We propose Majorana-assisted nonlocal spin correlation as a manifestation of Majorana nonlocality in quasi-one-dimensional (1D) Kitaev spin liquids. Focusing on the flux-free sector of the Kitaev honeycomb model in a quasi-1D geometry, we uncover its topological nature and show that it hosts Majorana zero modes localized at both ends, which are stabilized by finite-size-induced topology. We further show that the nonlocal Majorana fermion parity operator, $P_{\text{MF}}=i{\gamma }_L{\gamma }_R$, is mapped to a nonlocal spin-string operator, producing an end-to-end spin correlation proportional to the product of $P_{\text{MF}}$ and total fermion parity operators when local perturbations remove redundant ground-state degeneracies while preserving the Majorana and total fermion parities in the flux-free sector. Numerical calculations confirm a finite nonlocal spin correlation generated by these Majorana zero modes without any local magnetization. Our results establish a concrete signature of intrinsic Majorana nonlocality in quantum spin liquids.

Antisite disorder is a crystallographic defect that normally disrupts lattice continuity and dilutes magnetism. However, in some rare cases, instead of being suppressed, the spin order is reconfigured by antisite disorder, the detailed process of which, as well as the microscopic mechanism for the presence of antisite disorder, remains elusive. Here, we address these issues by investigating a newly synthesized postspinel oxide ${\mathrm{CaZnFe}}_2{\mathrm{O}}_5$, prepared through a high-pressure and high-temperature approach. Combined neutron diffraction and bulk magnetization measurements reveal A-type magnetic order below $T_{\mathrm{N}}\approx 190$ K, accompanied by a small uniform spin canting, possibly triggered by Dzyaloshinskii–Moriya interactions. Meanwhile, neutron refinement reveals a pronounced $\mathrm{Z}{\mathrm{n}}^{2+}$ and $\mathrm{F}{\mathrm{e}}^{3+}$ antisite disorder by 1/3, which, corroborated by Heisenberg model simulations, reshapes the competing exchange interaction network, converting the otherwise incommensurate magnetic ground state into an A-type spin configuration. First-principles calculations yield a much smaller energy increase in ${\mathrm{CaZnFe}}_2{\mathrm{O}}_5$ (89 meV per formula unit, f.u.) than in ${\mathrm{CaCuFe}}_2{\mathrm{O}}_5$ (340 meV/f.u.) upon antisite defect, providing quantitative support for the role of the lack of a Jahn–Teller distortion in facilitating the pronounced Zn and Fe antisite disorder, which profoundly impacts the macroscopic magnetic properties by reconfiguring exchange pathways.

We investigate the emergence of nontrivial topology in a twisted cuprate bilayer described by the Hubbard model in the weak-interaction regime. Our results show that the topological character depends sensitively on the doping level. For $U/t=3.85$, the Chern number assumes a value of $\pm 8$ in the electron-doped case, whereas it vanishes (0) in the hole-doped regime. The presence of nontrivial topology is further supported by an analysis of the associated edge states and their chirality in a finite-width geometry, while keeping full correlations.

We show that the transconductance of multilayer ${\mathrm{WSe}}_2$ field-effect transistors serves as a direct electrical spectrometer of the intervalley relaxation time ${\tau }_{\mathrm{iv}}$, previously accessed mainly by ultrafast optical techniques. Extending an equilibrium valley-thermodynamics framework with a single relaxation equation for the $\mathrm{\Gamma }$-valley carrier fraction $f_{\mathrm{\Gamma }}\left(t\right)$, we predict three signatures: (i) a Lorentzian transconductance $g_m\left(\omega \right)=g_{m,0}+g_{m,v}^0/(1+i\omega {\tau }_{\mathrm{iv}})$, whose imaginary part peaks at ${\omega }_c={\tau }_{\mathrm{iv}}^{-1}$ with opposite signs for bilayer and trilayer; (ii) a two-stage current transient after a gate step, exhibiting bilayer overshoot or trilayer undershoot; and (iii) sweep-rate-proportional hysteresis whose gate-voltage profile and the layer-dependent transconductance sign reversal distinguish valley from trap-induced dynamics. All three signatures provide quantitative electrical access to ${\tau }_{\mathrm{iv}}$ with standard radio-frequency (rf) and direct-current (dc) instrumentation.

Axis-dependent conduction polarity (ADCP) and nonsaturating magnetoresistance (MR) are distinct transport responses that both reflect anisotropic carrier dynamics governed by Fermi surface geometry. Here, we combine density functional theory and semiclassical Boltzmann transport calculations to investigate the evolution of magnetotransport in ${\mathrm{MgB}}_2$, a model system containing a band saddle point near the Fermi level. Tuning the chemical potential (μ) across the saddle point induces a Lifshitz transition with the emergence of open Fermi surface sheets. During this evolution, the calculated Hall response exhibits polarity reversal, whereas the magnetoresistance changes from saturating to nonsaturating behavior involving open orbits. Opposite Hall contributions from convex and concave portions of the same Fermi surface modify the degree of compensation and thereby shape the field dependence of the calculated magnetoresistance. Calculations for ${\mathrm{CaB}}_2$ and ${\mathrm{SrB}}_2$ reveal analogous Fermi surface features, extending the discussion to layered diborides. These results reveal a microscopic connection between ADCP and nonsaturating MR through the evolution of the Fermi surface and offer a basis for analyzing anisotropic magnetotransport in comparable materials.

Achieving nonvolatile and multistate manipulation of charge-spin conversion, including the Edelstein effect (EE) and spin Hall effect (SHE), is crucial for high-density spintronic memory. Here, we propose a mechanism to simultaneously control both EE and SHE in two-dimensional ferroelectric bilayers, where interlayer-parallel and interlayer-antiparallel polarization configurations can coexist. Symmetry analysis shows that in the interlayer-parallel states, reversal of the total polarization switches the sign of the EE, whereas changing to an interlayer-antiparallel configuration suppresses the EE to zero, enabling electrically switchable current-induced spin accumulation among three distinct states that could be used for ternary logic operations. Meanwhile, the magnitude of the SHE can be tuned by switching between two different classes of polarization configurations (interlayer-parallel and interlayer-antiparallel). Using first-principles calculations, we demonstrate this mechanism in bilayer metallic ferroelectric ${\mathrm{PtBi}}_2$, where both interlayer-parallel and interlayer-antiparallel polarization configurations are energetically stable. The EE coefficient ${\chi }_{yx}$ in interlayer-parallel states, which reaches ${10}^9–{10}^{10}\hslash /\left(\text{A}\text{cm}\right)$ near the Fermi energy and can be reversed by polarization switching, arises from competing electron- and hole-pocket contributions near the Fermi surface. The intrinsic SHE coefficients, which are in the range of 100–1000 $(\hslash /e)\left(\text{S/cm}\right)$ near the Fermi energy, originate from spin Berry curvature that can be reshaped by polarization configuration variation and Fermi-level tuning. Our results establish ferroelectric bilayers as an all-in-one platform for electrically programmable charge-spin conversion.

Quantum interfaces are a cornerstone of photonic quantum computing protocols. They consist of quantum emitters coupled to propagating light pulses, enabling the reversible transfer of information between emitter degrees of freedom, such as energy or spin, and photonic degrees of freedom, including polarization or photon number. In practice, propagating light pulses are multimode wave packets and can undergo substantial spectral distortions during their interactions with the emitters. This effect introduces an intrinsic source of decoherence that has been largely overlooked in early proposals based on idealized monochromatic fields. Here, we investigate the consequences of this decoherence for three key protocols implemented with a solid-state spin-photon interface: the generation of photon-number superposition states, the realization of a controlled photon-photon gate, and the generation of photonic cluster states. Our analysis is based on a full Hamiltonian description of the joint emitter-field dynamics. The model further incorporates realistic features of the quantum dot spin dynamics, including decoherence induced by hyperfine interactions. From this framework, we derive analytical expressions for the resulting fidelity losses. Our results demonstrate a pronounced degradation of performance for the photon-photon gate, a moderate reduction in the fidelity of linear photonic cluster states, and a negligible impact on the generation of photon-number superpositions. These findings highlight the critical role of multimode effects in assessing the feasibility and scalability of photonic quantum information protocols.

Symmetry plays a fundamental role in many-body systems, both in and out of equilibrium. The quantum Mpemba effect (QME)—a phenomenon where systems initially farther from equilibrium can thermalize faster—can be understood in terms of how rapidly a symmetry, broken by initial conditions, is dynamically restored. In this work, we study the QME in a one-dimensional spin-1/2 XYZ model with power-law decaying interactions in the presence of a magnetic field. In the prethermal regime generated by large field strengths, the system develops a continuous U(1) symmetry, enabling the QME to emerge. However, due to the Hohenberg-Mermin-Wagner theorem, the QME can only arise when interactions are sufficiently short-ranged. This leads to an interplay between the external field, interaction range, and dynamical symmetry restoration. We systematically explore this interplay and analyze the dependence of the QME on the effective temperature set by the initial state. Our results demonstrate the tunability of the QME via long-range interactions, which can be probed in experimental platforms of trapped ions, polar molecules, and NV centers.

Magnetic suppression of the non-Hermitian skin effect (NHSE) offers a viable route for its control. While the NHSE has been realized in various classical-wave platforms, only pseudomagnetic fields (PMFs), which preserve time-reversal symmetry, can be engineered in such systems; however, their interplay with the NHSE remains underexplored. Here, we investigate this interplay in a non-Hermitian honeycomb lattice by considering two distinct mechanisms for generating PMFs: monotonically increasing strain and spatially modulated gain and loss. We show that in both scenarios, PMFs can efficiently suppress the NHSE by driving skin modes into the bulk, accompanied by a reduction of the skin topological area and a contraction of the complex-energy spectrum under periodic boundary conditions. This mechanism is insensitive to boundary details and holds for various edge terminations, including zigzag, bearded, armchair, and twig edges. Our results establish PMFs as a versatile and effective means to control the NHSE, and point toward feasible implementations in a broad range of artificial platforms, including photonic and acoustic metamaterials as well as topolectrical circuits.

We study the van der Waals-London force, which is typically associated with fluctuating electric dipoles in atoms, in a mesoscopic circuit consisting of two inductively coupled superconducting loops. We investigate the inductive van der Waals-London interaction using both semiclassical and quantum electrodynamic (QED) approaches. The semiclassical model predicts a repulsive interaction due to anticorrelated current fluctuations. In contrast, the QED framework, which incorporates virtual photon exchange, reveals a predominantly attractive force. A key contribution comes from a state-independent two-photon exchange, which is absent in the semiclassical description and undetectable by spectroscopy. Our study introduces a theoretical framework for exploring the van der Waals force between individual artificial atoms via controlled mesoscopic circuits.

Boson peak dynamics in glasses produce a robust crossover in the terahertz (THz) dielectric response that standard Debye or Lorentz models do not capture. We develop a continuum description of this THz response, coupling an infrared-effective charge fluctuation spectrum to a frequency-dependent shear modulus, and apply it to glycerol glass. The model reproduces the measured complex dielectric function and the nearly linear infrared light-vibration coupling around the boson peak, and it highlights the dominant role of transverse shear dynamics.

Altermagnetism represents a novel magnetic phase combining zero net magnetization with momentum-dependent spin splitting. Here, we theoretically investigate the Landau levels and magneto-optical conductivity in $d$-wave altermagnets, explicitly incorporating the orientation of the anisotropic spin-split Fermi surfaces. We derive exact analytical solutions for the system in the absence of spin-orbit coupling. Although the Landau-level energy spectrum remains isotropic, the optical response retains the anisotropic nature of the altermagnet, manifesting as a $\pi$-periodic modulation. Additionally, we investigate the topological phase transitions arising from the interplay of Rashba spin-orbit coupling and the Dirac mass. We demonstrate that the magneto-optical conductivity spectrum provides characteristic signatures such as the sign reversal of the circular conductivity and anomalous peak splitting. Our findings demonstrate that magneto-optical spectroscopy can serve as a versatile probe for detecting both the altermagnetic orientation of the spin-split Fermi surfaces and topological phase transitions, providing theoretical guidance for future optospintronic applications.

Quasicrystals (QCs) host long-range order without translational symmetry, a regime in which the very foundations of BCS theory are not straightforwardly applicable, yet experiments on QCs and their approximant crystals (ACs) point to conventional, $s$-wave, electron–phonon-coupled superconductivity. Here, we test the predictive power of the electron–phonon framework in a representative decagonal AC from first principles. Using state-of-the-art ab initio methods, we compute the superconducting properties of the recently discovered AC ${\mathrm{Al}}_{13}{\mathrm{Os}}_4$ and quantitatively reproduce its bulk $T_{\text{c}}$. This provides an ab initio determination of $T_{\text{c}}$ for an AC and establishes that the electron–phonon framework is predictive in these systems. Using the generalized quasichemical approximation for alloy modeling in the decagonal Al–Os family, we predict tunable superconductivity in ${\mathrm{Al}}_{13}{\mathrm{Os}}_{4-x}{\mathrm{Re}}_x$ and ${\mathrm{Al}}_{13}{\mathrm{Os}}_{4-x}{\mathrm{Ir}}_x$; in particular, ${\mathrm{Al}}_{13}{\mathrm{Re}}_4$ is dynamically stable and estimated to have a $T_{\text{c}}$ about 30% above that of ${\mathrm{Al}}_{13}{\mathrm{Os}}_4$. Finally, we discuss the role of ACs as high-fidelity proxies for their parent QCs. Although long-range quasiperiodicity may introduce subtle electronic features, our findings indicate that the key ingredients for superconductivity are already encoded in the local structural motifs preserved by the AC. This places the Al–Os and Al–Re families among the most promising candidates for the highest-$T_{\text{c}}$ quasicrystalline superconductivity.

We investigate high-energy spin excitations in hole-doped ${\mathrm{La}}_{2-x}{\mathrm{Ca}}_x{\mathrm{CuO}}_{4-\delta }$ (LCCO) films across a broad Ca doping range ($x=0.05–0.50$) using resonant inelastic x-ray scattering (RIXS). Polarization analysis and incident-photon energy detuning measurements confirm the persistence of collective paramagnon excitations up to $x=0.50$. Consistent with previous studies on other cuprate families, we observe a pronounced crossover near $x=0.15$, where paramagnon spectral weight is transferred to incoherent spin-flip excitations associated with the particle-hole continuum. The overall behavior of paramagnons in LCCO resembles that in other hole-doped cuprates and appears insensitive to the persistence of superconductivity at high doping levels in LCCO—up to at least $x=0.50$, as demonstrated in prior work. These findings support the view that high-energy magnetic excitations probed by RIXS are not a major contributor to superconducting pairing, in line with theories of spin-fluctuation mediated superconductivity.

The conventional empirical treatment of defect scattering fails to accurately capture carrier transport behavior under realistic doping conditions. Here, we demonstrate a precise first-principle computational approach for modeling doping behavior in semiconductors under various doping elements and concentrations. The methodology is applied to cubic silicon carbide (3C-SiC) to evaluate dopant performance. Based on first-principles calculations and self-consistent Fermi level determination, we obtained realistic, temperature-dependent defect concentrations consistent with experiments. Unlike empirical models, defect scattering strongly depends on defect types. In nitrogen- and phosphorus-doped systems, ionized defect scattering dominates at low temperatures, while phonon scattering becomes dominant at higher temperatures. In aluminum-doped systems, an unconventional temperature-dependent trend was found. Phonon and ionized defect scattering collectively contribute to the transport properties at low temperatures, while ionized defect scattering gradually becomes the dominant scattering mechanism at higher temperatures. The calculated electron and hole mobilities both show good agreement with experimental data. The study provides crucial insights into defect-limited carrier transport and offers guidance for optimizing doping strategies in 3C-SiC-based electronic devices.

Grain-boundary-mediated dislocation nucleation controls the onset of plasticity in crystalline materials, yet its atomistic kinetics are difficult to resolve because conventional molecular dynamics (MD) rarely reaches the timescales relevant to these processes. Accelerated MD methods based on collective variables (CVs), such as adaptive boost MD (ABMD), can overcome this limitation, but they generally require the rare event of interest to be specified a priori. Here, we present an exploration-driven workflow for quantitative accelerated MD and apply it to dislocation nucleation from a Cu Σ9 symmetric tilt grain boundary under uniaxial tension. In the exploratory stage, we modify shuffling accelerated MD (SAMD) by replacing the nearest-neighbor off-centering absolute displacement with the smoother nearest-neighbor off-centering displacement, thereby reducing artifacts while efficiently sampling rare events. The sampled initial and final states are then used to identify the transition pathway, and a CV constructed nonempirically from the saddle-point structure is employed in ABMD for quantitative free-energy evaluation. This workflow captures the stress-dependent transition in grain-boundary dislocation nucleation from a single-dislocation mode to a multiple-dislocation mode without prescribing the mechanism in advance. The switching stress between the two modes is consistent with previous studies, and the activation free energies obtained by ABMD vary smoothly with stress and agree with those obtained from conventional MD where direct comparison is possible. These results show that the present methodology combines mechanistic discovery with quantitative accuracy, providing a general route for identifying and evaluating competing defect-activation processes in solids.

Magnetic nanoparticles (MNPs) are central to magnetic particle imaging (MPI) and magnetic hyperthermia. The intrinsic properties of MNPs critically determine the performance of each modality individually. The integration of imaging and therapy within a single MPI-hyperthermia platform is especially attractive, as it enables mapping of MNP tracer distribution using MPI prior to thermal treatment, thereby guiding the subsequent delivery of localized hyperthermia. In such dual-functional systems, however, nanoparticle properties play a more complex and potentially different role than in standalone applications. Understanding how these intrinsic characteristics govern the sequential imaging and heating performance within a unified platform is therefore essential for the rational design of effective theranostic systems. Nevertheless, the impact of the nanoparticles’ inherent characteristics on achieving optimal imaging and heating performance across both imaging and therapeutic stages has not yet been thoroughly investigated. In this work, we present a comprehensive modeling-based framework to optimize dual-functional MPI-hyperthermia performance by systematically investigating three MNP core sizes (20, 25, and 30 nm) over broad ranges of anisotropy constants and saturation magnetizations using a stochastic Langevin model. Magnetization dynamics are evaluated at 25 kHz (for MPI use) and 350 kHz (for hyperthermia use) alternating magnetic fields. Performance is quantified using the full width at half-maximum and signal-to-noise ratio to assess MPI spatial resolution and signal quality, respectively, and the specific absorption rate to evaluate hyperthermia efficiency. The competing behavior of these performance metrics is first analyzed through direct visualization of the simulated data, revealing clear trade-offs between spatial resolution, signal quality, and heating efficiency. To capture the underlying nonlinear relationships more rigorously, Gaussian process surrogate models are constructed for each metric and validated for predictive accuracy. Building on these models, a multiobjective optimization framework is employed to identify optimal combinations of anisotropy constant and saturation magnetization for each core size that balance MPI and hyperthermia performance. The results demonstrate a strong dependence of the optimal parameter regions on MNP core size, with distinct trade-offs emerging between imaging and therapeutic objectives. This study provides a systematic and extensible framework for the rational design of dual-functional MNPs and offers quantitative guidance for optimizing particle properties in combined MPI-guided magnetic hyperthermia applications.

Tuning the propagation characteristics of spin waves (or magnons) is a central task in antiferromagnetic magnonics. Here, we theoretically investigate the spin-wave flat band (FB) behavior in antiferromagnetic magnonic crystals formed by a periodic Dzyaloshinskii-Moriya interaction (DMI). The conditions required for the emergence of magnon FBs are identified. In addition, we find that these FBs essentially describe a series of magnon standing-wave modes localized in regions of high DMI. Notably, an external magnetic field can lift the degeneracy of magnon polarization, leading to a few purely left- and right-handed magnon FBs. Micromagnetic simulations confirm the theoretical predictions with good agreement. Our work offers a simple method to obtain localized magnons with pure polarization in antiferromagnets, which may facilitate the design of diverse functional magnonic devices by harnessing the magnon polarization degree of freedom.

Kagome lattice materials have attracted considerable attention due to their intriguing topological properties and potential applications in next-generation quantum and spintronic technologies. In particular, rare-earth permanent magnets with kagome structure provide an ideal platform that combines robust magnetism with nontrivial quantum phenomena. However, their anomalous transport properties, particularly thermoelectric responses, remain insufficiently explored. In this work, we perform systematic first-principles calculations on the anomalous Hall and anomalous Nernst effects in kagome permanent magnets $R{\mathrm{Co}}_5$ ($R=\mathrm{Ce}$, La, Sm, Gd). Our calculations show that across the series, the Co-sublattice-derived electronic structure provides a common framework in which spin-orbit coupling-induced avoided crossings generate pronounced Berry-curvature hotspots near the Fermi level, leading to sizable intrinsic anomalous responses. While the quantitative values and peak positions can depend on the rare-earth element and treatment of the $4f$ sector, the underlying mechanism is common across the family. Our results establish ${R\mathrm{Co}}_5$ compounds as a promising platform for exploring Berry-curvature-driven anomalous transport.