short of quantitative experimental diagnosis or actionable design guidance. Here, we introduce a unified loss-analysis framework applicable to both built-in junction (BIJ) and semiconductor-electrolyte junction (SEJ) photoelectrodes within a consistent set of physically meaningful parameters. The framework delivers current-voltage curves and efficiency metrics under ideal and real conditions, constructing efficiency maps to delineate theoretical limits and material-selection windows. Critically, by fitting experimental current-voltage data, it enables quantitative energy-loss decomposition into thermodynamic, optical, recombination, and interfacial contributions, pinpointing performance bottlenecks in real devices and mapping them directly onto optimization strategies such as co-catalyst integration or nanostructuring. Energy flows are visualized through Sankey diagrams, providing an intuitive picture of how incident solar energy is absorbed, dissipated, or converted into chemical output. Validated against state-of-the-art literature results spanning solar water splitting, CO2 reduction, NH3 synthesis, and solar redox flow batteries, the framework further enables systematic comparison of photovoltaic-grade absorbers (e.g., Si, perovskites) with intermediate-bandgap semiconductors (e.g., hematite, BiVO4), identifying key factors limiting each material class. Together, these capabilities support a paradigm shift from empirical optimization to mechanism-informed rational design of high-efficiency PEC energy-conversion systems.

We report on a phase-based lock-in thermography approach, combined with a multilayered thermal model (often employed in thermoreflectance analysis), to measure the thermal conductivity of bulk materials and layered structures. The spatial distribution of the material's thermal phase is monitored with an infrared camera, which is locked into the frequency of a modulated laser used to heat the material. This phase distribution is then fit with a thermal model, in which properties such as thermal conductivity are extracted as fit parameters. This approach enables non-contact, front-side measurements, which are insensitive to surface roughness. The technique does not strictly require the application of a transducer layer, but we highlight the practical benefits of applying a removable adhesive layer to serve as a near-surface absorber. We demonstrate the efficacy of the method by measuring materials with thermal conductivities that span over three orders of magnitude (approximately 1 W/m/K to > 2000 W/m/K).

Wave turbulence describes the statistical dynamics of dispersive waves with weakly nonlinear interactions. While the classical kinetic equation captures the mean evolution of the wave spectrum, the study of its fluctuations due to finite-size effects and intermittency requires a probabilistic framework for space-time trajectories of the spectrum dynamics. Following the previous large deviation theories for wave turbulence, we develop a simplification meant for qualitative and numerical predictions of measurable quantities. We derive a new large deviation principle in the case of local wave interactions. It fully characterizes typical and rare fluctuations of the spectrum. In a joint article, we obtain a theory which is a generalised form of Macroscopic Fluctuation Theory, but with 2 conserved quantities (mass and energy). In this paper, we use it to analyse the structure of the equation for Gaussian fluctuations around out-of-equilibrium spectra. In addition to the usual equilibrium contribution, we obtain long-range correlations, which can be decomposed into 3 contributions: one is driven by the flux in the bulk and another is driven by the forcing and its possible fluctuations. In addition, these contributions are computed for the first time with a method adapted to boundary conditions where only the fluxes are fixed. The results provide a general, replicable method for analyzing wave turbulence in more complex settings. Finally, the generalization of this theory to the inhomogeneous wave turbulence provides a possible explanation to the instability of the Kolmogorov-Zakharov spectra in some 1D inhomogeneous models with 4-wave interactions such as the Majda-McLaughlin-Tabak. This work opens the discussion regarding universal and non universal properties in two-point correlation functions. This opens new range of study on the phenomena of intermittency which is partially developed here.

Periodic equation-of-motion coupled-cluster theory with single and double excitations (EOM-CCSD) has shown promise for quantitative calculations of band structures in solids. However, its steep computational scaling has limited calculations to relatively coarse $k$-point meshes, leading to sizable finite-size errors and discrepant estimates of thermodynamic-limit band gaps in recent benchmarks. In this work, we revisit EOM-CCSD band gaps for ten semiconductors and insulators using interacting-bath dynamical embedding theory (ibDET), a systematically improvable Green's function embedding framework that enables dense Brillouin-zone sampling at modest computational cost. By pushing the $k$-point sampling up to $10\times10\times10$, well beyond the system sizes accessible in canonical periodic EOM-CCSD calculations, we significantly reduce finite-size errors and obtain stable thermodynamic-limit extrapolations. We further compare $G_0W_0$@PBE, $G_0W_0$@HF, and EOM-CCSD on an equal footing using the same numerical settings in PySCF. We find that EOM-CCSD yields a mean absolute error of 0.32 eV relative to experimental band gaps for a test set of ten semiconductors and insulators, lower than that of $G_0W_0$@PBE. For ZnO, EOM-CCSD also accurately describes the Zn $3d$-band binding energy, despite overestimating the band gap. These results demonstrate that ibDET offers a practical route to high-accuracy many-body electronic structure calculations in periodic systems.

Due to high current interest to Bose-Einstein condensation, the related topics, such as spontaneous gauge symmetry breaking, ergodic decomposition, and particle fluctuations, are intensively discussed in literature. These discussions, unfortunately, involve quite a number of controversies and confusions. The goal of the present brief survey is to clarify some of these confusions, concentrating on the principal points, such as the relationship between the conditions of Bose-Einstein condensation, the Bogolubov method of quasiaverages, spontaneous gauge symmetry breaking, ergodic decomposition, the presumed existence of nonthermodynamic particle fluctuations leading to the so-called “grand canonical catastrophe", and the requirements for system stability.

We report on the bulk multiband superconductivity and charge density wave (CDW) in HfxZr1-xTe3 single crystals. The parent compound ZrTe3 is a layered van der Waals material that undergoes a CDW transition near 63 K and exhibits only filamentary superconductivity below 2.0 K. Upon the introduction of a small amount of Hf (x = 0.02), the CDW transition temperature is reduced to TCDW ~ 53 K, while a robust bulk superconducting state emerges at Tc ~ 3.3 K, underscoring a subtle competition between CDW order and superconductivity in this quasi-one-dimensional system. Electrical resistivity, magnetic susceptibility, Hall effect, Seebeck coefficient, and specific heat measurements consistently confirm the bulk nature of the superconducting phase. The temperature dependence of the upper critical field Hc2(T) deviates markedly from single-band behavior, and it is well described by a two-band model, consistent with multiband superconductivity. Analysis of the Hall effect, and thermoelectric behavior reveal pronounced electronic anisotropy, with enhanced effective carrier masses, indicating that the subtle structural modification introduced by Hf substitutions affects the Fermi surface topology, as well as electronic correlations. Measurements of electrical resistivity in hydrostatic pressures up to ~ 2 GPa reveal that pressure drives TCDW to higher temperatures while suppressing Tc. These findings show that Hf doping can be used to fine-tune the balance between the CDW instability and superconductivity, possibly by means of chemical pressure effects, stabilizing a multiband superconducting state in Hf-doped ZrTe3.

The continuum-limit theory of dislocations in crystals predicts divergences in the elastic energy at crystal-geometry dependent limiting velocities $v_L$. The $v_L$ separate subsonic, transonic, and supersonic dislocation glide regimes and are therefore important for material strength models at high strain rates. Although it is known how to calculate these limiting velocities, there is one special case - edge dislocations with reflection symmetry, but non-vanishing elastic constants $c'_{16}$ or $c'_{26}$ - where previous methods have been notoriously slow. In this letter, we address this deficiency by deriving a computationally efficient method for determining the $v_L$ of edge dislocations with reflection symmetry which is two orders of magnitude faster than the previous method.

In our work, based on an exact solution of the Ising model on a decorated square lattice with an arbitrary number of decorating spins, we have demonstrated the fundamental possibility of describing the phenomenon of multiple magnetic phase transitions (magnetic reentrancy) in the regime of competing exchange interactions. We analyzed the magnetic behavior of the system and established the conditions for the occurrence of magnetic reentrancy. We have determined the relationships of the model parameter under which the formation of one, three, and even five magnetic phase transitions is possible, which is confirmed by a complicated magnetic phase diagram. We have also proposed a unique method for finding critical temperatures that allows for the precise determination of their number and values, including those at extremely low temperatures.

Ferroelectric AlScN is promising for CMOS-compatible non-volatile memory, but thickness scaling is limited by leakage, premature breakdown, and defect-mediated failure. Here we show that compositional grading within a continuous wurtzite AlN-AlScN lattice mitigates these limitations by distributing structural and polarization discontinuities across the film thickness, reducing defect formation and local field concentration. In a 20 nm graded heterostructure, monotonic Sc incorporation and AlN-rich boundaries produce reversible ferroelectric switching, an as-grown metal-polar state, a 21% higher breakdown field, 10% enhanced remanent polarization, and 40x higher resistivity relative to homogeneous AlScN. Time-domain PUND measurements reveal strongly suppressed post-switching leakage, consistent with reduced defect-assisted and polarization-coupled conduction. This improved dielectric robustness enables ferroelectric functionality in 5 nm graded stacks containing only a 2 nm $\mathrm{Al}_{0.64}\mathrm{Sc}_{0.36}\mathrm{N}$ region, with measurable switching near 1 V. These results establish compositional grading as a defect- and field-management strategy for scalable ultrathin wurtzite ferroelectrics.

Reactive metallic multilayers store chemical energy that can be released rapidly through interdiffusion and intermetallic formation. Predictive control of this heat release requires distinguishing transport and phase-formation processes that occur in rapid succession. Here we combine free-standing nanoscale Ni/Al multilayers with chip-based flash calorimetry and isoconversional kinetic analysis over five orders of magnitude in heating rate. Selected reaction states are quenched and examined by scanning transmission electron microscopy. This workflow separates pre-ignition interdiffusion into two regimes and quantifies activation energies of (81 $\pm$ 24) and (168 $\pm$ 17) kJ/mol, consistent with grain-boundary and lattice diffusion of Ni in Al, respectively. Microscopy supports this assignment: no significant compositional changes are observed after the first regime, whereas the second increases the Ni content of the Al layers and produces Ni-enriched features spaced by 5$-$10 nm, matching the Al grain size. These results identify the Al grain-boundary network as the dominant low-barrier pathway, providing rapid transport across the Al layers and priming lattice-mediated mixing and intermetallic phase formation. More broadly, the workflow links calorimetric signatures to pathway-specific kinetics and transient microstructures, enabling direct assessment of how microstructural design redirects coupled transport and reaction pathways in reactive multilayers and other materials driven far from equilibrium.

We develop a unified dynamical-spectral framework for equilibration in isolated quantum systems based on a subspace coarse-graining approach. Central to our formulation is the Leakage Fidelity Function (LFF), defined as the probability that a unitarily evolving state escapes the support of its initial subspace. This quantity provides a direct, operational measure of information flow and memory loss without invoking ensemble assumptions or perturbative arguments. We derive universal bounds on temporal fluctuations of the LFF, in terms of the spectral gap structure and the square of the effective dimension, evincing that large spectral delocalization suppresses fluctuations and guarantees equilibration on average. By introducing spectral power distributions and associated entropic measures, we establish a quantitative link between phase mixing, gap participation, and dynamical stability. We further investigate the equilibration timescale by connecting the LFF to quantum speed limits, thereby revealing the average time required for equilibration. Our results provide a state-dependent, geometrically transparent perspective on how spectral complexity and subspace information leakage jointly govern irreversibility in closed quantum many-body systems.

We study a simplified model of a ferromagnetic metal proximitized by a fully-gapped $s-$wave superconductor and integrated with a microwave resonator. The low-energy excitations in the combined system consist of ferromagnetic magnons, Bogoliubov excitations of the superconductor, and cavity photons. We show here that when the magnons and photons have comparable frequencies and are subject to an external drive, the hybridized driven magnon-polaritons induce a non-equilibrium crossover from the expected proximitized nodal $p-$wave superconductor to a fully gapped $(p_x+ip_y)-$superconductor. Moreover, the characteristic crossover temperature is inversely related to the magnon-photon detuning. We compute the temperature-dependent renormalization of the cavity photon frequencies across this nodal to nodeless evolution, which modifies the kinetic inductance of the resonator, and find a number of non-trivial features tied to the non-equilibrium (i.e., driven) nature of the problem. We compare and contrast these results with a recent circuit quantum electrodynamics (cQED) based experiment studying a permalloy-niobium bilayer, where a non-trivial dependence of the low-temperature cavity response on the magnon-photon detuning was observed. Our results pave the way for a principled exploration of engineering novel states of matter by coupling cavity photons to electronic collective modes in correlated two-dimensional materials and interfaces.

Given a quantum critical wavefunction in any dimension, we propose a reconstructed Hamiltonian, analogous to the ones previously found for 1+1d CFT and for 2+1d bosonic liquid topologically-ordered states. We test numerically that, for known regularized approximate CFT groundstates (on the icosahedron and the fuzzy sphere), (1) they are close to the groundstate of their reconstructed Hamiltonian, and (2) the spectrum of their reconstructed Hamiltonian on the unit sphere has CFT properties (integer spacing of descendants) and matches known low-lying energies. We show that this provides an automated method to improve the finite-size effects in a fixed Hilbert space.

`Solvable' circuits, such as dual unitaries and its generalisations, have arisen as paradigmatic examples of tractable chaotic non-equilibrium dynamics, both in classical and quantum systems. However, while increasingly complicated sufficient conditions have been proposed, a systematic theory classifying and understanding general features of Solvable circuits is missing. In this work we develop such a theory by deriving the most general local necessary and sufficient conditions under which a $(1+1)D$ circuit is Solvable. Concretely, we define a circuit to be influence-solvable if its influence matrix, representing the `bath' generated by its own evolution, is given by a uniform MPS with finite bond-dimension $\chi$. This property allows for efficient computation of subsystem dynamics and essentially contains all known examples of Solvable circuits. The set of necessary and sufficient local conditions follows from a new version of the fundamental theorem of MPS for open boundary conditions. Next, we apply our theory to brickwork circuits with $\chi=1$ influence-solvability and perform a systematic classification of classical brickwork circuits with local dimension up to $d=3$ and quantum brickwork circuits with $d=2$. Our search reveals new Solvable circuits that are not captured by known conditions.

A new moiré material platform was recently proposed based on twisting two-dimensional atomic monolayers whose low-energy states lie at the three M-points of the Brillouin Zone. Continuum and ab initio modeling suggest that electrons in the conduction bands of these materials realize three-valley Hubbard models with valley-selective, quasi-one-dimensional hopping. Remarkably, the onsite Hubbard repulsion is almost $U(6)$-symmetric without fine-tuning. Here, we show that this class of systems naturally admits sign-free determinantal Quantum Monte Carlo simulations at a filling of three electrons per moiré unit cell. We use these to explore the phase diagram for interactions of various strengths and $U(6)$-breaking anisotropies. We show that for near-isotropic interactions as relevant to, e.g., AA-stacked twisted SnSe$_2$, the system exhibits an extended intermediate-coupling regime in which local-moment formation and itinerancy compete, and the crossover to a putative low-temperature ordered state can be understood in terms of fluctuating $U(6)$ local moments. We argue that many of these features persist beyond the idealized sign-problem-free limit.

Topological quantum computation relies on braiding non-Abelian anyons, but requires the underlying topological order to survive imperfect state preparation and environmental noise. We show that the instability of topological order to wavefunction deformations and to decoherence, with the latter probed by syndrome distributions, is generically captured by stat-mech models whose $G\times \textrm{Rep}(G)$ symmetry naturally exposes the corrupting anyonic excitations. As an example, we combine this framework with Monte-Carlo simulations to resolve the stability of $D_4$ topological order under deformations and quantum channels that proliferate multiple non-Abelian anyon species that are individually unable to condense. We show that beyond a finite threshold, proliferation of two non-Abelian anyon species parasitically condenses a shared Abelian-anyon fusion outcome—destroying the topological order. Our symmetry-based approach suggests the resulting trivial phase is distinct from that obtained by condensing all Abelian anyons; in other words, the trivial phase "remembers" which anyons condensed. This framework provides a first step into identifying the relevant symmetry for optimal decoders, conditioned on syndrome measurements, of non-Abelian topological order.

We study the time evolution of tripartite genuine multientropy in heavy local quenches via AdS${}_3$/CFT${}_2$. Its linear response around the vacuum cancels pointwise for arbitrary adjacent intervals. At finite backreaction, the vacuum-subtracted genuine multientropy arises only from an incompatibility gap between the triplet of windings selected by the trivalent geodesic network and the windings selected independently by the bipartite geodesics. The heavy-light vacuum-block calculation reproduces the same formula from the boundary perspective. The time dependence is kinematically fixed and is independent of the heavy operator dimension. These results show that the genuine multipartite entanglement is controlled by global saddle transition rather than by local energy response or quasiparticle propagation.

We derive semiclassical equations of motion for general composite bound states in insulators and semiconductors, covering excitations such as excitons and trions. For neutral composites we find that a uniform external electric field does not couple to a Berry curvature term, contrary to the naive expectation from single-electron dynamics. Instead, a distinct quantum geometric quantity appears generically in the equations of motion. This quantity is the difference between inequivalent Berry connections that can be defined for the composite, generalising the concept of the quantum geometric dipole previously studied for excitons. In the case of charged composites such as trions, we find an additional Berry curvature contribution to the equations of motion. As we demonstrate, however, there is an infinite family of inequivalent composite Berry curvatures, and so care must be taken to make the correct choice that describes the physical dynamics. We explain how this choice should be made dependent on the definition of a spatial centre for the composite. We end by discussing composite dynamics that have no single-electron counterpart. We find that trions in magic-angle twisted bilayer graphene undergo a transverse drift under an applied electric field and that this is driven not only by the Berry curvature contribution but also by the quantum geometric dipole. The interplay of these two geometric contributions further imprints itself on the trion's internal dynamics, causing its dipole moment to oscillate in time.

The periodic table of elements transformed chemistry by revealing simple organizing principles underlying atomic behavior. Despite decades of effort, no analogous framework has emerged for crystalline materials – their microscopic complexity and vast configurational space have defied reduction to fundamental organizing principles. Current databases catalog thousands of synthesized materials, but extracting predictive, interpretable models from this wealth of data remains a formidable challenge. Here we demonstrate that the materials landscape possesses a hidden geometric organization that can be unveiled through unsupervised nonlinear dimensionality reduction. Applying differential geometry techniques to the Inorganic Crystal Structure Database (ICSD), we reveal that just a few combinations of microscopic descriptors capture the vast majority of variance in material properties. This low-dimensional embedding autonomously segregates superconductors from ordinary materials and further distinguishes superconducting families in ways that transcend chemical similarity alone. Remarkably, the discovered geometric organization directly governs critical temperatures ($T_c$) across diverse superconducting families, enabling accurate $T_c$ predictions without any knowledge of the pairing mechanism. Our approach uncovers emergent organizing principles that control macroscopic quantum behavior, offering a new paradigm in how we build models of complex quantum materials directly from experimental data.

We present a temperature-modulated de Haas-van Alphen measurement technique that allows selective addressing of quantum oscillations with different effective masses $m^{\ast}$ using a non-monotonic amplitude evolution with temperature and magnetic field, governed by the temperature derivative of the Lifshitz-Kosevich factor. The technique relies on harmonic modulation of the sample temperature and phase-sensitive detection of quantum oscillations in the voltage induced in a pick-up coil. We use a set of frequencies with strong Zeeman-driven harmonic content in the compensated topological semimetal MoSi$_{2}$ as a natural linear mass comb ranging from 1$m^{\ast}$ to 13$m^{\ast}$ to demonstrate the tunability of the mass-dependent quantum oscillation amplitudes experimentally. The technique allows to reliably isolate weak contributions of heavy orbits that are inaccessible in conventional de Haas-van Alphen frequency spectra because their frequency peaks overlap with much stronger frequency peaks of lighter orbits.

We analyze Maxwell theory coupled to an axion domain wall as a spectral boundary value problem. We find that a finite-width axion domain wall generically supports a localized normalizable chiral electromagnetic mode with linear, gapless dispersion. This mode arises from helicity-dependent coupling sourced by the axion gradient: one polarization experiences an effective attractive potential and forms a bound state, while the opposite polarization is repelled. The existence of this chiral surface photon is robust over a wide regime of wall structures and axion masses. Our result shows that axion domain walls generically support a localized chiral photon that has been missed in previous analyses.