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Physics Condensed Matter

cond-mat Watch Condensed Matter

Wednesday 3 June

Mesoscale and Nanoscale Physics

Curvature-Controlled Infrared Regularization of Crystalline Membranes

Pablo A. Morales and Pavel Castro-Villarreal

We show that negative Gaussian curvature regularizes the infrared sector of crystalline membranes. In a covariant formulation of embedded elasticity, the Green strain contains a symmetry-required linear coupling between the normal phonon field and extrinsic curvature. Integrating out the in-plane phonons converts this coupling into a finite quadratic contribution to the inverse flexural response. Anomalous roughening is thereby replaced by curvature-controlled saturation, and the mechanism survives on minimal hyperbolic patches. Hyperbolic geometry preempts anomalous elasticity before the flat infrared regime is reached, implying the absence of a crumpling phase at the harmonic level. The same Gaussian-order coupling admits sound propagation in the infrared.
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Strongly Correlated Electrons

Correlated States in Quantum Dot Clusters Coupled to a Common Superconductor

Martin Žonda, Jakub Rękas, Tobiáš Poláček et al. (+3 more)

We study an effective model of regular quantum dot clusters coupled to a common superconductor. By applying a canonical transformation, we map the system onto a particle-number-conserving representation, enabling an efficient treatment with standard fermionic neural-network quantum-state variational Monte Carlo methods. We show that the excitation gap can close under a particular high-symmetry condition, which, in finite non-interacting systems, corresponds to crossings between singlet ground states of different character. At this high-symmetry condition the model can be mapped to a standard Hubbard model in grand-canonical ensemble with fixed chemical potential away from half-filling. Combining exact methods, density matrix renormalization group, and neural quantum-state variational Monte Carlo calculations, we identify three distinct interacting regimes: a trivial superconducting singlet phase, a strongly correlated regime related to an effective Heisenberg model, and a critical intermediate regime with qualitatively different behavior in one and two dimensions. In one-dimensional systems, the intermediate regime exhibits a sequence of singlet-doublet transitions and becomes gapless in the thermodynamic limit even for finite Coulomb interaction. In two-dimensional clusters, we find robust triplet ground states. These results connect the physics of superconducting nanostructures with correlated lattice models and show that standard fermionic neural quantum states can capture the relevant interacting regimes.
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All authors Martin Žonda, Jakub Rękas, Tobiáš Poláček, Jana Kodrlová, Vladislav Pokorný, Martin Friák

Soft Condensed Matter

Contact-network organization and motion statistics in shear-thickening suspensions

Michel Orsi, Rahul Pandare, Brolin Adu-Poku et al. (+2 more)

We use lubricated-flow discrete-element-method (LF–DEM) simulations to examine how contact-network organization shapes particle motion in dense shear-thickening suspensions. The primary system studied is a two-dimensional bidisperse monolayer where rigid clusters are identified by the $(3,3)$ pebble game; three-dimensional simulations are shown to have qualitatively similar rotational velocity statistics. Across the stress–solid-fraction state diagram, frictional contact number, $k\ge 3$ percolation, and rigid-cluster fluctuations all strengthen in the same region where translational velocity correlations grow, \Revision{consistent with coherent translation within rigid clusters and a state-dependent contrast in relative motion between particles inside and outside them}. Rotational motion provides a complementary view: non-affine angular-velocity distributions broaden, \Revision{near-contact non-affine rotational fluctuations become increasingly anti-correlated, and particles inside and outside rigid clusters carry distinct statistics}. Connectivity, rigidity, and velocity correlations are related but distinct signatures of the constrained collective motion that accompanies shear thickening and the approach to shear jamming.
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All authors Michel Orsi, Rahul Pandare, Brolin Adu-Poku, Bulbul Chakraborty, Jeffrey F. Morris

Materials Science

Spin-polarization of the electric current in half-metallic Co$_2$MnSi Heusler thin films

José Solano Córdova, Anna Maria Friedel, Quentin Rossi et al. (+6 more)

Using propagating spin wave spectroscopy we measure the spin wave Doppler shift in patterned MgO/Co$_2$MnSi/MgO thin films and determine the degree of spin-polarization of the electric current. Our measurements reveal that the current is fully spin-polarized in the devices. This shows that the half-metallic character of the electron band structure translates into a fully spin polarized current flowing across the patterned films. Additionally, we measure a current-induced change of the spin-wave attenuation from which we estimate the non-adiabatic spin-transfer-torque parameter.
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All authors José Solano Córdova, Anna Maria Friedel, Quentin Rossi, Jérôme Robert, Yves Henry, Philipp Pirro, Sébastien Petit-Watelot, Stéphane Andrieu, Matthieu Bailleul

Mesoscale and Nanoscale Physics

Efficient Magnetic Spin-Filtering and Persistent Spin-Currents in Lifshitz-Transitioned Altermagnets: A Route to Open-Orbit Spintronics

Wun-Hao Kang, Yu-Ting Hsiao, Jozef Genzor et al. (+3 more)

Altermagnets offer a unique venue for spin transport due to their vanishing net magnetization and momentum-dependent spin splitting. We demonstrate that a homotopic Lifshitz transition in two-dimensional altermagnets creates a regime where carriers are confined to geometrically protected, spin-selective open channels. These channels originate from non-contractible Fermi contours and act as metallic analogues of topological edge modes: they are sharply directional, spin-pure, and protected by Fermi-surface winding rather than an energy gap or boundary confinement. We predict three striking magneto-transport signatures of such topologically reconfigured altermagnets: open-orbit focusing with perfect lensing and retroreflection, high-efficiency magnetic spin filtering, and chirality-tunable spin persistent currents in altermagnetic nanotubes. Our results establish altermagnets as a platform where Fermi-surface winding directly engineers spin transport, bypassing the requirements for ferromagnetism or strong spin-orbit coupling. These findings identify Lifshitz-transitioned altermagnets as a route to topology-enabled spintronics that transcends the limitations of conventional edge-state paradigms.
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All authors Wun-Hao Kang, Yu-Ting Hsiao, Jozef Genzor, Yaroslav Zhumagulov, Ming-Hao Liu, Denis Kochan

Superconductivity

Antiferromagnetic Quantum Criticality in Infinite-Layer Cuprates Sr1-xNdxCuO2

Bin-Jie Wu, Ze-Xian Deng, Guang-Ran Wei et al. (+8 more)

The interplay between quantum criticality and Fermi surface reconstruction is central to elucidating the phase diagram of high-temperature cuprate superconductors. While studies on electron-doped T'-structure cuprates suggest an antiferromagnetic origin of this reconstruction, quantitative consensus has been hindered by apical oxygen instabilities and uncontrolled oxygen vacancies. Here, we overcome these limitations by utilizing ozone-assisted molecular beam epitaxy to synthesize high-quality, oxygen-stoichiometric thin films of infinite-layer cuprate Sr1-xNdxCuO2 across its entire superconducting dome. Hall transport measurements reveal a sharp carrier-type transition signaling a Fermi surface reconstruction at a critical doping xc ~ 0.155. We show that a spin-density-wave tight-binding model quantitatively reproduces the transport evolution, supporting an antiferromagnetic origin of this quantum phase transition. Furthermore, upon suppressing superconductivity with magnetic fields, the normal-state resistivity exhibits a pristine strange metal behavior that persists down to 2 K in the vicinity of xc. Our findings establish an intrinsic, universal antiferromagnetic quantum criticality in electron-doped cuprates, positioning the structurally simplest infinite-layer cuprates as a clean benchmark platform for theories of unconventional superconductivity.
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All authors Bin-Jie Wu, Ze-Xian Deng, Guang-Ran Wei, Xi Zhou, Ji-Hai Zhang, Da-Zhuang Deng, Qun Zhu, Yong Zhong, Can-Li Song, Xu-Cun Ma, Qi-Kun Xue

Disordered Systems and Neural Networks · Cross-listed from quant-ph

Extremely slow scaling of minimal Hamming distance in quantum sampling data

P. S. Golubev, I. A. Iakovlev and V. V. Mazurenko

Quantum data can be obtained from a diverse range of sources, including direct measurements from noisy quantum processors, cold-atom simulators, and classical approximations such as variational neural-network states. However, our ability to characterize these systems is fundamentally limited, as the available measurement data are often sparse compared to the exponentially large Hilbert space of the system. To address this, we propose using the expected minimal Hamming distance calculated for a set of unique bitstrings as a robust metric revealing a distinct power-law behaviour. Crucially, we have established a direct connection between the empirical power-law parameters and the intrinsic dimension of the quantum measurement outcomes. Through various examples of real experiments and simulations, we show that the power-law parameters reliably characterize the underlying geometric structure of measurement outcomes and identify quantum phase transitions from limited quantum information, without the need for accumulating extensive statistics or explicitly calculating physical observables. This enables the analysis of completely different quantum experiments within a single framework. Furthermore, we demonstrate the versatility of our approach on classical high-dimensional data, showing that the power-law parameters can successfully discriminate different classes of handwritten digits from the MNIST dataset.
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Quantum Gases · Cross-listed from hep-ph

Minimal superfluid vortices in chiral perturbation theory

Fabrizio Canfora, Mart{\i}n Garrido, Massimo Mannarelli et al. (+1 more)

We derive some properties of rotational vortices in the pion condensed phase. Employing leading order chiral perturbation theory we determine the minimal energy condition for vortex nucleation. Vortices have quantized angular momentum along the rotation axis, a hallmark of superfluidity, and self-confined pions. The critical rotation frequency for vortex nucleation is estimated.
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All authors Fabrizio Canfora, Mart{\i}n Garrido, Massimo Mannarelli, Anibal Neira

Mesoscale and Nanoscale Physics

Probing PbTe-Pb nanowire devices with radio-frequency reflectometry

Xin-Yi Tang, Lin Li, Zezhou Xia et al. (+10 more)

We report the implementation of radio-frequency (rf) reflectometry on selective-area-grown PbTe-Pb nanowire devices on a CdTe substrate. These nanowires are predicted to host Majorana zero modes. We demonstrate the compatibility of the rf technique, including both resistive and capacitive sensing, with these nanowires. The effect of dielectric loss from the CdTe substrate is quantitatively characterized. Furthermore, the feasibility of rf reflectometry is verified under finite magnetic fields where zero-energy modes can emerge. Our results establish the fast control of PbTe quantum devices, paving the way for their applications in topological quantum computation.
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All authors Xin-Yi Tang, Lin Li, Zezhou Xia, Jierong Huo, Wenyu Song, Lining Yang, Zonglin Li, Jiaye Xu, Peilin Li, Runan Shang, Qi-Kun Xue, Ke He, Hao Zhang

Soft Condensed Matter

Vibrational model of entropy in dense two-dimensional fluids

Sergey Khrapak

A vibrational paradigm of atomic dynamic in dense fluids is known to provide useful insight on the transport and thermodynamic properties of fluids in three dimensions. In this paper, a vibrational model is generalized to describe the excess entropy of two-dimensional (2D) fluids. A simple practical implementation of this model is demonstrated to deliver accurate results for various systems, such as one-component plasmas with Coulomb and logarithmic interactions, a 2D fluid of dipole particles, and a 2D Yukawa fluid. The applicability limits, relevance to three-dimensional fluids, relations to other 2D phenomena, and potential practical applications are briefly discussed.
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Materials Science

Mechanical bistability and hysteresis in graphene-CNT hybrid systems: from atomistic simulations to macroscale structural responses

Mingda Ding, Nanami Sakurai, Man Shen et al. (+11 more)

Hybrid systems composed of graphene (Gr) and carbon nanotubes (CNTs), such as films and aerogels, have attracted broad attention for applications in electronics, mechanics, energy, and environmental science. Since the microstructures of Gr-CNT hybrids strongly affect their properties, it is essential to establish mechanical principles that govern these structures. In this study, we investigated the structural stability and mechanical behavior of Gr-CNT hybrid systems by combining molecular dynamics (MD) simulations and nanoindentation experiments. MD simulations of stacked Gr-CNT structures, in which two Gr layers confine CNTs between them, identified the energetically stable configurations and their governing parameters, i.e., intertube spacing, CNT diameter, and wall number. Specifically, under certain conditions, the structures exhibit mechanical bistability with two stable configurations: adhesion and separation of the Gr layers, arising from the competition between interlayer van der Waals attraction and elastic deformation of Gr and CNTs. Simulated loading–unloading curves display hysteresis and energy dissipation related to the stable configurations. In addition, reduced graphene oxide (rGO)-CNT hybrid films were experimentally fabricated as macroscopic assemblies of the unit structures modeled in the simulations. Atomic force microscopy-based nanoindentation measurements on the rGO-CNT films exhibit clear hysteresis and higher dissipation energy compared with pure rGO, in good agreement with the simulation results. These results provide valuable insights into Gr-CNT hybrid systems and offer guidance for designing microstructures with enhanced properties for advanced applications.
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All authors Mingda Ding, Nanami Sakurai, Man Shen, Taiki Inoue, Takahisa Matsuzaki, Takuo Mizuno, Kento Suzuki, John Isaac Enriquez, Harry Handoko Halim, Yuji Hamamoto, Yuta Nishina, Hiroshi Y. Yoshikawa, Yoshitada Morikawa, Yoshihiro Kobayashi

Other Condensed Matter · Cross-listed from quant-ph

Arbitrary manipulation of nuclear spins in hexagonal boron nitride

Fattah Sakuldee and Mehdi Abdi

Due to its localized nature and controllability, the negatively charged boron vacancy centers (V$_\text{B}^-$) in hexagonal boron nitride (hBN) are a promising spin platform for accessing its neighboring nuclei with potential for performing quantum computational tasks. However, the methods of utilizing and manipulating the nuclear spins are still lacking. In this work, we propose a protocol for the preparation of single- and multi-qubit gates on the nuclear spins, utilizing the electron spin as an auxiliary qubit. By applying a background magnetic field and a multi-tone continuous drive, we show that the electron spin coupling to the nuclei can be efficiently engineered. This allows for suppressing the undesired electron-nuclear interactions through the Hahn echo pulse sequence. The target gates are then implemented by employing proper RF drives. Our numerical results for realistic parameters show gate fidelities as high as $99\%$ for single-qubit and $95\%$ for multi-qubit gates. With the gate execution durations being less than $300$ ns, our protocol evades electron spin decoherence effects. Therefore, our scheme sets the stage for the practical application of V$_\text{B}^-$ in hBN for quantum computation purposes.
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Mesoscale and Nanoscale Physics

When Screening Current Controls Ferroelectric Switching: From Field-Limited to Current-Limited Regimes

Denis Alikin, Anastasya Meng, Michael Kosobokov et al. (+2 more)

Tip-induced switching in ferroelectrics is commonly framed as a field-driven process controlled by domain-wall kinetics. Here we argue for a more universal viewpoint: under a scanning probe, polarization reversal is fundamentally constrained by how fast screening charge can be supplied and redistributed. By combining local switching experiments with finite-element simulations, we identify a screening-current-limited mechanism in which charge injection and its space-charge-limited relaxation set the pace of switching and the scaling of domain growth. This framework naturally explains regime changes and the apparent breakdown of intrinsic domain-wall laws often inferred in the nanoscale piezoelectric hysteresis measurements. Beyond a reinterpretation of tip switching, the results position screening currents as a hidden control parameter of ferroelectric reversal across materials, turning current regulation into a practical handle for deterministic nanoscale domain engineering.
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All authors Denis Alikin, Anastasya Meng, Michael Kosobokov, Semen Melnikov, Violetta Safina

Disordered Systems and Neural Networks · Cross-listed from q-bio.NC

Discrete signaling mediates chaotic regularization in recurrent neural networks

Jan Bauer, Christian Keup, Jonathan Kadmon et al. (+1 more)

Cortical circuits operate in a regime of intrinsic chaos, where even tiny changes in input can lead to divergent neural responses. Yet, remarkably, population codes in the brain vary smoothly with sensory stimuli, forming coherent representational manifolds. How can chaotic networks sustain such stable coding? Here, we develop a theoretical framework that links the microscopic chaos of recurrent networks to the macroscopic geometry of neural representations. Combining kernel methods with dynamical mean-field theory, we show that chaotic dynamics induce local roughness (introducing sharp distortions at small scales) while preserving global smoothness across larger stimulus variations. This structural property acts as an intrinsic regularizer, enhancing generalization while maintaining expressivity. Moreover, we show how chaotic networks naturally produce power-law spectral signatures, closely matching experimental observations in cortical recordings. These results explain how chaotic spiking networks can sustain smooth, differentiable population codes and establish a theoretical framework linking network dynamics, computational structure, and recorded neural activity.
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All authors Jan Bauer, Christian Keup, Jonathan Kadmon, Moritz Helias

Disordered Systems and Neural Networks · Cross-listed from cs.LG

Shortcomings and capacities of real-constrained neural networks in complex spaces

Andrew Gracyk

We find the asymptotic ratio between the storage capacities when enforcing real pre-activations in a complex hypothesis class as opposed to complex ones in the same class. We use weights drawn from the complex Gaussian, which converge asymptotically in norm to the square root of dimension almost surely. Our methods depend on Gardner volume-type comparisons at critical capacity. Our proof relies on an application of the Harish-Chandra-Itzykson-Zuber (HCIZ) formula, nonstandard in literature. With the HCIZ formula, we may obtain a more robust approximation for the final asymptotic ratio. This strategy is applicable to our work specifically since we integrate over the unitary and orthogonal compact manifolds, facilitated via the Weyl integration formula and the Haar measure.
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Mesoscale and Nanoscale Physics

Perfect Nonreciprocal Axion-polaritons

Abhinava Chatterjee and Chao-Xing Liu

Dynamical axion describes a massive axion quasiparticle that arises from fluctuations of the magnetic order parameter. These fluctuations couple to electromagnetic fields, forming axion-polaritons – collective modes that are physically magnon-polaritons. We show that under appropriate static external electric and magnetic fields, axion-polaritons acquire a nonreciprocal dispersion, $\omega(\textbf{k}) \neq \omega(-\textbf{k})$, arising intrinsically from direction-dependent axion-photon coupling. Strikingly, we identify a regime of perfect nonreciprocity in which the photon propagating in one direction is completely decoupled from the axion while the counter-propagating photon hybridizes strongly. Furthermore, the nonreciprocal dispersion manifests as an optical isolator – a device transmitting light preferentially in one direction. Our results establish nonreciprocal axion-polaritons as a powerful probe of axion quasiparticles and suggest experimentally accessible routes for their detection.
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Soft Condensed Matter

Effect of cations on van der Waals interactions between particles in aqueous alkali nitrate electrolytes

Micah P. Prange, Jaehun Chun, Gregory K. Schenter et al. (+5 more)

The van der Waals interaction has been extensively studied for colloidal forces and resultant emergent phenomena such as colloidal stability, aggregation, and suspension rheology, but the effect of electrolytes on this interaction, especially at intermediate and high electrolyte concentrations, remains incompletely understood. We have extended the Lifshitz theory for van der Waals interactions in pure water to alkali nitrate solutions at arbitrary concentrations by developing a dielectric response model for alkali nitrate solutions that is based on electronic structure calculations of the molecular constituents. Due to their importance in catalysis, ceramics, and coating technologies, the Hamaker constants for rutile, boehmite, and alumina nanoparticles suspended in alkali nitrate solutions are calculated as a function of salt concentration. Contrary to prevailing assumptions, increasing the concentration of sodium (Na), potassium (K), and rubidium (Rb) nitrate solutions causes appreciable increases of the Hamaker constants relative to pure water instead of decreases, whereas cesium nitrate (CsNO3) has almost no effect on the Hamaker constant. We discussed the influence of the solution molar volume, the polarizability of the dissolved ions, and optical properties of the interacting particles in the context of previously published work. Our study indicates a non-vanishing role of van der Waals interactions on colloidal stability at intermediate and high electrolyte concentrations, leading to physical insights on emergent phenomena associated with nanoparticles.
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All authors Micah P. Prange, Jaehun Chun, Gregory K. Schenter, Elias Nakouzi, Yihui Wei, Aurora E. Clark, Kevin M. Rosso, Carolyn I. Pearce

Tuesday 2 June

Statistical Mechanics · Cross-listed from cs.AI

Constituency Optimisation Through Hamiltonian Representation Of Mandates (COTHROM): Algorithmic Redistricting of Irish Election Boundaries

Ruaidhrí Campion, Matthew Fenlon, Joshua Cooney Mercedal et al. (+3 more)

Electoral redistricting in Ireland's Proportional Representation Single Transferable Vote (PR-STV) system faces the challenge of selecting an optimally representative set of electoral boundaries from an enormous set of possible configurations, and where “representative” is a delicate balance of constitutional objectives that are often in tension with one another. We present the first computational framework for Irish electoral redistricting that systematically optimises across multiple constitutional requirements while making trade-offs explicit and quantifiable. The electoral redistricting problem is parsed using statistical physics, where constitutional objectives are considered as terms in a Potts Hamiltonian. Markov Chain Monte Carlo (MCMC) methods and simulated annealing are employed to minimise this objective function, systematically exploring this configuration space, with coupling constants as proxies for objective weightings. Multi Criterion Decision Analysis (MCDA) and Pareto Optimality is then utilised to remedy the ambiguity in choosing a certain objective weighting combination over others. With respect to proportional representation and compactness objectives evaluated in County Cork, COTHROM consistently improves on the existing legal constituency boundaries for a range of objective weightings.
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All authors Ruaidhrí Campion, Matthew Fenlon, Joshua Cooney Mercedal, Casey Farren-Colloty, Eliza Somerville, Michael A.J. Mitchell

Materials Science · Cross-listed from physics.geo-ph

Auditing Representation-Induced Geometry in Acoustic-Emission Fracture Transients

Jose Sanchez-Andreu

Fixed convolutional representations can induce structured geometry in time-frequency data even without task-specific or source-domain training. We audit a previously reported morphology-space analysis of two granite acoustic-emission experiments. The original cumulative angular-path endpoint is reproduced to within 2.1e-7 in the Archive-B/Archive-A ratio. However, the same directional contrast is obtained with ImageNet features and with three randomly initialized EfficientNet-B0 encoders: the preserved Aether representation gives a ratio of 1.411, ImageNet gives 1.361, and the random encoders give 1.480–1.503. We therefore withdraw the attribution of this contrast to interferometric pretraining. We also correct a reversal between archived OG1/OG3 file identifiers and the physical experiments. Phase randomization and temporal shuffling alter the preserved trajectory, but these responses are reinterpreted as pipeline-dependent diagnostics rather than evidence of a learned universal elastic morphology. The corrected result is narrower: multiple fixed convolutional maps expose a reproducible contrast between two acoustic-emission datasets. The signal statistics and architectural biases responsible for that contrast remain open questions.
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Strongly Correlated Electrons · Cross-listed from hep-th

O(N) BCFT: new data from conformal partial wave expansions

Jozef Csipes and Petr Vaško

The $\mathsf{O}(N)$ $\mathsf{BCFT}$ is analyzed in the large $N$ expansion in a generic bulk dimension $2<d+1<4$. Focus is on boundary conditions corresponding to the ordinary transition, however techniques used can be generalized to special or extraordinary transitions. We study the system of bulk $2$-pt functions $\langle \phi\phi\rangle$, $\langle \phi^2 \phi^2\rangle$ and $\langle \sigma\sigma \rangle$, where $\sigma$ is the Hubbard–Stratonovich field. They are expanded in bulk/boundary conformal partial waves. The coefficient functions of this expansion – the spectral functions – encode $\mathsf{BCFT}$ data and determine bulk/boundary conformal block expansions. We prove conjectures about boundary spectral functions in Dujava et al. [arXiv:2503.16345] and reproduce the bulk expansion of $\langle \phi\phi \rangle$ in Giombi et al. [arXiv:2007.04955]. The bulk expansion of $\langle\sigma\sigma\rangle$ is new and allows to extract the leading large $N$ expression for an unknown OPE coefficient $C_{\sigma\sigma\sigma^3}$ (the computation outputs as a byproduct also a mixing coefficient, which matches an existing result by Derkachov et al. [arXiv:hep-th/9705020], providing further support for the main result). Besides these derived data infinitely many constraints are produced, though due to operator mixing growing in complexity as degeneracy increases, they cannot be disentangled without further input.
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Soft Condensed Matter

Polyethylene-based thermo-mechanically recyclable stretchable yarns for circular sustainable textiles

SeongHyeon Kim, Duo Xu, Volodymyr Korolovych et al. (+4 more)

Most high-performance elastic textiles rely on yarns composed of chemically dissimilar polymers, rendering them difficult to recycle. Here, we demonstrate fully thermo-mechanically recyclable stretchable yarns composed of polyethylene (PE) family materials. Inspired by structure-property relationships in natural materials, we engineer a library of melt-spun PE fibers spanning mechanical properties from elastomeric to functional by tuning polymer crystallinity and chain orientation. These fibers are assembled into core-sheath yarns comprising an olefin block copolymer elastic core and a high-strength PE sheath, forming a helical architecture. The resulting yarns exceed mechanical performance of commercial PET-spandex yarns while maintaining full recyclability. We further show that PE homopolymers and copolymers can be jointly melt-processed and recycled without phase separation or loss of performance. This approach enables stretchable recyclable textiles from fibers with previously demonstrated cooling, moisture-wicking and stain-resisting performance and provides a scalable pathway toward circular garments compatible with existing polyethylene recycling streams.
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All authors SeongHyeon Kim, Duo Xu, Volodymyr Korolovych, Domingo R. Flores-Hernandez, Kaniz Moriam, Daniel J. Braconnier, Svetlana V. Boriskina

Soft Condensed Matter

Morphogenesis driven by nematic defects in active biological networks

Silvia Paparini, Giulio G. Giusteri and L. Angela Mihai

Cellular morphogenesis, the process by which biological tissues acquire shape and structure, remains a fundamental challenge in understanding pattern formation and the coordinated remodeling of cellular assemblies. Under appropriate conditions, cytoskeletal filaments can organize into a nematic phase exhibiting partial orientational order. Topological defects within this nematic organization generate localized mechanical stresses that destabilize the tissue and promote deformation and structural rearrangements to relieve internal stresses. We develop a continuum framework that models living tissues as active biological networks represented as nematic polymer networks capable of heterogeneous growth and remodeling. The model captures macroscopic effects through spatial variations in the fiber order parameter which drives the system away from equilibrium. Morphogenesis is described as a sequence of quasi-static equilibrium states governed by the coupling between nematic order, elasticity, stress-driven growth, and adaptive relaxation. Finite element simulations illustrate Hydra regeneration and development when topological defects are prescribed according to the mature organism's expected morphology. The results show that defect topology controls stress localization and shape evolution: $+1$ defects drive protrusion formation, while $-1/2$ defects act as structural stabilizers with minimal growth. By varying the initial defect configuration, we model diverse morphogenetic outcomes, including uniaxial regeneration, tentacle formation, and biaxial development.
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Materials Science

First-principles calculations of electronic structure

Arpan Das

The emergence of high-mobility at provides a fertile platform for exploring emergent quantum phenomena and next-generation oxide electronics. Here, using first-principles density functional theory (DFT) calculations, we uncover the microscopic origin of the formed at the interface between insulators. Despite both constituents being insulating in bulk, the heterostructure develops robust metallicity at the interface, in agreement with experimental observations. This charge redistribution stabilizes at the interface. The electronic states forming enforcing carrier motion strictly within the interfacial plane. Remarkably, the spin-up parabolic band hosting the 2DEG exhibits an exceptionally small effective mass – indicating the potential for significantly enhanced carrier mobility. Furthermore, the calculated interfacial electron density exceeds that of by nearly an order of magnitude, consistent with experimental measurement. These findings identify the heterostructure as a compelling platform for realizing and open new avenues for engineering correlated oxide interfaces for quantum electronic applications.
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Materials Science

Physical properties of R$_2$Co$_6$Al$_{20-\delta}$ (R = Gd-Tm, Y) single crystals

Sushma Kumari, Fernando A. Garcia, Juan Schmidt et al. (+6 more)

Rare-earth (R) based intermetallic compounds can often exhibit diverse physical properties and distinct magnetic anisotropies. A Notable example are the light rare earth members of the mono-clinic, R$_2$Co$_6$Al$_{19}$ series that are known to display a range of physical properties, from non-Fermi liquid behavior to antiferromagnetic (AFM) ordering, with properties that vary depending on R. In this work, we have extended this series to the heavy rare earths and systematically investigate the synthesis, crystal structure, and physical properties of single crystals of R$_2$Co$_6$Al$_{20-\delta}$ for R = Gd - Tm and Y. Single crystal X-ray diffraction reveals that these materials adopt an orthorhombic Imma-type structure with delta varying non-monotonically across the heavy rare earths; ranging from 0.73 for Dy to 0.91 for Gd. Temperature-dependent specific heat, resistivity, and magnetization measurements demonstrate AFM ordering in all materials, with the Neel temperature (TN) ranging from 1.8 K for Ho to 11.8 K for Tb. Notably, Gd and Tb-based materials exhibit two distinct AFM transitions, separated by approximately 2 - 3 K. These findings establish the heavy rare-earth members of the R2Co6Al20-delta series as anisotropic antiferromagnets with strong crystal electric field effects and exchange anisotropy. The observed deviation from de Gennes scaling and the anisotropy crossover across the series highlight the important interplay between RKKY exchange and crystal electric field interactions in this orthorhombic system.
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All authors Sushma Kumari, Fernando A. Garcia, Juan Schmidt, Tyler J. Slade, Aashish Sapkota, Ajay Kumar, Yaroslav Mudryk, Paul C. Canfield, Raquel A. Ribeiro

Mesoscale and Nanoscale Physics

Breaking the width-scaling limit in high-performance atomically thin 2D nanoribbon transistors

Sameer Kumar Mallik, Adrian Christiansen and Saroj P. Dash

State-of-the-art transistors have been successfully scaled the gate lengths and channel thicknesses down to 5 nm for high-performance and energy-efficient information processing. However, reducing channel width below 40-50 nm remains a bottleneck, as dangling bonds, edge disorder, and lateral depletion suppress drive current and degrade device performance. Here, we break this width-scaling wall using ultra-scaled two-dimensional semiconductor (2DSC) nanoribbon transistors down to 15 nm. In contrast to the conventional scaling rule of degradation of current density upon width scaling, our atomically-thin monolayer and bilayer molybdenum disulfide nanoribbon transistors exhibit enhancement of on-current density of up to 230% and 170%,respectively, followed by a saturation for the narrowest channels down to 15 nm. The ultra-narrow nanoribbon transistors maintain the highest on/off ratios reported so far for similar device dimensions, with improved mobility and threshold-voltage stability, indicating reduced edge scattering and depletion with a stronger electrostatic control. These findings lead to a breakthrough in width scaling rules using 2DSC nanoribbons with enhanced performance at narrower channel widths, which is promising for the ultimate scaling of transistors.
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Materials Science

Emergence of Macroscopic Quantum Order via Translational Zero Modes

Kenan Gundogdu

Macroscopic quantum coherence in solids, such as in superfluids, superconductors, and condensates, is generally limited to low temperatures because order forms within a fixed excitation spectrum whose competing states become thermally populated as temperature rises. Here, we show that strong coupling between electronic excitations and a deformable lattice enables a different route. Above a critical density, this coupling nucleates self generated confining potentials that trap the very excitations generating them. Unlike rigid external traps, these potentials can translate through the host lattice without changing their internal structure, defining a translational zero mode. Coupling to this zero mode provides a shared dynamical coordinate that lowers and isolates a single collective many body configuration, opening a density dependent gap that suppresses thermal occupation of competing states and supports off diagonal long range order at elevated temperatures. As a concrete realization, we identify high-temperature superfluorescence in lead halide perovskites as the radiative instability of this zero mode dressed ordered excitonic state. More broadly, this establishes a general route to macroscopic quantum order: not cooling within a fixed spectrum, nor pairing instabilities, but a self generated mobile confining structure whose translational zero mode reconstructs the many-body spectrum to protect coherence.
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Mesoscale and Nanoscale Physics

Electronic primary thermometry – experimental comparison of the Coulomb Blockade and Shot Noise Thermometer

Eemil Praks, Libin Wang, Yu-Cheng Chang et al. (+4 more)

Since the redefinition of the kelvin in 2019, new methods of primary thermometry have been considered to replace the currently agreed temperature scale in the very high and low temperature limits. These new methods should provide improved uncertainties and, most importantly, a more direct link to the definition of the kelvin. We present an experimental comparison of two such primary thermometers working in the mK region: the Coulomb Blockade Thermometer (CBT) and the Shot Noise Thermometer (SNT). Both thermometers measure temperature hinging only on the natural constants $k_\mathrm{B}$, and $e$. Furthermore both of them are based on electron tunneling current and, thereby, need only electrical measurements, enhancing the practicality. CBT and the SNT are inter-compared in a range of 20 mK to 235 mK. The results show that the agreement of SNT and CBT is approximately within 2.5 % in this range. Basic measurement uncertainty is analyzed and we show that uncertainty in the measurement frequency can cause significant error to temperature measurement of the SNT at low temperatures where finite frequency plays a role.
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All authors Eemil Praks, Libin Wang, Yu-Cheng Chang, Renan P. Loreto, Mika Prunnila, Joonas T. Peltonen, Jukka P. Pekola

Mesoscale and Nanoscale Physics

Moiré enabled spin pumping and preservation in MoSe2/WS2 heterobilayers

Leo Yu, Kateryna Pistunova, Sudipta Kundu et al. (+5 more)

The spin degree of freedom is a fundamental quantum mechanical attribute with implications spanning from magnetism to quantum computing. Consequently, the relaxation of spin states for extended, Bloch electrons in solids has been studied for decades as it defines many of their properties and applications. We show that moiré patterns in layered materials can extend spin relaxation times by two orders of magnitude to 1 millisecond and beyond. This is achieved by suppressing spin mixing for electrons in 2D semiconductor heterostructures, particularly in the MoSe2/WS2 system, as we elucidate both experimentally and theoretically. The extended longitudinal lifetime facilitates spin alignment over 50% using only nanowatt levels of optical power. Our findings highlight the potential of moiré engineering for future quantum sensing and information processing.
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All authors Leo Yu, Kateryna Pistunova, Sudipta Kundu, Jenny Hu, Kenji Watanabe, Takashi Taniguchi, Felipe H. da Jornada, Tony F. Heinz

Soft Condensed Matter

Controlled Chemical Signaling between Enzymatic Nanomotors

Shuqin Chen, Giorgio Lovato, Oriol Jutglar Soler et al. (+3 more)

The coordinated interactions between organisms enhance collective functionality, a feature that artificial systems such as enzymatic nanomotors seek to replicate. A key objective, yet still a major challenge, is to achieve chemical communication among nanomotors. Progress has been limited by the difficulties in verifying effective signaling processes, including chemical signal propagation and the response of receiving nanomotors. Here, we address this challenge using an enzymatic nanomotor system that demonstrates communication between two populations through generically non-reciprocal phoretic response. A primary swarm of glucose-responsive nanomotors migrates toward a glucose gradient while producing H2O2 as a diffusible communication signal. This self-generated chemical gradient then acts as a chemoattractant for a secondary swarm of catalase-powered nanomotors. Through carefully designed experiments, we visualize the propagating H2O2 gradient and quantify the spatiotemporal response of the receiver nanomotors to the chemical front. Combined experimental and theoretical analysis has revealed that the synergy between different combinations of chemo-attractive and chemo-repulsive mobilities and catalytic rates of consumption and production of substrates and products gives rise to a wealth of different collective responses in the system. This work represents a step toward programmable synthetic systems at the collective level, broadening the functionality of chemical nanomotors and opening opportunities for future hybrid living-synthetic systems.
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All authors Shuqin Chen, Giorgio Lovato, Oriol Jutglar Soler, Daniel Sánchez-deAlcázar, Ramin Golestanian, Samuel Sánchez

Superconductivity

Probing pairing symmetries through quasiparticle interference in chiral Bloch bands

Sayan Banerjee, Subrata Mandal, Peter P. Orth et al. (+1 more)

Recent experiments in van der Waals multi-layer systems have demonstrated that superconductivity can emerge from symmetry-reduced, chiral normal states. We here provide a theory for quasiparticle interference (QPI) of superconductors with chiral Bloch bands. Our analysis reveals how the non-trivial quantum geometry of the Bloch states crucially affects the interference pattern even in the normal state, inducing significant sublattice dependence. In the superconducting state, the behavior becomes more complex due to the interplay of the quantum geometry of the Bogoliubov quasiparticles with the momentum-dependent phase of the order parameter. We reveal how the spatial dependence of the local spectral function around impurities can be used to distinguish between different candidate pairing states, both with zero and finite center-of-mass momentum. Our work thus provides guidance to interpreting QPI patterns in materials with chiral bands, which may be useful when probing the rich physics of pairing in such systems.
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All authors Sayan Banerjee, Subrata Mandal, Peter P. Orth, Mathias S. Scheurer