Papers

Temperature-dependent electrical resistivity $\rho(T)$ in cuprate, iron-based, and nickelate superconductors represents one of unresolved problems in modern solid-state physics, because of the high absolute value of $\rho(T)$, which, in many cases, exceeds the Ioffe-Rigel criterion, and a large difference in the $\rho(T)$ shape for samples with different doping. Here I show that the nearest neighbors parallel resistivity model (arXiv: 2607.23484) can well describe the in-plane resistivity $\rho_{ab}(T)$ in iron-based superconductors (IBS) of type 11, 111, 122, 1111, 1144 and 42214 in which the spin density wave phase or nematic order is suppressed by doping. The model is based on the postulate that $\rho_{ab}(T)$ is a sum of two parallel conduction channels, where one channel is described by the Bloch-Grüneisen equation and the other by the Arrhenius hopping equation. Consequently, the variety of $\rho_{ab}(T)$ in the IBS is explained as a variation of the Debye temperature $\Theta_D$ and the hopping activation energy $E_a$. The derived Debye temperatures were used to estimate the electron-phonon coupling constant $\lambda_{e-ph}$in the studied IBS.

Starting from the cyclic duality tensors introduced by Vernier, Miao, and Yamazaki (VMY), whose endpoint-traced matrix-product operators obey $\mathbb Z_N$ Tambara–Yamagami fusion and realize topological defect lines of the compactified-boson conformal field theory, we retain the virtual endpoint as an $N$-state dynamical degree of freedom and construct an exactly movable seam in the spin-$\tfrac12$ XXZ chain at $q=\mathrm e^{\mathrm i\pi M/N}$ with $\gcd(M,N)=1$. The local movement identity holds for any unitary $q$-Weyl pair; in the finite cyclic realization, all output phases are locally gauge equivalent and share the same four seam eigenvalues. On a ring, the output gauge becomes a directed twist on a single bond, while endpoint conjugacy reduces the $2N$ labels to two relative $\mathbb Z_2$ flux classes. An explicit antiunitary symmetry protects the class $\eta\equiv M-1\pmod 2$: for even $N$ it pairs distinct charge sectors isospectrally, whereas for odd $N$ it fixes one sector and squares to $-I$ there. Hence every many-body energy eigenspace in the protected class has even multiplicity. The source value $\eta_{\rm VMY}=1-M$ satisfies this condition for every coprime root, whereas the ungauged value $\eta=0$ does so only for odd $M$. Exact finite-size controls show that the opposite class can contain simple levels, so a global flux invisible to local gauge equivalence distinguishes the two classes spectrally.

We present a robotic electrospinning platform and design method for depositing nanofiber membranes onto non-planar, three-dimensional conductive geometries. Conventional electrospinning relies on fixed emitters and planar grounded collectors, which restricts deposition to flat substrates: on concave geometries, field shielding prevents fibers from reaching recessed regions, and material bridges across elevated features instead. We address this with a custom end-effector integrated with a six-axis UR20 arm. The tool carries a localized stepper-driven syringe pump that maintains consistent polymer flow independent of orientation, and routes high-voltage DC (up to 25 kV) directly to a robot-mounted needle, turning the arm into a mobile emitter with full kinematic control over position, orientation, working distance, and traversal velocity. Toolpaths that continuously reorient the emitter along surface normals give access to concave topologies unreachable by fixed-axis systems. We characterize the resulting deposition behavior in two parts. A catalog of four bio-compatible polymer systems (PEO, PVA, keratin-PEO, silk-PEO) establishes the operating envelope, reporting deposition speed, jet stability, fiber size, alignment, and durability for each. A taxonomy of 3D-printed conductive scaffolds spanning geometric primitives, hybrid compositions, and square, triangular, and hexagonal lattices links collector geometry to fiber alignment, density, and cross-void bridging. We also demonstrate programmable grounding, in which selectively energized pins in an array steer deposition without changing physical geometry. Assembly instructions and toolpath-generation code are released as an open-source repository.

We study hard spherocylinders on a sphere with axes rigidly locked to a tangential director field at fixed angle $\tilt$ to the meridian, necessarily singular at the poles. Three lengths set the problem: the rod length $\Lrod$, the diameter $\Drod$, and the host radius $\Rsph$. Monte Carlo simulations across fifteen geometries and four coverages give two main results for the polar marginal, the azimuthal average of rod-center density. First, the tilt is a continuous handle on the width of the depleted region that packing induces around each singularity. Under meridian locking it is set principally by the rod length; turning the director toward the latitude contracts it substantially, the contraction being spent well before latitude locking. Second, how uniform the polar marginal can be made is limited by geometry, not tilt. The smallest variance on the sampled grid follows a power law in $\Lrod^{2}/(\Rsph\Drod)$, which measures how far a straight rod's ends stand off the curved surface in rod diameters, with an effective exponent between $1.1$ and $1.3$. Long rods on small hosts cannot be made uniform at any sampled tilt; the remedy is geometric, not orientational. The polar marginal is equator-heavy almost everywhere, inverting only at high coverage and tilt; meridian locking is the least uniform choice, and the variance-minimizing tilt usually lies in a sampled band from $31.7^{\circ}$ to $55^{\circ}$. The golden-ratio tilt $\arctan(1/\phigold)$ is one of those angles: a benchmark, not one the model selects. Both results describe the infinitely locked athermal ensemble.

A simple regularization of the smooth quantum hydrodynamic model equations to prevent an unstable growing mode is proposed. The regularization involves replacing the spatial derivative of the electron density on the right-hand side of the momentum conservation equation by using the classical Boltzmann distribution for electron density. Time-dependent simulations of the resonant tunneling diode to steady state using this regularization are presented, which show realistic negative differential resistance (the experimental signal of quantum resonance) and hysteresis in the current-voltage curve. The simulations are in good agreement with fully quantum mechanical simulations of the resonant tunneling diode.

Denoising score matching trains diffusion models by regressing onto a conditional score, although generation ultimately requires the marginal score. The two objectives share the same population minimizer, but the conditional target remains random at fixed noisy state and introduces an irreducible excess in the training loss. We isolate this excess and show that, for a general corruption kernel under mild regularity assumptions, it is exactly the trace of the Fisher–Rao metric of the conditional endpoint family, integrated along the diffusion trajectory. This gives an exact conditional-variance decomposition of the denoising objective and identifies the information geometry observed in diffusion latent spaces as an intrinsic component of the training loss. We derive the result from a Schr"odinger bridge variational principle, in which the ideal objective arises as excess path-space relative entropy. For corruption diffusions, the Fisher term is proportional to the rate at which the noisy state loses mutual information about the clean data, separating the loss floor into an information flow determined by the data and a weight determined by the corruption schedule and objective. In the Gaussian case, this yields a closed form for the floor, recovers reparametrization invariance of the continuous-time objective, and relates its high-SNR divergence to the information dimension of the data. Finally, we show that raw losses obtained with different noise ranges or weightings need not rank models consistently because they contain different additive floors, and contrast the second-order geometry seen by training with the third-order conditional statistics entering numerical sampling error.

Motivated by the ubiquity of ramified fractal deposits in nature and engineered systems, we investigate the irreversible adsorption of diffusion-limited aggregation (DLA) clusters on a square lattice. We study the role of cluster shape diversity on jamming properties of the system by systematically controlling the number of distinct shapes used across and within realizations, encompassing both monodisperse and polydisperse model variants. Our large-scale simulations over a broad range of cluster sizes $2\leqslant k\leqslant4096$ show that the jamming density decreases with cluster size as a power-law $p_j(k)-p_j^\infty\sim k^{-\alpha}$. Both $\alpha$ and $p_j^\infty$ are found to depend on the degree of shape diversity, with $\alpha$ ranging from $0.374(2)$ to $0.417(1)$. It is observed that increasing shape polydispersity promotes denser packing. Importantly, the fluctuations of the jamming density exhibit distinct scaling behavior: $\sigma(L)\sim1/L$ for a fixed pool of cluster shape(s), but remain $L$-independent when the pool of shape(s) is refreshed across different realizations. Furthermore, our results demonstrate that the differences between the model variants systematically diminish with increasing $k$ and are expected to vanish as $k\to\infty$ due to the statistical self-similarity of the DLA clusters.

Reentrant transitions and temperature chaos are two unusual properties of spin glasses. We recently established a general logical relation between these two phenomena [Phys. Rev. E 112, 044140 (2025)]. In the present paper, we provide an explicit example of this logical relation in the fully connected Ising $p$-spin glass with a ferromagnetic bias. By expanding the free energy around the triple point, we show analytically that the ferromagnetic–spin glass boundary is reentrant in the vicinity of the triple point throughout the examined range of finite $p>2$. It then follows from the above logical relation that there exists at least one pair of distinct temperatures in the spin glass phase for which the overlap of spin configurations vanishes. This is a necessary condition for temperature chaos, but it would be quite unusual for the overlap to vanish only for selected temperature pairs but not for others within a single spin glass phase. These results therefore strongly suggest the existence of temperature chaos in the sense that the overlaps of spin configurations vanish for all temperature pairs throughout the spin glass phase. Independent evidence for this behavior is provided by a two-temperature replica calculation.

Microwave kinetic inductance detectors are typically operated at high readout power to raise the detector signal above system noise. At sufficiently large readout power, the current-dependent kinetic inductance couples the detector response to its readout bias. Using a nonlinear resonator framework and time-domain circuit calculations, we show that the amplitude, shape, and relaxation time of the driven detector's response depend on both the absorbed energy and on the readout bias. Strongly driven bias points produce amplified, extended, and non-exponential pulse responses. Qualitative agreement between calculated and measured pulse responses indicates that these effects are dominated by the driven nonlinear resonator dynamics rather than by altered quasiparticle dynamics. Beyond resonance bifurcation, sufficiently large pulse events drive the resonator between stable branches, resulting in a metastable latched state which persists after the quasiparticle transient has decayed. The pulse energy required for branch switching is set by the readout bias, suggesting a mode of triggered detection with an in-situ tunable threshold. Although nonlinear operation requires calibration of the bias- and energy-dependent response, the enhanced pulse amplitude and duration, together with tunable latching and the ability to select these parameters via the readout operating state, are likely to be of interest for single-photon and rare-event experiments, especially those limited by amplifier or system noise.

We study the minimisers of the Hartree–Fock functional for flat bands in the chiral model of twisted bilayer graphene introduced by Tarnopolsky, Kruchkov, and Vishwanath. Our model is a continuous version of the discrete model considered by Becker, Lin and Stubbs in previous works and the first result is a direct analogue of main theorems of those papers: at half filling of the flat band of multiplicity two, there are exactly two minimisers, obtained by occupying either one of the two sub-bands. (A more general version of this result, stressing its topological origins, was presented in Appendix A.8 of the Lecture Notes by Tao-Zworski.) The new contribution is the strict coercivity of the Hessian of the Hartree–Fock functional at the two minimisers. It is a consequence of the difference between the Chern numbers of the component bands and can be optimistically considered as a soft version of a “spectral gap”.

Predicting thermal stability during handling and storage is essential for the design of safe and reliable energetic materials. However, experimental measurements vary significantly across laboratories due to differences in protocols and analysis methods, making it difficult to train reliable predictive models. We address this challenge through differential learning. Rather than predicting absolute decomposition temperatures, we instead train message passing neural networks to predict relative differences between pairs of molecules. This approach reduces sensitivity to systematic experimental errors and achieves >85% accuracy in ranking compounds by thermal stability, outperforming conventional regression methods on the same heterogeneous dataset. To understand what drives these predictions, we compare neural network models with interpretable alternatives built from descriptors derived from ab initio calculations and cheminformatics software. This analysis identifies bond dissociation enthalpy as a key determinant of thermal stability rankings, providing further insight into the complex chemistry of thermal decomposition. The differential learning framework generalizes across model architectures, from graph neural networks to classical descriptor-based approaches. Our results demonstrate that learning relative properties rather than absolute values offers a practical solution for modeling noisy experimental data, with direct applications in materials design where thermal stability predictions inform safety protocols.

Structured light offers a powerful means of controlling light-matter interactions through multiple tunable optical degrees of freedom. Using micromagnetic simulations, we investigate the nucleation of asymmetric bimerons and antibimerons by pulsed Laguerre-Gaussian optical vortices in chiral ferromagnetic thin films with $C_{nv}$ and $D_{2d}$ symmetries, respectively. For optical vortices with orbital angular momentum (OAM) $|m|=1$, circularly polarized beams deterministically nucleate a single bimeron or antibimeron via the interplay of spin angular momentum, OAM, and magnetic chirality, whereas linearly polarized beams produce textures whose topological charge directly follows the OAM ($Q=m$). Optical vortices with OAM $|m|>1$ nucleate clusters and other configurations composed of multiple spin textures, whose morphology and topological charge depend sensitively on the optical quantum numbers and pulse parameters. These findings reveal a route to topology-selective writing through the encoding of optical quantum numbers into distinct in-plane topological magnetic states.

Efficient generation and control of spin-polarized currents in semiconductors remain central challenges for spin-based electronics, particularly due to impedance mismatch and the reliance on magnetic fields or ferromagnetic contacts. Here, we introduce a materials platform for spectrally programmable spin transport based on a van der Waals heterostructure combining the antiferromagnetic semiconductor NiPS$_3$ with WSe$_2$. In a p-n diode architecture, circularly polarized excitation produces pronounced photoconductive resonances with spin polarization reaching 80% near the Neel temperature and persisting at 30% at room temperature. Remarkably, selected spectral bands retain their polarization sign across the magnetic phase transition, evidencing robust, spectrally protected spin-polarized current generation. Polarization-resolved photogalvanic measurements reveal a dominant circular injection-current mechanism, confirming spin-polarized carrier transport. First-principles calculations show that an applied electric field induces interfacial hybridization and spin-layer locking, giving rise to localized symmetry breaking and enhanced optical absorption while preserving global time-reversal symmetry. These results establish spectral tuning of excitation as a new control knob for spin transport, enabling spin-current generation without magnetic fields or polarization switching. Our findings position magnetic van der Waals heterostructures as a versatile platform for opto-spintronic functionality and spectrally programmable spintronic devices.

The low-temperature density-wave state of La$_3$Ni$_2$O$_7$ hosts pronounced spin-density-wave (SDW) order, while recent experiments further reveal charge redistribution and a concomitant lattice-symmetry lowering. However, the microscopic relationship among spin, charge, and lattice remains unclear. Using first-principles calculations, we investigate the pressure evolution of the electronic structure and static spin susceptibility of La$_3$Ni$_2$O$_7$, together with the energetics and lattice response of representative magnetic configurations. We trace the SDW instability to strong Fermi-surface nesting and find that the high-pressure spin response closely tracks $T_{\mathrm C}$, suggesting spin-fluctuation-mediated pairing. Among the candidate magnetic states considered, the spin-charge-stripe states emerge as energetically favored and dynamically stable, developing pronounced disproportionation of both the local Ni moments and the Ni–O bond lengths. Remarkably, the lowest-energy a-stripe state spontaneously relaxes into the experimentally proposed polar Am2m structure through a polar distortion along the b axis. These results establish a unified picture in which spin, charge, and lattice responses are strongly intertwined in the low-pressure density-wave state, while spin fluctuations remain a plausible ingredient of superconductivity under pressure.

Lithium chalcohalide antiperovskites are a promising, non-toxic alternative to lead halide perovskites, with potential as solid electrolytes for Li-ion batteries. we computationally investigate a relatively unexplored anion-interchange mechanism by which cubic Li$_{3}$$AB$ derivatives are obtained from the parent cubic antiperovskite Li$_{3}$$BA$ ($A$ = O, S, Se, Te, Po; $B$ = F, Cl, Br, I). The calculated relative energy landscape provides a useful guide for anion-site selectivity and its role in structural stability. The energetic stability results reveal that the smaller anion inside the octahedron stabilizes the structures. The lattice-dynamic calculations confirm that Li$_{3}$F$A$ ($A$ = Te, Po) and Li$_{3}$O$B$ ($B$ = Cl, Br, I), which are the most energetically stable compounds, are dynamically stable cubic phases without imaginary phonon modes. However, Li$_{3}$FS and Li$_{3}$FSe, while energetically stable, are dynamically unstable at equilibrium and become dynamically stable under triaxial compressive strain. In addition, we report the electronic structure and density of states (DOS) of all compounds, which show a substantial change in band gap upon anion interchange. The strain engineering of the lithium chalcohalide family illustrates how a few percent of the strain can tune the electronic band gap within the electrochemical stability window for solid battery applications. This study unveils essential characteristics of the anion site-interchange mechanism and provides a foundation for the understanding and design of lithium chalcohalide antiperovskites.

We develop a general procedure for constructing time-dependent integrable chiral field theories from autonomous unitary difference-form $S$-matrices satisfying the Yang-Baxter equation. Spectral parameters are transported along the free right- and left-moving characteristics, defining a map from physical spacetime to spectral space on which the two-body scattering data are evaluated. Requiring spatially homogeneous right-left scattering forces the characteristic map to be affine. The inverse Cayley transform then determines the local contact interaction, while evaluation along the affine spectral trajectory fixes its time dependence. Thus, the nonautonomous interaction is determined by the autonomous scattering data together with chiral kinematics and spatial homogeneity, rather than being introduced independently. The Yang–Baxter equation supplies the factorized many-body transport, and on a spatial circle periodicity leads to quantum Knizhnik–Zamolodchikov (qKZ) equations whose compatibility defines a flat discrete transport in spectral space. Pulling the corresponding spectral-space amplitudes back to physical coordinates gives the time-dependent many-body wavefunctions. Rational $SU(N)$, trigonometric $U_q(\widehat{\mathfrak{sl}}_2)$, and rational $O(N)$ scattering illustrate how the same mechanism generates distinct nonautonomous interactions. The resulting framework gives a geometric route from autonomous factorized scattering data to time-dependent integrable field theories.

Exact flat bands provide a versatile setting for correlated and topological phenomena, yet their properties are controlled not only by their dispersion but also by the structure of their Bloch projectors. Here, we establish a projector-based classification of non-Hermitian flat bands. In contrast to Hermitian flat bands, non-Hermiticity introduces a biorthogonal projector whose left-right pairing permits a distinct norm-pole singularity. We identify four classes: analytic NH-A, continuous but nonanalytic NH-C, bounded but discontinuous NH-D, and pole-singular NH-E. We show that continuity of the biorthogonal projector preserves the locking of the right, left, and biorthogonal Chern numbers, $C_R=C_L=C_{\rm bi}$, thereby realizing non-Hermitian critical topological flat bands. Once continuity is lost, this locking can break down; in particular, a mismatch $C_R\neq C_L$ can occur in the NH-E class. Finally, we show that this Chern number mismatch ensures to produce an anomalous enhancement of resonant cross-orbital transfer. Our results establish biorthogonal projector regularity as the organizing principle linking compact localized states, topology, and driven response in non-Hermitian flat bands.

We report multi-hour stable trapping and steady state of non-laser-coolable Cs$^{+}$ ions in a linear Paul trap, achieved via resonant charge-exchange (RCE) cooling with a precisely centered ultracold Cs cloud. Without cold atoms, all ions are lost within 3 minutes. With centered cold atoms, RCE cooling establishes a stable population of ions for 6 hours with no measurable decay – more than two orders of magnitude longer hold times compared to prior hybrid atom-ion systems. We observe a threshold behavior in the steady-state number of ions ($N_{s}$): initial ion loadings above $N_{s}$ ions converge downward to $N_{s}$ ions and remain constant thereafter; initial loadings below $N_{s}$ ions show no measurable decay. The dynamics is governed by a competition between ion-ion rf heating and ion-atom collisional cooling. The prolonged, simultaneous ion-atom trapping suggests an upper bound on the three-body recombination-induced Cs$_{2}^{+}$ formation rate constant: $k_{3} << 1.4 \times 10^{-25} cm^{6} s^{-1}$. This remarkable realization of long-lived steady state overcomes a critical limitation of prior hybrid atom-ion systems and enables extended studies of ultracold ion-neutral chemistry, rare inelastic collisions, and sympathetic cooling routes for complex molecular ions.

Biological and artificial networks compute by transforming time-dependent inputs into functional outputs. Because the internal state of a stochastic network relaxes on finite timescales, its output generally lags behind a changing environment, producing computational errors. We show that for reversible continuous-time Markov networks the error admits a universal thermodynamic bound. Decomposing the total error into representation and lag contributions, we derive an inequality relating the lag error to the entropy production rate and a memory time equal to the integrated equilibrium autocorrelation of the output observable. The bound implies that accurate dynamical computation requires either substantial dissipation or long-lived memory encoded in slowly relaxing modes. We demonstrate these principles in artificial Markov networks and in models of biochemical information processing. Our results establish a thermodynamic limit on information processing in stochastic networks and provide a quantitative framework for understanding the energetic costs of biological computation.

Conventional finite-size theories describe first-order coexistence through free-energy competition and interfacial tunneling, but the distinct spectral roles of sector balance and inter-sector connectivity are not usually explicit. We show that pseudo-transitions and thermodynamic phase coexistence are governed by two spectral coordinates: sector imbalance locates balance, while connectivity determines whether that balance remains avoided. At balance, finite connectivity produces a unique dominant state with equal spectral weights in the symmetrized two-sector representation. For short-range systems with positive interface tension, interfacial costs suppress the connectivity exponentially, close the coexistence splitting, and asymptotically restore reducibility. Thus, genuine phase coexistence emerges as the singular limit of finite-size avoided coexistence, whereas one-dimensional pseudo-transitions retain finite connectivity. In a decorated bilayer Ising model, the coexistence gap at independently est

We formulate split Galois descent for fusion categories through framed equivalences, reducing the existence of a split form to a group-theoretic splitting problem. The associated degree-two obstruction combines categorical coherence with stable descent of the simple objects, while fusion spaces impose index and parity restrictions. For quantum groups at roots of unity, we use the quasi-$R$-matrix to make the bar involution tensor-compatible and prove that the underlying fusion category $\mathcal C(\mathfrak g,k)$, associated with the simply connected root datum, has a split form over the maximal totally real subfield of the cyclotomic field generated by the quantum parameter. The same holds for all its cyclotomic Galois conjugates; in particular, every $\mathcal C(\mathfrak g,k)$ has a split real form. By contrast, no split real form exists for the standard braiding except on $\mathcal C(E_8,1)$ and $\mathcal C(D_{4m},1)$, $m \geq 1$. We further show that associative zesting can destroy real descent of $\mathcal C(\mathfrak g,k)$, while every braided zesting of $\mathcal C(\mathfrak g,k)$ still admits a split real form as an underlying fusion category. Applications to pointed and finite-group representation categories give criteria for real descent in terms of cohomology and Frobenius–Schur indicators.

In this study, we investigate structural, magnetic, and electronic properties of the copper-ruthenate based oxide double perovskite La$_{2-x}$Sm$_x$CuRuO$_6$ (x = 0, 1, 2), synthesized through the solid-state reaction method. X-ray diffraction analysis reveals that all compounds crystallize in a monoclinic symmetry, with varying degree of structural distortion that increases in moving from La$^{3+}$ to smaller size cation Sm$^{3+}$. Electrical resistivity studies indicate insulating behaviour in all compounds, with variable-range-hopping domination at low temperatures, due to presence of anti-site disorder. AC susceptibility and heat capacity measurements suggest suppression of frustration in Sm-bearing compounds, affecting the magnetic behavior. Our first-principles calculations suggest that the combined effects of lattice distortion and Sm magnetism play a crucial role in weakening magnetic frustration, thereby rationalizing the experimental observations. These findings shed light on the complex interplay of crystal structure and magnetism in Cu-Ru double perovskites, and open up an avenue for tuning of magnetic properties through rare-earth-ion substitution.

We report the observation of electron spin interactions between Rydberg atoms, which are driven by spin-orbit coupling through second-order dipole perturbation and exhibit a spatial anisotropy governed by the atomic configuration. Specifically, we observe coherent electron spin exchange dynamics, with the measured coupling strength agreeing well with both numerical calculations and theoretical models. Furthermore, we show that global microwave dressing enables active engineering and dynamical freezing of the spin exchange by introducing a differential AC Stark shift between the participating states. Additionally, we achieve tunability of the interaction by applying a stronger magnetic field, which effectively modifies the energy contributions of the underlying spin-orbit coupling channels. Finally, measuring spin dynamics in one-dimensional multi-atom chains aligned parallel or perpendicular to the magnetic field provides a self-consistent validation of the anisotropic XXZ framework. This electron spin interaction natively features spin-position coupling and enables a natural mapping onto the Heisenberg-Kitaev model. Our findings reveal a new class of electron spin-spin interactions among Rydberg atoms, expanding the scope of quantum simulation with Rydberg atom arrays.

Learning a quantum system's Hamiltonian is crucial for understanding and controlling its dynamics and has recently become a topic of widespread interest. To understand the learning protocol's error tolerances, i.e. its stability in the presence of inevitable errors, this work utilizes tensor network techniques to emulate Hamiltonian learning workflows at scale and with noise. Specifically, we employed a Hamiltonian learning technique based on approximate stationary states which are constructed using matrix product tools. We provide analytic bounds on the Hamiltonian learning estimation errors and perform numerical simulations that highlight learning error's stability under two families of errors. Using our workflow, we are able to scale up the protocol and learn mixed-field Ising model Hamiltonians of an $N=300$ site spin chain. By simulating the protocol at large scale, and empirically studying its practical limitations, our analysis of how errors affect the Hamiltonian learning process provides valuable lessons for future experiments. We conclude by discussing the avenues our work opens as well as future work that can support Hamiltonian learning experiments.

Despite their remarkable success in modeling complex data, generative models face a fundamental tradeoff. Global approaches can capture full structural coherence but suffer from high computational costs, while local models are efficient but often fail to reproduce long-range correlations and global coherence. The renormalization group (RG) bridges this gap by seamlessly connecting spatial structures across different length scales, retaining quasi-local descriptions at each step while preserving long-range correlations. We introduce renormalization group flow matching (RGFM), a generative framework that systematically structures data generation across different spatial scales. By using an exact RG flow as the probability path, RGFM progressively generates data from long- to short-wavelength structures. To reconcile scalability with global structure, we exploit two key properties of the RG: quasi-locality and scale separation. We rigorously show that the RGFM probability flow can be accurately approximated by local velocity fields acting over a spatial range $O(\Lambda^{-1}[\ln L+\ln(1/\varepsilon)])$ for RG wavenumber scale $\Lambda$, linear system size $L$, and prescribed error tolerance $\varepsilon$. This property enables local generative modeling with patches of size $O(\ln L)$ and a computational cost that scales nearly linearly with the system volume. We numerically demonstrate that local RGFM reproduces long-range correlations far beyond its receptive field in representative one-dimensional distributions, while conventional local flow matching exhibits substantial errors at long distances. On FFHQ images, RGFM yields far more coherent and higher-quality samples than local flow matching at 64x64 and 256x256. Our results establish RG-guided probability flows as a promising route toward scalable generative modeling that captures long-range structure using only local computation.

Strong interactions between $s$-orbital Rydberg atoms underpin atom-array-based quantum computation and quantum simulation. Typically, the spin dependence of these interactions is negligible and plays no practical role. In this Letter, we uncover that a strong electron-spin-dependent Rydberg interaction can emerge when the principal quantum numbers of the two $s$-orbital atoms differ by a sweet-spot value. This interaction originates from the fine-structure splitting of nearby $p$ orbitals, which endows it with distinct symmetry properties such that the electron spins are coupled to the relative position of the two atoms, featuring a spatially defined anisotropy. We further demonstrate that this interaction admits a universal form, independent of the principal quantum numbers, and highlight its fundamental distinction from conventional magnetic dipolar interactions, establishing it as a new type of native magnetic interaction in nature. Our findings introduce a new element to the Rydberg quantum simulation toolbox. As a concrete application, we propose a native realization of the Kitaev-Heisenberg model, which hosts an unusual stripe phase as a quantum many-body manifestation of spin-space locking.

The $F$-symbols of an anyon theory encode the associativity of fusion and constitute some of the theory's most fundamental and, simultaneously, subtle data. Much of the subtlety lies in the gauge-dependence of the $F$-symbols. Despite their generic complexity, many braided anyon theories admit gauges in which all $F$-symbols are real, a phenomenon for which no general organising principle has been known. We identify a physical mechanism underlying this reality. For a unitary ribbon fusion category admitting an appropriate braided charge-conjugation symmetry, we show that the complex-conjugated $F$-symbols are related to the original ones by a gauge transformation. Finding a real gauge is thereby reduced to a condition on these transformations. When the charge-conjugation symmetry is suitably "flat,” or equivalently when the associated "twisted” Frobenius-Schur (or "generalized” Kawanaka-Matsuyama) data respects a grading, these local transformations can be trivialised and a real gauge exists. This framework unifies a broad range of previously disparate examples, including families of Chern-Simons theories whose $F$-symbols are difficult to directly compute. Finally, we exhibit a unitary ribbon category that realizes a novel obstruction to the existence of a real gauge and therefore has inherently complex $F$-symbols.

We develop a gauge-invariant framework that relates two-magnon Raman circular dichroism (RCD) to higher-order magnon quantum geometry. In the magnon band basis, the Raman operator decomposes into interband Berry connections, their covariant derivatives, and products of successive connections, generating higher-order, multi-state geometric tensors beyond the conventional single-band quantum metric and Berry curvature. Applying this framework to a field-polarized Kitaev magnet, we show that higher-order geometric tensors govern the dichroic response. Our results establish RCD as a spectroscopic probe of generalized magnon quantum geometry.

We present a comprehensive exact-diagonalization study of interaction-driven phases in twisted bilayer MoTe$_2$ across experimentally relevant twist angles ($2.13^\circ$–$4^\circ$) and hole fillings. Using continuum-model moiré bands, we compare the one-band-per-valley (1BPV) projection with a two-band-per-valley (2BPV) calculation that includes interaction-driven band mixing, and we benchmark both the widely used first-harmonic continuum model and a parameter-free DFT “fitting-free” model. At odd-denominator fillings, the 2BPV calculation reproduces the experimentally observed hierarchy of fractional Chern insulators (FCIs) around $\theta\approx 3.7^\circ$, including robust incompressible states at $\nu=-2/3$, $-3/5$, and $-4/7$ while correctly finding the absence of an FCI at $\nu=-3/7$, and it favors a charge density wave ground state at $\nu=-1/3$ over the FCI. At half filling $\nu=-1/2$, the 1BPV calculation exhibits clear composite Fermi liquid (CFL) signatures, whereas the band mixing in 2BPV calculations destabilizes the CFL ground state. Finally, motivated by the Landau-level analogy at $\theta\approx 2.13^\circ$, we test the proposed non-abelian Pfaffian state at $\nu=-3/2$ in the fully-polarized spin sector but find no evidence for this state within the models and parameters studied. Our results establish a unified numerical benchmark for correlated and topological phases in twisted bilayer MoTe$_2$ and clarify where multi-band physics is essential for a quantitative comparison with experiments.

Identifying emergent flux excitations and signatures of their mutual statistics with itinerant Majorana fermions remains a central challenge in Kitaev spin liquids. We show that an isolated $\pi$ flux imprints an intrinsic Aharonov-Bohm-like interference pattern on the charge-neutral Majorana continuum. Spatially resolved scanning tunneling microscopy with inelastic electron tunneling spectroscopy (STM-IETS) probes this oscillation in the local dynamical spin response as a function of both bias voltage and tip-flux separation, reflecting the $\pi$ phase acquired by Majorana trajectories encircling the flux. We show that large-scale exact diagonalization of the Kitaev honeycomb model and a complementary low-energy continuum theory yield consistent radial oscillations. These results provide a finite-energy, spatially resolved tunneling signature of a preexisting flux and a diagnostic of fermion-flux mutual statistics without requiring manipulation of individual anyons in the Kitaev spin liquid.