Showing 1–50 of 1,600 results for author: Zhang, Z

Structural complexity of an SU(3) Fermi Hubbard model

Authors: Jiani Fu, Zewen Zhang, Eduardo Ibarra-García-Padilla

Abstract: Two-dimensional quantum gas microscopy provides an unparalleled tool to study quantum many-body systems using ultracold atoms. For the SU(2) Fermi Hubbard model (FHM), access to spin-resolved projective measurements has been vital for quantifying correlation functions and mapping out the phase diagram. Recent progress in quantum gas microscopy for experiments with ultracold alkaline-earth atoms, w… ▽ More Two-dimensional quantum gas microscopy provides an unparalleled tool to study quantum many-body systems using ultracold atoms. For the SU(2) Fermi Hubbard model (FHM), access to spin-resolved projective measurements has been vital for quantifying correlation functions and mapping out the phase diagram. Recent progress in quantum gas microscopy for experiments with ultracold alkaline-earth atoms, which are well described by the SU(N) FHM and are predicted to host exotic ground-state phases, calls for the development of theory-free numerical techniques to extract physical information from their projective measurements. To that end, we evaluate the multiscale structural complexity of snapshots of an SU(3) FHM in the square lattice at $1/3$-filling. We employ mean-field theory to generate spin-resolved density distributions and compute their structural complexity using rectangular coarse-graining windows. We demonstrate that these complexities are linked to relevant physical observables such as the entanglement entropy, and are extremely sensitive for locating phase boundaries. The results presented here validate the structural complexity as an efficient and reliable tool for analyzing the outputs of SU(N) quantum gas microscopes, offering a theory-free property, immediately accessible to experiments. △ Less

Submitted 20 August, 2026; originally announced August 2026.

Comments: 12 pages, 8 figures

Writing and erasing skyrmions by single ultrafast laser pulses in monolayer Janus 2D magnets

Authors: Guangyao Miao, Yonglong Ga, Chang Liu, Pan Chen, Yichen Jin, Florian Kronast, Wenxin Cheng, Zhaoqing Ding, Kai Hu, Zongnan Zhang, Nikolai Severin, Chenxi Meng, Patil Shubhada, Sergio Valencia, Meng Meng, Qinlin Guo, Xiaoran Liu, Jiandi Zhang, Yangmu Li, Carlos-Andres Palma, Jürgen P. Rabe, Hongxin Yang, Weihua Wang, Jiandong Guo

Abstract: Skyrmions in 2D magnets are promising candidates for nonvolatile, low-power, and high-density spintronic memories. However, their experimental realization at the 2D limit remains challenging, owing to the difficulty in engineering the required chiral magnetic interactions. Here, we report the creation and direct imaging of Néel-type skyrmions in Janus 2D chromium chalcogenides using synchrotron X-… ▽ More Skyrmions in 2D magnets are promising candidates for nonvolatile, low-power, and high-density spintronic memories. However, their experimental realization at the 2D limit remains challenging, owing to the difficulty in engineering the required chiral magnetic interactions. Here, we report the creation and direct imaging of Néel-type skyrmions in Janus 2D chromium chalcogenides using synchrotron X-ray photoemission electron microscopy, and scanning nitrogen-vacancy magnetometry, which exhibit field-free stability, nonvolatility, and size tunability. First-principles calculations and micromagnetic simulations reveal that Janus-surface-induced inversion-symmetry breaking enhances the Dzyaloshinskii-Moriya interaction, providing the microscopic mechanism for skyrmion stabilization and tunability. We further achieve reversible skyrmion writing and erasing using a single ultrafast laser pulse in a magnetic field as low as 300 Oe, demonstrating the excellent manipulability of this 2D magnetic system. These results establish Janus engineering as a route to creating and manipulating nonvolatile skyrmions in atomically thin magnets, with implications for skyrmion-based low-power spintronic devices. △ Less

Submitted 18 August, 2026; originally announced August 2026.

Breaking the mutual exclusivity between metallicity and ferroelectricity in a non-polar covalent semiconductor via orbital selective doping

Authors: Hui Li, Yunfan Yang, Junquan Huang, Yukun Feng, Guobin Wang, Qinci Wu, Jun Deng, Zhaolong Liu, Subi Du, Dongliang Gong, Zaihui Shen, Anmin Nie, Yang Xu, Junwei Yang, Zesheng Zhang, Huaping Song, Jiangang Guo, Wenjun Wang, Hailin Peng, Yongjun Tian, Xiaolong Chen

Abstract: The mutual exclusion of ferroelectricity and metallic conductivity is a long-standing tenet because itinerant electrons screen long-range Coulomb forces that stabilize the bulk polar order. Here, we break this paradigm by heavily doping a non-polar covalent semiconductor of cubic silicon carbide (3C-SiC) with nitrogen. This introduces heavy electron doping, inducing metallicity and driving a struc… ▽ More The mutual exclusion of ferroelectricity and metallic conductivity is a long-standing tenet because itinerant electrons screen long-range Coulomb forces that stabilize the bulk polar order. Here, we break this paradigm by heavily doping a non-polar covalent semiconductor of cubic silicon carbide (3C-SiC) with nitrogen. This introduces heavy electron doping, inducing metallicity and driving a structural transition from the non-polar F-43m to the polar R3m symmetry via the pseudo-Jahn-Teller effect. Remarkably, we provide direct, atomic-scale visualization of about 180° polarization reversal under an external voltage bias in a ferroelectric metal. The strongly directional character of antibonding orbitals occupied by conduction electrons prevents them from screening the local Si-C polarization, resulting in the coexistence of metallicity and ferroelectricity. Ferroelectric tunnel junctions demonstrate nonvolatile memory properties with a well-defined high-resistance state (HRS) and low-resistance state (LRS), an ultrahigh response speed (~50 ns), an ultralow operating voltage (1 V), an endurance exceeding 85927 cycles, and a projected retention time of 100 years. Our results provide a novel strategy for pioneering ferroelectricity in a metal, a new ferroelectric metal platform for exploring exotic properties, and a ferroelectric device with high performance that meets the requirements for low consumption and high-speed non-volatile devices. △ Less

Submitted 18 August, 2026; originally announced August 2026.

Scalable dynamical inference of phase-field fracture from sparse and partial measurements

Authors: Hanfeng Zhai, Zisheng Zhang

Abstract: Evolving crack fields in structural health monitoring and fracture assessment must often be inferred from sparse mechanical measurements rather than dense full-field observations. We develop CNN2D--ConvGRU, a convolutional-recurrent framework for measurement-conditioned reconstruction of time-dependent phase-field brittle fracture. At each load step, the model maps a fixed-length history of phase… ▽ More Evolving crack fields in structural health monitoring and fracture assessment must often be inferred from sparse mechanical measurements rather than dense full-field observations. We develop CNN2D--ConvGRU, a convolutional-recurrent framework for measurement-conditioned reconstruction of time-dependent phase-field brittle fracture. At each load step, the model maps a fixed-length history of phase and displacement fields and sparse current-step displacement measurements to the current full-field state. New measurements are assimilated during sequential deployment, making the framework a state-inference surrogate rather than an autonomous time integrator. It reproduces crack paths, damage evolution, and bulk displacement response, with the largest errors near propagating crack tips and steep displacement gradients and some drift at late stages. Without retraining, weights learned on a $256 \times 256$ raster are evaluated on a $512 \times 512$ raster of the same physical domain and finite-element discretization using a proportionally refined measurement grid. This empirical raster-and-sensing transfer preserves the principal damage topology and global damage evolution, although fine-scale displacement errors increase near crack tips. Comparisons with alternative spatial and temporal architectures show that CNN2D--ConvGRU offers a favorable balance between reconstruction accuracy and computational cost. Relative to repeated finite-element solutions, sequential reconstruction achieves mean speedups of $175\times$ on CPU and $253\times$ on GPU. These results demonstrate efficient full-field fracture-state reconstruction from sparse observations while retaining the spatial structure and history dependence of phase-field fracture. △ Less

Submitted 15 August, 2026; originally announced August 2026.

Comments: 20 pages, 13 figures

Emergent trans-moiré orbitals and topology in rhombohedral graphene

Authors: Yuqin Wang, Jian Xie, Yi-Jie Wang, Jiajun Zhang, Yiting Gao, Zaizhe Zhang, Da Yi, Yan Xie, Jingjing Shi, Guanqin Zhao, Chengyu Xiong, Kenji Watanabe, Takashi Taniguchi, Zhi-Da Song, Xiaobo Lu, Yi Chen

Abstract: The fractional quantum anomalous Hall effect (FQAHE) exhibited in fractional Chern insulators has recently been demonstrated in twisted MoTe2 and rhombohedral graphene/hBN moiré superlattices, promising new routes toward topological quantum computation. Central to realizing this promise is the understanding of the underlying microscopic mechanism. This, however, remains elusive in the case of rhom… ▽ More The fractional quantum anomalous Hall effect (FQAHE) exhibited in fractional Chern insulators has recently been demonstrated in twisted MoTe2 and rhombohedral graphene/hBN moiré superlattices, promising new routes toward topological quantum computation. Central to realizing this promise is the understanding of the underlying microscopic mechanism. This, however, remains elusive in the case of rhombohedral graphene, with the crux being its two seemingly paradoxical conditions: a pronounced small-twist-angle (θ) moiré interface, yet only when electrons are kept distant from it. Here, by scanning tunnelling microscopic imaging with both conditions fulfilled, we capture dramatic electronic structure reshaping in rhombohedral hexalayer graphene by unforeseen 'trans-moiré orbitals', which emerge on the other, distant side of the moiré interface but nevertheless enforce the moiré periodicity at all measured fillings. We visualize a hierarchy of spatially and energetically distinct trans-moiré orbitals which doped electrons must sequentially occupy--the lowest-energy orbital, expectedly responsible for the FQAHE at small fillings, carries a hollow-cage-like shape. Remarkably, these trans-moiré orbitals vanish at θ {\gtrsim} 1°, and so do QAHE plateaus in similar devices. Simulations reveal an interaction-driven charge-redistribution mechanism which shapes the trans-moiré orbitals and corresponding Chern minibands. With our findings providing the missing microscopic link, the paradoxical conditions find a natural explanation: electrons are not simply kept distant from a small-θ moiré interface; they are forced into topological trans-moiré orbitals, forged precisely under such conditions. Our microscopic diagnostics unlocks a wide range of possible 'synthetic' FQAHE platforms. △ Less

Submitted 19 August, 2026; v1 submitted 12 August, 2026; originally announced August 2026.

Strain-controlled sign reversal of the anomalous Hall effect in Ru/[Co/Ni]$_N$ multilayers

Authors: Jingying Zhang, Sigang Wang, Yue Xiang, Wenhui Xie, Zhe Yuan, Yi Liu, Zongzhi Zhang

Abstract: The anomalous Hall effect (AHE) is a hallmark transport phenomenon in ferromagnets arising from relativistic spin-orbit interaction. Here, we report an unexpected sign reversal of the AHE in Ru/[Co/Ni]$_N$ multilayers controlled by the stacking sequence of the Ru layer. When Ru is placed beneath, rather than atop, the Co/Ni multilayers, the anomalous Hall signal switches from positive to negative.… ▽ More The anomalous Hall effect (AHE) is a hallmark transport phenomenon in ferromagnets arising from relativistic spin-orbit interaction. Here, we report an unexpected sign reversal of the AHE in Ru/[Co/Ni]$_N$ multilayers controlled by the stacking sequence of the Ru layer. When Ru is placed beneath, rather than atop, the Co/Ni multilayers, the anomalous Hall signal switches from positive to negative. By systematically varying the multilayer repeat number N and combining transport measurements with first-principles calculations, we show that this reversal originates from in-plane tensile strain imposed by the Ru underlayer, which reshapes the electronic structure and redistributes Berry curvature near the Fermi level. Our findings establish interfacial strain as an effective knob for tuning Berry-curvature-driven transport and suggest a pathway toward strain-controlled topological transport phenomena in magnetic multilayers. △ Less

Submitted 12 August, 2026; originally announced August 2026.

Fluctuation-based evidence for number--phase dynamics in a frustrated orbital superfluid

Authors: Rui-Lang Zeng, Zi-Yao Zhang, Ling-Na Wu, Cong-Jie Zhang, Da-Gang Xia, Andreas Hemmerich, Xiao-Qiong Wang, Zhi-Fang Xu

Abstract: Frustrated quantum matter can host intertwined orders rooted in symmetry-related low-energy landscapes, yet static order parameters alone do not reveal how fluctuations are organized among competing configurations. Here we measure mode-resolved shot-to-shot population fluctuations in a $p$-orbital triangular-lattice superfluid with a tunable bias among three valleys. We observe a bias-tuned evolut… ▽ More Frustrated quantum matter can host intertwined orders rooted in symmetry-related low-energy landscapes, yet static order parameters alone do not reveal how fluctuations are organized among competing configurations. Here we measure mode-resolved shot-to-shot population fluctuations in a $p$-orbital triangular-lattice superfluid with a tunable bias among three valleys. We observe a bias-tuned evolution from enhanced, anticorrelated fluctuations of two minority valleys toward strong confinement of relative-population fluctuations in a selected two-valley stripe phase. The dominant fluctuation structure is captured by an effective canonical model that includes interactions among the condensed modes, supporting a quasi-equilibrium description of the coherent three-valley condensate. Together, the data and model reveal a quantum--thermal regime shaped by pair-tunneling-induced number--phase dynamics, in which relative-phase scrambling softens effective barriers in the minority-valley regime, while phase rigidity gives rise to macroscopic harmonic confinement in the stripe phase. Our results establish mode-resolved fluctuation measurements as a probe of hidden number--phase back-action in frustrated quantum fluids. △ Less

Submitted 8 August, 2026; originally announced August 2026.

Comments: 6+11 pages, 4 figures

Generalized Space Groups from Internal Configuration Spaces

Authors: Zeying Zhang, Zhenye Li, Zhi-Ming Yu, Gui-Bin Liu, Yugui Yao

Abstract: We develop a unified construction of generalized space groups for crystals with unconventional internal degrees of freedom. Starting from the full group $G_P$ of allowed internal transformations and the stabilizer $P$ of a reference object, we determine the pointwise and setwise symmetries, $J$ and $K$, of the allowed configuration set. Goursat's lemma then couples the internal quotient $K/J$ to a… ▽ More We develop a unified construction of generalized space groups for crystals with unconventional internal degrees of freedom. Starting from the full group $G_P$ of allowed internal transformations and the stabilizer $P$ of a reference object, we determine the pointwise and setwise symmetries, $J$ and $K$, of the allowed configuration set. Goursat's lemma then couples the internal quotient $K/J$ to a spatial quotient. The framework includes ordinary, magnetic, spin, and color space groups as special cases. As an example, we consider a dodecahedral object with $P=I\simeq A_5$, for which we obtain the nontrivial pair $T\triangleleft O$ with $O/T\simeq\mathbb Z_2$. The resulting generalized space group hosts a point node with topological charge $|C|=12$. △ Less

Submitted 5 August, 2026; v1 submitted 4 August, 2026; originally announced August 2026.

Comments: 6 pages, 2 figures

Gallium phosphide on insulator for nanophotonics and quantum technologies

Authors: Tobias Bucher, Otto Arnold, Muyi Yang, Zifei Zhang, Katsuya Tanaka, Annkathrin Köhler, Berit Marx-Glowna, Duk-Yong Choi, Isabelle Staude, Carsten Ronning

Abstract: Gallium phosphide is a promising material platform for visible and near-infrared photonics and quantum technologies owing to its high refractive index, low optical absorption, and strong second-order nonlinearity. Here, we demonstrate the fabrication of GaP-on-insulator substrates by ion slicing. The splitting depth and exfoliation behavior of bulk GaP are tailored by controlling the He$^{+}$ ion… ▽ More Gallium phosphide is a promising material platform for visible and near-infrared photonics and quantum technologies owing to its high refractive index, low optical absorption, and strong second-order nonlinearity. Here, we demonstrate the fabrication of GaP-on-insulator substrates by ion slicing. The splitting depth and exfoliation behavior of bulk GaP are tailored by controlling the He$^{+}$ ion implantation energy and fluence, enabling thin-film transfer onto amorphous substrates by anodic bonding and plasma-enhanced direct wafer bonding. Channeling Rutherford backscattering spectrometry and X-ray diffraction confirm that the transferred layers retain their single-crystalline structure, while implantation-induced disorder and optical absorption are substantially reduced by annealing at 500 °C and subsequent polishing. The annealed films exhibit linear optical properties approaching those of bulk GaP. In addition, a (110)-oriented GaP thin film shows the characteristic polarization dependence expected from the zinc-blende second-order nonlinear susceptibility tensor, demonstrating a near-pristine second-order nonlinear response. This flexible fabrication approach enables the integration of high-quality single-crystalline GaP with variable orientation for free-space and integrated nanophotonics as well as nonlinear and quantum optical devices. △ Less

Submitted 3 August, 2026; originally announced August 2026.

Comments: 12 pages, 3 figures

Inhomogeneous Ising Model on 2D kagomé Lattice: Fermionic field approach

Authors: Shahane A. Khachatryan, Zhidong Zhang, Ara G. Sedrakyan

Abstract: We investigate the two-dimensional inhomogeneous Ising model (2DIM) on the kagom'e lattice by mapping it onto a particular non-symmetric eight-vertex model and constructing the corresponding $R$-matrix. Using a fermionic representation, we evaluate the partition function and derive explicit expressions for the main thermodynamic quantities. In the thermodynamic limit, we obtain an exact equation f… ▽ More We investigate the two-dimensional inhomogeneous Ising model (2DIM) on the kagom'e lattice by mapping it onto a particular non-symmetric eight-vertex model and constructing the corresponding $R$-matrix. Using a fermionic representation, we evaluate the partition function and derive explicit expressions for the main thermodynamic quantities. In the thermodynamic limit, we obtain an exact equation for the critical surface determining the phase transition of the model. We also calculate the free energy, specific heat, and spontaneous magnetization in the ferromagnetic case. Furthermore, we show that when one or two coupling constants vanish, the model reduces, respectively, to the square-lattice and one-dimensional Ising models. In both limits, our results reproduce the corresponding exact critical couplings and free energies. △ Less

Submitted 3 August, 2026; originally announced August 2026.

Comments: 31 pages, 4 figures

Bulk Ising superconductivity in an intercalated TaSe2 bilayer structure

Authors: Yupeng Li, Zhaopeng Guo, Lihong Hu, Guoan Li, Siqi Wu, Xinyi Zheng, Xiao Deng, Zhiyuan Zhang, Anqi Wang, Xingchen Guo, Ziwei Dou, Peiling Li, Yuke Li, Fanming Qu, Guangtong Liu, Jin-Ke Bao, Guang-Han Cao, Li Lu, Jie Shen, Zhu-An Xu

Abstract: Ising spin-orbit coupling in bulk systems has drawn considerable interest for its ability to conveniently construct spin-orbit environments and enable exotic quantum phenomena. In this work, we synthesize intercalated 2Hb-TaSe$_2$ bilayers with noncentrosymmetric structure and, through multifaceted analysis, present multiple lines of evidence for the emergence of bulk Ising superconductivity. Resi… ▽ More Ising spin-orbit coupling in bulk systems has drawn considerable interest for its ability to conveniently construct spin-orbit environments and enable exotic quantum phenomena. In this work, we synthesize intercalated 2Hb-TaSe$_2$ bilayers with noncentrosymmetric structure and, through multifaceted analysis, present multiple lines of evidence for the emergence of bulk Ising superconductivity. Resistivity measurements reveal anisotropic superconducting behavior, with a remarkably large in-plane upper critical field $B_{c2}^{\|}$ that exceeds the Pauli limit $B_{p}$. Band structure calculations further show band splitting accompanied by out-of-plane spin polarization. Collectively, these observations point to the presence of Ising superconductivity. Additional measurements of the thickness-dependent ratio $B_{c2}^{\|}$/$B_{p}$ and the superconducting diode effect not only further support the Ising superconducting nature of this material, but also reveal additional features of bulk Ising superconductivity evolving with thickness. Our findings provide valuable insights that may contribute to the search for bulk Ising superconductors. △ Less

Submitted 2 August, 2026; originally announced August 2026.

Comments: 8 pages, 4 figures

Anisotropic Spin Polarization and magnetic spin hall effect in Ferromagnets

Authors: Jiabin Wang, Zhenhua Zhang, Wancheng Zhang, Jianxiong Zhao, Yong Liu, Rui Xiong, Zhihong Lu

Abstract: Spin-dependent transport in ferromagnets underpins the development of high-density spintronic memories. Spin-dependent transport in strong spin-orbit-coupled ferromagnets exhibits a significant anisotropy. Both the overall spin polarization during charge transport and the magnetic spin Hall conductivity are found to exhibit pronounced anisotropy when the magnetization is tilted away from the cryst… ▽ More Spin-dependent transport in ferromagnets underpins the development of high-density spintronic memories. Spin-dependent transport in strong spin-orbit-coupled ferromagnets exhibits a significant anisotropy. Both the overall spin polarization during charge transport and the magnetic spin Hall conductivity are found to exhibit pronounced anisotropy when the magnetization is tilted away from the crystallographic easy axis or when the electric field is rotated relative to the crystal axes. These anisotropic responses originate primarily from spin-orbit coupling, which is identified as the key driver of the large anisotropy observed in ferromagnet. Furthermore, strain tunability of the magnetic spin Hall anisotropy is demonstrated, with tensile strain progressively enhancing the oscillatory amplitude of the spin Hall conductivity. These findings establish strong spin-orbit-coupled ferromagnets as a platform for anisotropic spin-current generation and field-free spintronic devices that exploit intrinsic material anisotropy for improved performance and energy efficiency. △ Less

Submitted 29 July, 2026; originally announced July 2026.

Gauge Auxiliary-Field Quantum Monte Carlo Method for Many-Fermion Systems

Authors: Zhaozhan Zhang

Abstract: We propose novel Quantum Monte Carlo (QMC) methods for interacting many-fermion systems by leveraging the stochastic gauge freedom, originally developed in Gaussian phase-space QMC, within the phaseless auxiliary-field QMC (AFQMC) framework. In particular, we reinterpret the conventional force bias in phaseless AFQMC as a drift gauge and explore Fermi gauges based on natural orbitals of a reduced… ▽ More We propose novel Quantum Monte Carlo (QMC) methods for interacting many-fermion systems by leveraging the stochastic gauge freedom, originally developed in Gaussian phase-space QMC, within the phaseless auxiliary-field QMC (AFQMC) framework. In particular, we reinterpret the conventional force bias in phaseless AFQMC as a drift gauge and explore Fermi gauges based on natural orbitals of a reduced one-body density matrix defined via a mixed estimator, yielding stochastic, time-dependent Hartree-Fock-like dynamics. We propose a symmetry-projection sampling scheme to enhance the sampling efficiency. As a proof of concept, we apply these gauge-augmented AFQMC methods to a simple shell-model Hamiltonian: the Lipkin-Meshkov-Glick model. Numerical results illustrate the potential of stochastic gauges to enhance accuracy and reduce fluctuations, underscoring the promise for advancing these new techniques toward more realistic shell-model applications. △ Less

Submitted 23 July, 2026; originally announced July 2026.

Comments: 8 pages, 4 figures

Adverse Selection with Quality Variance: A Maximum-Entropy Approach

Authors: Zhi-Lei Zhang, Tan-Ji Zhou, C. P. Sun

Abstract: The adverse-selection mechanism in markets explains how asymmetric information between buyers and sellers can drive high-quality goods out of the market, thereby causing market deterioration. In its simplest formulation, only the mean quality is used to describe the market, and this is insufficient to determine how fast the market deteriorates or how the quality distribution evolves. To resolve th… ▽ More The adverse-selection mechanism in markets explains how asymmetric information between buyers and sellers can drive high-quality goods out of the market, thereby causing market deterioration. In its simplest formulation, only the mean quality is used to describe the market, and this is insufficient to determine how fast the market deteriorates or how the quality distribution evolves. To resolve the two problems, we describe the adverse selection as a dynamic truncation of the quality distribution: buyers set an upper bound proportional to the mean quality by a rate $ξ$ that is larger than unity, and sellers whose quality exceeds this upper bound reject an offer and exit the market. The retained market is then characterized by the conditional distribution obtained after this truncation, and the corresponding evolution process is iterated until market quality reaches a stable state. This statistical approach gives three results. (i) We identify a mechanism for preventing complete adverse selection, defined as the process where the quality of the market is driven down to the minimum quality floor. (ii) A larger quality variance or a smaller price premium, defined as the amount by which the payment upper bound exceeds the current mean quality, raises the upper bound on the deterioration in mean quality. (iii) A maximum-entropy benchmark shows numerically how quality variance and the payment rate jointly determine market deterioration and the final stable quality platform. This approach also clarifies how market interventions can slow adverse selection: they may raise buyers' payment rate, reduce quality variance, or increase the minimum quality floor. △ Less

Submitted 19 July, 2026; originally announced July 2026.

Quantum-classical crossover in fault-tolerant quantum dynamics simulation

Authors: Jinzhao Sun, Bozhen Zhou, Jue Xu, Yuan Yao, Zhenyu Du, Zixu Zhang, Yuntian Gu, Junxiang Huang, Shuo Zhou, Ziruo Wang, Alexander Yosifov, Wenzheng Dong, Yiming Huang, Daniel Serrano, Xinzhao Wang, Tianfeng Feng, Shreyas Sadugol, Wenjun Yu, Zhou You, Dayue Qin, Xiao-Ming Zhang, Yantao Wu, Aditya Iyer, You Zhou, Tongyang Li , et al. (6 additional authors not shown)

Abstract: While quantum computers promise to solve classically intractable problems, identifying the point at which fault-tolerant quantum computation outperforms the best classical algorithms for practical applications remains an outstanding challenge. Here we establish a concrete quantum-classical crossover for quantum many-body dynamics under realistic hardware conditions. We introduce a scalable fault-t… ▽ More While quantum computers promise to solve classically intractable problems, identifying the point at which fault-tolerant quantum computation outperforms the best classical algorithms for practical applications remains an outstanding challenge. Here we establish a concrete quantum-classical crossover for quantum many-body dynamics under realistic hardware conditions. We introduce a scalable fault-tolerant framework that combines coherent observable estimation with a space-time-efficient implementation of non-Clifford rotations, suppressing the residual logical errors that limit existing partially fault-tolerant approaches. A benchmark against state-of-the-art tensor-network and variational Monte Carlo algorithms reveals a concrete crossover for mixed-field Ising dynamics at modest system sizes. For a physical error rate of $p=10^{-3}$, fault-tolerant simulation requires approximately 2 hours and $3.7 \times 10^5$ physical qubits for a 100-site 1D system, whereas tensor network approaches would require about 100 years. For 2D models, where rapid entanglement growth limits the classical evolution time, we project quantum runtimes within minutes. A physical error rate of $p=10^{-4}$ leads to at least an order of magnitude reduction in qubit count ($3.1 \times 10^4$ physical qubits) and runtime (minutes for 1D and seconds for 2D). The reduction in quantum runtime arises from our improved rotation-state injection and co-design of quantum error correction and observable-estimation protocols, which jointly suppress logical-error accumulation and reduce sampling overhead. Our results establish a scalable route towards practical quantum advantage and identify quantitative engineering targets for future fault-tolerant architectures. △ Less

Submitted 17 July, 2026; originally announced July 2026.

Comments: 45 pages, 25 figures, 7 tables

A cryogenic neutral-atom platform with full optical access and 2-hour trap lifetime

Authors: Akhil Kumar, Lorenzo Festa, Avishay Grinberg, Eran Reches, Dimitrios Tsevas, Kevin P. Mours, Zhao Zhang, Robin Eberhard, Sebastian Blatt, Andrea Alberti, Johannes Zeiher, Immanuel Bloch, Max Melchner

Abstract: Neutral-atom quantum processors are rapidly scaling toward system sizes of more than ten thousand qubits, allowing for the realization of a new class of quantum computing algorithms and quantum simulation experiments. However, current neutral-atom platforms generally have to find a compromise between the optical accessibility and the storage time of atoms in optical potentials, limiting the availa… ▽ More Neutral-atom quantum processors are rapidly scaling toward system sizes of more than ten thousand qubits, allowing for the realization of a new class of quantum computing algorithms and quantum simulation experiments. However, current neutral-atom platforms generally have to find a compromise between the optical accessibility and the storage time of atoms in optical potentials, limiting the available qubit numbers. Here we report on the operation of a novel, cryogenically enhanced, neutral-atom apparatus that overcomes these apparently conflicting requirements. We demonstrate vacuum-limited trapping lifetimes of up to two hours of single $^{88}\mathrm{Sr}$ atoms in an optical tweezer array while preserving full optical access and without the need for complex cryogenic enclosures. Our measurements show that exceptionally long single-atom lifetimes can be achieved with a relatively simple cryostat design. Our architecture can be straightforwardly ported to other atomic species and shows a viable path for scaling up to sorted arrays of tens of thousands of atoms. △ Less

Submitted 14 July, 2026; originally announced July 2026.

Tellurium sublattice instability driven amorphization in the chalcogenide AgSbTe2 under pressure

Authors: Baihong Sun, Zihan Zhang, Wei Luo, Sergei Grazhdannikov, Wenting Lu, Shiyu Feng, Haikai Zou, Chenxin Wei, Martin Kunz, Hirokazu Kadobayashi, Bihang Wang, Azkar Saeed Ahmad, Yaron Amouyal, Rajeev Ahuja, Elissaios Stavrou

Abstract: Pressure provides a powerful thermodynamic route to access hidden structural states in functional materials, yet the microscopic origin of pressure-induced amorphization remains elusive in many complex chalcogenides. Here we report a detailed high-pressure structural study of AgSbTe2,combining synchrotron X-ray diffraction with density functional theory and molecular dynamics calculations up to 60… ▽ More Pressure provides a powerful thermodynamic route to access hidden structural states in functional materials, yet the microscopic origin of pressure-induced amorphization remains elusive in many complex chalcogenides. Here we report a detailed high-pressure structural study of AgSbTe2,combining synchrotron X-ray diffraction with density functional theory and molecular dynamics calculations up to 60 GPa. We uncover a pressure-driven transformation from the ambient R-3m phase to a fully disordered cubic Im3m phase, through an extended intermediate amorphous state. Enthalpy calculations reveal a near-degeneracy between the R3m and Im3m structures over a broad pressure range, dictating amorphization. Contrary to previously speculated cation vacancies, the amorphization is governed by a pronounced displacement instability of the Te sublattice. Remarkably, the time dependent decompression pathway controls the final structural state, resulting in either amorphous (slow decompression) or fully crystalline (fast decompression) states, indicative of a strong counterintuitive kinetic effect. △ Less

Submitted 5 July, 2026; originally announced July 2026.

Comments: 9 pages, 8 figures

One-dimensional carbon nanostructures with periodic graphitic nitrogen substitution

Authors: Nicolò Bassi, Shantanu Mishra, Zheng Zhang, Xiao-Ye Wang, Feifei Xiang, Nils Krane, Carlo A. Pignedoli, Klaus Müllen, Pascal Ruffieux, Akimitsu Narita, Roman Fasel

Abstract: Heteroatom substitution is a powerful route to tune the chemical and electronic properties of carbon nanomaterials. In particular, replacement of an sp2 hybridized carbon atom in the graphene lattice with a nitrogen atom (denoted as graphitic nitrogen) induces substantial changes in the electronic properties. These include changes in the band structure that can influence electronic transport, and… ▽ More Heteroatom substitution is a powerful route to tune the chemical and electronic properties of carbon nanomaterials. In particular, replacement of an sp2 hybridized carbon atom in the graphene lattice with a nitrogen atom (denoted as graphitic nitrogen) induces substantial changes in the electronic properties. These include changes in the band structure that can influence electronic transport, and magnetism. A key requirement for applications is both the periodic and precise incorporation of the heteroatoms in extended carbon lattices. Here, we report the on-surface synthesis and characterization of two one dimensional carbon nanostructures, a polymer and a graphene nanoribbon, consisting of periodically incorporated graphitic nitrogen atoms. The on-surface reactions toward formation of the nanostructures were monitored by scanning tunneling microscopy. The bond-resolved chemical structures of the reaction intermediates and products were investigated by atomic force microscopy, which enabled atomic-scale visualization of the graphitic nitrogen sites. The electronic properties of the nanostructures were studied by scanning tunneling spectroscopy and density functional theory calculations. Our analyses revealed the presence of localized nitrogen-centered electronic states. In the gas phase where the nanostructures are in a neutral charge state, these states undergo spin polarization leading to an open-shell ground state. Upon adsorption on Au(111), the nanostructures exhibit electron transfer to the surface, which resulted in a closed-shell ground state. Our results demonstrate a straightforward and generally applicable route to synthesize graphitic nitrogen-substituted carbon nanomaterials with potential applications in spintronics, catalysis and energy storage. △ Less

Submitted 3 July, 2026; originally announced July 2026.

Comments: Manuscript: 24 pages and 4 figures; Supporting Information: 19 pages and 18 figures

In-Situ Polarimetry in Collimated Magneto-Infrared Spectroscopy System

Authors: Zeping Shi, Wenbin Wu, Zhiwei Zhang, Yuhan Du, Chenyao Xu, Congming Hao, Xiangyu Jiang, Xin Chen, Guangyi Wang, Mingsen Zhou, Chunhui Pan, Wei Lu, Hao Shen, Haifeng Pan, Zhenrong Sun, Junhao Chu, Xiang Yuan

Abstract: Magneto-infrared spectroscopy under strong magnetic fields provides a powerful probe of Landau quantization and field-induced collective excitations, yet its full potential has long been constrained by the lack of in-situ polarization control, because the highly divergent infrared beam propagating through narrow light tubes undergoes multiple wall reflections, leading to severe polarization degrad… ▽ More Magneto-infrared spectroscopy under strong magnetic fields provides a powerful probe of Landau quantization and field-induced collective excitations, yet its full potential has long been constrained by the lack of in-situ polarization control, because the highly divergent infrared beam propagating through narrow light tubes undergoes multiple wall reflections, leading to severe polarization degradation. Here we report a collimated magneto-infrared spectroscopy system that integrates continuous in-situ polarimetry. The system employs incident and exit collimation chambers forming a Kepler type optical architecture, which converts the large-aperture FTIR output into a low-divergence beam and strongly suppresses multi-reflection trajectories inside long gold-plated light tubes, thereby enhancing both optical throughput and polarization fidelity. A remotely controlled polarization module, consisting of an automated linear polarizer and a switchable Fresnel rhomb positioned entirely outside the high-field region, enables continuous in-situ tuning between linear, circular, and arbitrary elliptical polarization states without thermal cycling, manual realignment, or breaking vacuum. Interchangeable compact focusing modules further support Faraday and Voigt geometries in both transmission and reflection experiments within a 50 mm magnet bore, providing efficient beam focusing and signal collection while maintaining polarization fidelity. The setup achieves a minimum root-mean-square noise of 0.0033%, an average noise of 0.0082%, and a linear polarization extinction ratio up to 40:1. We demonstrate the capability through continuous in-situ linear polarimetry and broadband circular polarimetry in the magneto-infrared spectroscopy of various single crystals. This platform establishes a robust experimental framework for in-situ polarization-resolved magneto-infrared spectroscopy. △ Less

Submitted 1 July, 2026; originally announced July 2026.

Journal ref: Advanced Science Instruments,1(1),100005.(2026)

Ultrafast non-thermal suppression of ferroelectricity by carrier screening in LiNbO3

Authors: Man Tou Wong, Zhuquan Zhang, Zi-Jie Liu, Keith A. Nelson

Abstract: Ferroelectric materials are key to energy-efficient electronics, memory, and optical applications. While charge carriers typically screen and suppress ferroelectricity, their role under nonequilibrium conditions remains elusive. Here, we use femtosecond laser pulses to liberate trapped carriers in LiNbO3 and track the response using time-resolved second-harmonic generation and stimulated Raman sca… ▽ More Ferroelectric materials are key to energy-efficient electronics, memory, and optical applications. While charge carriers typically screen and suppress ferroelectricity, their role under nonequilibrium conditions remains elusive. Here, we use femtosecond laser pulses to liberate trapped carriers in LiNbO3 and track the response using time-resolved second-harmonic generation and stimulated Raman scattering. Even dilute photoexcited carriers induce a rapid yet enduring suppression of polarization and Raman susceptibility. Fluence- and temperature-dependent analyses confirm the suppression is non-thermal and arises from transient carrier screening. These findings reveal an efficient, reversible, and symmetry-preserving mechanism to modulate ferroelectricity on ultrafast timescales, offering a new route to control ferroic and competing quantum phases. △ Less

Submitted 25 June, 2026; originally announced June 2026.

Interfacial-melt stability as a thermodynamic prerequisite for solid-state synthesis

Authors: Zihan Zhang, Mengyi Chen, Qianxiao Li, Peichen Zhong

Abstract: Computational materials discovery commonly ranks candidate materials by their thermodynamic stability on the formation energy convex hull, yet many predicted-stable phases resist synthesis. We propose that solid-state synthesizability through interfacial-melt-mediated routes requires an additional thermodynamic condition: the interfacial melt at the target composition must itself remain locally st… ▽ More Computational materials discovery commonly ranks candidate materials by their thermodynamic stability on the formation energy convex hull, yet many predicted-stable phases resist synthesis. We propose that solid-state synthesizability through interfacial-melt-mediated routes requires an additional thermodynamic condition: the interfacial melt at the target composition must itself remain locally stable against spinodal decomposition. We demonstrate this in the classical Fe--B system, where thermodynamically stable FeB$_4$ has been reported under high-pressure synthesis but not in low-pressure synthesis attempts. Using melt--quench molecular dynamics driven by a fine-tuned machine-learning interatomic potential, we find that, at ambient pressure, the B-rich interfacial melt near the FeB$_4$ composition develops a concave free-energy landscape, signaling a demixing instability that is corroborated by the concentration--concentration structure factor and correlated with low-energy icosahedral and pentagonal-pyramidal boron motifs. Applied pressure introduces a convex $PV$ contribution that restores melt stability, consistent with the experimental synthesis boundary. Interfacial-melt stability, which atomistic simulations can assess via structure-factor divergence, is thus proposed as a practical thermodynamic screening descriptor of synthesizability for AI-assisted materials discovery. △ Less

Submitted 22 June, 2026; originally announced June 2026.

Spectroscopic fingerprints of a ferroaxial charge density wave

Authors: Jiangchang Zheng, Zhongyi Zhang, Fazhi Yang, Josh Leeman, Luanjing Li, Zihan Lin, Zijian Fei, Tianhao Guo, Siyu Heng, Xin Liang, Leslie M. Schoop, Junzhang Ma, Hoi Chun Po, Berthold Jäck

Abstract: Unconventional charge density waves (CDWs) with complex order parameters can host exotic collective modes and non-trivial topologies. They have emerged as a new frontier in the study of quantum matter. Recent experiments on rare-earth tritellurides have reported evidence for a ferroaxial CDW through the detection of characteristic Raman modes. This phase, often regarded as a hidden order, has been… ▽ More Unconventional charge density waves (CDWs) with complex order parameters can host exotic collective modes and non-trivial topologies. They have emerged as a new frontier in the study of quantum matter. Recent experiments on rare-earth tritellurides have reported evidence for a ferroaxial CDW through the detection of characteristic Raman modes. This phase, often regarded as a hidden order, has been recognized to arise from the coupling between charge and orbital degrees of freedom in these materials. Yet, spectroscopic insight into its underlying electronic structure and the explicit form of its order parameter symmetry has remained elusive. Here, we present results from linearly polarized angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM) measurements of the CDW phase in LaTe$_3$. Our ARPES measurements reveal a complex landscape of spectral gaps across the reconstructed Fermi surface, while our STM-based quasiparticle interference (QPI) mapping, enhanced through the selective deposition of atomic scattering centers, directly reveals an inter-orbital CDW with mixed $p_x$-$p_z$ orbital character. The detailed analysis of the QPI characteristics in terms of the order parameter symmetry within the orbital subspace of the Fermi surface suggests a mixed CDW phase with substantial ferroaxial component, which breaks all vertical mirror symmetries. More broadly, our work establishes a powerful spectroscopic pathway, based on scattering off individual atoms, for identifying and characterizing hidden, multi-component electronic orders in quantum materials using STM and ARPES measurements. △ Less

Submitted 20 June, 2026; originally announced June 2026.

Nonlocal Sensing Drives Hybrid Phase Separation in Brownian Matter

Authors: Benchang Wu, Ziluo Zhang, Shutong Guo, Hepeng Zhang, Zhihong You

Abstract: Matter can organize not only through forces, but also through the information its constituents acquire from their surroundings. Here we use perceptive Brownian particles as a minimal model to isolate nonlocal sensing as an organizing principle for nonequilibrium matter. The particles undergo purely Brownian motion, with no mechanical interactions, self-propulsion, alignment, or auxiliary fields. T… ▽ More Matter can organize not only through forces, but also through the information its constituents acquire from their surroundings. Here we use perceptive Brownian particles as a minimal model to isolate nonlocal sensing as an organizing principle for nonequilibrium matter. The particles undergo purely Brownian motion, with no mechanical interactions, self-propulsion, alignment, or auxiliary fields. Their only coupling is informational, through diffusivity regulated by density measured over a finite perception zone. Whereas local sensing, when unstable, produces conventional long-wavelength demixing, nonlocal perception restructures the instability spectrum, introducing finite-wavelength patterning and nonlinear bubbling instabilities. More fundamentally, it reshapes the ordering pathway by assembling a cascade of instabilities: macroscopic demixing creates dense domains, finite-wavelength modes pattern them internally, and nonlinear feedback hollows them into void bubbles. This produces hybrid phase separation, where a macroscopic dense phase coexists with a dilute background while retaining ordered internal microstructure, whose symmetry, anisotropy, and length scales are selected by the perception kernel. These results establish information acquisition as a constitutive principle of nonequilibrium matter, capable of governing both phase stability and the dynamical pathways through which order emerges. △ Less

Submitted 19 June, 2026; originally announced June 2026.

Comments: 5 pages, 4 figures

sft-wick: A formalism and package for Feynman-diagram expansion and evaluation in stochastic field theories

Authors: Zheng Zhang

Abstract: When stochastic field dynamics are cast into a path-integral formulation, perturbation theory becomes systematic but the resulting expansion quickly grows combinatorially large. The setting targeted here includes multi-component, multi-dimensional fields with matrix propagators, tensor-valued couplings, and non-Gaussian driving noise specified by arbitrary $n$-point cumulants. Wick pairings grow f… ▽ More When stochastic field dynamics are cast into a path-integral formulation, perturbation theory becomes systematic but the resulting expansion quickly grows combinatorially large. The setting targeted here includes multi-component, multi-dimensional fields with matrix propagators, tensor-valued couplings, and non-Gaussian driving noise specified by arbitrary $n$-point cumulants. Wick pairings grow factorially, and component indices must be routed through the tensor-valued vertices. The useful output is not a raw contraction list, but a diagram table: one entry per topology, with multiplicities, coupling sums, signs, and causal constraints resolved. We present sft-wick, an open-source Python package that constructs these diagram tables and computes their integrals numerically. Given an action and an observable, it enumerates topologically distinct Feynman diagrams, derives their algebraic coefficients, and evaluates the resulting diagram integrals from user-supplied response and cumulant functions. The core algorithm enumerates spatial topologies before routing component indices, avoiding contraction-by-contraction Wick expansion. Response-field constraints, including vanishing response-response contractions, the ito prescription, and the absence of causal response loops, are enforced during enumeration. Predictions are validated against direct Langevin simulation, agreeing to within the simulation's statistical noise. △ Less

Submitted 17 June, 2026; originally announced June 2026.

Comments: 32 pages, 5 figures, 2 tables. Submitted to Computer Physics Communications. The sft-wick package is open source and available at https://github.com/StatFieldTheory/sft-wick

AdsMind: A Physics-Grounded Multi-Agent System for Self-Correcting Discovery of Adsorption Configurations on Heterogeneous Catalyst Surfaces

Authors: Zongmin Zhang, Yuyang Lou, Bowen Zhang, Junwu Chen, Ryo Kuroki, Xuan Vu Nguyen, Edvin Fako, Lixue Cheng, Philippe Schwaller

Abstract: Identifying the lowest-energy surface-adsorbate configuration is critical for modeling heterogeneous catalysis, yet exhaustive exploration with ab initio calculations is computationally prohibitive. Machine-learning force fields (MLFFs) accelerate structural relaxation but leave the search over the vast configurational space a major bottleneck, and open-loop large language model (LLM) agents lack… ▽ More Identifying the lowest-energy surface-adsorbate configuration is critical for modeling heterogeneous catalysis, yet exhaustive exploration with ab initio calculations is computationally prohibitive. Machine-learning force fields (MLFFs) accelerate structural relaxation but leave the search over the vast configurational space a major bottleneck, and open-loop large language model (LLM) agents lack a physics-grounded feedback mechanism to correct erroneous initial guesses. We propose AdsMind (Adsorption configuration discovery with Machine intelligence and relaxation feedback), a closed-loop multi-agent framework that enables autonomous error correction through MLFF relaxation feedback. Across four LLM backends, AdsMind achieves consistently high search reliability, with success rates of 100% and 98.8% on the benchmarks AA20 and OCD-GMAE62. Relative to its single-pass (1-Shot) ablation it reduces cross-backend energy dispersion, and it uses only 4.11 and 4.67 MLFF relaxations per case, respectively -- an approximately 14-fold reduction over heuristic enumeration baselines. Density functional theory (DFT) validation using VASP/PBE on six representative AA20 systems shows that the reported open-loop Adsorb-Agent outputs exhibit qualitative adsorption-energy sign errors for molecular adsorbates, whereas AdsMind preserves the correct sign in all tested cases with closer quantitative agreement. AdsMind thus delivers reliability, self-reflection, and interpretability simultaneously, supporting more DFT-informed autonomous chemistry workflows. △ Less

Submitted 17 June, 2026; originally announced June 2026.

Comments: 37 pages, 5 figures

Dynamically suppressed lattice rotations in SrTiO$_3$ as a basis for photo-induced ferroelectricity

Authors: Huaiyu Hugo Wang, Michael Fechner, Giovanni De Vecchi, Sylvia L. Griffitt, Gal Orenstein, Jade Stanton, Viktor Krapivin, Man T. Wong, Zhuquan Zhang, Mina Bionta, Vincent Esposito, Meredith Henstridge, Matthias C. Hoffmann, Patrick L. Kramer, Zach Porter, Ryan A. Duncan, Takahiro Sato, Soyeun K. Kim, Hasan Yavas, Samuel Teitelbaum, Keith Nelson, Ankit S. Disa, Michael F"orst, Mariano Trigo, Andrea Cavalleri

Abstract: Photo-induced ferroelectricity in the quantum paraelectric SrTiO$_3$ involves the dynamical interplay between a coherently driven Ti-O stretching vibration and multiple structural degrees of freedom, including antiferrodistortive rotations, strain, and the polar mode instability. In the high-temperature cubic phase, in the absence of average antiferrodistortion, time-resolved X-ray diffuse scatter… ▽ More Photo-induced ferroelectricity in the quantum paraelectric SrTiO$_3$ involves the dynamical interplay between a coherently driven Ti-O stretching vibration and multiple structural degrees of freedom, including antiferrodistortive rotations, strain, and the polar mode instability. In the high-temperature cubic phase, in the absence of average antiferrodistortion, time-resolved X-ray diffuse scattering has evidenced a correlation between a photo-induced reduction in antiferrodistortive fluctuations and the emergence of ferroelectric order. Here, we complement these measurements with time-resolved elastic X-ray diffraction in the low-temperature tetragonal phase, in which antiferrodistortive fluctuations are small but a finite average rotation has set in. In this phase, we observe a long-lived reduction of the equilibrium antiferrodistortive rotation angle. A unified theory of the nonlinear lattice dynamics based on first-principles calculations describes the dynamics in both high-temperature cubic and low-temperature tetragonal phases, providing a basis for light-induced ferroelectricity in SrTiO$_3$. △ Less

Submitted 15 June, 2026; originally announced June 2026.

Comments: Huaiyu Hugo Wang and Michael Fechner contributed equally to this work

Floquet-Sambe Bottleneck and Frequency-Selective Localization in a Driven Synthetic Spin Chain

Authors: J. Cao, K. L. Zhang, R. Wang, X. Z. Zhang

Abstract: We study a finite Floquet chain in which a uniform nearest-neighbor hopping coexists with a periodically rotating, \textrm{SU(2)}-dictated spin-assisted hopping profile. The resulting coupling is spatially inhomogeneous -- weakest at the chain boundaries and strongest in the bulk -- and produces a frequency-dependent Floquet-Sambe bottleneck. In the closed system, the mean inverse participation ra… ▽ More We study a finite Floquet chain in which a uniform nearest-neighbor hopping coexists with a periodically rotating, \textrm{SU(2)}-dictated spin-assisted hopping profile. The resulting coupling is spatially inhomogeneous -- weakest at the chain boundaries and strongest in the bulk -- and produces a frequency-dependent Floquet-Sambe bottleneck. In the closed system, the mean inverse participation ratio (\textrm{MIPR}) of the Floquet eigenstates exhibits a striking nonmonotonic dependence on the driving frequency $ω$: the states remain extended at both low and high frequencies, but become maximally localized at an intermediate frequency. We demonstrate that this localization maximum occurs at $ω_{\mathrm{peak}}\sim μ_{-s}=\sqrt{% 2s}$, a scale controlled by the first boundary bottleneck. To connect these spectral properties to measurable transport, we construct an open-system Floquet-Sambe Green-function inverse participation ratio from the spatial density of the injected scattering state. This open-system diagnostic recovers the same nonmonotonic localization trend as its closed-system counterpart, with the peak shifted to higher frequencies by the static bandwidth and the lead self-energy. These findings establish the driven synthetic spin chain as a directly realizable, frequency-tunable platform for coherent information storage and retrieval, rooted in the interplay of Floquet-Sambe virtual channels, boundary-controlled localization, and frequency-selective transport in emerging multi-level superconducting circuit architectures. △ Less

Submitted 13 June, 2026; originally announced June 2026.

Lattice dynamics and the spectroscopic signatures of H-bond disorder in $δ$-AlOOH

Authors: Chenxing Luo, Sangjoon Lee, Hongjin Wang, Zhen Zhang, Renata Wentzcovitch

Abstract: Raman and infrared anomalies associated with H-bond symmetrization in $δ$-AlOOH, including mode softening and linewidth broadening at 5-10 GPa, occur at significantly lower pressures than predicted by static harmonic theory. To resolve this discrepancy, we combine harmonic phonon calculations with strongly constrained and appropriately normed (SCAN)-based deep-potential molecular dynamics and phon… ▽ More Raman and infrared anomalies associated with H-bond symmetrization in $δ$-AlOOH, including mode softening and linewidth broadening at 5-10 GPa, occur at significantly lower pressures than predicted by static harmonic theory. To resolve this discrepancy, we combine harmonic phonon calculations with strongly constrained and appropriately normed (SCAN)-based deep-potential molecular dynamics and phonon quasiparticle analysis at 300 K. This framework extracts temperature- and pressure-dependent frequencies and lifetimes from long-time trajectories, capturing the branch reorganization and rapid linewidth growth characteristic of the disordering regime. Incorporating quasiparticle renormalization and directional longitudinal-optical-transverse-optical (LO-TO) splitting further yields near-quantitative agreement with the ambient-pressure OH-stretching Raman multiplet. These results identify finite-temperature dynamical effects and the progressive loss of spectral coherence as the origin of the spectroscopic signatures of H-bond symmetrization. △ Less

Submitted 12 June, 2026; originally announced June 2026.

Comments: 12 pages, 6 figures; Supplemental Material: 5 pages, 4 figures

Interference of critical dynamics associated with zero modes

Authors: Zhi-Han Zhang, Han-Chuan Kou, Peng Li

Abstract: We study the interference of critical dynamics associated with zero modes (ICDZM) in the generalized Creutz ladders using closed quench paths that pass through two critical points successively. By reading out the final zero-mode transfer probability, we find rich ICDZM interference patterns dependent on the quench path. In particular, when the closed path links two topologically nontrivial phases,… ▽ More We study the interference of critical dynamics associated with zero modes (ICDZM) in the generalized Creutz ladders using closed quench paths that pass through two critical points successively. By reading out the final zero-mode transfer probability, we find rich ICDZM interference patterns dependent on the quench path. In particular, when the closed path links two topologically nontrivial phases, the ICDZM pattern may either vanish or exhibit period doubling. Within the framework of WKB analysis, this phenomenon is well clarified by the interference phase accumulated in the quench procedure. We also demonstrate that the zero-mode transfer probability can be detected by the deviation of the boundary particle number from its initial fractional value, which arises from the blending of bulk modes in the critical dynamics. As an edge defect, the zero-mode transfer probability captures both the ICDZM oscillation and the known anomalous defect production in a non-closed quench path. These results identify ICDZM and the corresponding edge defect as probes for critical dynamics associated with topological zero modes. △ Less

Submitted 12 June, 2026; v1 submitted 11 June, 2026; originally announced June 2026.

Comments: Supplementary figure added; minor figure/color and language changes; license updated

Hall conductivity reveals the nature of quantum coherence in strongly correlated metals

Authors: Emily Z. Zhang, Thomas P. Devereaux

Abstract: Linear-in-temperature resistivity is a hallmark for strange metallic transport, and appears universally in many strongly correlated electron systems. However, the focus on the longitudinal channel often overshadows the profound microscopic insights contained within the transverse response. Here, we utilize numerically exact determinantal quantum Monte Carlo simulations of the doped Hubbard model i… ▽ More Linear-in-temperature resistivity is a hallmark for strange metallic transport, and appears universally in many strongly correlated electron systems. However, the focus on the longitudinal channel often overshadows the profound microscopic insights contained within the transverse response. Here, we utilize numerically exact determinantal quantum Monte Carlo simulations of the doped Hubbard model in a magnetic field to calculate longitudinal and transverse transport. We demonstrate that while the resistivity is robustly $T$-linear across parameter sets, the Hall response is highly sensitive to particle-hole asymmetry, Fermi surface topology, and many-body correlation effects. Specifically, the combination of these effects determine a crossover scale in which the system becomes quantum-coherent, and is reflected in the Hall conductivity. Our results demonstrate that while the $T$-linearity in resistivity appears universal, the Hall response reveals a crossover from semi-classical to quantum-coherent transport otherwise masked in the longitudinal channel. △ Less

Submitted 10 June, 2026; originally announced June 2026.

Comments: 17+8 pages, 5+9 figures

Unveiling Orbital-mediated Ultrafast Demagnetization in Rare Earth-Transition-Metal Ferrimagnets

Authors: Jianwen Gao, Linlin Zhang, Mingli Ge, Runhua Zhang, Jinshan Wang, Hui Li, Xiaowei Zhou, Zhu Liu, Zongzhi Zhang, Li Xi, Yalu Zuo, Chenglong Jia, Feng Qiu, Shaojie Hu, Yang Ren

Abstract: The ultimate speed limit of magnetic recording and spintronic devices is set by the efficiency of angular-momentum transfer during ultrafast demagnetization, yet its microscopic pathway in Rare-Earth-Transition-Metal (RE-TM) ferrimagnets remains debated. Here, we establish an orbital-mediated framework in which 3d spin-orbit coupling (SOC) governs angular momentum (AM) dissipation. Strong 3d-SOC i… ▽ More The ultimate speed limit of magnetic recording and spintronic devices is set by the efficiency of angular-momentum transfer during ultrafast demagnetization, yet its microscopic pathway in Rare-Earth-Transition-Metal (RE-TM) ferrimagnets remains debated. Here, we establish an orbital-mediated framework in which 3d spin-orbit coupling (SOC) governs angular momentum (AM) dissipation. Strong 3d-SOC in RE-Co enables sub-picosecond, single-step demagnetization via direct orbital-to-lattice transfer, whereas weak 3d-SOC in RE-Fe redirects AM into 4f orbitals, producing slower two-step dynamics. The second-stage rate scales with 4f-SOC strength, revealing a distinct orbital-mediated dissipation channel. Using time-resolved magneto-optical Kerr measurements, supported by an extended four-temperature model, corroborate this picture across diverse RE-TM systems (RE = Sm, Gd, Tb, Dy, Ho and TM = Fe, Co, CoNi). Our results identify the SOC-driven competition between 3d and 4f orbital channels as the universal mechanism governing ultrafast demagnetization in RE-TM ferrimagnets, enabling rational design of the switching speed for next-generation spintronic devices. △ Less

Submitted 9 June, 2026; originally announced June 2026.

The Yang-Baxter Equation for the Chiral Potts Model and Integrable Parafermions

Authors: Zhao Zhang

Abstract: A new type of Yang-Baxter equation (YBE) for $R$-operators depending on three spectral parameters is constructed from the star-triangle relation for the chiral Potts model. As the $Z_N$ symmetric generalization to the Ising model, its Boltzmann weights are known to depend on two variables describing a curve with genus larger than one for $N>2$, except for the self-dual point corresponding to the F… ▽ More A new type of Yang-Baxter equation (YBE) for $R$-operators depending on three spectral parameters is constructed from the star-triangle relation for the chiral Potts model. As the $Z_N$ symmetric generalization to the Ising model, its Boltzmann weights are known to depend on two variables describing a curve with genus larger than one for $N>2$, except for the self-dual point corresponding to the Fateev-Zamolodchikov chain. Combined with the fact that quantum Hamiltonians of edge-type models such as the Ising model contain both nearest-neighbor interaction and onsite potential terms, this leads naturally to an additional spectral parameter in the associated $R$-operator. The construction extends the edge-vertex correspondence of solvable lattice models, and provides a bridge between the Bazhanov-Stroganov four-parameter $R$-matrix---realized as an intertwiner of cyclic representations of $U_q(\mathfrak{sl}_2)$ at a root of unity---and Shastry's two-parameter $R$-operator obtained from the decorated YBE. △ Less

Submitted 15 August, 2026; v1 submitted 9 June, 2026; originally announced June 2026.

Comments: 27 pages, 7 figures

Designing electronic magnetoelectric matter with organic quantum spin trimers

Authors: Yuko Hosokoshi, Christopher P. Aoyama, Zhuowei Zhang, Toshio Ono, Kosuke Takada, Ayaka Higashiguchi, Seitaro Iisaka, Koudai Yamasaki, Hironori Yamaguchi, Shengzhi Zhang, Mohammad Irfan, Minseong Lee, Eun Sang Choi, Yasuyuki Shimura, Toshiro Sakakibara, Zhiyuan Xie, Hiroki Nakano, Yasu Takano, Cristian D. Batista, Yoshitomo Kamiya

Abstract: Magnetoelectric (ME) phenomena are commonly driven by spin-lattice coupling. Here we demonstrate a different route based on frustrated quantum spin trimers that intrinsically intertwine magnetic moments and electric dipoles. Using molecular design principles, we realize a weakly coupled lattice of equilateral $S=1/2$ spin trimers in the organic radical crystal TNN$\cdot$CH$_3$CN. In this material,… ▽ More Magnetoelectric (ME) phenomena are commonly driven by spin-lattice coupling. Here we demonstrate a different route based on frustrated quantum spin trimers that intrinsically intertwine magnetic moments and electric dipoles. Using molecular design principles, we realize a weakly coupled lattice of equilateral $S=1/2$ spin trimers in the organic radical crystal TNN$\cdot$CH$_3$CN. In this material, correlated electronic fluctuations within each trimer generate electric dipoles, while geometrically frustrated intertrimer interactions organize them into collective ME states. Magnetization, thermodynamic, and dielectric measurements reveal multiple magnetic-field-induced phases, including the $1/3$-magnetization plateau marked by pronounced dielectric anomalies. Effective low-energy theories and numerical simulations show that these phenomena are driven by electronically generated trimer dipoles whose collective order is stabilized by frustration relief of the intertrimer interactions, establishing a direct connection between geometric frustration and emergent magnetoelectricity. Our results identify quantum spin trimers as multifunctional building blocks, providing a bottom-up route for designing correlated ME materials from electronically active quantum spin clusters. △ Less

Submitted 8 June, 2026; originally announced June 2026.

Comments: 13 pages, 6 figures; Supplementary Information included

Fragile electron-phonon superconductivity in MnB4 under pressure

Authors: Renhai Wang, Shiya Chen, Feng Zheng, Zhen Zhang, Xingzhi Wang, Huafeng Dong, Cai-Zhuang Wang, Vladimir Antropov, Kai-Ming Ho, Yang Sun

Abstract: The origin of pressure-induced superconductivity in MnB4 remains unclear. Here we show that it can be explained by electron-phonon coupling once the structural space is mapped using both volume and the Mn dimer distance as key structural parameters under compression. Minor changes in the dimer distance significantly affect electronic and phonon properties, bringing the calculated Tc into agreement… ▽ More The origin of pressure-induced superconductivity in MnB4 remains unclear. Here we show that it can be explained by electron-phonon coupling once the structural space is mapped using both volume and the Mn dimer distance as key structural parameters under compression. Minor changes in the dimer distance significantly affect electronic and phonon properties, bringing the calculated Tc into agreement with experiment. Our results suggest that MnB4 is a highly responsive system, providing a platform for probing the subtle interplay between structural instability, superconductivity and magnetism. △ Less

Submitted 5 June, 2026; originally announced June 2026.

Autonomous heterogeneous catalyst discovery with a self-evolving multi-agent digital twin

Authors: Zhilong Song, Zongmin Zhang, Lixue Cheng

Abstract: Theoretical heterogeneous catalysis promises rapid catalyst discovery, yet computational and machine-learning predictions often deviate from experiment and stay confined to narrow material families, for want of a faithful, condition-aware catalytic simulator. We present CatDT (Catalysis Digital Twin), a self-evolving multi-agent system that builds an autonomous digital twin of a working catalyst,… ▽ More Theoretical heterogeneous catalysis promises rapid catalyst discovery, yet computational and machine-learning predictions often deviate from experiment and stay confined to narrow material families, for want of a faithful, condition-aware catalytic simulator. We present CatDT (Catalysis Digital Twin), a self-evolving multi-agent system that builds an autonomous digital twin of a working catalyst, unifying gas-solid and liquid-solid modeling. From only a bulk crystal and a natural-language reaction description, eight specialized agents and 27 scientific tools predict stable facets, reconstruct working surfaces, enumerate and rank reaction pathways, locate transition states, and compute kinetics in 5-30 min on a single GPU. Two innovations address the hardest steps: UniMech finds dominant pathways for novel materials at over $10^3\times$ lower cost than exhaustive enumeration by fusing agent-guided proposals with energy-cached graph search, and a memory-augmented reinforcement loop raises barrier-calculation success from 41% to 84% across 600 catalytic surfaces. Across seven gas-solid benchmarks -- stepped metals, single-atom catalysts, ordered intermetallics, vacancy-rich 2D sulfides and carbides, and a strong-metal--support-interaction (SMSI) interface -- every CatDT prediction lies within 0.5-2 times experiment over four orders of magnitude. For propane dehydrogenation, CatDT independently discovers non-precious candidates rivaling the Pt-based industrial benchmark, with a proposed Ni@ZrO$_2$ SMSI overlayer reaching a simulated TOF of $1.63~\text{s}^{-1}$ at $\sim$100% selectivity. More broadly, the decisive factor for a faithful catalyst digital twin -- or any multi-stage scientific simulator -- is not raw LLM capability but the engineered harness around it: deterministic tools, persistent memory, and verified self-improvement that compound across models, tools, and runs. △ Less

Submitted 8 July, 2026; v1 submitted 3 June, 2026; originally announced June 2026.

Trapping 11,000 Atoms in a Tweezer Array Generated by a Single Metasurface

Authors: Yuqing Wang, Zhongchi Zhang, Tao Zhang, Yuxuan Liao, Hanteng Wang, Ye Tian, Binjie Ji, Yujia Wu, Luming Ma, Chen Qing, Chengshu Li, Wei Zhang, Yidong Huang, Wenjun Zhang, Xue Feng, Wenlan Chen, Hui Zhai

Abstract: The scalability of physical qubit numbers is a central challenge toward a universal fault-tolerant quantum computer. The inherent scalability of atom array quantum computers stems from the identical nature of atomic qubits, so the available qubit resource is primarily limited by the number of atoms that can be trapped and controlled. Here, we robustly trap 11,000 individual atoms in a tweezer arra… ▽ More The scalability of physical qubit numbers is a central challenge toward a universal fault-tolerant quantum computer. The inherent scalability of atom array quantum computers stems from the identical nature of atomic qubits, so the available qubit resource is primarily limited by the number of atoms that can be trapped and controlled. Here, we robustly trap 11,000 individual atoms in a tweezer array, thereby enabling the available qubit resource to reach the tens-of-thousands scale for the first time among all quantum computation platforms. This advance is enabled by a single metasurface, approximately 2 cm in diameter, that generates the entire tweezer array without the need for microscope objectives, thereby maximizing laser-power efficiency. The large aperture ensures a working distance of about 1.5 cm, allowing the metasurface to be placed outside the vacuum cell and avoiding the technical complications of in-vacuum operation. We further characterize the randomly loaded atom array using the statistical theory of percolation phase transitions. This work takes an important first step toward a quantum computer at the 10,000-qubit scale. △ Less

Submitted 1 June, 2026; originally announced June 2026.

Evolution of the intertwining correlated topological phases in iron-based superconductor Fe(Te,Se)

Authors: Yue Sun, Shiying He, Zhongyi Zhang, Yong Huang, Jingheng Chen, Weixiang Yan, Chunbo Yu, Yuyang Dong, Kohei Aido, Xin Zhou, Zhengtai Liu, Mao Ye, Jishan Liu, Haruhisa Kitano, Zhixiang Shi, Hong Ding, Takeshi Kondo, Xianxin Wu, Peng Zhang

Abstract: Multiple topological electronic phases can coexist within a single quantum material and induce different topological superconducting states, offering deeper insights into interplay of topological superconducting states and Majorana modes, which may also be influenced and modified by correlation effect. Iron-based superconductors, with both topological states and correlation effect, is an ideal pla… ▽ More Multiple topological electronic phases can coexist within a single quantum material and induce different topological superconducting states, offering deeper insights into interplay of topological superconducting states and Majorana modes, which may also be influenced and modified by correlation effect. Iron-based superconductors, with both topological states and correlation effect, is an ideal platform to study these phenomena. Here, with high resolution angle resolved photoelectron spectroscopy, we directly resolve two distinct intertwining topological states in iron-based superconductor Co-doped Fe(Te,Se), and study their evolution with electron doping. We identify a region where both topological insulator surface states and topological Dirac semimetal states intersect the Fermi level. The topological states are affected by the strong correlation effect and are isolated from trivial bulk states. The evolution between distinct topological phases offers a good opportunity to study various Majorana modes from different superconducting phases according to theoretical analysis. Our findings establish an ideal platform for exploring the interaction between multiple topological superconducting states and the related Majorana modes. △ Less

Submitted 1 June, 2026; originally announced June 2026.

Comments: 6 pages, 4 figures

Journal ref: JACS (2026)

Carrier Localization in Pnictogen-Based Chalcohalides from Defect-Bound Hot Polarons

Authors: Xiaoyu Guo, Junzhi Ye, Cibrán Lopez Alvarez, Maciej Oskar Liedke, Maik Butterling, Mutibah Alanazi, Yi-Teng Huang, Jiajie Wu, Zhilong Zhang, Lars Van Turnhout, Yorrick Boeije, Bofeng Xue, Qingyu Wang, Hugh Lohan, Seán R. Kavanagh, Andreas Wagner, Eric Hirschmann, Robert A. Taylor, Akshay Rao, Edgardo Saucedo, Claudio Cazorla, Robert L. Z. Hoye

Abstract: Pnictogen-based solar absorbers have gained prominence as promising nontoxic and stable alternatives to lead-halide perovskites (LHPs), but are severely limited by carrier localization, preventing their performance from approaching those of LHPs. Recent efforts have uncovered routes to overcome carrier localization, but these early efforts only considered intrinsic factors. Herein, we push beyond… ▽ More Pnictogen-based solar absorbers have gained prominence as promising nontoxic and stable alternatives to lead-halide perovskites (LHPs), but are severely limited by carrier localization, preventing their performance from approaching those of LHPs. Recent efforts have uncovered routes to overcome carrier localization, but these early efforts only considered intrinsic factors. Herein, we push beyond these limited early efforts, examining the role of defects, not only on cold carriers but also hot carriers. Focusing on the structurally one-dimensional pnictogen chalcohalide BiSBr, we find that whilst this material intrinsically does not exhibit carrier localization, vacancies introduced during synthesis or post-treatment lead to pronounced extrinsic self-trapping via the formation of defect-bound hot polarons-excited charge-carriers strongly coupled to local defect-induced vibrational modes. These above-gap defect states divert hot carriers from cooling to the band edge, thus depleting the mobile carrier population. Our findings establish the key role of defect-bound hot polarons in mediating extrinsic localization and offer new mechanistic insights into the interplay between defects, lattice coupling, and excited-state charge-carrier transport, which are critical to designing efficient perovskite-inspired solar absorbers. △ Less

Submitted 28 May, 2026; originally announced May 2026.

Comments: 20 pages, 5 figures

Field-induced multipolar character in the dipolar ground state of the honeycomb rare-earth chalcohalide NdOF

Authors: Tiantian Liu, Yanzhen Cai, Mingtai Xie, Helin Mei, Anmin Zhang, Feng Jin, Jianting Ji, Zheng Zhang, Qingming Zhang

Abstract: Field-tunable reconstruction of crystalline electric field (CEF) doublets offers a promising avenue for inducing multipolar character, while its observation in real materials has been little explored so far. Here we establish the honeycomb rare-earth chalcohalide NdOF as such a platform. Raman spectroscopy identifies four CEF excitations at 1.7, 15.6, 19.2, and 80.9~meV, and a Zeeman--CEF analysis… ▽ More Field-tunable reconstruction of crystalline electric field (CEF) doublets offers a promising avenue for inducing multipolar character, while its observation in real materials has been little explored so far. Here we establish the honeycomb rare-earth chalcohalide NdOF as such a platform. Raman spectroscopy identifies four CEF excitations at 1.7, 15.6, 19.2, and 80.9~meV, and a Zeeman--CEF analysis reproduces their nonlinear field splitting into seven branches. Magnetization and susceptibility over 0.1--9~T are well described by a CEF model for the total angular momentum $J = 9/2$ manifold, confirming the robustness of the extracted CEF scheme. These results demonstrate a field-driven continuous evolution of the ground-state doublet from dipolar to dipolar-multipolar character, with pressure providing a complementary tuning knob, establishing NdOF as a model system for exploring the controlled induction of multipolar components in rare-earth magnets. △ Less

Submitted 28 May, 2026; originally announced May 2026.

Comments: 7 pages, 4 figures

Journal ref: Phys. Rev. B 113, 205151 (2026)

Machine-learning-accelerated discovery of synthesizable high-temperature altermagnets with giant spin splitting

Authors: Yi-Fei Jiang, Jia-Xuan Guo, Zhen Zhang, Xin-Wei Yi, Jing-Yang You

Abstract: Altermagnets offer a route to spin-polarized electronic states without macroscopic magnetization, because compensated magnetic order can generate momentum-dependent spin splitting through crystal-symmetry-controlled exchange fields. However, experimentally viable altermagnets combining large spin splitting, thermodynamic stability and high magnetic ordering temperatures remain scarce. Here, we dev… ▽ More Altermagnets offer a route to spin-polarized electronic states without macroscopic magnetization, because compensated magnetic order can generate momentum-dependent spin splitting through crystal-symmetry-controlled exchange fields. However, experimentally viable altermagnets combining large spin splitting, thermodynamic stability and high magnetic ordering temperatures remain scarce. Here, we develop a machine-learning-accelerated high-throughput framework to explore the tetragonal AB$_2$C$_2$D compounds. Screening 8640 variants identifies 1347 compensated antiferromagnetic candidates satisfying altermagnetic symmetry. An interpretable XGBoost model trained on first-principles spin-splitting data then isolates 34 low-hull-energy candidates,including four previously reported, with giant non-relativistic spin splittings exceeding 1.5 eV near the Fermi level. Detailed first-principles calculations of the representative RbMn$_2$Te$_2$O confirm a maximum spin splitting of $\sim$1.88 eV with dynamical stability and an estimated Néel temperature of $\sim$390 K. The giant splitting originates from symmetry-locked Mn-sublattice exchange fields amplified by directional Mn-d/Te-p hybridization. Furthermore, we uncover a profound soft-mode-driven structural transition associated with an interlayer dimensionality crossover in SrMn$_2$Te$_2$O, yet the unfolded electronic structure demonstrates that the altermagnetic spin splitting remains robust after lattice reconstruction. Hydrostatic pressure provides an additional tuning route, producing non-monotonic modulation of the spin-split Fermi surface governed by local coordination and orbital hybridization. These results establish tetragonal AB$_2$C$_2$D compounds as a tunable materials platform for stray-field-free spintronic devices and provide a general data-driven strategy for discovering robust giant-splitting altermagnets. △ Less

Submitted 26 May, 2026; originally announced May 2026.

Comments: 32 pages,6 figures

Structural Alter-Phononics: Sublattice-Momentum Locking in Spinless Lattice Dynamics

Authors: Jing-Yang You, Zhen Zhang, Xianlei Sheng, Gang Su

Abstract: The discovery of altermagnetism has shown that crystal symmetry can generate momentum-dependent internal polarization without net magnetization. Whether an analogous form of symmetry-organized momentum-space order can exist for spinless lattice vibrations remains unresolved. Here we identify a structural mechanism for $alter$-$phononics$, in which phonon eigenmodes formed from structurally equival… ▽ More The discovery of altermagnetism has shown that crystal symmetry can generate momentum-dependent internal polarization without net magnetization. Whether an analogous form of symmetry-organized momentum-space order can exist for spinless lattice vibrations remains unresolved. Here we identify a structural mechanism for $alter$-$phononics$, in which phonon eigenmodes formed from structurally equivalent sublattices acquire momentum-dependent sublattice polarization and frequency splitting in nonmagnetic crystals. The central quantity is the sublattice-resolved dynamical asymmetry $Δ(\mathbf q)=D_{AA}(\mathbf q)-D_{BB}(\mathbf q)$, which controls the associated eigenvector polarization. We show that this effect requires an alter-generator that maps equivalent sublattices onto one another while rotating the wave vector, together with the absence of inversion exchange and little-group sublattice-exchange constraints that would otherwise enforce sublattice equipartition. These symmetry rules generate nematic $d$-wave, tetragonal $d/g$-wave, and tripartite six-lobe phonon textures. First-principles calculations demonstrate the mechanism in representative nonmagnetic crystals and show how a symmetry-preserving structural distortion can unlock a hidden $d_{x^2-y^2}$-type texture by removing glide-induced equipartition traps while retaining the screw-axis alter-generator. We further show that the eigenvector texture is inherited by sublattice-projected electron-phonon coupling and anharmonic response functions. Our results establish structural alter-phononics as a spinless counterpart to altermagnetic momentum-space order and provide experimentally testable signatures in finite-$\mathbf q$ phonon spectra and displacement patterns. △ Less

Submitted 25 May, 2026; originally announced May 2026.

Comments: 4 figures

AutoDFT: A Closed-Loop Multi-Agent Framework for Autonomous DFT Calculations

Authors: Penghui Yang, Zhonghan Zhang, Yue Li, Xinrun Wang, Yanchen Deng, Yuhao Lu, Bijun Tang, Zheng Liu, Bo An

Abstract: Density functional theory (DFT) serves as the basis for computational discovery in materials science and chemistry, yet each calculation demands extensive human effort: adjusting algorithms when convergence stalls, revising plans when unexpected physics emerges, and inserting steps as intermediate results reshape the problem. Existing LLM-based agents automate only the initial planning stage, prod… ▽ More Density functional theory (DFT) serves as the basis for computational discovery in materials science and chemistry, yet each calculation demands extensive human effort: adjusting algorithms when convergence stalls, revising plans when unexpected physics emerges, and inserting steps as intermediate results reshape the problem. Existing LLM-based agents automate only the initial planning stage, producing a full execution plan upfront and leaving all subsequent adaptation to hand-crafted rules. As a result, these workflows remain fragile, do not generalize well beyond pre-planned scenarios, and often require expert intervention when failures or unexpected intermediate results require changes to the calculation path. Here, we introduce AutoDFT, a closed-loop multi-agent framework that embeds LLM reasoning into every stage of the DFT lifecycle, where a strategic planner produces a skeletal plan of step objectives; a step planner generates numerical parameters just in time from preceding results; and a monitor-recover-reflect cycle diagnoses failures, repairs them, and revises the plan when the evidence justifies it. We demonstrate both breadth and depth: breadth on VASPBench, a purpose-built benchmark spanning 34 tasks and 9 DFT calculation types, where AutoDFT achieves 94.1% task-level success with GPT-5.2; and depth on established materials databases, where AutoDFT produces quantitatively reliable property predictions across electronic, magnetic, and energetic properties. By closing the loop between planning and execution, AutoDFT enables experimentalists without deep computational expertise to obtain reliable first-principles results. △ Less

Submitted 4 June, 2026; v1 submitted 25 May, 2026; originally announced May 2026.

Spin layer groups and their corepresentations

Authors: Zeying Zhang, Gui-Bin Liu, Mu Tian, Run-Wu Zhang, Zhi-Ming Yu, Yugui Yao

Abstract: Spin layer groups are the crystallographic symmetry groups with a periodic plane, and their symmetry operations are inherited from three-dimensional (3D) spin space groups. However, the direct application of 3D symmetry groups to two-dimensional systems is often inadequate due to anisotropic axes and dimensional reduction. In this work, we systematically classify inequivalent spin layer groups and… ▽ More Spin layer groups are the crystallographic symmetry groups with a periodic plane, and their symmetry operations are inherited from three-dimensional (3D) spin space groups. However, the direct application of 3D symmetry groups to two-dimensional systems is often inadequate due to anisotropic axes and dimensional reduction. In this work, we systematically classify inequivalent spin layer groups and analytically derive their irreducible corepresentations. This classification establishes a foundational framework for investigating symmetry-protected properties and novel quantum states in low-dimensional magnetic materials. △ Less

Submitted 28 May, 2026; v1 submitted 25 May, 2026; originally announced May 2026.

Comments: 10 pages, 0 figures

Emergent Dispersive Multipolar Excitations in NaErSe$_{2}$

Authors: Zheng Zhang, Mingfang Shu, Mingtai Xie, Weizhen Zhuo, Yanzhen Cai, Christian Balz, Jianting Ji, Feng Jin, Jie Ma

Abstract: In most condensed-matter systems, local and collective excitations remain decoupled due to their distinct energy scales. Here, we identify coupled local-collective excitations in the triangular antiferromagnet NaErSe$_2$ by combining neutron spectroscopy with total angular momentum modeling. The low-lying crystalline electric field (CEF) doublets include a dipolar $Γ_4$ ground state forming stripe… ▽ More In most condensed-matter systems, local and collective excitations remain decoupled due to their distinct energy scales. Here, we identify coupled local-collective excitations in the triangular antiferromagnet NaErSe$_2$ by combining neutron spectroscopy with total angular momentum modeling. The low-lying crystalline electric field (CEF) doublets include a dipolar $Γ_4$ ground state forming stripe-$x$ order and a $Γ_{5,6}$ excited state with dipole-octupole character. High-resolution spectra reveal emergent symmetry-selected dispersions, where magnon branches from the ground state are replicated on higher $Γ_4$ levels but couple with the $Γ_{5,6}$ levels to form a distinct multipolar band. An applied magnetic field reconstructs the CEF wavefunctions and polarizes the system into a multipolar ferromagnet, further reshaping the spectra. This study demonstrates the emergent coupling of local and collective excitations driven by strong spin-orbit coupling and establishes NaErSe$_2$ as a platform for field-tunable multipolar excitations in frustrated magnets. △ Less

Submitted 23 May, 2026; originally announced May 2026.

Comments: 7 pages, 4 figures

Journal ref: Phys. Rev. Lett. 135, 256503 (2025)

Light-Driven Ferroic Switching Enables Reversible Control of Hydrogen Adsorption Thermodynamics

Authors: Xueqing Wan, Zhenlong Zhang, Charles Paillard, Jian Zhou, Jinyang Ni, Chuanlu Yang, Zhijun Jiang, Laurent Bellaiche

Abstract: Reversible ultrafast switching of surface thermodynamics is highly desirable for hydrogen storage and catalysis yet remains elusive at the nanoscale. Here we demonstrate that photoinduced ferroic-order switching in two-dimensional ionic ferroelectric monolayers enables rapid, reversible control of hydrogen binding. In TiGeSe$_3$, carrier-density-driven redistribution of transition-metal 3\textit{d… ▽ More Reversible ultrafast switching of surface thermodynamics is highly desirable for hydrogen storage and catalysis yet remains elusive at the nanoscale. Here we demonstrate that photoinduced ferroic-order switching in two-dimensional ionic ferroelectric monolayers enables rapid, reversible control of hydrogen binding. In TiGeSe$_3$, carrier-density-driven redistribution of transition-metal 3\textit{d} orbital occupations triggers a sequential evolution from the ferroelectric ground state to paraelectric phases with staggered or Zig-Zag antiferromagnetic order. This switch continuously tunes the hydrogen adsorption free energy from 0.33 to 1.11 eV, shifting the interface from near-thermoneutrality to spontaneous desorption. Nonadiabatic dynamics indicate that electron-phonon coupling promotes nonthermal H release, while picosecond carrier recombination rapidly restores the initial ferroic order, closing an ultrafast reversible cycle. Generality is further validated in AgBiP$_2$Se$_6$ and CuInP$_2$S$_6$, establishing ferroic order as an optically addressable knob for dynamic thermodynamic reconfiguration beyond static design. △ Less

Submitted 22 May, 2026; originally announced May 2026.

Comments: 21 pages, 6 figures

Antiferromagnetic Ordering Enhanced Magnetic Damping in Mn2Au/CoFeB Bilayers

Authors: Donghang Xie, Haozhe Wang, Zhe Zhang, Zishuang Li, Jiahua Lu, Ronghua Liu, Jun Du, Bo Liu, Yu Yan, Liang He, Jing Wu, Rong Zhang, Bo Liu, Tiejun Zhou, Yongbing Xu, Xuezhong Ruan

Abstract: Antiferromagnets (AFMs) hold significant potential for spintronic devices owing to their insensitivity to external magnetic fields and the absence of stray fields. Beyond these inherent advantages, an AFM can manipulate the magnetic dynamics of a ferromagnet (FM) layer in AFM/FM bilayers, whereas the mechanism of such manipulation remains controversial. Here, we investigate the magnetic dynamics o… ▽ More Antiferromagnets (AFMs) hold significant potential for spintronic devices owing to their insensitivity to external magnetic fields and the absence of stray fields. Beyond these inherent advantages, an AFM can manipulate the magnetic dynamics of a ferromagnet (FM) layer in AFM/FM bilayers, whereas the mechanism of such manipulation remains controversial. Here, we investigate the magnetic dynamics of AFM/FM Mn2Au/CoFeB bilayers via Ferromagnetic Resonance (FMR). It is found that the Néel temperature of 2-nm-thick Mn2Au is as low as ~40 K, in sharp contrast to that of bulk Mn2Au, which exceeds 1000 K. In the Mn2Au(2 nm)/CoFeB(4 nm) bilayer, the magnetic damping $α$ of the CoFeB layer increases from 0.013 to 0.047 as temperature decreases from 160 K to 10 K, accompanied by a synchronous increase in the exchange coupling field H_rot. Such an increase in $α$ is attributed to the enhanced spin angular momentum transfer from CoFeB to Mn2Au, mediated through AFM-FM exchange coupling between Mn2Au and CoFeB, which is enhanced by the Mn2Au antiferromagnetic ordering as the temperature decreases. Our study provides deeper insights into AFM/FM dynamics and spintronic storage technology. △ Less

Submitted 21 May, 2026; originally announced May 2026.

Comments: 19 pages, 10 figures

High-Density Horizontal Arrays of Single-Chirality Carbon Nanotubes

Authors: Yanzhao Liu, Zilong Qiu, Yuguang Chen, Nie Zhang, Bing Han, Huimin Yin, Bojun Liu, Min Lyu, Zhihong Li, Yiran Ma, Jian Sheng, Jiahui Shao, Zeyao Zhang, Li Ding, Hao Hong, Chuanhong Jin, Sheng Wang, Kaihui Liu, Xiaowei He, Lian-Mao Peng, Yan Li

Abstract: Highly ordered high-density arrays of single-chirality single-walled carbon nanotubes (SWCNTs) are greatly desired for exploring the intrinsic anisotropic properties and collective performance of such 1-dimensional (1D) nanomaterials. Here we present a Marangoni flow-induced self-assembly (MISA) strategy to fabricate monolayered SWCNT arrays achieving a packing density of ~200 ${μm}^{-1}$ and a 2-… ▽ More Highly ordered high-density arrays of single-chirality single-walled carbon nanotubes (SWCNTs) are greatly desired for exploring the intrinsic anisotropic properties and collective performance of such 1-dimensional (1D) nanomaterials. Here we present a Marangoni flow-induced self-assembly (MISA) strategy to fabricate monolayered SWCNT arrays achieving a packing density of ~200 ${μm}^{-1}$ and a 2-dimensional order parameter ($S_{2\mathrm{D}}$) of ~0.95. Relying on its general compatibility with both organic and aqueous dispersions, we prepare single-chirality and enantiomer-pure SWCNT arrays from organic and aqueous dispersions resulting from the sorting processes. The anisotropic optical and electrical properties of the arrays are demonstrated by the polarization-dependent Rabi splitting as well as polarized near-infrared light emission and detection. With the great tolerance to solutions, substrates, and materials, as well as the feasibility and controllability, MISA shows great potential in the assembly of 1D nanomaterials. △ Less

Submitted 18 May, 2026; originally announced May 2026.

Interface Piezoelectric Loss in Superconducting Qubits

Authors: Haoxin Zhou, Kangdi Yu, Yashwanth Balaji, Sanjit Shirol, Leo Sementilli, Zi-Huai Zhang, Adam Schwartzberg, Alp Sipahigil

Abstract: Dissipation remains a central obstacle to improving superconducting quantum circuits, yet the microscopic origins of loss in widely used materials platforms are not fully understood. Here, we report the observation of interface piezoelectricity-induced dissipation in superconducting qubits fabricated on high-resistivity silicon. Our devices use a transmon qubit with a shunt capacitor that simultan… ▽ More Dissipation remains a central obstacle to improving superconducting quantum circuits, yet the microscopic origins of loss in widely used materials platforms are not fully understood. Here, we report the observation of interface piezoelectricity-induced dissipation in superconducting qubits fabricated on high-resistivity silicon. Our devices use a transmon qubit with a shunt capacitor that simultaneously serves as an interdigital transducer embedded in a surface acoustic wave resonator. By tuning the qubit transition into resonance with discrete mechanical modes, we observe up to a factor-of-two reduction in qubit lifetime, consistent with energy exchange between the qubit and mechanical modes mediated by piezoelectric coupling at the aluminum-silicon interface. Our findings provide direct evidence for interface piezoelectricity as a distinct loss channel in superconducting qubits. Combined with multiphysics simulations, these findings suggest that interface piezoelectric loss can dominate over loss from two-level systems at sufficiently high frequencies. △ Less

Submitted 14 May, 2026; originally announced May 2026.

Rongzai agent: A Large Language Model-Based Autonomous Assistant for Rietveld Refinement of Neutron Diffraction Data

Authors: Qingmeng Li, Hao Wang, Dongbo Xiong, Jiajun Zhong, Wenhai Ji, Hao Hu, Yiyu Zhang, Bolun Zhang, Hong Wang, Yongfeng Zhu, Rong Du, Zhengde Zhang, Fazhi Qi, Junrong Zhang

Abstract: Neutron diffraction (ND) is an indispensable technique for determining atomic positions (especially light elements) and thus serves as a critical probe for revealing microscopic structures in materials science. However, traditional Rietveld refinement of ND data relies heavily on manual operation of specialized software, which is time-consuming, labor-intensive, and highly dependent on user expert… ▽ More Neutron diffraction (ND) is an indispensable technique for determining atomic positions (especially light elements) and thus serves as a critical probe for revealing microscopic structures in materials science. However, traditional Rietveld refinement of ND data relies heavily on manual operation of specialized software, which is time-consuming, labor-intensive, and highly dependent on user expertise, severely hindering automated analysis. The automation of Rietveld refinement has long been a long-standing and challenging problem in crystallography. To address this challenge, this paper presents the Dr.Sai-Rongzai agent, an autonomous refinement assistant based on a large language model (LLM), a specialist knowledge base, and the GSAS-II refinement engine, achieving for the first time an intelligent refinement that integrates knowledge-driven decision-making. The agent accomplishes a fully automated workflow from natural language task parsing to autonomous decision-making, execution of refinement strategies, and report generation. Evaluation on five representative samples shows that the Rongzai agent achieves lower Rwp values than human specialists on three samples (2.88% vs. 4.42%, 5.06% vs. 5.40%, 7.60% vs. 9.00%), while on the other two samples its results are very close to those of the specialists. The agent is currently deployed at the China Spallation Neutron Source (CSNS) and is open for external user registration, providing an intelligent and user-friendly analytical tool for materials research. This work fully leverages the cutting-edge advantages of LLM, offers a new path to solve the long-standing problem of automated refinement, takes a key step toward intelligent and fully automated crystallographic analysis, and holds great potential to accelerate AI for Science discoveries in neutron-based materials characterization. △ Less

Submitted 13 May, 2026; originally announced May 2026.

Microscopic resonant-shell mechanism for slow Liouvillian sectors in an open correlated lattice

Authors: X. Z. Zhang

Abstract: We develop a microscopic theory for how slow Liouvillian sectors are selected in an open correlated lattice. The starting point is not a postulated non-Hermitian band, but a local interacting resonance between an on-site doublon and a branch-resolved nearest-neighbor bond. This resonance defines a composite shell orbital whose doublon weight controls reservoir visibility and whose mixed doublon-bo… ▽ More We develop a microscopic theory for how slow Liouvillian sectors are selected in an open correlated lattice. The starting point is not a postulated non-Hermitian band, but a local interacting resonance between an on-site doublon and a branch-resolved nearest-neighbor bond. This resonance defines a composite shell orbital whose doublon weight controls reservoir visibility and whose mixed doublon-bond character controls shell mobility. Projecting the microscopic hopping onto the selected shell yields a branch-selective dimerized channel. In the dilute regime, a boundary doublon-loss channel yields an exponentially slow edge-memory pole through a Zeno-type return. At the shell-critical point, the edge pole is replaced by a near-zero standing-wave doublet with an algebraic coherent spacing. At finite shell filling, the same local shell becomes density dressed. A number-conserving phase-locking jump removes a bright mismatch sector, leaving defects as the asymptotic slow variables and producing a diffusive finite-size gap. We derive the local shell, the projected branch topology, the edge-memory law, the shell-critical doublet, the density-dressed shell Hamiltonian, and the defect generator within one Schur-projection framework. The resulting mechanism identifies the reservoir-engineered fast block as the selector of the observable slow sector, while the microscopic parent shell remains fixed. △ Less

Submitted 9 May, 2026; originally announced May 2026.

Comments: 13 pages, 7 figures