Materials Science
Low-Field Ferroelectricity in 10 nm AlBScN Thin Films
Xiaolei Tong, Pedram Yousefian, Ziyi Wang et al. (+5 more)
Ferroelectric aluminum scandium nitride (Al1-xScxN, AlScN) offers CMOS-compatible integration but suffers from high coercive fields and leakage currents that hinder thickness scaling. Further reduction in thickness is essential for low-voltage embedded nonvolatile
memory applications. Boron incorporation into AlScN (AlBScN) suppresses leakage current in films down to 40 nm, yet its ferroelectric characteristics in ultrathin films remains unexplored. This letter demonstrates robust ferroelectric switching in 10 nm sputtered AlBScN capacitors with a low coercive field and approximately two orders of magnitude lower leakage than AlScN. Notably, ferroelectric switching was observed at 2.2 MV/cm in capacitance-voltage measurements, and symmetric polarization reversal occurred near 4.6 MV/cm in positive-up-negative-down (PUND) measurements using 2 {\mu}s pulses. Moreover, Weibull analysis revealed a breakdown-to-coercive-field ratio (EBD/Ec) of ~2.2. These findings demonstrated AlBScN as a promising candidate for CMOS back-end-of-line (BEOL) compatible ferroelectric applications with improved energy consumption and reduced leakage current.
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All authors Xiaolei Tong, Pedram Yousefian, Ziyi Wang, Meenakshi A. Saravanan, Rajeev Kumar Rai, Giovanni Esteves, Eric A. Stach, Roy H. Olsson III
Soft Condensed Matter
The Role of Elastic Anisotropy in Active Nematics
Alexander J. H. Houston
We analyse the effect of anisotropy in elastic constants on the hydrodynamics of active nematics. Building on the multipole framework for a single elastic constant, we determine the leading effect of elastic anisotropy on the active response of generic distortions. The key findings are a new active torque, proportional to the anisotropy, in response to monopole distortions, and modifications to the propulsion of dipoles in both the direction of motion and changes in speed of up to 50%. For point defects in two dimensions we find that, despite the large morphological changes in the director field, elastic anisotropy has only a minor impact on their hydrodynamics, with the self-propulsion speed of $+1/2$ defects lowered by less than 5%. Finally, we determine the elastic torques exerted on defect pairs due to elastic anisotropy.
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Superconductivity
Interband pairing as the origin of the sublattice dichotomy in monolayer FeSe/SrTiO_3
Zhipeng Xu, Shengshan Qin, Kun Jiang et al. (+1 more)
Sublattice dichotomy in monolayer FeSe/SrTiO$_3$, signaling the breaking of
symmetries exchanging the two Fe sublattices, has recently been reported. We propose that interband pairing serves as the origin of this dichotomy, regardless of whether the
symmetry is broken in the normal state or in the pairing state. If
symmetry breaking occurs in the normal state, the
Fermi surfaces are sublattice-polarized, and the intersublattice d-wave pairing naturally acts as interband pairing, reproducing the observed dichotomy in the spectra. Alternatively, if
symmetry breaking takes place in the pairing state, it manifests as the coexistence of intraband and interband pairing, with the constraint that interband pairings share the same sign while intraband pairings carry opposite signs. In both cases, interband pairing is indispensable, establishing it as a key ingredient for understanding superconductivity in monolayer FeSe/SrTiO$_3$.
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All authors Zhipeng Xu, Shengshan Qin, Kun Jiang, Jiangping Hu
Quantum Gases
Microscopy of cavity-induced density-wave ordering in ultracold gases
Tabea Bühler, Aurélien Fabre, Gaia Bolognini et al. (+4 more)
We demonstrate high-resolution in-situ imaging of density-wave ordering induced by cavity-mediated interactions in a
unitary Fermi gas. We observe long-range spatial correlations throughout the formation of density waves, both for adiabatic preparation and following a quench, with a pattern controlled by the cavity mode structure. Our single-shot microscopic images together with the real-time readout of the cavity
photons provide access to atom-
photon correlations. We use this capability to investigate order fluctuations as a function of time following a quench and to directly confirm the correspondence between optical and atomic observables. Our system opens rich perspectives, from local patterning to correlation measurements in long-range interacting
quantum gases.
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All authors Tabea Bühler, Aurélien Fabre, Gaia Bolognini, Zeyang Xue, Timo Zwettler, Giulia Del Pace, Jean-Philippe Brantut
Superconductivity
Polarization Controlled Supercurrent in Ferroelectric Josephson Junction
Yaozu Tang, Mazhar N. Ali, Gerrit E. W. Bauer et al. (+1 more)
Josephson junctions are essential devices in superconducting electronics and
quantum computing hardware. Here we predict electrical control of the supercurrent in composite
superconductor-
insulator-ferroelectric-
insulator-
superconductor (S-I-FE-I-S) Josephson junctions. Inversion
symmetry broken by unequal dielectric barrier thicknesses and/or potentials converts ferroelectric polarization reversal into a substantial change of the critical current. With a WKB tunneling model we obtain non-volatile switching of the critical current with on-off efficiency up to 0.9 for physically realistic parameters. This can be achieved by optimizing the thicknesses and potential barriers of the insulating layers, as well as the thickness and dielectric constant of the ferroelectric layer. We also derive a compact linear expression for the critical current valid for small polarizations. Our results identify ferroelectric Josephson junctions as electrically programmable superconducting current switches for cryogenic
memory and logic applications.
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All authors Yaozu Tang, Mazhar N. Ali, Gerrit E. W. Bauer, Yaroslav M. Blanter
Soft Condensed Matter
Phase behaviour and dynamical features of a two-dimensional binary mixture of active/passive spherical particles
Diego Rogel Rodriguez, Francisco Alarcon, Raul Martinez et al. (+2 more)
In this work we have characterized the phase behaviour and the dynamics of bidimensional mixtures of active and passive Brownian particles. We have evaluated state diagrams at several concentrations of the passive components finding that, while passive
agents tend to hinder phase separation, active
agents force
crystal-like structures on passive colloids. In order to study how passive particles affect the dynamics of the mixture, we have computed the long-time
diffusion coefficient of each species, concluding that active particles induce activity and super-diffusive behaviour on passive ones. Interestingly, at the density at which the system enters a MIPS state the active particles' diffusivity shows an inflection point and the passive particles' one goes through a maximum, due to the change in the dynamics of the active components, as shown in the displacement's probability distribution function.
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All authors Diego Rogel Rodriguez, Francisco Alarcon, Raul Martinez, Jorge Ramirez, Chantal Valeriani
Superconductivity
Kinetic Inductance of Few-Layer NbSe$_2$ in the Two-Dimensional Limit
Sameia Zaman, Joel Î-j. Wang, Thomas Werkmeister et al. (+19 more)
Van der Waals (vdW)
superconductors remain superconducting down to the monolayer limit, enabling the exploration of emergent physical phenomena and functionality driven by reduced dimensionality. Here, we report the characterization of the kinetic inductance of atomically thin NbSe$_2$, a two-dimensional van der Waals
superconductor, using superconducting coplanar waveguides and microwave measurement techniques familiar to
circuit quantum electrodynamics (cQED). The kinetic inductance scales inversely with the number of NbSe$_2$ layers, reaching 1.2 nH/$\Box$ in the monolayer limit. Furthermore, the measured kinetic inductance exhibits a thickness-dependent crossover from clean- to dirty-limit behavior, with enhanced dirty-limit contributions emerging in the ultra-thin regime. These effects are likely driven by increased surface scattering, multi-band superconductivity, and
geometric confinement. Additionally, the self-Kerr nonlinearity of the NbSe$_2$ films ranges from $K/2\pi$ = -0.008 to -14.7 Hz/
photon, indicating its strong potential in applications requiring compact, nearly linear, high-inductance superconducting
quantum devices and detectors. The fabrication and characterization techniques demonstrated here are extensible to the investigation of other two-dimensional
superconductors.
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All authors Sameia Zaman, Joel Î-j. Wang, Thomas Werkmeister, Miuko Tanaka, Thao Dinh, Max Hays, Daniel Rodan-Legrain, Aranya Goswami, Réouven Assouly, Ahmet Kemal Demir, David K. Kim, Bethany M. Niedzielski, Kyle Serniak, Mollie E. Schwartz, Kenji Watanabe, Takashi Taniguchi, Philip Kim, Riccardo Comin, Jeffrey A. Grover, Terry P. Orlando, Pablo Jarillo-Herrero, William D. Oliver
Soft Condensed Matter
Multiscale Dynamics of Roughness-Driven Flow in Soft Interfaces
Qian Wang, Suhaib Ardah, Tom Reddyhoff et al. (+1 more)
Soft lubricated contacts exhibit complex interfacial behaviours governed by the coupled effects of multiscale surface roughness and non-linear fluid-solid interactions. Accurately capturing this interplay across thin-film flows is challenging due to the strong synergy between contact mechanics and hydrodynamic flow, spanning over various spatiotemporal scales. Here, we develop a rigorous computational framework to simulate the frictional behaviour of soft lubricated interfaces; its modularity and the use of optimal solvers provides solutions for realistic configurations in lubrication regimes ranging from direct solid contact to complete fluid separation. Surface roughness is described via Persson's statistical theory as well as a deterministic Conjugate Gradient with Fast
Fourier Transform (CG-FFT) approach, while limitations associated with classical half-space models are addressed by developing the Reduced Stiffness Method (RSM) to rigorously model pressure-induced surface responses. The integrated framework captures the full
evolution of frictional behaviour, validated against experiments on rough elastomer-glass interfaces, revealing how surface roughness and material compliance together drive the transition from solid contact to fluid-mediated sliding. The developed approach establishes a robust and versatile simulation tool for analysing a plethora of soft interfacial systems shaped by fluid-solid interactions, with potential applications including but not limited to biomechanics, soft robotics and microfluidic systems.
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All authors Qian Wang, Suhaib Ardah, Tom Reddyhoff, Daniele Dini
Strongly Correlated Electrons · Cross-listed from quant-ph
Comment on "Role of Matter Interactions in Superradiant Phenomena"
Max Hörmann, Anja Langheld, Jonas Leibig et al. (+2 more)
Recently, Mendonça et al. [arXiv:2503.04961] investigated the Dicke-XXZ model and the Dicke-Ising model. For the latter model, their calculated
quantum phase diagram contradicts claims about the existence of an intermediate phase with superradiant and
antiferromagnetic order and the change in order of some phase transition lines, observed in other studies. In this comment we demonstrate that both features are indeed present in the Dicke-Ising model for the investigated parameter range in [arXiv:2503.04961].
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All authors Max Hörmann, Anja Langheld, Jonas Leibig, Andreas Schellenberger, Kai Phillip Schmidt
Quantum Gases · Cross-listed from quant-ph
Comparison of Two Optimization Methods for a Rydberg Quantum Gate
Luis S. Yagüe Bosch and Sandro Wimberger
A shortcut-to-adiabaticity is compared with a numerically optimized protocol for implementing a high-fidelity
quantum gate on Rydberg atoms. The counterdiabatic method offers an analytical framework for accelerating high-fidelity gates by mimicking the time
evolution of a counterdiabatic
Hamiltonian using fast-oscillating fields. This approach is contrasted with a numerically optimized gate designed using the Boulder Opal platform. The numerically optimized gate achieves higher fidelities while demonstrating robustness against errors similar to that of the effective counterdiabatic gate. The study serves as an example of the performance of analytic shortcut-to-adiabatic-inspired protocols compared to brute-force numerical optimization techniques for state-of-the-art
quantum computing platforms. It stresses the important role played by constraints on the optimized pulses in time and in amplitude that are crucial in determining the quality of the optimization method.
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Materials Science
Synergetic Enhancement on Bulk and Grain Boundary Ionic Conduction of Mg Doped High-Entropy NASICON-Type Solid Electrolyte for Solid-State Na+ Batteries by Spray Flame Synthesis
Tianyi Wu, Yiyang Zhang, Zhu Fang et al. (+3 more)
All-solid-state sodium batteries represent a promising next-generation energy storage technology, owing to cost-effectiveness and enhanced safety. Among solid electrolytes for solid-state sodium batteries, NASICON-structured Na3Zr2Si2PO12 has emerged as a predominant candidate. However, its widespread implementation remains limited by suboptimal ionic conductivity in both bulk and grain boundary regions. In this study, we demonstrate a novel approach utilizing swirling spray flame synthesis to produce Mg-doped NASICON solid electrolyte nanoparticles. This method facilitates efficient doping and homogeneous mixing for scalable production, resulting in core-shell non-NASICON structures with nano-scale high-
entropy mixing. Notably, the atomic migration distances achieved by flame synthesis are significantly reduced compared to conventional solid-state reactions, thereby enabling reactive sintering to preserve high sinterability of nanoparticles during post-treatment processes. High-temperature sintering yields dense NASICON-structured solid electrolytes. Among those, Mg0.25NZSP exhibits an optimal ionic conductivity of 1.91 mS/cm at room temperature and an activation energy of 0.200 eV. The enhancement mechanism can be attributed to incorporation into the NASICON phase and formation of a secondary phase. The low-melting-point secondary phase significantly improves grain boundary contact to enhance grain boundary conductivity. The process achieves simultaneous enhancement of both bulk and grain boundary conduction through a single-step procedure. Comparative analysis of sintering temperatures and ionic conductivities among NASICON solid electrolytes synthesized via different methods demonstrates flame-synthesized nanoparticles offer superior performance and reduced post-treatment costs, owing to their exceptional nano-scale sinterability and uniform elemental distribution.
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All authors Tianyi Wu, Yiyang Zhang, Zhu Fang, Shuting Lei, Xing Jin, Shuiqing Li
Materials Science
Porous-B$_{18}$: An Ideal Topological Semimetal with Symmetry-Enforced Orthogonal Nodal-Line and Nodal-Surface States
Xiao-jing Gao, Yanfeng Ge and Yan Gao
Topological semimetals (TSMs) featuring
symmetry-protected band degeneracies have attracted considerable
attention due to their exotic
quantum properties and potential applications. While nodal line (NL) and nodal surface (NS) semimetals have been extensively studied, the realization of a material where both NL and NS coexist and are intertwined, particularly with an ideal electronic band structure, remains a significant challenge. Here, we predict via first-principles calculations and
symmetry analysis a metastable boron allotrope, Porous-B$_{18}$ (space group $P6_3/m$, No.~176), as a pristine TSM hosting a NS and two straight NLs near the
Fermi level. The structure, a honeycomb-like porous 3D framework, exhibits excellent dynamical, thermal (stable up to 1000~K), and mechanical stability. Its electronic band structure is remarkably clean: only the highest valence band (HVB) and the lowest conduction band (LCB) cross linearly within a large energy window of 1.84~eV, free from trivial-band interference. The nodal surface lies on the $k_z = \pm \pi$ planes, protected by combined time-reversal
symmetry ($T$) and twofold screw-rotational
symmetry ($S_{2z}$), yielding a full-plane Kramers-like degeneracy. The two nodal lines along $K$–$H$ and $K'$–$H'$ are protected by inversion and time-reversal
symmetries, carry a quantized Berry phase of $\pm \pi$, and connect orthogonally to the nodal surface, forming an intertwined nodal network. Drumhead surface states on the $(1\bar{1}0)$ surface further confirm the nontrivial
topology. Porous-B$_{18}$ thus provides an ideal platform for investigating the interplay between nodal-line and nodal-surface
fermions and exploring novel
quantum transport phenomena.
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Materials Science
Critical temperatures of two dimensional magnets beyond linear spin wave theory: application to CrI$_3$, MPS$_3$ (M=Ni, Mn, Fe) and CrSBr
Varun Rajeev Pavizhakumari and Thomas Olsen
Magnetic anisotropy is crucial for sustaining long range
magnetic order in two-dimensional materials (2D) and must be taken into account by any approximate scheme for calculating critical temperatures. While 2D ferromagnets have received significant
attention with regard to predicting Curie temperatures, the treatment of 2D anti-ferromagnetism has largely been restricted to classical approaches, which typically underestimate Néel temperatures. The concept of anti-ferromagnetism can be regarded as a special case of single-$Q$
magnetic order, and for such systems the critical temperature can be calculated from the
magnon dispersion using either Holstein-Primakoff (HP) bosonization or Green's function-based Random Phase Approximation (RPA). Here, we study the effects of single-ion anisotropy in general single-$Q$ systems in both the HP and RPA methods. In the case of RPA, we generalize the approach to include the Callen Decoupling (CD) correction, which has previously been shown to yield good agreement with experimental Curie temperatures for 2D ferromagnets. We compare the calculated critical temperatures of CrI$_3$ (uniaxial ferromagnet), MPS$_3$ (M=Ni, Mn, Fe) (uniaxial anti-ferromagnets) and CrSBr (triaxial ferromagnet) monolayers with experimental values and find that the Green's function-based methods are much more reliable than HP and that the CD decoupling appears to be more accurate than RPA if the single-ion anisotropy is large.
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Materials Science
Identification of Empirical Constitutive Models for Age-Hardenable Aluminium Alloy and High-Chromium Martensitic Steel Using Symbolic Regression
Evgeniya Kabliman and Gabriel Kronberger
Process-structure-property relationships are fundamental in materials science and engineering and are key to the development of new and improved materials. Symbolic regression serves as a powerful tool for uncovering mathematical models that describe these relationships. It can automatically generate equations to predict material behaviour under specific manufacturing conditions and optimize performance characteristics such as strength and elasticity. The present work illustrates how symbolic regression can derive constitutive models that describe the behaviour of various metallic
alloys during plastic deformation. Constitutive modelling is a mathematical framework for understanding the relationship between stress and strain in materials under different loading conditions. In this study, two materials (age-hardenable aluminium
alloy and high-chromium martensitic steel) and two different testing methods (compression and tension) are considered to obtain the required stress-strain data. The results highlight the benefits of using symbolic regression while also discussing potential challenges.
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Strongly Correlated Electrons · Cross-listed from math-ph
Stacking and the triviality of invertible phases
Sven Bachmann, Alan Getz, Pieter Naaijkens et al. (+1 more)
We study the superselection sectors of two
quantum lattice systems stacked onto each other in the operator algebraic framework. We show in particular that all irreducible sectors of a stacked system are unitarily equivalent to a product of irreducible sectors of the factors. This naturally leads to a faithful functor between the categories for each system and the category of the stacked system. We construct an intermediate `product' category which we then show is equivalent to the stacked system category. As a consequence, the sectors associated with an invertible state are trivial, namely, invertible states support no anyonic quasi-particles.
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All authors Sven Bachmann, Alan Getz, Pieter Naaijkens, Naomi Wray
Strongly Correlated Electrons · Cross-listed from hep-th
Anomaly induced transport from symmetry breaking in holography
Ashis Tamang, Nishal Rai, Karl Landsteiner et al. (+1 more)
We study the transport properties of relativistic fluids induced by
quantum anomalies in presence of explicit
symmetry breaking. To this end we consider a
holographic Einstein-Maxwell model in 5 dimensions with pure gauge and a mixed gauge-gravitational Chern-Simons terms, coupled with a scalar field. To study the
chiral vortical effects and the energy transport sector, apart from the
chiral magnetic effects, we have considered the full backreaction of the gauge field on the metric. We have studied the anomalous effects by using Kubo formulae involving correlators of the charged currents and the energy current. Our findings reveal that, in the presence of explicit
symmetry breaking, anomaly-induced transport phenomena can extend beyond anomalous currents and affect non-anomalous sectors as well. In particular, we find that all the conductivities display a distinct sensitivity to the mass parameter controlling the
symmetry breaking, thus reflecting the interplay between anomaly coefficients and explicit
symmetry breaking terms. These findings highlight the role played by pure gauge and mixed gauge-gravitational anomalies in
holographic transport, and their importance for strongly coupled systems with broken
symmetries.
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All authors Ashis Tamang, Nishal Rai, Karl Landsteiner, Eugenio Megias
Mesoscale and Nanoscale Physics
D-Wave Phonon Angular Momentum Texture in Altermagnets by Magnon-Phonon Hybridization
Hannah Bendin, Alexander Mook, Ingrid Mertig et al. (+1 more)
In altermagnets, the
magnon bands are anisotropically
spin-split in reciprocal space without relativistic or dipolar
spin-
spin interactions. In this work, we theoretically study
magnons and
phonons coupled by
spin-
lattice interaction in a two-dimensional square-
lattice d-wave altermagnet. We show that
phonon-chirality-selective
magnon-
phonon hybridization can be caused by interfacial Dzyaloshinskii-Moriya interaction leading to the emergence of hybrid quasiparticles that possess finite
phonon angular momentum. These hybrid quasiparticles are called
magnon polarons and consist of
spin-polarized
magnons and
chiral phonons. Their
phonon angular momentum texture follows the d-wave character of the
magnon spin texture opening up the possibility of phononic counterparts to the electronic response effects in altermagnets, such as a
phonon angular momentum splitter effect, i.e., the generation of a transverse
phonon angular momentum current induced by a temperature gradient – the bosonic analog of the
spin-splitter effect.
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All authors Hannah Bendin, Alexander Mook, Ingrid Mertig, Robin R. Neumann
Materials Science
Revealing the Hidden Third Dimension of Point Defects in Two-Dimensional MXenes
Grace Guinan, Michelle A. Smeaton, Brian C. Wyatt et al. (+6 more)
Point defects govern many important functional properties of two-dimensional (2D) materials. However, resolving the three-dimensional (3D) arrangement of these defects in multi-layer 2D materials remains a fundamental challenge, hindering rational defect engineering. Here, we overcome this limitation using an artificial intelligence-guided electron microscopy workflow to map the 3D
topology and clustering of atomic vacancies in Ti$_3$C$_2$T$_X$ MXene. Our approach reconstructs the 3D coordinates of vacancies across hundreds of thousands of
lattice sites, generating robust statistical insight into their distribution that can be correlated with specific synthesis pathways. This large-scale data enables us to classify a hierarchy of defect structures–from isolated vacancies to nanopores–revealing their preferred formation and interaction mechanisms, as corroborated by molecular dynamics simulations. This work provides a generalizable framework for understanding and ultimately controlling point defects across large volumes, paving the way for the rational design of defect-engineered functional 2D materials.
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All authors Grace Guinan, Michelle A. Smeaton, Brian C. Wyatt, Steven Goldy, Hilary Egan, Andrew Glaws, Garritt J. Tucker, Babak Anasori, Steven R. Spurgeon
Mesoscale and Nanoscale Physics
Cooling of electrons via superconducting tunnel junctions and their arrays exhibiting nodal lines
Linus Aliani and Viktoriia Kornich
We study theoretically a process of cooling electrons using a superconducting tunnel junction with a $\pi$ phase difference and a usual
insulator or a ferroelectric in-between, and an array of such junctions with ferroelectric layers in-between. These setups have a complex structure of
entropy due to nodal lines, where the density of states can be divergent or larger than for a free electron gas at a chemical potential level. We consider a small current running from the bath of electrons through the setup, where electrons have to have higher
entropy, and thus remove heat from the bath.
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Strongly Correlated Electrons · Cross-listed from quant-ph
Quantum annealing for lattice models with competing long-range interactions
Jan Alexander Koziol and Kai Phillip Schmidt
We use superconducting
qubit quantum annealing devices to determine the ground state of Ising models with algebraically decaying competing long-range interactions in the thermodynamic limit. This is enabled by a unit-
cell-based optimization scheme, in which the finite optimizations on each unit
cell are performed using commercial
quantum annealing hardware. To demonstrate the capabilities of the approach, we choose three exemplary problems relevant for other
quantum simulation platforms and material science: (i) the calculation of devil's staircases of magnetization plateaux of the long-range Ising model in a longitudinal field on the triangular
lattice, motivated by atomic and molecular
quantum simulators; (ii) the evaluation of the ground state of the same model on the Kagome
lattice in the absence of a field, motivated by artificial
spin ice metamaterials; (iii) the study of models with additional few-nearest-neighbor interactions relevant for frustrated Ising compounds with potential long-range interactions. The approach discussed in this work provides a useful and realistic application of existing
quantum annealing technology, applicable across many research areas in which
lattice problems with resummable long-range interactions are relevant.
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Materials Science
Machine-learning interatomic potential for AlN for epitaxial simulation
Nicholas Taormina, Emir Bilgili, Jason Gibson et al. (+3 more)
A machine learned interatomic potential for AlN was developed using the ultra-fast force field (UF3) methodology. A strong agreement with density functional theory calculations in predicting key structural and mechanical properties, including
lattice constants, elastic constants, cohesive energy, and surface energies has been demonstrated. The potential was also shown to accurately reproduce the experimentally observed atomic core structure of edge dislocations. Most significantly, it reproduced the experimentally observed wurtzite
crystal structure in the overlayer during homoepitaxial growth of AlN on wurtzite AlN, something that prior potentials failed to achieve. Additionally, the potential reproduced the experimentally observed layer-by-layer growth mode in the epilayer. The combination of accuracy, transferability, and computational speed afforded by the UF3 framework thus makes large-scale, atomistic simulations of epitaxial growth of AlN feasible.
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All authors Nicholas Taormina, Emir Bilgili, Jason Gibson, Richard Hennig, Simon Phillpot, Youping Chen
Materials Science
Sliding properties of Transition Metal Dichalcogenide bilayers
Pier Luigi Silvestrelli, S. Subashchandrabose, Alberto Ambrosetti et al. (+1 more)
Transition-metal dichalcogenides (TMDs) are valuable as solid lubricants because of their layered structure, which allows for easy shearing along the basal planes. Using Density Functional Theory (DFT) we conducted a first-principles study of the sliding properties of several TMD
bilayers: MoS$_2$, MoTe$_2$, WS$_2$, WSe$_2$, VS$_2$, VSe$_2$, TaS$_2$, TaSe$_2$, TiS$_2$, TiSe$_2$, HfS$_2$, ZrS$_2$, MoS$_2$WS$_2$, MoS$_2$VS$_2$. Given the crucial role of van der Waals (vdW) interactions in accurately describing the interlayer interactions in TMD
bilayers, we employed vdW-corrected DFT functionals. Our research confirms the dominance of vdW effects by estimating the fraction of interlayer binding energy attributable to these interactions. We also examined how the choice of different vdW-corrected DFT functionals might influence quantitative results. Using MoS$_2$ as a reference TMD
bilayer system, we found that most other TMD
bilayers studied exhibit stronger interlayer bonds and greater corrugation. However, TiSe$_2$ shows a profile similar to MoS$_2$, while, interestingly, TiS$_2$, VS$_2$, and ZrS$_2$ are characterized by weaker bonding and lower corrugation than MoS$_2$. We explored relationships between various properties of TMD
bilayers, with a particular focus on potential connections between tribological and electronic properties often characteristic of solid interfaces. To this end, we evaluated adhesion energies, work of separation, charge density redistributions in interface regions, differential charge densities, and corrugation. While corrugation and thus resistance to sliding generally tends to increase with the size of the chalcogen element and is typically proportional to the adhesion energy, the relationships between other structural, energetic, and electronic properties do not follow a single, well-defined trend.
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All authors Pier Luigi Silvestrelli, S. Subashchandrabose, Alberto Ambrosetti, Maria Clelia Righi
Statistical Mechanics · Cross-listed from astro-ph.GA
Thermodynamic blocking in self-gravitating systems
Barnabás Deme and Jean-Baptiste Fouvry
Building upon a thermodynamic formalism, we show that self-gravitating systems in hydrostatic
equilibrium with a uniform density are maximal
entropy states when submitted to perturbations which are slow on dynamical timescale. We coin this phenomenon "thermodynamic blocking", given its similarity with the more general "kinetic blocking". This result underlines the importance of the thermodynamic formalism which proves useful when kinetic equations break down.
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Materials Science · Cross-listed from astro-ph.EP
Remanent crustal strain on Mars in non-poikilitic olivine of NWA 7721
Yaozhu Li, Szilvia Kalácska, Phil McCausland et al. (+5 more)
We present a multiscale microstructural analysis of olivine from the non-poikilitic lithology of the poikilitic shergottite NWA 7721, using dark-field X-ray microscopy (DFXM), electron backscatter diffraction (EBSD), and context in situ 2D micro-XRD. A single olivine
crystal contains two distinct subgrain populations. Type 1 subgrains are fine (1-5 micrometers), randomly oriented, and nearly strain-free, whereas Type 2 subgrains are coarse (greater than 30 micrometers), aligned, and strongly strained. Layered DFXM data reveal slip-band features in Type 2 that are absent in Type 1. We interpret Type 1 as products of shock-induced recrystallization, whereas Type 2 preserves remnants of a highly deformed parent grain. This bimodal microstructure, not observed in other Martian meteorites including the paired NWA 1950 and ALH A77005, points to a heterogeneous response to impact influenced by pre-existing strain in the olivine grain. We propose that NWA 7721 olivine experienced substantial crustal or magmatic stress before impact. The subsequent shock wave imposed a rapid load-release cycle that mobilized dislocations and produced low-angle boundaries in Type 2, while driving recrystallization of Type 1. Grain-growth constraints limit the post-shock heating duration to approximately 2.3 s, consistent with rapid quenching. These results provide the first evidence that non-poikilitic olivine in NWA 7721 preserves dynamic crustal deformation on Mars in the Late Amazonian.
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All authors Yaozhu Li, Szilvia Kalácska, Phil McCausland, Roberta L. Flemming, Callum Hetherington, Bo Zhao, Can Yildirim, Carsten Detlefs
Strongly Correlated Electrons · Cross-listed from hep-th
Semiclassical spectrum of the Ising CFT
Oleg Antipin, Jahmall Bersini, Jacob Hafjall et al. (+2 more)
We develop a semiclassical framework to determine scaling dimensions of neutral composite operators in scalar conformal field theories. For the critical Ising $\lambda\phi^4$ theory in $d=4-\epsilon$, we obtain the full spectrum of composite operators built out of $n$ fields transforming according to the various Lorentz representations to next-to-leading order in the double–scaling limit $n\rightarrow \infty$ and $\lambda \rightarrow 0$ with $\lambda n$ fixed. At any given order, the semiclassical expansion resums an infinite number of Feynman diagrams. Combining our results with existing perturbative computations further yields the complete five-loop scaling dimensions in the $\epsilon$-expansion for the family of $\phi^n$ operators. Finally, extrapolating the semiclassical results to three dimensions leads to a competitive alternative to existing methodologies.
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All authors Oleg Antipin, Jahmall Bersini, Jacob Hafjall, Giulia Muco, Francesco Sannino
Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Enhancing Circuit Fidelity in Transmon Qubit Rings via Operation Duration Tuning under Strong Connectivity Noise
Quan Fu, Xin Wang and Rui Xiong
Superconducting transmon
qubits are a promising platform for
quantum computation, yet they face significant fidelity degradation due to connectivity noise, particularly in the intermediate coupling regime where noise levels are substantial. While prior works suggest that high fidelity requires operating in regimes with strongly suppressed noise, maintaining such conditions under practical experimental constraints remains challenging. To address this, we investigate
quantum gate operations in fully connected transmon rings, examining both SWAP and general
circuits. Our study reveals that fidelity can be significantly enhanced by tuning gate operation durations, with local maxima emerging even under strong noise conditions. These fidelity enhancements occur consistently across different
qubit numbers and operation types, and for specific initial states – particularly those with favorable
symmetry or
entanglement properties – the achieved fidelities approach
quantum error correction thresholds. Furthermore, we develop a supervised machine learning model that accurately predicts the optimal operation durations for new devices, enabling efficient optimization without extensive experimental simulations. These results provide a pathway toward robust
quantum circuit design in noisy experimental environments.
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Materials Science
Effect of W in Cu-Zr-W thin films: Molecular dynamics simulations and experimental verification
Hassan Ataalite, Jiri Houska, Deepika Thakur et al. (+2 more)
We investigate the effects of W incorporation into Cu-Zr thin film metallic glasses using molecular dynamics (MD) simulations combined with magnetron sputtering. All studies are carried out in the whole range of W concentrations (0 to 100 at. %) and the MD studies also in a wide range of incident energies (1 to 500 eV) and deposition angles (0 to 60{\deg}). Calculated X-ray diffractograms, packing factor, short-range order (bonding fractions and coordination numbers), medium-range order (network ring and common neighbor statistics) and stress are correlated with measured X-ray diffractograms and properties (hardness, hardness/Young's modulus ratio and elastic recovery). The simulations explain the experimental results at the atomic level and provide a lot of information that is not available experimentally. Special
attention is paid to non-monotonic dependencies on the elemental composition and incident energy. Collectively, the results explain the role of W in modifying the structure and improving the mechanical performance of Cu-Zr metallic glasses, predict optimum compositions which maximize some of the mechanical properties, and contribute to the development of advanced materials for various applications.
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All authors Hassan Ataalite, Jiri Houska, Deepika Thakur, Michaela Cervena, Petr Zeman
Strongly Correlated Electrons · Cross-listed from math-ph
Geometric Categories for Continuous Gauging
Devon Stockall and Matthew Yu
We develop a unified categorical framework for gauging both continuous and finite
symmetries in arbitrary spacetime dimensions. Our construction applies to
geometric categories i.e. categories internal to stacks. This generalizes the familiar setting of fusion categories, which describe finite group
symmetries, to the case of Lie group
symmetries. Within this framework, we obtain a functorial
Symmetry Topological Field Theory together with its natural boundaries, allowing us to compute associated endomorphism categories and Drinfeld centers in a uniform way. For a given
symmetry group $G$, our framework recovers the electric and
magnetic higher-form
symmetries expected in $G$-gauge theory. Moreover, it naturally encodes electric breaking
symmetry in the presence of charged matter, reproducing known physical phenomena in a categorical setting.
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Materials Science
Ferroelectric Order and Enhanced Interfacial Superconductivity in Lightly-Doped Quantum Paraelectric KTa$_{1-x}$Nb$_x$O$_3$
F. Yang and L. Q. Chen
Ferroelectric
quantum criticality in perovskite
oxides offers a fertile ground for emergent collective phenomena. Here we develop a first-principles-inspired
quantum-statistics-based theoretical analysis of the ferroelectric order and interfacial superconductivity in lightly-doped
quantum paraelectric, niobium (Nb)-doped KTaO$_3$. We demonstrate that local distortions induced by the doped Nb atoms beyond its
quantum critical composition induce a long-range ferroelectric order. The predicted dielectric properties quantitatively agree with the experimental measurements over the entire temperature range from the
symmetry-broken ferroelectric phase across the phase transition to the paraelectric region. As the same soft
phonon mode that governs dielectric behavior provides the essential pairing channel for interfacial superconductivity of KTaO$_3$, we predict a pronounced enhancement of this superconductivity on (111) surface when the system is tuned to its
quantum-critical composition via Nb doping, providing a concrete avenue for experimental verification. This finding establishes ferroelectric
quantum criticality as a unique design principle for engineering enhanced superconductivity and discovering emergent
quantum phases in polar
oxide heterostructures, explicitly suggesting that similar materials-tuning strategies (e.g., epitaxial strain) could be exploited to enhance superconductivity in
quantum paraelectric systems.
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Superconductivity
Cuprate Twistronics for Quantum Hardware
Tommaso Confalone, Flavia Lo Sardo, Yejin Lee et al. (+12 more)
Recent advances in the manipulation of complex
oxide layers, particularly the fabrication of atomically thin cuprate superconducting films via molecular beam epitaxy, have revealed new ways in which nanoscale engineering can govern superconductivity and its interwoven electronic orders. In parallel, the creation of twisted cuprate
heterostructures through cryogenic stacking techniques marks a pivotal step forward, exploiting cuprate
superconductors to deepen our understanding of exotic
quantum states and propel next-generation
quantum technologies. This review explores over three decades of research in the emerging field of cuprate twistronics, examining both experimental breakthroughs and theoretical progress. It also highlights the methodologies poised to surmount the outstanding challenges in leveraging these complex
quantum materials, underscoring their potential to expand the frontiers of
quantum science and technology.
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All authors Tommaso Confalone, Flavia Lo Sardo, Yejin Lee, Sanaz Shokri, Giuseppe Serpico, Alessandro Coppo, Valerii M. Vinokur, Luca Chirolli, Valentina Brosco, Uri Vool, Domenico Montemurro, Francesco Tafuri, Golam Haider, Kornelius Nielsch, Nicola Poccia