Materials Science
First-principles electronic transport properties of Ti and Ti-6Al-4V for modeling ultrashort-pulse laser ablation
Korbinian Hobmaier, Guillaume E. Allemand, Alberto Marmodoro et al. (+4 more)
Predictive modeling of ultrashort-pulse
laser ablation requires temperature-dependent material parameters derived from the electronic structure, namely the electronic thermal conductivity, electron–
phonon coupling, and heat capacity. These parameters are well documented for elemental metals but remain sparsely documented for
alloys, apart from application-relevant exceptions such as stainless steels. The technologically important titanium
alloy Ti-6Al-4V is a prominent example, which is still modeled using elemental-titanium values. We compute the electronic transport of hcp Ti and Ti-6Al-4V from first principles, using the Kubo–Greenwood formalism within the Korringa–Kohn–Rostoker coherent-potential-approximation framework, treating chemical and thermal disorder on equal footing. For elemental Ti, the calculated electrical resistivity agrees with independent abinit electron–
phonon calculations and experiment, and also reproduces the high-temperature saturation near the Mott–Ioffe–Regel limit. Under electron–
phonon nonequilibrium, the electronic thermal conductivity saturates and then decreases with electronic temperature, reaching a maximum of about \SI{2.97}{\kilo\watt\per\metre\per\kelvin} in Ti but only \SI{0.47}{\kilo\watt\per\metre\per\kelvin} in Ti-6Al-4V, a factor of 6.4 lower. In two-temperature-model simulations the
alloy and elemental parameter sets yield peak
lattice temperatures differing by only about 1.4%, consistent with reported experimental ablation thresholds that differ by about 3%, well within their measurement uncertainties. Replacing the first-principles thermal conductivity with the low-temperature Drude limit shifts the peak
lattice temperature by up to 19%, showing that the functional form of the transport model is even more important than the elemental vs
alloy distinction for predictive accuracy.
Read the full abstract ▾
All authors Korbinian Hobmaier, Guillaume E. Allemand, Alberto Marmodoro, Matthieu J. Verstraete, Ján Minár, Heinz P. Huber, David Redka
Mesoscale and Nanoscale Physics
Resonant excitations via low frequency pumping in driven magnon systems
Jan Mathis Giesen, Alexandre Abbass Hamadeh, Imke Schneider et al. (+2 more)
We analyse resonant excitations of
ferromagnetic magnons via microwave pumping using Floquet theory. Special focus is put on driving frequencies that are below the corresponding
magnon energy, which can be excited in large parameter regions via parametric resonances. We develop a theoretical framework that analytically predicts the regions of resonances and resonance thresholds in thin films of ferro- and ferri-
magnetic materials like YIG as a function of damping, amplitude and frequency. Resonance regions are separated by exceptional points of the quasi-energies and the results are compared with micromagnetic simulations. The corresponding threshold amplitudes can be estimated from a characteristic powerlaw with damping, leading to the possibility of targeted exciatations at selected wavenumbers using low frequency drive.
Read the full abstract ▾
All authors Jan Mathis Giesen, Alexandre Abbass Hamadeh, Imke Schneider, Philipp Pirro, Sebastian Eggert
Materials Science
DFT+U+V is equivalent to DFT+U with density-dependent hybridized projectors
Edward Linscott, Alberto Carta and Nicola Marzari
Hubbard-corrected density-functional theory (DFT+$U$) is a popular tool for first-principles modeling of materials with localized $d$ or $f$ electrons, but its on-site corrections tend to over-localize charge and break covalent bonds. Inter-site $+V$ corrections were introduced to counter this and are now widely used, but a formal justification has been lacking. Here we show that – to first order in $V/U$ – inter-site corrections are exactly equivalent to on-site DFT+$U$ evaluated on a density-
matrix-dependent redefinition of the Hubbard projectors, hybridized with those of neighboring sites, providing insight into the explicit mechanism by which $V$ affects covalency. If the projectors are held frozen, as is common practice, the equivalence partially breaks down. Beyond reinterpreting the formalism, these results sharpen the questions of how $V$ should be computed and what the Hubbard subspaces fundamentally are.
Read the full abstract ▾
Materials Science
Foundry CMOS platform for multimodal quantum materials characterization
Sharad Kumar Yadav, Luca Nessi, Ondrej Dyck et al. (+13 more)
Quantum materials experiments increasingly rely on microwave, electrical, thermal, optical, and structural probes, but these capabilities are typically assembled from custom hardware that limits reproducibility and scalability. Here we show that a commercial 65-nm CMOS process can be repurposed as a passive, foundry-manufacturable characterization platform by functionally partitioning its metal stack into microwave, thermal, and electrical subsystems within a 1 mm2 footprint. The integrated RF architecture enables cryogenic
magnetic susceptibility measurements of Fe3GeTe2
heterostructures at 1.75 K without sample-specific fabrication. We further demonstrate NV-center optically detected
magnetic resonance (ODMR) with >20% contrast at 4-9 dBm microwave power, reducing power requirements by 20-25 dB relative to conventional
antenna-based approaches while maintaining sensitivities of 2-3 uT/sqrt(Hz). We additionally confirm compatibility with in-situ electron-beam imaging, showing no measurable degradation in image quality upon device operation. These results establish a scalable, foundry-manufacturable platform for
multimodal quantum sensing and materials characterization.
Read the full abstract ▾
All authors Sharad Kumar Yadav, Luca Nessi, Ondrej Dyck, Jinchen Wang, Bogdan Dryzhakov, Alex Melendez, Huan Zhao, Qian Song, Doha Amer, Cole Brabec, Saleh Alqazlan, Ruonan Han, Riccardo Comin, Stephen Jesse, Dirk Englund, Jawaher Almutlaq
Disordered Systems and Neural Networks · Cross-listed from math.PR
FRSB in the SK spin glass: convergence to full-interval support at zero temperature
Hong-Bin Chen
We prove full replica
symmetry breaking for the zero-field Sherrington-Kirkpatrick model at zero temperature: the Parisi minimizer is absolutely continuous, has a smooth density, and has support $[0,1)$. At inverse temperature $\beta>1$, [arxiv.org/abs/2607.11756v3] recently proved that the Parisi measure has support $[0,q_\beta]$. Here, we show $q_\beta$ converges to $1$ as $\beta\to\infty$.
Read the full abstract ▾
Strongly Correlated Electrons
Universal Dynamic Scaling of 2D Quantum Ising Transition on the Fuzzy Sphere
Meng Zeng, Shuai Yin and Roderich Moessner
We revisit the problem of real-time
quantum dynamics of the paradigmatic two dimensional transverse-field Ising model using the recently developed fuzzy sphere regularization scheme. By linearly ramping the transverse field from the paramagnetic phase to criticality, we study the finite-time scaling behavior of the squared order parameter $\langle m_z^2 \rangle$, the excitation energy density $Q$, and the two-point correlation function of $m_z$. We establish numerically that, at intermediate quench rate, $\langle m_z^2 \rangle$ follows the conventional Kibble-Zurek prediction set by the critical exponents of the $3$D Ising universality class, and the correlation function exhibits the expected exponential decay whose correlation length can be used to estimate the non-universal scaling coefficient in the freeze-out time/length. In contrast, the excitation energy density $Q$ does not reach the same scaling regime at available system sizes due to large effective finite-size gap from
symmetry-enforced level sparsity in the energy spectrum. At slow quench rates the universal quasi-adiabatic scaling for both $\langle m_z^2 \rangle$ and $Q$ is recovered. Since the fuzzy sphere construction can realize not only the Ising conformal field theory (CFT), but a broad family of $(2+1)d$ CFTs, our results establish a route to the real-time critical dynamics of strongly coupled CFTs that are otherwise computationally challenging to study.
Read the full abstract ▾
Strongly Correlated Electrons
Phonon dynamics in Chromium under pressure: absence of phonon criticality at the approach of the quantum critical point
P. Rodière, J.E. Lorenzo, Q. N. Meier et al. (+2 more)
Fermi surface nesting is key to understanding the origin of the itinerant
antiferromagnetic spin density wave in chromium. This
magnetic order is accompanied by a charge-density wave, and both density waves disappear above the critical pressure $P_c \approx 10$ GPa at low temperatures, defining a
quantum critical point. Whether this pressure-induced
quantum phase transition is accompanied by a
phonon instability remains an open question. Here, we use inelastic x-ray scattering to track the room-temperature acoustic
phonon dispersions at pressures up to $P=15.6$ GPa, well above $P_c$. We focus on the Kohn anomalies near the $H$ and $N$ points of the Brillouin zone, with the $H$ point anomaly lying close to the incommensurate
spin-density-wave ordering vector. The
phonon branches harden smoothly under pressure, while the positions and wave-vector extents of both anomalies remain essentially unchanged across $P_c$, with no additional critical softening. Ab initio calculations likewise show that
Fermi surface nesting remains robust above $P_c$. These results indicate that the pressure-induced
quantum phase transition is not driven by a
phonon instability and support a primarily
spin-density-wave-driven mechanism in presence of a robust Kohn anomaly.
Read the full abstract ▾
All authors P. Rodière, J.E. Lorenzo, Q. N. Meier, L. Paolasini, A. Bosak
Statistical Mechanics
Expansion of a free Fermi gas released from an isotropic trapping potential
J M Luck and P L Krapivsky
We consider a system of non-interacting
fermions prepared in the many-body ground state of an isotropic trapping potential in any dimension, and investigate the ballistic expansion of the fermionic cloud after the potential is suddenly released. Using semi-classical techniques, we derive the full late-time profile of the expanding cloud in the regime when the
fermion number is large. We thus obtain explicit expressions for power-law potentials with arbitrary exponent $a$ and in all dimensions $d$. The momentum distribution and the spatial profile of the cloud exhibit a universal edge exponent $d/a$, thus generalizing the Wigner semi-circle law and the Thomas-
Fermi distribution.
Read the full abstract ▾
Statistical Mechanics · Cross-listed from physics.soc-ph
A principled closure framework for higher-order SIS epidemic models on networks
Kevin Teo, Peter L Simon and István Zoltán Kiss
Susceptible-infected-susceptible (SIS) epidemic models on networks are governed by hierarchical moment equations where the dynamics of smaller subsystems depend on the state of larger ones. Moment closure approximations, which truncate this hierarchy by expressing higher-order state probabilities in terms of lower-order ones, are essential for obtaining tractable reduced systems. Higher-order networks, which extend the pairwise structure to include group interactions, introduce a combinatorial explosion of closure configurations, making systematic derivation harder. Consequently, existing higher-order SIS models are derived heuristically, where structural and dynamical assumptions underpinning their closures are not always apparent from the formulation alone. We develop a bottom-up derivation of higher-order SIS dynamics, building systematically from node-level equations to pairs, triplets, and three-body interactions. Central to our approach is a network-dependent closure operator that generates topologically appropriate approximations from local pairwise and triadic structure. Using this framework, we recover three existing higher-order SIS models–Burgio et al.'s maximal clique, Malizia et al.'s pair-based and inter-order models–as special cases, each arising under specific topological and dynamical assumptions. Our derivation reveals assumptions that are invisible from heuristic approaches: for instance, Malizia et al.'s inter-order overlap parameter is insufficient alone to express the model within our framework despite performing well against simulations, with the original derivation implicitly invoking additional structural assumptions. Our framework offers both a foundation for higher-order epidemic modeling and a constructive pathway for understanding the assumptions implicit in heuristically derived mean-field closures and provides a principled method of generating new models.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
Stripe-Order Altermagnetism: Nematic Spin Splitting beyond the $l$-Wave Classification
Zheng-Yang Zhuang and Zhongbo Yan
Altermagnetism combines compensated
magnetic order with nonrelativistic
spin splitting, yet established mechanisms predominantly rely on
spin-reversing rotations in Néel-order antiferromagnets. Here we establish stripe-order altermagnetism governed instead by a
spin-reversing mirror, placing it outside the usual rotation-based $l$-wave classification. Using two-orbital models, we show that the interplay between stripe
spin and orbital orders can yield a stripe altermagnet with mirror-constrained nematic
spin splitting or a stripe anti-altermagnet with
spin-degenerate bands. The latter can support ferroelectric-like electrical control of
spin splitting in suitable buckled structures. Random-phase-approximation (RPA) calculations show that stripe-order altermagnetism is favored near half filling under strong hopping anisotropy. The
spin-reversing mirror further enforces a purely transverse Drude
spin current for an electric field parallel or normal to the mirror plane, while
spin-resolved mirror and rotation probes distinguish this response from that of rotation-governed $l$-wave altermagnets.
Read the full abstract ▾
Strongly Correlated Electrons
Frustration induced dimensional reduction and coexistence of long and short-range magnetic order in NdCl$_{3}$
Eli Zoghlin, Matthew B. Stone, Vasile O. Garlea et al. (+3 more)
The phenomenon of frustration greatly enriches the accessible physics of
quantum magnets. With this in mind we study the magnetism of \NC using a combination of bulk properties measurements and
neutron scattering techniques. The low-temperature heat capacity reveals two
magnetic transitions at $T_{N1}$ = 270 mK and $T_{N2}$ = 180 mK. However, much of the
magnetic entropy is released above $T_{N1}$, manifesting as a broad peak centered at $T^{*} \approx$ 450 mK. A similar broad peak is observed in the
magnetic susceptibility, which possesses a clear anisotropy; this data can be well fit using a 1-dimensional XXZ model, yielding an
antiferromagnetic nearest-neighbor exchange $J_{NN}$ = -0.962(2) K and exchange anisotropy close to the Ising limit. Single
crystal elastic
neutron scattering reveals highly anisotropic
magnetic diffuse scattering above $T_{N1}$, confirming that quasi-one-dimensional, short-range,
antiferromagnetic order is the origin of the broad peak in the heat capacity and
magnetic susceptibility.
Magnetic Bragg peaks characterized by a $\vec{k}$ = ($0$ $0$ $\frac{1}{2}$) propagation vector emerge below $T_{N1}$. Interestingly, the
magnetic diffuse scattering persists for $T_{N2} < T < T_{N1}$, indicating a regime of coexisting short and long-range order. The
magnetic Bragg peaks exhibit an additional increase in intensity below $T_{N2}$ with no change in $\vec{k}$. Concomitantly, the diffuse scattering disappears indicating the attainment of full long-range order. While the precise nature of the ordered
magnetic ground state remains unresolved, the observed
magnetic scattering indicates predominate $c$-axis moments with a small $ab$-plane component. We propose that the quasi-one-dimensional behavior and the coexistence of short and long-range order are driven by frustration of exchange interactions with significant anisotropy.
Read the full abstract ▾
All authors Eli Zoghlin, Matthew B. Stone, Vasile O. Garlea, Matthias D. Frontzek, Andrew D. Christianson, Andrew F. May
Superconductivity
A Voltage-Controlled Josephson Frequency Comb
Giorgio De Simoni and Francesco Giazotto
Microwave frequency combs constitute promising resources for
quantum technologies, cryogenic electronics, and multiplexed sensing architectures. In this work, we propose a frequency-comb generator based on a Josephson field-effect transistor operated in a relaxation-oscillation regime. The device comprises a gate-tunable ballistic
superconductor-
semiconductor-
superconductor junction embedded in a resistively shunted
circuit, in which electrostatic control of the carrier density enables in situ tuning of both the critical current and the Josephson inductance. Time-domain
circuit simulations indicate that the resulting oscillator produces coherent voltage pulses whose
Fourier spectrum forms a microwave frequency comb. In contrast to conventional Josephson-based comb architectures, the proposed platform provides direct electrical control of the comb spacing, emission frequencies, and modal power distribution via a gate electrode. For a representative Al/InAs implementation, we demonstrate continuous frequency coverage in the technologically relevant 1-10 GHz range. Furthermore, the concept is shown to be compatible with higher-$T_c$
superconductors, underscoring its potential as a compact and scalable microwave source for cryogenic
quantum information and sensing applications.
Read the full abstract ▾
Soft Condensed Matter
Mirror vs. inversion symmetry breaking in mesogenic dimers: NTB vs. NF phase
Małgorzata Bakiera, Jakub Karcz, Damian Pociecha et al. (+4 more)
The recently discovered twist-bend nematic NTB and ferroelectric nematic NF phases are distinct examples of spontaneous
symmetry breaking in
liquid crystals. Here, we report the occurrence of both type nematic phases within the same homologous series of dimers consisting of two strongly dipolar mesogenic units linked by a flexible spacer. The NF phase, observed for dimers having spacer with even number of atoms, exhibits the strong polar order; in the NTB phase, observed for dimers with odd number of atoms in the spacer, short-pitch heliconical director structure develops.
Read the full abstract ▾
All authors Małgorzata Bakiera, Jakub Karcz, Damian Pociecha, Katarzyna Kwiatkowska, Mateusz Pawlak, Przemysław Kula, Ewa Gorecka
Strongly Correlated Electrons
Basavaraja G and Mukul Kabir
In the two-dimensional limit, the intrinsic
magnetic topological
insulator MnBi2Te4 provides a compelling platform for exploring thickness-dependent
quantum states and their
evolution under external perturbations. Using first-principles calculations and classical Heisenberg Monte Carlo simulations, we demonstrate that electrostatic gating and surface chemical functionalization can drive a systematic crossover from the topological to the conventional anomalous
Hall regime. This transition is governed by the simultaneous shift of the
Fermi level away from the topological gap and a reversal of interlayer coupling from
antiferromagnetic to
ferromagnetic order. Results reveal that hole doping drives the
Fermi level into the valence bands, inducing an exceptionally high anomalous
Hall conductivity of 1127 S/cm arising from Berry
curvature hot spots. In contrast, surface chemical doping drives a topological state where intrinsic $\sigma_{xy}$ is reduced from $e^2/h$ to $\sim 0.86\ e^2/h$ by the spectral coexistance of
chiral edge mode with metallic bulk states of the two-dimensional film. Furthermore, we show that both tuning routes significantly enhance in-plane exchange interactions, leading to a substantial increase in the
magnetic ordering temperature relative to the pristine
bilayer. These results establish a versatile framework for the simultaneous engineering of topological,
magnetic, and transport properties in ultrathin MnBi2Te4, offering direct implications for the development of reconfigurable
quantum devices.
Read the full abstract ▾
Materials Science
Spin-phonon interaction in a symmetry-enforced spin-polarized state
Suman Kalyan Pradhan, Dayal Das, Shubham Patel et al. (+8 more)
Symmetry-governed
magnetic materials have emerged as a promising platform for spintronic functionalities without net magnetization or stray
magnetic fields, motivating the exploration of how
lattice dynamics couple to
symmetry-derived
spin-polarized electronic states. Understanding
spin-
phonon coupling in these systems is therefore essential for uncovering the microscopic origin of
spin-
lattice interactions and for enabling their control in
quantum materials. However, this mechanism remains poorly understood because
spin polarization originates from
crystal symmetry rather than conventional
magnetic order. Here, we address this issue in the g-type altermagnet CoNb4Se8 using temperature- and polarization-resolved Raman spectroscopy, complemented by measurements on a structurally analogous Co-deficient compound lacking well-defined long-range
magnetic order. We observe pronounced
symmetry-selective
phonon renormalization across the
magnetic transition in CoNb4Se8, while related
phonon anomalies persist in the Co-deficient system, demonstrating that the
lattice response cannot be explained solely by conventional exchange-striction associated with coherent
magnetic ordering. First-principles calculations reveal that
spin-orbit coupling establishes a
symmetry-dependent interaction channel between
lattice vibrations and
symmetry-governed electronic states. Our results identify an alternative mechanism for
spin-
phonon coupling in
symmetry-governed
magnetic materials and demonstrate that
phonons provide a sensitive probe of
symmetry-driven
spin polarization even without robust
magnetic order. More broadly, this work provides a framework for understanding and engineering
spin-
lattice functionality in
symmetry-driven
quantum materials, offering design principles for coupling
lattice dynamics to
spin-polarized electronic states.
Read the full abstract ▾
All authors Suman Kalyan Pradhan, Dayal Das, Shubham Patel, Subhajit Mahapatra, Sachin Majee, Dibyendu Majee, Arnab Bera, Achintya Singha, Snehasish Nandy, Samik DuttaGupta, Atindra Nath Pal
Materials Science · Cross-listed from physics.chem-ph
RuNNer 2.0: A Software Suite for High-Dimensional Neural Network Potentials
Alexander L. M. Knoll, Moritz R. Schäfer, K. Nikolas Lausch et al. (+11 more)
We present RuNNer 2.0, the "Ruhr University Neural Network energy representation", a highly optimized software suite for training and evaluating high-dimensional neural network potentials (HDNNPs) of the second, third, and fourth generation. Long-range electrostatics and charge equilibration (QEq) for the description of non-local charge transfer in fourth-generation (4G) HDNNPs are accelerated by quasi-linear-scaling plane-wave methods, reducing QEq computational complexity from $\mathcal{O}(N^3)$ to $\mathcal{O}(N\log^2 N)$ such that linear or quasi-linear scaling is achieved across all HDNNP generations. An optimized
memory management strategy eliminates the training overhead traditionally associated with long-range interactions, allowing 4G-HDNNPs to be trained with the same efficiency as their local counterparts. Developed in modern Fortran (2003/2008 standards), combined with a hybrid MPI/OpenMP parallelization scheme, RuNNer 2.0 has been designed to run efficiently in any CPU environment, from cost-effective local workstations to massive HPC clusters. Its modular library architecture facilitates straightforward binding to external simulation software; native interfaces to LAMMPS and the Atomic Simulation Environment (ASE) provide full access to all its features, including built-in committee-based uncertainty quantification. The high efficiency and scalability of the RuNNer 2.0 ecosystem are demonstrated through detailed
benchmarks.
Read the full abstract ▾
All authors Alexander L. M. Knoll, Moritz R. Schäfer, K. Nikolas Lausch, Moritz Gubler, Henry Wang, Richard Springborn, Redouan El Haouari, Alea Miako Liebetrau, Jonas A. Finkler, Emir Kocer, Marco Eckhoff, Stefan Goedecker, Gunnar Schmitz, Jörg Behler
Quantum Gases · Cross-listed from quant-ph
Strong Quantum Mpemba Effect from Exact Slow-Mode Selection in Constrained Rydberg Chains
Mingdi Xu, Kaixiang Lu, Zijun Wei et al. (+3 more)
CStrong
quantum Mpemba acceleration requires suppressing the slowest visible Liouvillian relaxation channel, but a robust many-body mechanism for enforcing such suppression remains challenging. We identify such a mechanism in locally dephased constrained Rydberg chains through exact slow-mode selection. For constrained single-
spin-flip
Hamiltonians, local dephasing turns the
Hamiltonian itself into an exact left Liouvillian eigenmode, $\mathcal L^\dagger(H)=-\gamma H$. A finite-temperature reference state generically overlaps with this $H$-like slow mode, whereas translationally invariant states with $\mathrm{Tr}(H\rho_0)=0$ remove it and are confined to the $Q=0$ operator sector. When the next visible $Q=0$ mode decays faster, these selected states exhibit a strong
quantum Mpemba effect. We demonstrate this mechanism in the PXP chain for a zero-energy scar eigenstate, the all-zero product state, and a translation-invariant $Z_2$ cat state, and show that it persists in the $(2,3)$ model and the longer-range blockade family. Our results identify Liouvillian mode visibility, rather than special scar wave functions, as the organizing principle for anomalously fast relaxation in constrained open
quantum systems.
Read the full abstract ▾
All authors Mingdi Xu, Kaixiang Lu, Zijun Wei, Xiang-Ping Jiang, Haiping Hu, Lei Pan
Materials Science
Informatics Modeling of High Tg Polymers: Assessing the Role of Processing versus Chemistry
Qinrui Liu and Scott R. Broderick
Despite the advances in structure-based modeling of
polymer properties, accurately predicting glass transition temperature (Tg) is still challenging for
polymers whose behavior is strongly influenced by intermolecular interactions and processing conditions. We previously developed a machine-learning model based on
polymer topological descriptors to predict Tg. The model performed well and was based solely on the chemistry and structure of the
polymer without any inclusion of processing parameters. In this work, we have extended that work by first applying that same model to a larger range of
polymers and second by integrating processing parameters into the feature set. The chemistry-based model still demonstrates consistent predictive performance for most
polymers, indicating that Tg is indeed primarily chemistry and structure driven and not strongly impacted by processing. However, several
polymers exhibited deviations between predicted and experimental Tg values. Detailed analysis reveals that these differences are related to strong intermolecular interactions and processing-dependent factors, particularly for
polymers prepared by solution casting and high temperature annealing. These results demonstrate that molecular
topology provides a strong foundation for Tg prediction; however, this approach also screens out those classes of
polymers for with processing conditions play an important role.
Read the full abstract ▾
Statistical Mechanics
Large scale behavior in the Kuramoto-Sivashinsky equation: The Schwinger-Dyson route
Olivier Coquand
The present paper is a study of the large scale properties of the Kuramoto-Sivashinsky equation. By using a Schwinger-Dyson framework, we aim to provide a proof that the only solutions that can sustain a stable scaling in the infrared limit have a negative effective viscosity (in the Kuramoto-Sivashinsky sense) with a minimal set of hypotheses, thereby showing that this constitutes a general property of the wave equation that does not depend on a specific set of truncations of a renormalisation group flow, or limitations of a given numerical scheme for example.
Read the full abstract ▾
Materials Science
The Recurrent Structural Frameworks of Stable Inorganic Materials
Roee Asher, Nadav Moav and Lee A. Burton
The number of possible
crystal structures vastly exceeds the number realized among thermodynamically stable inorganic materials, suggesting that experimentally accessible structure space is organized around a limited set of preferred structural frameworks. Analysis of 23,160 structures on the thermodynamic convex hull identifies 6,820 distinct structural frameworks, of which 2,382 recur across multiple chemically distinct materials and are therefore classified as structural prototypes. Within a filtered
dataset, metallic systems exhibit particularly strong structural recurrence, with 6,270 materials grouped into 535 frameworks and 327 prototypes, while 5,557 ionic compounds occupy 1,704 frameworks and 696 prototypes. These results demonstrate that stable inorganic materials occupy a highly compressible region of structure space and establish a recurrence-based catalog of structural prototypes that provides an empirical measure of framework prevalence, enabling the relative likelihood of structural frameworks in future materials to be estimated from their recurrence among known compounds.
Read the full abstract ▾
Materials Science
Chemical filters for ultra-high-throughput materials screening and generation
Kinga O. Mastej, Panyalak Detrattanawichai, Hyunsoo Park et al. (+3 more)
Generative artificial intelligence is rapidly transforming materials design by enabling de novo exploration of immense chemical spaces. Yet a large proportion of AI-generated compositions remain implausible, violating established chemical principles, which limits the reliability and interpretability of generative materials design. Here, we introduce a chemical validity operator that recasts heuristic chemical rules as a configurable algorithmic prior for evaluating and guiding generative materials discovery. Built on the open-source SMACT package, a data-informed oxidation-state model exposes tunable thresholds, allowing users to interpolate continuously between permissive and conservative chemical constraints, while supporting both exploratory and conservative materials-design workflows. Benchmarking six state-of-the-art generative models for inorganic
crystals shows that most reproduce stoichiometry but under-represent realistic oxidation-state combinations, and that filtering removes compositions reliant on rarely observed oxidation states while preserving low-energy compounds near the convex hull. Beyond screening, the same operator can also serve as a reinforcement-learning reward, steering a latent
diffusion model towards chemically grounded compositions. By encoding chemical heuristics and observations, this work establishes a foundation for oxidation-state-aware generative models.
Read the full abstract ▾
All authors Kinga O. Mastej, Panyalak Detrattanawichai, Hyunsoo Park, Anthony Onwuli, Masahiro Negishi, Aron Walsh
Statistical Mechanics
A Unified Discrete and Continuous Theory of Core-Halo Complexity Maximizers
Akshat Sharma
The maximization of statistical complexity has long been associated with the emergence of probability distributions lying between perfect order and complete disorder. While previous studies have shown that complexity-maximizing distributions exhibit a two-level structure in finite discrete systems, an analogous unified treatment for both discrete and continuous probability spaces has remained unavailable. In this work, we develop a general variational framework for a generalized statistical complexity constructed from Shannon and Renyi
entropies. We derive a common stationary equation governing both discrete probability masses and continuous probability densities and prove that every stationary solution necessarily possesses exactly two probability levels, establishing a universal core-
halo structure. We further demonstrate that the optimization problem reduces to a single multiplicity parameter and prove that the global complexity maximum is attained by the smallest admissible core, corresponding to a single dominant state in the discrete case and an infinitesimal core in the continuous limit. These results provide a complete analytical characterization of the complexity-maximizing distributions and reveal a common mathematical structure underlying complexity optimization in both discrete and continuous settings. The framework establishes a unified foundation for generalized statistical complexity with potential applications in statistical mechanics, information theory, and the analysis of complex systems.
Read the full abstract ▾
Materials Science
Localized crystallization of Ce:YIG thin films on Si using CO2 laser annealing for integrated nonreciprocal photonic device applications
Xinran Ji, Junxian Wang, Tianchi Zhang et al. (+6 more)
Laser annealing (LA) technique has emerged as an effective method for localized crystallization of magneto-optical (MO) garnet thin films on
semiconductor substrates. However, no studies have explored the crystallization and magneto-optical (MO) properties of cerium-substituted yttrium iron garnet (Ce:YIG, Ce1Y2Fe5O12) thin films for integrated photonic device applications using LA technique. In this study, we provide a comprehensive investigation into the
laser annealing of Ce:YIG films deposited on SiO2 substrates and silicon nitride photonic waveguides for integrated nonreciprocal photonic device applications. Garnet phase was successfully observed in films grown on SiO2 substrates, and SiN waveguides with
laser annealing of sputtered Ce:YIG films on top of a
laser annealed Y3Fe5O12 seed layer. The magneto-optical (MO) properties of Ce:YIG films on oxidized Si substrates were found to be comparable to those prepared by rapid thermal annealing (RTA). A Mach-Zehnder Interferometer (MZI) type optical isolator based on Ce:YIG film on SiN was fabricated, exhibiting a saturation Faraday rotation of -2317.7 deg/cm and propagation loss of 188.2 dB/cm. Isolation ratio of 27.1 dB and insertion loss of 10.1 dB were achieved at 1552.7 nm wavelength.
Read the full abstract ▾
All authors Xinran Ji, Junxian Wang, Tianchi Zhang, Xuan Zhao, Di Wu, Zixuan Wei, Yizhi Chen, Jialong Wang, Lei Bi
Statistical Mechanics
On the use of the Belopol'skaya-Daletskii representation of a diffusion on a Riemann manifold to construct path integrals
Paolo Muratore-Ginanneschi
We show that the Belopol'skaya-Daletskii formulation of
stochastic differential equations on a Riemann
manifold offers an elementary way to construct equivariant representations of finite-dimensional approximations to the path measure of a
diffusion. The key ingredient is the use of the exponential map to describe increments of the
diffusion.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
Physics-constrained machine learning for decoding multi-nanobubble configurations in graphene
Jihye Kim, Taegeun Song and Nojoon Myoung
Identifying multiple
graphene nanobubbles from electronic spectra is challenging because their strain-induced features overlap. We develop a physics-constrained machine-learning framework that decodes nanobubble configurations from density-of-states (DOS) spectra. For spatially separated nanobubbles, previous full
quantum-transport calculations established that the multi-bubble DOS is numerically equivalent to the normalized sum of the constituent single-bubble spectra. We encode this validated additive relation in a compact neural decomposition model. For each target spectrum, the basis coefficients are optimized independently, and the resulting weights directly identify the constituent geometries. The method accurately reconstructs configurations of increasing complexity and remains robust to repeated constituents, incomplete basis dictionaries, and simulated measurement noise. The framework provides an interpretable route for characterizing strain-engineered
graphene nanostructures and may extend to other
quantum materials with additive spectral responses.
Read the full abstract ▾
Soft Condensed Matter
Molecular chirality controls droplet division and helical fiber formation in liquid crystal emulsions
Simon Čopar, Mariana V. M. Rodriguez, Peter Marinko et al. (+9 more)
Molecular chirality is a source of broken mirror
symmetry, but using it to control mesoscale structures with a tunable length scale remains challenging. Here, we demonstrate that adding a
chiral dopant to nematic
liquid crystal droplets bounded by a deformable two-surfactant interface controls their morphogenesis: the ratio of droplet diameter to cholesteric pitch determines whether droplets divide asymmetrically or symmetrically upon cooling, and whether they transform into single- or double-strand helical fibers. The fiber periodicity and thickness both scale linearly with the cholesteric pitch, which varies by less than 2% with temperature across the self-shaping window. Numerical simulations reveal that chirality-driven elastic stresses at the interface destabilize the droplets and trigger cusp-mediated shape transformations. These results establish cholesteric pitch as a design variable to precisely control droplet division and decouple the dimensions of spontaneously formed mesoscale structures from temperature dependence.
Read the full abstract ▾
All authors Simon Čopar, Mariana V. M. Rodriguez, Peter Marinko, Seyed Reza Seyednejad, Jan Dolinar, Miha Škarabot, Karthik Peddireddy, Khoa V. Le, Samo Kralj, Slobodan Žumer, Miha Ravnik, Venkata S. R. Jampani
Materials Science · Cross-listed from eess.SY
Multisine electrochemical impedance spectroscopy for Li-ion battery characterisation
Noël Hallemans, Heiko Seel-Mayer, Peter Keil et al. (+2 more)
Electrochemical impedance spectroscopy (EIS) is a valuable tool for non-invasive battery characterisation, providing a compact representation of physical processes over a wide range of time scales. Commonly, sinusoids at different frequencies are injected sequentially (single-sines). Alternatively, a multisine excitation (a sum of sines) is advantageous for reducing experiment time and allowing impedance to be measured during operation. In this work, we demonstrate high-fidelity multisine EIS measurements on Li-ion
cells over a wide frequency range (20 mHz to 1 kHz), taken with a commercial potentiostat modified to give access to the underlying current and voltage time-series data, and compare these to single-sine EIS. We show how this allows the conditions of linearity and stationarity to be verified directly, which is not possible with impedance data alone. We then measure broadband impedance during charging and discharging, temperature change, and relaxation. Because impedance is a linearisation of the response about an operating point, each of these conditions probes a state that classical EIS excludes by definition: kinetics linearised about a non-zero current, thermally activated reaction rates, and relaxing concentration gradients, respectively. Operando multisine EIS is therefore not simply a faster measurement approach, but one that resolves behaviour that steady-state EIS cannot.
Read the full abstract ▾
All authors Noël Hallemans, Heiko Seel-Mayer, Peter Keil, Stephen R. Duncan, David A. Howey
Other Condensed Matter
Spin relaxation in $X$-wave magnets with $X=p, d, f, g, i$
Lijie Liu, Mingbo Dou, Xu Chen et al. (+4 more)
Spin relaxation results in the
spin decoherence and a finite
spin lifetime, which are detrimental to spintronic devices. To achieve a long
spin lifetime desirable for spintronic devices, elucidating the
spin relaxation mechanism and factors influencing the
spin lifetime is of vital importance. Here, we investigate the
spin relaxation in $X$-wave magnets ($X=p, d, f, g, i$) with Rashba
spin-orbit coupling within the framework of D'yakonov-Perel' mechanism. We calculate the general
matrix of the
spin relaxation time for an arbitrary Néel vector direction of the $X$-wave magnet. As an illustration, we study the
spin relaxation for the Néel vector along the $[001]$ direction. It is found that the reciprocal
spin-relaxation-time
matrices are anisotropic and diagonal for the $d$-, $f$-, $g$- and $i$-wave magnets. For the $p$-wave magnet, we derive the analytical expressions for the temporal
evolution of
spins. Moreover, the
spin relaxation rate is proportional to the momentum relaxation time, Rashba and altermagnetic
spin-split strengths for all $X$-wave magnets. Our results shine more light on the fundamental understanding of the
spin relaxation mechanism in $X$-wave magnets.
Read the full abstract ▾
All authors Lijie Liu, Mingbo Dou, Xu Chen, Xianjie Wang, M. Ye. Zhuravlev, A. V. Nikolaev, L. L. Tao
Mesoscale and Nanoscale Physics
Impurity-induced Inverse Faraday Effect
A. A. Kopasov, A. A. Bespalov and A. S. Mel'nikov
We provide a
quantum-mechanical description of the photoinduced dc current states and
magnetic fields around nonmagnetic point
impurities in a two-dimensional (2D) electron gas irradiated by a circularly polarized electromagnetic wave. Based on the solution of the corresponding time-dependent Schrodinger equation within the second-order perturbation theory in the electromagnetic wave amplitude we find that the resulting dc
magnetic field component perpendicular to the plane of the 2D system is distributed like in a set of random
magnetic fluxes bound to the positions of
impurities. As a result, the spatially averaged dc
magnetic field does not vanish far from the sample edges and, thus, our scenario of the inverse Faraday effect in disordered systems differs strongly from the standard one based on the relaxation time approximation within the hydrodynamic or kinetic equation approaches which would give only the photoinduced currents flowing along the sample edges. The predicted mechanism for formation of rectified currents flowing around the
impurity centers is shown to be generic both for 2D and three-dimensional systems. The internal dc
magnetic field can give rise to the photoinduced
Hall effect and Faraday rotation for a probing electromagnetic signal.
Read the full abstract ▾
Superconductivity
Oval-shaped resonance distortion as a signature of quasiparticle heating effect in a niobium superconducting resonator
Zhenyuan Sun, Genting Dai, Xiao Geng et al. (+8 more)
We investigate the nonlinear behavior of a superconducting microwave resonator subjected to a dissipative mechanism where the associated quality factor (Q factor) decreases with increasing dissipated power, leading to a dissipative feedback effect. By modifying the Rothwarf-Taylor equations, we establish a macroscopic quasiparticle heating (QPH) model that directly links the quality factor to the microwave readout power. The key finding is the identification of a distinctive oval-shaped distortion in the resonance circle in the complex plane. This distortion serves as a practical experimental signature for identifying the readout power regime in which QPH dominates the loss, under conditions where other nonlinear mechanisms are sufficiently weak. To validate the model, we design and fabricate a niobium (Nb) half-wavelength coplanar waveguide (CPW) resonator and conduct systematic bath temperature and readout power sweeps. The model provides a well fit to the observed oval-shaped resonance circle distortion across a wide range of operating conditions, confirming the QPH mechanism as the primary source of the dissipative non-linearity in the parameter space investigated.
Read the full abstract ▾
All authors Zhenyuan Sun, Genting Dai, Xiao Geng, Liangliang Yang, Mingjun Cheng, Qing Yu, Jinlin Chang, Yi Yang, Linpan Jiang, Jianshe Liu, Wei Chen