Papers

The occupation number is a key observable for diagnosing thermalization, as it connects directly to standard statistical laws such as Fermi–Dirac, Bose–Einstein, and Boltzmann distributions. In the context of spin systems, it represents the population of the sublevels of the magnetization in the $z$-direction. We use this quantity to probe the onset of thermalization in the isolated quantum and classical one-dimensional spin-1 Ising model with transverse and longitudinal fields. Thermalization is achieved when the long-time average of the occupation number converges to the microcanonical prediction as the chain length $L$ increases, consistent with the emergence of ergodicity. However, the finite-size scaling analysis in the quantum model is challenged by the exponential growth of the Hilbert space with $L$. To overcome this limitation, we turn to the corresponding classical model, which enables access to much larger system sizes. By tracking the dynamics of individual spins on their three-dimensional Bloch spheres and employing tools from random matrix theory, we establish a quantitative criterion for classical ergodicity in interacting spin systems. We find that deviations from classical ergodicity decay algebraically with system size. This power-law scaling then provides a quantitative bound on the approach to thermal equilibrium in the quantum model.

Correlated physics in nearly flat topological bands is a central theme in the study of moiré materials. While ground states at integer fillings are typically identified as quantum Hall ferromagnets within a Hartree-Fock framework, we propose the existence of symmetric topological Mott insulators (STMIs) that transcend this Slater determinant picture. Focusing on half-filling of each flavor per unit cell, we demonstrate the existence of STMIs which exhibit a quantized charge or spin Hall response. We first establish this phase in a bilayer Haldane-Hubbard model with localized orbitals on the $A$ sublattice and dispersive band on the $B$ sublattice. Starting from a trivial Mott insulator on the $A$ sublattice, tuning the sublattice potential drives a Bose-Einstein-condensation (BEC) to Bardeen-Cooper-Schrieffer (BCS) transition of the associated $p-\mathrm{i}p$ exciton pairing, realizing a topological Mott insulator with $C=1$ per flavor. We further generalize this construction to a single-layer spinful model, where the resulting STMI hosts charge edge modes coexisting with bulk local moments. A Mott semimetal is identified at the quantum critical point between the STMI and the trivial Mott insulator. Finally, we discuss applications to AA-stacked MoTe$_2$/WSe$_2$, proposing a ferromagnetic Chern insulator phase as a low-temperature descendant of the symmetric Mott semimetal.

Altermagnets represent a promising class of magnetic materials owing to their distinctive spin-split band structures in the absence of net magnetization. Here, we present a first-principles investigation of altermagnetism in magnetically intercalated transition metal dichalcogenides (TMDs) with the general formula T$_y$MX$_2$ (T= 3$d$-transition metal, M= transition-metal, X=chalcogen, $y$= 1/3 or 1/4). For a TMD host with 2H structure, compounds exhibiting A-type antiferromagnetism are $g$-wave altermagnets by symmetry. We identify several intercalated TMDs fulfilling the conditions for altermagnetic order to be realized. Several of these candidate materials display spin-splittings at the Fermi level as large as 100 meV.

We define a quantum charger as an interacting quantum system that transfers energy between two drives. The key figure of merit characterizing a charger is its charging power. Remarkably, the presence of long-range interactions within the charger can induce a collective steady-state charging mode that depends superlinearly on the size of the charger, exceeding the performance of noninteracting, parallel units. Using the driven Lipkin-Meshkov-Glick model and power-law interacting spin chains, we show that this effect persists up to a critical system size set by the breakdown of the high-frequency regime. We discuss optimal work output as well as experimentally accessible initial states. The superlinear charging effect can be probed in trapped-ion experiments, and positions interacting Floquet systems as promising platforms for enhanced energy conversion.

In charge neutral fluids, such as the Dirac fluid in graphene at the Dirac point, charge transport remains diffusive despite the presence of ballistically propagating sound waves: sound waves “hydrodynamically decouple” from the slower charge fluctuations. For quasi-one-dimensional charge neutral fluids, we show that this convective charge diffusion is not smoothly connected to the normal diffusion that arises when momentum conservation is broken by noise (or static impurities). Instead, the charge diffusion constant is a discontinuous function of noise, which (in the weak-noise limit) depends only on the ratio of momentum and energy relaxation rates. In the special limit of momentum-conserving noise (e.g., spatially uniform fluctuations of the Hamiltonian), the diffusion constant diverges in the presence of noise. We describe the resulting superdiffusion in terms of coupled Burgers equations. We present a general mechanism—hydrodynamic recoupling—by which weak noise can induce singular changes in transport coefficients. Our results highlight the limits of zero-noise extrapolation for predicting dynamical quantities like diffusion constants.

We investigate the inverse Edelstein effect in a non-homogeneous system consisting of a ferromagnetic layer coupled to a Rashba two-dimensional electron gas. Within a semiclassical Boltzmann framework, we derive analytical expressions for the charge and spin currents and analyze their dependence on key parameters such as the chemical potential and the Rashba coupling strength. We show how interfacial exchange and spin-orbit interactions jointly control the efficiency of spin-to-charge conversion, leading to distinct regimes characterized by qualitatively different transport responses. A central outcome of our work is the availability of closed-form analytical results, which provide direct physical insight and enable a transparent and quantitative benchmarking with experiments on complex oxide interfaces, such as LaAlO$_3$/SrTiO$_3$.

The two-dimensional $O(N)$ nonlinear sigma model (NLSM) is asymptotically free for $N>2$: it exhibits neither a nontrivial fixed point nor spontaneous symmetry-breaking. Here we show that a nontrivial fixed point generically does exist in the complex coupling plane and is described by a complex conformal field theory (CCFT). This CCFT fixed point is generic in the sense that it has a single relevant singlet operator, and is thus expected to arise in any non-Hermitian model with $O(N)$ symmetry upon tuning a single complex parameter. We confirm this prediction numerically by locating the CCFT at $N = 3$ in two non-Hermitian spin-1 antiferromagnetic Heisenberg chains, and in a non-Hermitian spin-$1/2$ ladder, finding good agreement between the complex central charge and scaling dimensions and those obtained by analytic continuation of real fixed points from $N\leq 2$. We further construct a realistic Lindbladian for a spin-1 chain whose no-click dynamics are governed by the non-Hermitian Hamiltonian realizing the CCFT. Since the CCFT vacuum is the eigenstate with the smallest decay rate, the system naturally relaxes under dissipative dynamics toward a CFT state, thus providing a route to preparing long-range entangled states through engineered dissipation.

First-principles density functional theory (DFT) calculations were used to study the effects of elastic strains on the binding and diffusion activation energies of Au adatom and CeO2 admolecule on Au (001), Ce-terminated CeO2 (001), MgO (001), SrO- and TiO2-terminationed SrTiO3 (001) surfaces. In preparation for computing these energies, normal and shear strains within the range 0.15% were applied in the plane of the surface of the supercell prior to placing the adsorbed species on the surface. Our study shows that the dependence of binding energies and diffusion barriers of adatoms and molecules on the strain varies significantly among surfaces. The strain was found to alter the symmetry of surface diffusion pathways causing anisotropy of the diffusion barriers. This strain-induced anisotropy depends on the orientation of the applied strains relative to the in-plane crystallographic directions of the free surface. The binding and diffusion activation energies were fit linearly in terms of strain components in the range 0.15% and the extrapolated values compared favorably to DFT computed values up to 0.5%. The scheme presented here for the computation and fitting of the binding and diffusion energies in terms of strain can be used to inform models of surface diffusion, clustering and growth of multi-component and multi-phase thin films and investigate the effect of strain on the self-organization in such systems.

Band degeneracies, ranging from Hermitian Dirac points to non-Hermitian exceptional points (EPs), play a central role in topological phase transitions. Beyond the topology of individual degeneracies, their mutual interactions yield richer phenomena. A representative example is the anomalous non-annihilating collision of pairwise-created degeneracies, previously believed to occur only in non-Abelian multiband systems. Here, we theoretically reveal and experimentally demonstrate that such an anomalous collision can emerge even in a simple two-band system without non-Abelian nature. In a two-dimensional non-Hermitian lattice whose Brillouin zone forms a nonorientable Klein bottle, two EPs with opposite topological charges, pairwise created from a hybrid point, merge into a new vortex point upon re-encounter, instead of annihilating. Remarkably, the hybrid point is a defective degeneracy featuring no eigenenergy braiding, whereas the vortex point is a non-defective degeneracy yet exhibits nontrivial eigenenergy braiding. This process manifests a non-Hermitian phase transition from a gapped phase to a gapless phase, a scenario that we directly observe in a hybrid-dimensional acoustic lattice via momentum-resolved band braid and Berry phase measurements. Our findings identify nonorientability as a new arena for engineering band degeneracies and topological phases, and pave the way for experimentally exploring the interplay between exceptional and nonorientable topology.

In this work, the optoelectronic characteristics of kesterites of the Cu2NiXS4 system (X = Si, Ge, Sn) were studied. The electronic properties of the Cu2NiXS4 (X = Si, Ge, Sn) system were studied using first-principles calculations within the framework of density functional theory. For calculations, ab initio codes VASP and Wien2k were used. The high-precision modified Beke-Jones (mBJ) functional and the hybrid HSE06 functional were used to estimate the bandgap, electronic and optical properties. Calculations have shown that when replacing Si with Ge and Sn, the band gap decreases from 2.58 eV to 1.33 eV. Replacing Si with Ge and Sn reduces the overall density of electronic states. In addition, new deep (shallow) states are formed in the band gap of these crystals, which is confirmed by the behavior of their optical properties. The obtained band gap values are compared with existing experimental measurements, demonstrating good agreement between HSE06 calculations and experimental data. The nature of changes in the dielectric constant, absorption capacity and optical conductivity of these systems depending on the photon energy has also been studied. The statistical dielectric constant and refractive index of these materials were found. The results will help increase the amount of information about the properties of the materials under study and will allow the use of these compounds in a wider range of optoelectronic devices, in particular, in solar cells and other devices that use solar radiation to generate electric current.

In this work, using theoretical calculations within the framework of the density functional theory, taking into account the dispersive VDW interaction, the processes of adsorption and interaction of a water molecule with a TiO2 surface in various configurations are investigated. At the atomic/molecular level, the interactions of a water molecule with a TiO2 surface have been studied for various orientations. The results of calculations within the framework of DFT+ VDW show that the adsorption energies of single water molecules in different initial positions on the substrate surface vary from-0.72 to-0.84 eV, and the most stable adsorbate structure is the TiO2+ H2O system upon adsorption of a molecule of water, parallel to the Y axis, because during the adsorption of H2O parallel to the Y axis, some favorable effects are observed in the band structure of titanium dioxide. On the one hand, the band gap decreases to 2.59 eV, and on the other hand, a new energy state appears in the band gap with an energy contribution of 0.17 eV, when water is physisorbed and interacts with a titanium atom at a distance of 2.12 Å and occupies a perpendicular position relative to the surface.

The exploration of topological and transport properties of collinear antiferromagnets and the role of Kitaev interactions in realising topological states therein have rarely been systematically addressed in literature. In this context, we consider a zigzag-ordered antiferromagnet with both extended Kitaev and Dzyaloshinskii-Moriya interactions (DMI) in presence of an external magnetic field to focus on the topological phases demonstrated by the magnon band structure and validated by the transport properties. The hybridization between the up- and down-spin sectors carries evidences of opening bulk gaps in the magnon band structure, giving rise to nontrivial topological phases characterized by finite Chern numbers, chiral edge modes, and a nonzero thermal Hall conductivity. Furthermore, generally speaking, a finite magnon orbital moment can exist and contribute to the Nernst response even when the net spin moment vanishes owing to the fundamental independence of the spin and orbital magnetizations. This motivates us to investigate the magnon orbital moment, orbital Berry curvature, and the resulting orbital Nernst conductivity associated with the magnon bands. We find that a giant orbital Nernst conductivity emerges even in the absence of an external magnetic field. Moreover, the distinction between different topological phases is more lucidly manifested via the orbital Nernst conductivity, thereby highlighting an enhanced sensitivity of the orbital transport to the underlying band topology. For completeness, we briefly discuss the scenario corresponding to a Néel-ordered spin alignment, which leads to a vanishing Chern number and consequently suppressed thermal Hall and orbital Nernst conductivities compared to the zigzag-ordered case, even in the presence of DMI and Kitaev interactions.

Quantum geometry in centrosymmetric systems has motivated the search for photocurrent responses beyond second order. In particular, electric field-induced nonlinear responses may also enable intrinsic polarization-sensitive optical detectors. Despite numerous efforts, clear methods are still needed to remove experimental artifacts, separating intrinsic from extrinsic effects, and disentangling linear responses from their higher-order counterparts. Here, we provide a systematic study of fabrication and measurement techniques to remove external artifacts in photoelectronic responses. This reveals a previously hidden photothermoelectric response in the transverse photoresistivity of symmetric thin films of simple metals. We identify its origin in thermal gradients producing current deflection and determine the device design and measurement parameters to minimize extrinsic effects that arise in photoinduced electronic responses.

Mapping microstructure to properties is central to materials science. Perhaps most famously, the Hall-Petch relationship relates average grain size to strength. More challenging has been deriving relationships for properties that depend on subtle microstructural features and not average properties. One such example is the initiation of energetic materials under dynamical loading, dominated by energy localization on microstructural features such as pores, cracks, and interfaces. We propose a conditional convolutional neural network to predict the shock-induced temperature field as a function of shock strength, for a wide range of microstructures, and obtained via two different simulation methods. The proposed model, denoted MISTnet2, significantly extends prior work that was limited to a single shock strength, model, and type of microstructure. MISTnet2 can contribute to bridging atomistics with coarse-grain simulations and enable first principles predictions of detonation initiation and safety of this class of materials.

Fluctuating hydrodynamics provides a quantitative, large-scale description of many-body systems in terms of smooth variables, with microscopic details entering only through a small set of transport coefficients. Although this framework has been highly successful in characterizing macroscopic fluctuations and correlations, a systematic derivation of fluctuating hydrodynamics from underlying stochastic microscopic dynamics remains obscure for broad classes of interacting systems. For stochastic lattice gas models with gradient dynamics and a single conserved density, we develop a path-integral based coarse-graining procedure that recovers fluctuating hydrodynamics in a controlled manner. Our analysis highlights the essential role of local-equilibrium averages, which go beyond naïve mean-field-type gradient expansions. We further extend this approach to interacting Brownian particles by coarse-graining the Dean-Kawasaki equation, revealing a mobility proportional to the density and a diffusivity determined by the thermodynamic pressure.

Utilizing a combination of dynamical mean field theory and density functional theory (DMFT/DFT), it has been theoretically proposed that PuB$_6$ is a strongly correlated topological insulator characterized by nontrivial $\mathbf{Z}_{2}$ topological invariants and metallic surface states (X. Deng et al., Phys. Rev. Lett. 111, 176404 (2013)). Here, we demonstrate through low-temperature magneto-transport measurements and first-principles calculations that PuB$6$ exhibits characteristics of a topological Kondo insulating state. These features include a transition in electrical resistivity from high-temperature, thermally activated behavior with a narrow gap at the Fermi level ($\Delta{\rho} \sim$ 20 meV) to a distinctive low-temperature plateau, as well as a surface-to-volume dependence of electrical resistivity at low temperatures. The topological nature of PuB$_6$ is further supported by the theoretical calculations, which show that GGA+$U$ is capable of capturing electronic, topological, and lattice properties of PuB$_6$ with much lower computational cost than DMFT.

We investigate the angle of repose ${\theta}_r$ of dense suspensions of colloidal silica particles ($d = 2$ $\mu m$ to $7$ $\mu m$) in water-filled microfluidic rotating drum experiments, to probe the crossover between the thermal (colloidal) and athermal (granular) regimes. For the smallest particles, thermal agitation promotes slow creep flows, and piles always flatten completely regardless of their initial inclination angle, resulting in ${\theta}_r = 0$. Above a critical particle size, piles of colloids stop flowing at a finite angle of repose, which increases with particle size but remains below the minimal value expected for athermal frictionless granular materials: $0 < {\theta}_r < {\theta}_{ath} \approx 5.8{\deg}$. We quantify the arrest dynamics as a function of the gravitational Péclet number $Pe_g$, which characterizes the competition between particle weight and thermal agitation. Our measurements are consistent with a recent rheological model [Billon et al., Phys. Rev. Fluids 8, 034302, 2023], in which the arrested state stems from a crossover between glass and jamming transitions as the granular pressure in the pile increases relative to the thermal pressure.

Characterizing magnetic fluctuations is one of the keys to understanding the origin of superconductivity in the spin-triplet superconductor UTe$_2$ which exhibits two superconducting (SC) phases (SC1 and SC2) under pressure: SC1 where a superconducting transition temperature of $T_{\rm c}$ decreases with pressure while $T_{\rm c}$ of SC2 rises with pressure. Previously, D. Ambika et al. [Phys. Rev. B 105, L220403 (2022)] have reported the possible coexistence of ferromagnetic (FM) and antiferromagnetic (AFM) spin fluctuations in UTe$_2$ under pressure from their nuclear magnetic resonance (NMR) measurements. To delve the relationship between the magnetic fluctuations and the two SC phases, we have carried out detailed $^{125}$Te NMR measurements on a single crystal of UTe$_2$ with $T_{\rm c}$ = 1.6 K at various pressures ranging from 0 to 2.05 GPa. By comparing the temperature $T$ dependence of nuclear spin-lattice relaxation rates divided by temperature 1/$T_1T$ with that of the Knight shift $K$ for magnetic fields along the $a$, $b$, and $c$ directions, we evidence the enhancement of AFM spin fluctuations with increasing pressure. Based on the results, we suggest that FM spin fluctuations are more favorable for SC1 and AFM spin fluctuations are crucial for SC2. Our findings will inspire further study on this material to understand the peculiar SC phases in detail.

In the quest to understand large-scale collective behavior in active matter, the complexity of hydrodynamic and phoretic interactions remains a fundamental challenge. To date, most works either focus on minimal models that do not (fully) account for these interactions, or explore relatively small systems. The present work develops a generic method that combines high-fidelity simulations with symmetry-preserving descriptors and neural networks to predict hydro-phoretic interactions directly from particle coordinates (effective interactions). This method enables, for the first time, self-contained particle-only simulations and theories with full hydro-phoretic two-body interactions.

We propose a disorder-free one-dimensional single-particle Hamiltonian hosting an exact mobility edge (ME), placing the system outside the assumptions of no-go theorems regarding unbounded potentials. By applying a linear Stark potential selectively to one sublattice of a dimerized chain, we generate an effective Hamiltonian with unbounded, staggered hopping amplitudes. The unbounded nature of the hopping places the model outside the scope of the Simon-Spencer theorem, while the staggered scaling allows it to evade broader constraints on Jacobi matrices. We analytically derive the bulk spectrum in reciprocal space, identifying a sharp ME where the energy magnitude equals the inter-cell hopping strength. This edge separates a continuum of extended states from two distinct localized branches: a standard unbounded Wannier-Stark ladder and an anomalous bounded branch accumulating at the ME. The existence of extended states is supported by finite-size scaling of the inverse participation ratio up to system sizes $L \sim 10^9$. Furthermore, we propose an experimental realization using photonic frequency synthetic dimensions. Our numerical results indicate that the ME is robust against potential experimental imperfections, including frequency detuning errors and photon loss, establishing a practical path for observing MEs in disorder-free systems.

Quantitative 3D characterization of materials degradation in oxidizing environments remains limited. Here, we apply a correlative tomography-based mass balance framework to Cr$_2$AlC, a coating candidate for accident tolerant nuclear fuel claddings and turbine blades, and show that decomposition and pore evolution during oxidation, quantified by integrating volumetric, structural and compositional data, are strongly governed by grain morphology. The oxidation of sputtered Cr$_2$AlC coatings with equiaxed and columnar grain morphologies was analyzed. While Cr$_7$C$_3$ formed in both coating morphologies, pores formed exclusively in columnar coatings. The expected Cr$_7$C$_3$ volume was estimated by mass-balance calculations assuming that Al-deintercalation enables oxide scale and Al-O-C-N precipitate formation, leading to complete transformation of the Al-deintercalated Cr$_2$AlC into Cr$_7$C$_3$. In equiaxed coatings, the predicted carbide volume agreed with tomography within 3 $\pm$ 3 %, confirming Al-deintercalation-driven Cr$_7$C$_3$ formation. Despite the smaller molar volume of Cr$_7$C$_3$ relative to Cr$_2$AlC, absence of pores imply that transformation shrinkage is likely accommodated by coating thickness reduction. In columnar coatings, the predicted Cr$_7$C$_3$ volume exceeds the measured value by 22 $\pm$ 4 %, and the pore volume expected from transformation shrinkage alone is 13-16 % lower than measured, indicating partial Al deintercalation and clustering of pre-existing defects. This combined methodology provides a general route to quantitatively resolve degradation mechanisms.

The identification, control and theoretical modelling of spin-triplet superconductors (STC) remain a central theme in quantum materials research. Intrinsic STC are rare but offer rich condensate properties and unique surface properties allowing insights into the nature of the spin-triplet order, and promising applications in quantum technologies. Owing to interactions, the order parameter in STCs can often be intertwined with other symmetry breaking orders like charge/spin density waves (CDW/SDW) or pair density waves (PDW) complicating their phase diagrams. UTe2 stands out as the only known odd-parity, STC that harbors such intertwined orders on the surface and possible topological surface states composed of Majorana fermions. While the (0-11) facet is the most heavily studied, the fermiology of this surface that gives rise to such exotic phenomena is still lacking and continues to be an area of active interest. Here, we employ low-temperature spectroscopic imaging to reveal the Fermi surface of UTe2 through quasiparticle interference. We find scattering originating from the uranium-derived bands that play a major role in the formation of the CDW and the PDW phases. Tunneling spectroscopy further reveals spectral signatures of the CDW gap, corroborating its onset temperature. Suppressing the CDW with a magnetic field, highlights the presence of small, circular Fermi pockets that disperse strongly near the Fermi energy. We discuss the nature of the interference patterns and the origin of the small Fermi pockets in the context of the calculated band structure and the unconventional CDW phase.

We develop a fractional-order Ginzburg-Landau (GL) framework for nonreciprocal superconducting transport in Josephson junctions formed by fractal superconductors or superconducting media with nonlocal correlations, separated by a noncentrosymmetric normal layer. We show that nonreciprocity and the superconducting diode effect arise from the interplay between the Lifshitz invariant and fractional kinetics, with the latter serving as an effective, symmetry-consistent representation of fractal geometry and finite-range memory. Two complementary approaches are pursued. In a fractional integral GL formulation, spatial integration on a fractal space yields analytic solutions and reveals how rectification scales with the dimensionality of the fractal media and the strength of the Lifshitz-like drift. In a fractional derivative-based formulation derived via the Agrawal variational principle with left/right Caputo operators, we obtain a gauge-invariant free energy, the corresponding GL equations, and a current density. We use fractional orders as effective parameters that represent nonlocal and memory effects induced by fractal microstructure. Within a two-mode plane-wave approximation we derive a compact current-phase relation and an expression for the diode efficiency, and we map the rectification amplitude across the fractional kinetic and the Lifshitz/memory order. An exact single-sided solution in terms of Prabhakar functions further confirms robust, tunable nonreciprocity, including a near-ideal diode response. This identifies a pathway to near-perfect superconducting diodes by engineering fractal (fractional-kinetic) transport achieved by tuning the fractional orders and Lifshitz strength without invoking magnetic fields or geometric ratchets. In the integer limit of local kinetics and Lifshitz-like drift, both constructions reduce to the standard $\varphi_0$ Josephson junction.

Actin filaments, crosslinkers and myosin molecular motors form contractile networks. For instance, the cell cortex is a thin network below the cell membrane ; contraction of the cell cortex allows cells to round up during cell division. Contractile actin-myosin networks are often represented at large scale by continuous theories such as active gel models. However, experimental perturbations are microscopic while parameters in continuous models are macroscopic, thus making those models hard to falsify experimentally. Here we use numerical simulations, in which we can access both microscopic and macroscopic quantities, to show that active gel models can indeed be applied to describe contractile actin. We predict that contractile stress should scale linearly with actin density, which is confirmed by numerical simulations. Moreover, we can accurately predict how the contractile stress depends on motor properties such as unloaded speed and stall force.

Recent advances in quantum technologies and related experiments have created a need for highly accurate, versatile, and computationally efficient simulation techniques for the dynamics of open quantum systems. Long-lived correlation effects (non-Markovianity), system-environment hybridization, and the necessity for accuracy beyond the Born-Markov approximation form particular challenges. Approaches to meet these challenges have been introduced, originating from different fields, such as hierarchical equations of motion, Lindblad-pseudomode formulas, chain-mapping approaches, quantum Brownian motion master equations, stochastic unravelings, and refined quantum master equations. This diversity, while indicative of the field's relevance, has inadvertently led to a fragmentation that hinders cohesive advances and their effective cross-community application to current problems for complex systems. How are different approaches related to each other? What are their strengths and limitations? Here we give a systematic overview and concise discussion addressing these questions. We make use of a unified framework which very conveniently allows to link different schemes and, this way, may also catalyze further progress. In line with the state of the art, this framework is formulated not in a fully reduced space of the system but in an extended state space which in a minimal fashion includes effective reservoir modes. This in turn offers a comprehensive understanding of existing methods, elucidating their physical interpretations, interconnections, and applicability.

Quantum machine learning (QML) is expected to offer new opportunities to process high-dimensional data efficiently by exploiting the exponentially large state space of quantum systems. In this work, we apply quantum extreme reservoir computing (QERC) to the classification of microstructure images of polymer alloys generated using self-consistent field theory (SCFT). While previous QML efforts have primarily focused on benchmark datasets such as MNIST, our work demonstrates the applicability of QERC to engineering data with direct materials relevance. Through numerical experiments, we examine the influence of key computational parameters-including the number of qubits, sampling cost (the number of measurement shots), and reservoir configuration-on classification performance. The resulting phase classifications are depicted as phase diagrams that illustrate the phase transitions in polymer morphology, establishing an understandable connection between quantum model outputs and material behavior. These results illustrate QERC performance on realistic materials datasets and suggest practical guidelines for quantum encoder design and model generalization. This work establishes a foundation for integrating quantum learning techniques into materials informatics.

We propose a neural network-based model capable of learning the broad landscape of working regimes in quantum dot simulators, and using this knowledge to autotune these devices - based on transport measurements - toward obtaining Majorana modes in the structure. The model is trained in an unsupervised manner on synthetic data in the form of conductance maps, using a physics-informed loss that incorporates key properties of Majorana zero modes. We show that, with appropriate training, a deep vision-transformer network can efficiently memorize relation between Hamiltonian parameters and structures on conductance maps and use it to propose parameters update for a quantum dot chain that drive the system toward topological phase. Starting from a broad range of initial detunings in parameter space, a single update step is sufficient to generate nontrivial zero modes. Moreover, by enabling an iterative tuning procedure - where the system acquires updated conductance maps at each step - we demonstrate that the method can address a much larger region of the parameter space.

Electrochemical creatinine sensors offer great promise towards rapid, reagent-free and point-of-care (POC) kidney-function monitoring. However, challenges related to analyte binding, data reproducibility, sensitivity, fouling and device degradation deter its widespread implementation. Here, we show how a carbon electrode modified with a combination of poly(3,4-ethylene dioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) and copper nanoparticles (CuNPs) can rapidly and accurately detect creatinine (CT) in artificial urine media employing electrochemical techniques. Applying redox potential sweeps (vs Ag/AgCl) using copper sulfate (CuSO4) solution on such sensor facilitates the CuNP embedding process inside the conjugated polymer matrix which has been further validated by supporting techniques. We predicted and validated the formation and contribution of two Cu-CT coordination complexes corresponding to Cu(I) and Cu(II) states, which are responsible for CT detection. The fabricated CT sensor exhibits high selectivity against major artificial urine interferents and is stable for a month showing minimal degradation (0.53%) in peak current value. Such sensors can be utilized to detect and monitor different stages of renal failure in real-time patient samples.

The statistical "monomer-based" segment length $b$ and the Kuhn length $l_k$ are central to polymer physics, yet the minimal size required for a truly statistical segment - Gaussian, uncorrelated, and valid as an entropic spring - is not rigorously established. Using atomistic simulations of entangled polyethylene, we re-evaluate these foundational quantities. By fitting end-to-end distance distributions of C–C bond blocks and validating with higher-moment analyses, we identify for the first time the minimal sizes corresponding to a statistical segment and an entropic spring. A single Kuhn segment (approximately 11 bonds) is the smallest statistically uncorrelated unit, but its distance distribution is strongly non-Gaussian, while the monomer-based segment $b$, used in rheology and classical tube-theory formulations, is not statistical at all. True Gaussianity emerges only for blocks containing multiple Kuhn segments. At the Kuhn scale, we uncover a previously unresolved conformational heterogeneity. Each segment samples a broad range of conformations, from coiled (approximately 4~Å) to extended (approximately 14~Å), giving rise to three distinct substructures: aligned chain segments (ACS), random conformational sequences (RCS), and chain ends (CE). These exhibit distinct dynamical signatures. ACS relax with a stretched-exponential exponent $\beta \approx 0.5$, consistent with quasi-one-dimensional, defect-mediated localized modes, whereas RCS and CE relax with $\beta \approx 0.7$. By connecting these results to localized-mode theory and continuous-time random-walk models, we provide a molecular interpretation of stretched-exponential relaxation in polymer melts.

Elastodynamic cohesive-zone models for defects such as cracks or dislocations (such as the Geubelle-Rice model for cracks, or the Dynamic Peierls Equation for flat-core dislocations), feature the same stress-response convolution kernel in space and time. It accounts for in-plane elastic wave propagation, while its associated instantaneous radiative term accounts for radiative losses in the surrounding medium. These objects are well-known for isotropic elasticity, with their space-time representations involving generalized functions. For anisotropic elasticity they were unknown. The paper presents a derivation using the Stroh formalism. Their Fourier representation rests exclusively on the so-called prelogarithmic Lagrangian factor $L(v)$, while their space-time form involves its derivative $p(v)=L'(v)$, the prelogarithmic impulsion function. A straightforward consequence is the reformulation of the stress in the Weertman model of steadily-moving dislocations in terms of $L(v)$. Special care being paid to the causality constraint, the theory covers indifferently subsonic, intersonic and supersonic regimes of motion. The theory proposed is suitable to phase-field-type Fourier-based numerical codes for planar systems of defects in anisotropic elastodynamics.