Superconductivity
In-plane ferromagnetism-driven topological nodal-point superconductivity with tilted Weyl cones
Maciej Bazarnik, Levente Rózsa, Ioannis Ioannidis et al. (+11 more)
The potential application of topological superconductivity in
quantum transport and
quantum information has fueled an intense investigation of hybrid materials with emergent electronic properties, including magnet-
superconductor heterostructures. Here, we report evidence of a topological nodal-point superconducting phase in a one-atom-thick in-plane ferromagnet in direct proximity to a conventional $s$-wave
superconductor. Low-temperature scanning tunneling spectroscopy data reveal the presence of a double-peak low-energy feature in the local density of states of the hybrid system, which is rationalized via model calculations to be an emergent topological nodal-point superconducting phase with tilted Weyl cones. Our results further establish the combination of in-plane ferromagnetism and conventional superconductivity as a route to design two-dimensional topological
quantum phases.
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All authors Maciej Bazarnik, Levente Rózsa, Ioannis Ioannidis, Eric Mascot, Philip Beck, Krisztián Palotás, András Deák, László Szunyogh, Stephan Rachel, Thore Posske, Roland Wiesendanger, Jens Wiebe, Kirsten von Bergmann, Roberto Lo Conte
Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Integration and Resource Estimation of Cryoelectronics for Superconducting Fault-Tolerant Quantum Computers
Shiro Kawabata
Scaling superconducting
quantum computers to the fault-tolerant regime calls for a commensurate scaling of the classical control and readout stack. Today's systems largely rely on room-temperature, rack-based instrumentation connected to dilution-refrigerator cryostats through many coaxial cables. Looking ahead, superconducting fault-tolerant
quantum computers (FTQCs) will likely adopt a heterogeneous
quantum-classical architecture that places selected electronics at cryogenic stages – for example, cryo-CMOS at 4~K and superconducting digital logic at 4~K and/or mK stages – to curb wiring and thermal-load overheads. This review distills key requirements, surveys representative room-temperature and cryogenic approaches, and provides a transparent first-order accounting framework for cryoelectronics. Using an RSA-2048-scale
benchmark as a concrete reference point, we illustrate how scaling targets motivate constraints on multiplexing and stage-wise cryogenic power, and discuss implications for functional partitioning across room-temperature electronics, cryo-CMOS, and superconducting logic.
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Mesoscale and Nanoscale Physics
A current source with metrological precision made on a 300mm silicon MOS process
Nathan Johnson, Stefan Kubicek, Julien Jussot et al. (+5 more)
Although the measurement of current is now defined with respect to the electronic charge, producing a current standard based on a single-electron source remains challenging. The error rate of a source must be below 0.01 ppm, and many such sources must be operated in parallel to provide practically useful values of current in the nanoampere range. Achieving a single electron source using an industrial grade 300 mm wafer silicon metal
oxide semiconductor (MOS) process could offer a powerful route for scaling, combined with the ability for integration with control and measurement electronics. Here, we present measurements of such a single-electron source indicating an error rate of 0.008 ppm, below the error threshold to satisfy the SI Ampere, and one of the lowest error rates reported, implemented using a gate-defined
quantum dot device fabricated on an industry-grade silicon MOS process. Further evidence supporting the accuracy of the device is obtained by comparing the device performance to established models of
quantum tunnelling, which reveal the mechanism of operation of our source at the single particle level. The low error rate observed in this device motivates the development of scaled arrays of parallel sources utilising Si MOS devices to realise a new generation of metrologically accurate current standards.
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All authors Nathan Johnson, Stefan Kubicek, Julien Jussot, Yann Canvel, Kristiaan De Greve, M. Fernando Gonzalez-Zalba, Ross C. C. Leon, John J. L. Morton
Strongly Correlated Electrons
Electronic Structure of UGe$_{2\pm x}$ Thin Films from Photoelectron Spectroscopy
Sonu George Alex, Oleksandr Romanyuk, Ivan Zorilo et al. (+7 more)
Uranium digermanide UGe$_2$, the first
ferromagnetic superconductor, represents a key composition in the U-Ge system dominated by U-5$f$ states. To examine the impact of controlled stoichiometric deviations on the electronic structure, UGe$_{2\pm x}$ thin films ($0 \le x \le 1$) were prepared by triode sputtering and studied on pristine surfaces by X-ray (XPS) and Ultraviolet (UPS) photoelectron spectroscopy. XPS and UPS reveal a robust metallic valence band with a dominant U-5$f$ contribution at the
Fermi level and a broad incoherent feature at higher binding energies, without qualitative changes in spectral line shape across the composition range. The experimental spectrum of UGe$_2$ thin films is well reproduced by DFT+U(ED) valence-band calculations combining density functional theory with exact diagonalization of the multiconfigurational U-5$f$ shell. These results demonstrate that the overall U-Ge electronic framework of UGe$_2$ thin films remains resilient to moderate stoichiometric deviations, providing a reliable electronic baseline for future studies of interface- and
heterostructure-driven phenomena in uranium-based systems.
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All authors Sonu George Alex, Oleksandr Romanyuk, Ivan Zorilo, Alexander Andreev, Frank Huber, Thomas Gouder, Petr Malinsky, Maliha Siddiqui, Alexander B. Shick, Evgenia A. Tereshina-Chitrova
Soft Condensed Matter
Clustering Dynamics of SiO2-Pt Active Janus Colloids
Harishwar Raman, Aniket Shivhare, Amit Kumar et al. (+5 more)
Active colloid clustering is central to understanding non-
equilibrium self-organization, with implications for programmable active materials and synthetic or biological assemblies. While most prior studies have focused on dimers or small aggregates, the dynamics of larger clusters remain relatively unexplored. Here, we experimentally investigate chemically active, monodisperse SiO2-Pt Janus colloid (JC) clusters as large as n=9 in a dynamic clustering regime, where clusters continuously form, dissolve, and merge as swimmer density increases. We show that clusters move in circular trajectories, and that both their translational and rotational dynamics can be predicted directly from the orientations of constituent JCs. Furthermore, we identify that their formation undergoes a mechanistic transition: while small clusters are mediated by chemical interactions, larger clusters are predominantly formed by steric effects. This transition arises from a mismatch of motilities between incoming JCs and clusters, combined with increased Pt-surface exposure. Our results extend prior dimer-focused studies to larger aggregates and establish a predictive description that bridges individual swimmer behavior with collective dynamics.
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All authors Harishwar Raman, Aniket Shivhare, Amit Kumar, Madhav Penukonda, Pawan Kumar, Karnika Singh, Akash Choudhary, Rahul Mangal
Soft Condensed Matter
Mechanisms in Slide Electrification of Liquid and Frozen Drops on Hydrophobic Surfaces
Rutvik Lathia, Benjamin Leibauer, Aaron D. Ratschow et al. (+2 more)
The microscopic and fundamental origin of slide electrification, where droplets of water move across insulating surfaces accumulating and depositing electrical charges, is still debated. Charge transfer is often attributed to ion transfer at the receding contact line. However, it is still unclear whether ion transfer alone can fully account for the observed charge separation. We examined slide electrification of two polar, self-ionizing
liquids (water, formamide) and two non-polar
liquids (diiodomethane, bromonaphthalene). By cooling below the melting temperature, we were able to compare this process to tribocharging of the respective frozen components. Despite reduced ion mobility at sub-freezing temperatures, the frozen polar compounds continue to accumulate significant charge. Non-polar
liquids exhibit lower charging (<25% of polar
liquids) and nearly identical charging behaviour in both their
liquid and frozen phases on five different substrates. Since non-polar
liquids contain few free ions, these observations indicate an alternative charging mechanism, which could be electron transfer. Our findings suggest that slide electrification operates through at least two mechanisms, with the dominant charge transfer pathway shifting between ions and electron transfer depending on the electronegativity, phase, and temperature.
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All authors Rutvik Lathia, Benjamin Leibauer, Aaron D. Ratschow, Werner Steffen, Hans-Jürgen Butt
Materials Science
Cleavage toughness of single crystals
Faming Gao
Griffith thermodynamic energy balance is employed to analyze cleavage phenomenon from atomic level. Results show that the cleavage toughness, the strain energy release rate, and the surface energy can be defined by the bond strength (the appropriate elastic modulus ) and the bond density. Such simple definition of fracture parameters is different from Irwin ones. This appropriate elastic modulus of single
crystals is obtained using the complex variable function method. The calculated results of cleavage toughness and surface energy of typical ionic and covalent
crystals by the present formulae are in excellent agreement with the experimental values. It demonstrates that our method offers a concise tool for predicting the cleavage toughness, the energy release rate and the surface energy of
crystal cleavage planes.
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Materials Science
Ultrafast laser-driven topological phase patterning
Jianyu Wu, Arthur Niedermayr, Gaolong Cao et al. (+2 more)
Microscopic and dynamic control over
quantum states is essential for bridging fundamental studies of material properties to device function. Realizing such control at combined high spatial resolution and ultrafast temporal precision remains a major challenge. Here, we demonstrate femtosecond
laser-driven patterning of topological
quantum states in the Weyl semimetal WTe2. By engineering the excitation field into a transient optical grating, we spatially selectively and reversibly drive phase transitions between the topological Td and topologically trivial 1T* phases. Using ultrafast transmission electron microscopy, we directly visualize the formation of a periodic Td/1T*
heterostructure, observe the propagation of a phase front, and analyze nanoscale confinement of coherently excited optical
phonon modes. Our findings establish a platform for all-optical, spatially programmable, and reconfigurable control of
quantum states, paving the way for optically addressable topological devices.
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All authors Jianyu Wu, Arthur Niedermayr, Gaolong Cao, Oscar Grånäs, Jonas Weissenrieder
Strongly Correlated Electrons · Cross-listed from hep-lat
Phases of the $q$-deformed $\mathrm{SU}(N)$ Yang-Mills theory at large $N$
Tomoya Hayata, Yoshimasa Hidaka and Hiromasa Watanabe
We investigate the $(2+1)$-dimensional $q$-deformed $\mathrm{SU}(N)_k$ Yang-Mills theory in the
lattice Hamiltonian formalism, which is characterized by three parameters: the number of colors $N$, the coupling constant $g$, and the level $k$. By treating these as tunable parameters, we explore how key properties of the theory, such as confinement and topological order, emerge in different regimes. Employing a variational mean-field analysis that interpolates between the strong- and weak-coupling regimes, we determine the large-$N$ phase structure in terms of the 't Hooft coupling $\lambda_\mathrm{tH}=g^2N$ and the ratio $k/N$. We find that the topologically ordered phase remains robust at large $N$ under appropriate scalings of these parameters. This result indicates that the continuum limit of large-$N$ gauge theory may be more intricate than naively expected, and motivates studies beyond the mean-field theory, both to achieve a further understanding of confinement in gauge theories and to guide
quantum simulations of large-$N$ gauge theories.
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Materials Science
High-pressure synthesis of quantum magnet M-YbTaO4 with a stretched diamond lattice
Nicola D. Kelly, Xuan Liang, Siân E. Dutton et al. (+2 more)
We report bulk
magnetic properties of ytterbium tantalate in its monoclinic fergusonite modification, M-YbTaO4. The
spin-1/2 Yb3+ ions in this phase are arranged on a geometrically frustrated "stretched diamond"
lattice. M-YbTaO4 cannot be prepared at ambient pressure and was instead prepared in a belt-type apparatus at 6 GPa and 1800 C. Susceptibility and specific heat data show no long-range ordering down to 1.8 K and are consistent with a Jeff = 1/2 Kramers doublet which splits in an applied field. Furthermore, under high-pressure synthesis the entire solid solution YbNbxTa1-xO4 (0 < x < 1) can be stabilised in the M phase, in contrast to ambient-pressure synthesis which favours the competing M' phase for Ta-rich compositions. Subsequent annealing of the Nb-Ta mixed samples resulted in colour changes, suggesting oxygen deficiency in some of the as-prepared high pressure samples. There was little variation in the bulk
magnetic properties upon varying either the Nb/Ta ratio or the annealing conditions.
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All authors Nicola D. Kelly, Xuan Liang, Siân E. Dutton, Kazunari Yamaura, Yoshihiro Tsujimoto
Mesoscale and Nanoscale Physics
Quantum Otto heat-engine with Kitaev-Heisenberg cluster: Possible roles of frustration, magnons, and duality
Sheikh Moonsun Pervez and Saptarshi Mandal
We study the performance of Kitaev-Heisenberg (KH) clusters as working media realizing a
quantum Otto engine (QOE). An external Zeeman field with linear time dependency is used as the driving mechanism. The efficiency strongly depends on Kitaev ($\kappa$) and Heisenberg ($J$) exchange interaction. Interestingly, efficiency is comparable when the relative magnitude of $\kappa$ and $J$ is the same but of opposite signs. The above results are explained due to a subtle interplay of frustration,
quantum fluctuation, and duality of eigen-spectra for the KH system when both the signs of $\kappa$ and $J$ are reversed. The maximum efficiency is shown to be dynamically related to eigen-spectra forming discrete narrow bands, where total
spin angular momentum becomes a good
quantum number. We relate this optimum efficiency to the realization of weakly interacting
magnons, where the system reduces to an approximate eigen-system of the external drive. Finally, we extend our study to the large
spin Kitaev model and find a
quantum advantage in efficiency for $S=1/2$. The results could be of practical interest for materials with KH interactions as a platform for QOE.
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Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Topological Sensing in the Dynamics of Quantum Walks with Defects
Xiaowei Tong, Xingze Qiu, Xiang Zhan et al. (+4 more)
Topological
quantum sensing leverages unique topological features to suppress noise and improve the precision of parameter estimation, emerging as a promising tool in both fundamental research and practical application. In this Letter, we propose a sensing protocol that exploits the dynamics of topological
quantum walks incorporating localized defects. Unlike conventional schemes that rely on topological protection to suppress disorder and defects, our protocol harnesses the
evolution time as a resource to enable precise estimation of the defect parameter. By utilizing topologically nontrivial properties of the
quantum walks, the sensing precision can approach the Heisenberg limit. We further demonstrate the performance and robustness of the protocol through
Bayesian estimation. Our results show that this approach maintains high precision over a broad range of parameters and exhibits strong robustness against disorder, offering a practical pathway for topologically enhanced
quantum metrology.
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All authors Xiaowei Tong, Xingze Qiu, Xiang Zhan, Quan Lin, Kunkun Wang, Franco Nori, Peng Xue
Soft Condensed Matter
Ghost-Mode Filtered Fluctuating Lattice Boltzmann Method
Marco Lauricella, Andrea Montessori, Adriano Tiribocchi et al. (+1 more)
Fluctuating
lattice Boltzmann solvers are widely employed to model mesoscopic fluid behavior in soft-matter systems, including colloidal suspensions and dilute
polymer solutions. Despite their utility, these methods can lose accuracy and stability when non-hydrodynamic modes interfere with the dynamics, especially in single–relaxation-time schemes. Here, we introduce a ghost-mode filtered fluctuating
lattice Boltzmann method (GMF-FLBM) for the D3Q27
lattice, obtained by selectively eliminating the propagation of the ghost deterministic content while preserving the necessary
stochastic forcing. We show, over a broad range of relaxation times, that GMF-FLBM recovers the amplitudes of
equilibrium fluctuations with a comparable accuracy as a fully regularized high-order formulation, while requiring only minor adjustments to the conventional BGK collision framework.
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All authors Marco Lauricella, Andrea Montessori, Adriano Tiribocchi, Sauro Succi
Materials Science
Physically Consistent Machine Learning for Melting Temperature Prediction of Refractory High-Entropy Alloys
Mohd Hasnain
Predicting the melting temperature (Tm) of multi-component and high-
entropy alloys (HEAs) is critical for high-temperature applications but computationally expensive using traditional CALPHAD or DFT methods. In this work, we develop a gradient-boosted decision tree (XGBoost) model to predict Tm for complex
alloys based on elemental properties. To ensure physical consistency, we address the issue of data leakage by excluding temperature-dependent thermodynamic descriptors (such as Gibbs free energy of mixing) and instead rely on physically motivated elemental features. The optimized model achieves a coefficient of determination (R2) of 0.948 and a Mean Squared Error (MSE) of 9928 which is about 5% relative error for HEAs on a validation set of approximately 1300 compositions. Crucially, we validate the model using the Valence Electron Concentration (VEC) rule. Without explicit constraints during training, the model successfully captures the known stability transition between BCC and FCC phases at a VEC of approximately 6.87. These results demonstrate that data-driven models, when properly feature-engineered, can capture fundamental metallurgical principles for rapid
alloy screening.
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Statistical Mechanics · Cross-listed from physics.comp-ph
Finding Graph Isomorphisms in Heated Spaces in Almost No Time
Sara Najem and Amer E. Mouawad
Determining whether two graphs are structurally identical is a fundamental problem with applications spanning mathematics, computer science, chemistry, and network science. Despite decades of study, graph isomorphism remains a challenging algorithmic task, particularly for highly regular structures. Here we introduce a new algorithmic approach based on ideas from spectral graph theory and geometry that constructs candidate correspondences between vertices using their
curvatures. Any correspondence produced by the
algorithm is explicitly verified, ensuring that non-isomorphic graphs are never incorrectly identified as isomorphic. Although the method does not yet guarantee success on all inputs, we find that it correctly resolves every instance tested in deterministic
polynomial time, including a broad collection of graphs known to be difficult for classical techniques. These results demonstrate that enriched spectral methods can be far more powerful than previously understood, and suggest a promising direction for the practical resolution of the complexity of the graph isomorphism problem.
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Materials Science · Cross-listed from physics.optics
DNA-Origami-Assembled Rhodium Nanoantennas for Deep-UV Label-Free Single-Protein Detection
Nicco Corduri, Malavika Kayyil Veedu, Yifan Yu et al. (+6 more)
Nanoparticles of plasmonic metals have significantly to the development of spectroscopic techniques, enabling strong confinement of electromagnetic fields at the nanoscale and corresponding signal amplification. However, to date, plasmonic applications have been limited mainly to the visible and near-infrared range, as materials supporting ultraviolet resonances typically exhibit poor chemical stability and lack robust surface functionalisation methods. In this work, we address these limitations by introducing a fully programmable approach to UV plasmonics based on rhodium nanocube dimers assembled using DNA origami templates. We have developed a reliable ligand exchange strategy that allows the functionalisation of rhodium nanocubes with DNA while maintaining their colloidal stability. These DNA-modified nanocubes act as modular building blocks that can be assembled into dimers with 69% efficiency and an average gap size of 10 nm. The DNA origami design also allows for the deterministic placement of a single streptavidin
protein in the plasmonic gap, unlike previous methods based on
stochastic diffusion. Experiments with single-molecule autofluorescence in UV, supported by numerical simulations, show an increase in brightness of up to 22, a reduction in fluorescence lifetime, and a more than tenfold increase in the total number of detected
photons. By creating a robust and versatile platform for the production of UV-resonant plasmonic nanoantennas, this work extends the functionality of plasmonics to the deep UV spectrum and opens up new possibilities for labelling-free single-
protein spectroscopy.
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All authors Nicco Corduri, Malavika Kayyil Veedu, Yifan Yu, Yanqiu Zou, Jie Liu, Denis Garoli, Guillermo P. Acuna, Jérôme Wenger, Karol Kołątaj
Disordered Systems and Neural Networks · Cross-listed from cs.LG
Learning Shrinks the Hard Tail: Training-Dependent Inference Scaling in a Solvable Linear Model
Noam Levi
We analyze neural scaling laws in a solvable model of last-layer fine-tuning where targets have intrinsic, instance-heterogeneous difficulty. In our Latent Instance Difficulty (LID) model, each input's target variance is governed by a latent “precision” drawn from a heavy-tailed distribution. While generalization loss recovers standard scaling laws, our main contribution connects this to inference. The pass@$k$ failure rate exhibits a power-law decay, $k^{-\beta_\text{eff}}$, but the observed exponent $\beta_\text{eff}$ is training-dependent. It grows with sample size $N$ before saturating at an intrinsic limit $\beta$ set by the difficulty distribution's tail. This coupling reveals that learning shrinks the “hard tail” of the error distribution: improvements in the model's generalization error steepen the pass@$k$ curve until irreducible target variance dominates. The LID model yields testable, closed-form predictions for this behavior, including a compute-allocation rule that favors training before saturation and inference attempts after. We validate these predictions in simulations and in two real-data proxies: CIFAR-10H (human-label variance) and a maths teacher-student
distillation task.
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Quantum Gases · Cross-listed from nucl-th
Gorkov algebraic diagrammatic construction for infinite nuclear matter
Francesco Marino, Carlo Barbieri and Gianluca Colò
We propose a novel many-body truncation for Gorkov self-consistent Green's function (SCGF) theory where pairing correlations are handled at first order, while dynamical correlations are described using the particle-number-conserving Dyson-SCGF scheme up to third order in the algebraic diagrammatic construction. The new method is enabled by the introduction of a scheme that allows to approximate the Gorkov propagator in terms of a particle-number-conserving optimized reference state. The approach provides state-of-the-art predictions of the equation of state and spectral properties of infinite
nuclear matter at zero temperature and in the presence of pairing. We find satisfactory results using modern saturating
Hamiltonians at next-to-next-to-leading order in
chiral effective field theory.
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Mesoscale and Nanoscale Physics
Electric-current control of anomalous Hall effect
Jianping Guo, Gusthavo M. S. Brizolla, Peng Rao et al. (+10 more)
We demonstrate robust and reversible electric-current control of the anomalous
Hall effect (AHE) in a two-dimensional WTe2/Fe3GeTe2 (FGT) stack. Applying a current through Td-WTe2 leads to a
giant modulation of the AHE of the adjacent FGT layer, with the relative change of the AHE conductivity exceeding 180%. Control experiments show that i) the observed effect is absent in pure FGT, ii) the modulation weakens in thicker FGT films, confirming its interfacial origin, and iii) the modulation peaks for
bilayer WTe2, indicating that the Berry-
curvature dipole (BCD) plays the dominant role in the modulation. We propose that the charge current I generates an out-of-plane magnetization Mz via BCD in WTe2 and Mz modifies the exchange splitting of FGT via the inverse
magnetic proximity effect, thereby altering its Berry
curvature and nontrivially influencing the AHE. The demonstrated method of AHE control offers new possibilities for magnetism control, i.e., for the study of AHE-transistors as well as electric-current control of
quantum magnets, especially
magnetic insulators.
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All authors Jianping Guo, Gusthavo M. S. Brizolla, Peng Rao, Jian Shao, X. H. Huang, Thomas N. G. Meier, Tailai Xu, Peirui Ji, Jonathan Finley, Jaroslav Fabian, Johannes Knolle, Christian Back, Lin Chen
Materials Science
Impact of MAPbI3 Phase Transitions on Solar Cell Performance
Ph Baranek, J P Connolly, A Gissler et al. (+3 more)
This paper presents a first step toward a pragmatic phenomenological multiscale approach to evaluate perovskite
solar cell performance which determines material properties at the atomistic scale with first-principles calculations, and applies them in macro-scale device models. This work focuses on the MAPbI3 (MA = CH3NH3) perovskite and how its phase transitions impact on its optical, electronic, and structural properties which are investigated at the first-principles level. The obtained data are coupled to a numerical drift-
diffusion device model enabling evaluation of the performance of corresponding single junction devices. The first-principles simulation applies a hybrid exchange-correlation functional adapted to the studied family of compounds. Validation by available experimental data is presented from materials properties to device performance, justifying the use of the approach for predictive evaluation of existing and novel perovskites. The coupling between atomistic and device models is described in terms of a framework for exchange of optical and electronic parameters between the two scales. The obtained results are systematically discussed in terms of first-principles levels of approximation performances.
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All authors Ph Baranek, J P Connolly, A Gissler, Ph Schulz, M Rérat, R Dovesi
Mesoscale and Nanoscale Physics · Cross-listed from hep-th
Scalar vacuum densities on Beltrami pseudosphere
T. A. Petrosyan
We investigate the combined effects of spatial
curvature and
topology on the properties of the
vacuum state for a charged scalar field localized on the (2+1)-dimensional Beltrami pseudosphere, assuming that the field obeys quasiperiodicity condition with constant phase. As important local characteristics of the
vacuum state the
vacuum expectation values (VEVs) of the field squared and energy-momentum tensor are evaluated. The contributions in the VEVs coming from geometry with an uncompactified azimuthal coordinate are divergent, whereas the compact counterparts are finite and are analysed both numerically and asymptotically. For small values of proper radius of the compactified dimension, the leading terms of topological contributions are independent of the field mass and
curvature coupling parameter, increasing by a power-law. In the opposite limit, the VEVs decay following a power-law in the general case. In the special case of a conformally coupled massless field the behavior is different. Unlike the VEV of field squared and
vacuum energy density, the radial and azimuthal stresses are increasing by absolute value. As a consequence, the effects of nontrivial
topology are strong for the stresses in this case at small values of radial coordinate.
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Quantum Gases
Interference-Induced Suppression of Doublon Transport and Prethermalization in the Extended Bose-Hubbard Model
Zhen-Ting Bao, Kai Xu and Heng Fan
The coherent mobility of doublons, arising from second-order virtual dissociation-recombination processes, fundamentally limits their use as information carriers in the strongly interacting Bose-Hubbard model. We propose a disorder-free suppression mechanism by introducing an optimized nearest-neighbor pair-hopping term that destructively interferes with the dominant virtual hopping channel. Using the third-order Schrieffer-Wolff transformation, we derive an analytical optimal condition that accounts for
lattice geometry corrections. Exact numerical simulations demonstrate that this optimized scheme achieves near-complete dynamical arrest and
entanglement preservation in one-dimensional chains, while in two-dimensional square
lattices, it significantly suppresses ballistic spreading yet permits a slow residual expansion. Furthermore, in the many-body regime, finite-size scaling analysis identifies the observed long-lived density-wave order as a prethermal plateau emerging from the dramatic separation of microscopic and thermalization timescales.
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Soft Condensed Matter · Cross-listed from physics.bio-ph
Roadmap for Condensates in Cell Biology
Dilimulati Aierken, Sebastian Aland, Stefano Bo et al. (+38 more)
Biomolecular condensates govern essential cellular processes yet elude description by traditional
equilibrium models. This roadmap, distilled from structured discussions at a workshop and reflecting the consensus of its participants, clarifies key concepts for researchers, funding bodies, and journals. After unifying terminology that often separates disciplines, we outline the core physics of condensate formation, review their biological roles, and identify outstanding challenges in nonequilibrium theory, multiscale simulation, and quantitative in-
cell measurements. We close with a forward-looking outlook to guide coordinated efforts toward predictive, experimentally anchored understanding and control of biomolecular condensates.
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All authors Dilimulati Aierken, Sebastian Aland, Stefano Bo, Steven Boeynaems, Danfeng Cai, Serena Carra, Lindsay B. Case, Hue Sun Chan, Jorge R. Espinosa, Trevor K. GrandPre, Alexander Y. Grosberg, Ivar S. Haugerud, William M. Jacobs, Jerelle A. Joseph, Frank Jülicher, Kurt Kremer, Guido Kusters, Liedewij Laan, Keren Lasker, Katrin S. Laxhuber, Hyun O. Lee, Kathy F. Liu, Dimple Notani, Yicheng Qiang, Paul Robustelli, Leonor Saiz, Omar A. Saleh, Helmut Schiessel, Jeremy Schmit, Meng Shen, Krishna Shrinivas, Antonia Statt, Andres R. Tejedor, Tatjana Trcek, Christoph A. Weber, Stephanie C. Weber, Ned S. Wingreen, Huaiying Zhang, Yaojun Zhang, Huan Xiang Zhou, David Zwicker
Materials Science · Cross-listed from astro-ph.EP
Protonic thermoelectric effect of Superionic H$_2$O and magnetic field generation in Uranus and Neptune
Daohong Liu, Wei Zhang, Yu He et al. (+3 more)
The origin of the anomalous
magnetic fields of Uranus and Neptune, with significant tilts and multi-dipole configurations, is central to understanding the internal structure and
evolution of the ice
giants. Recent investigations confirmed that superionic H$_2$O ice is thermodynamically stable and constitutes the dominant H$_2$O phase within their icy mantles. Here, we use deep learning and ab initio molecular dynamics to investigate the thermal and protonic transport properties of superionic H$_2$O ice. We demonstrate that superionic H$_2$O ice exhibits a pronounced protonic thermoelectric effect, with a maximum Seebeck coefficient that can reach $\sim 620$ $\mu$V K$^{-1}$ within the interior of Uranus, whereas Neptune's is lower, within the range of 570-585 $\mu$V K$^{-1}$. Consequently, the temperature gradients in the icy mantles can induce
proton migration, thereby driving
magnetic field generation. Based on this mechanism, and within a dipolar approximation that captures the mean field, the disparities in mean dipolar
magnetic field strength between Uranus and Neptune can be explained exclusively by their differing internal temperature gradients, and the predicted mean field strengths are comparable to those observed by Voyager 2.
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All authors Daohong Liu, Wei Zhang, Yu He, Xinzhuan Guo, Chuanyu Zhang, Yang Sun
Statistical Mechanics · Cross-listed from quant-ph
Additivity of disjoint interval entanglement in quasiparticle excited states
Zhouhao Guo and Jiaju Zhang
We investigate mixed-state
entanglement measures, namely reflected
entropy, mutual information and logarithmic negativity, for two disjoint intervals in one-dimensional systems excited by a finite number of quasiparticles. While whole system is in a pure state, the two disjoint intervals are in a generically mixed state. To address the problem that natural subsystem bases are generically non-orthonormal in such excited states, we use a general and efficient
algorithm that computes these measures directly from the density
matrix expressed in an arbitrary non-orthonormal basis. Applying this method to classical, bosonic, and fermionic quasiparticle excitations on a circle, we discover a universal additivity property: in the limit of large momentum differences, the mixed-state
entanglement of a multi-quasiparticle state decomposes exactly into the sum of independent contributions. This additivity unifies the
entanglement behavior across classical and
quantum statistics, with the classical result emerging naturally as a special case. Our findings establish a robust computational framework for mixed-state
entanglement in excited many-body systems and reveal a generic decoupling mechanism that governs
entanglement distribution beyond the ground state.
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Mesoscale and Nanoscale Physics
Koopman Nonlinear Non-Hermitian Skin Effect
Shu Hamanaka
Non-Hermitian skin effects are conventionally manifested as boundary localization of eigenstates in linear systems. In nonlinear settings, however, where eigenstates are no longer well defined, it becomes unclear how skin effects should be faithfully characterized. Here, we propose a Koopman-based characterization of nonlinear skin effects, in which localization is defined in terms of Koopman eigenfunctions in a lifted observable space, rather than physical states. Using a minimal nonlinear extension of the Hatano-Nelson model, we show that dominant Koopman eigenfunctions localize sharply on higher-order observables, in stark contrast to linear skin effects confined to linear observables. This lifted-space localization governs the sensitivity to boundary amplitude perturbations, providing a distinct dynamical signature of the nonlinear skin effect. Our results establish the Koopman framework as a natural setting in which skin effects unique to nonlinear non-Hermitian systems can be identified.
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Statistical Mechanics
Interplay of activity and non-reciprocity in tracer dynamics: From non-equilibrium fluctuation-dissipation to giant diffusion
Subhajit Paul, Manish Patel and Debasish Chaudhuri
Non-reciprocal interactions play a key role in shaping transport in active and passive systems, giving rise to striking nonequilibrium behavior. Here, we study the dynamics of a tracer – active or passive – embedded in a bath of active or passive particles, coupled through non-reciprocal interactions. Starting from the microscopic
stochastic dynamics of the full system, we derive an overdamped generalized Langevin equation for the tracer, incorporating a non-Markovian
memory kernel that captures bath-mediated correlations. This framework allows us to compute the tracer's velocity and displacement response, formulate a generalized nonequilibrium fluctuation-dissipation relation, and determine the mean-squared displacement (MSD). We find that while the MSD becomes asymptotically diffusive, the effective diffusivity depends non-monotonically on the degree of non-reciprocity and exhibits a pronounced enhancement near a resonance set by the number of bath particles. We refer to this regime as
giant diffusivity. We further show that this enhanced transport is accompanied by a strong increase in heat dissipation, revealing a direct thermodynamic cost of non-reciprocal transport. Our analytical predictions are supported by numerical simulations, including systems with short-range interactions, demonstrating the robustness of
giant diffusivity and highlighting experimentally accessible signatures of non-reciprocal interactions in soft materials.
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Mesoscale and Nanoscale Physics
Comments on the formula to extract current-induced torques from the harmonic Hall voltage measurements
Yong-Chang Lau, Yukihiro Marui, Zhendong Chi et al. (+2 more)
We examine the formulas commonly used to estimate current-induced
spin-orbit torques from harmonic
Hall voltage measurements. In particular, we focus on the factor of two discrepancy among expressions employed to fit harmonic
Hall signals measured under an in-plane rotating
magnetic field. By explicitly deriving the relevant relations, we clarify the origin of this discrepancy and present the correct form of the fitting formula. We further discuss the determination of the sign of the field-like torque from harmonic
Hall voltage measurements, which depends on the assumed form of the current-induced torques.
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All authors Yong-Chang Lau, Yukihiro Marui, Zhendong Chi, Masashi Kawaguchi, Masamitsu Hayashi
Mesoscale and Nanoscale Physics
Unitary Transformation of Two-Dimensional Spin-Orbit Coupled Models
Manish Kumar Mohanta
The Rashba, Dresselhaus, and Weyl
Hamiltonians form a foundational framework for modeling
spin-orbit interactions across condensed matter systems. Although they describe distinct material classes and produce seemingly different
spin textures, they are conventionally treated as separate, unrelated theoretical frameworks. Here, this work demonstrates that the linear 2D Rashba and Weyl models are connected by a specific
unitary transformation that maps one
Hamiltonian exactly onto the other. The same
unitary can be applied to map the linear Dresselhaus-1 model onto the Dresselhaus-2 models and vice versa. Such hidden correspondence establishes a unified theoretical foundation for
spin-orbit interactions, deepening our conceptual understanding of
spin-orbit coupling and opening new avenues for exploring complex
spin textures. To illustrate the application, this work introduces a unique, improved, and more realistic model
Hamiltonian H_MKM combining all known foundational spintronic models, where the stringent condition of equal
spin-orbit coupling strength of Rashba and Dresselhaus may not be required to observe persistent
spin texture under MKM transformation.
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Materials Science
Structural heterogeneity-induced enhancement of transverse magneto-thermoelectric conversion revealed by thermoelectric imaging in functionally graded materials
Sang J. Park, Ravi Gautam, Takashi Yagi et al. (+3 more)
Functionally graded materials (FGMs) exhibit continuous property variations that enable unique functionalities and provide efficient platforms for systematic property optimization. Here, we report the fabrication of FGMs with graded structural heterogeneity by annealing an amorphous metal under a one-dimensional temperature gradient. Using lock-in thermography (LIT), we spatially mapped transverse thermoelectric conversion with high spatial and temperature resolution. A pronounced non-monotonic response was observed, with the maximum anomalous Ettingshausen effect, transverse charge-to-heat conversion in
magnetic materials, appearing in the atomic-heterogeneity regime well before crystallization. This enhancement was not captured by conventional structural or longitudinal transport measurements, highlighting the exceptional sensitivity of transverse thermoelectric phenomena to subtle structural heterogeneity. Structural analyses using scanning transmission electron microscopy and atom probe
tomography revealed Fe-based crystalline
alloys and Cu nanoclusters embedded in the amorphous
matrix, whose heterogeneity accounts for the enhanced response. These findings establish temperature-gradient-annealed FGMs, combined with LIT, as a powerful methodology for probing structural-heterogeneity-driven transverse electron transport and designing high-performance flexible materials.
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All authors Sang J. Park, Ravi Gautam, Takashi Yagi, Rajkumar Modak, Hossein Sepehri-Amin, Ken-ichi Uchida