arXane › Physics › Condensed Matter
Wednesday, 4 November 2026: 2 new papers, 3 cross-lists and 3 replacements in Other Condensed Matter (cond-mat.other), in arXiv's order, with full abstracts. The same papers as arXiv's own listing, set as a newspaper; every title links to arXiv.
A mechanical version of the SSH model, made of equal masses joined by two alternating non-linear springs is studied in the continuum limit. Such a non-linear dimerized mechanical chain generates a nonlinear, dispersive, two-field hyperbolic system of Boussinesq type of differential equations, describing coupled acoustic and gapped optical fields. The corresponding Lagrangian density is found, revealing that the acoustic and optical degrees of freedom are coupled through a structure that is formally analogous to a synthetic spin-orbit coupling, where the spatial motion is locked to the internal sublattice degree of freedom. An emergent non-Abelian Berry connection term also appears. Some particular solitary-wave solutions are found using variational theory, as the effective optical field obeys an undamped and unforced cubic-quintic Duffing equation. Near the Brillouin-zone edge, the system becomes a nonlinear Dirac field theory of the Soler type, providing a direct mechanical realization of interacting relativistic solitons. By factoring out fast spatial oscillations, an effective Jackiw-Rebbi Hamiltonian is obtained, with topological zero modes at domain walls. These modes are akin to the electronic flat bands in moire graphene systems associated with superconductivity and charge fractionalization. Finally, we discuss the mechanical rigidity transition and its effects on the fields as the system evolves toward the fully dimerized limit, in which the zero modes are floppy modes.
Electrically reconfigurable spin-wave transport is central to realizing energy-efficient magnonic information technologies, yet existing current-driven approaches require current densities that undermine the fundamental dissipation advantage of spin-wave-based signal processing. Here, we demonstrate low-power electrical control of spin-wave propagation in a hybrid magnonic device comprising a low-damping yttrium iron garnet (YIG) film coupled to an adjacent vanadium dioxide ($\small\text{VO}_{2}$) stripe. Passing a small current through $\small\text{VO}_{2}$ triggers its insulator-to-metal transition (IMT), producing a sharp, reversible resistivity reduction exceeding three orders of magnitude. This abrupt phase transition locally modifies the spin-wave dispersion in YIG, reducing the group velocity and suppressing transmission by up to 40 dB near the ferromagnetic resonance frequency. Pulsed current excitation enables reconfiguration of spin-wave transport on a 10 ms timescale. Temperature-dependent measurements, corroborated by thermal modeling, decouple the respective contributions of current-induced heating of YIG and the IMT in $\small\text{VO}_{2}$, establishing the latter as the dominant control mechanism. Our results demonstrate that electrically induced phase transitions in correlated oxides constitute an energy-efficient strategy for dynamic spin-wave manipulation, providing a scalable route toward reconfigurable magnonic devices.
Proton transfer is responsible for the anomalous high conductivity in acidic or basic aqueous solutions. Yet, the contribution of the proton transfer mechanism to the conductivity of concentrated aqueous solutions is unknown. In this work, we compute the transport properties of KOH(aq) systems with different concentrations, using Molecular Dynamics simulations with a Machine Learning Interatomic Potential (MLIP), which includes proton transfer. We quantify the contribution of the proton transfer mechanism to the diffusivities of hydroxide ions and water molecules, and the ionic conductivity and transport numbers of the electrolytes. The contribution is substantial at lower concentrations, but diminishes at very high concentrations.
The complete statistical characterization of defects generated in a quantum phase transition has mostly been studied in exactly solvable models, and remains little explored in nonintegrable systems such as long-range interacting spin chains. We characterize the full defect counting statistics in a nonintegrable long-range spin chain, the fractional Ising model, by time-dependent variational-principle simulations within the matrix-product-state and matrix-product-operator formalism. Fractional interactions capture emergent multiscale correlations and long-range effects in nature, governed by the order of the underlying fractional derivative. Such couplings can be approximated on existing quantum simulation platforms, where the full defect statistics can be measured. The defect number cumulants follow power laws in the driving time, with exponents that vary continuously with the fractional order. At low fractional order, deep in the long-range regime, the mean defect number decays more slowly than predicted by the Kibble-Zurek mechanism (KZM), while at intermediate order the KZM holds with the numerically extracted many-body critical exponents. At large fractional order, the exactly solvable free-fermion limit of the model becomes progressively more accurate towards the short-range limit. We derive exact bounds on the kink-number cumulants and on the kink-kink correlations, implying an exact Gaussian limiting distribution for large system sizes. In the many-body simulations, however, kinks are more correlated, consistent with the confinement of domain walls, and these bounds are violated in the long-range regime, also in the bulk of the chain. Nevertheless, the kink distribution still approaches a Gaussian for large defect numbers, with proportionality partially broken between the cumulants.
Minimal model and its linear stability analysis (LSA) for Plateau-Rayleigh (PR) instability of an intermixed, solid binary alloy nanowire is presented. Model accounts only for the surface diffusions of the alloy components without anisotropies of a surface energies, and for a classical thermodynamic surface segregation. Model allows to assess a deviation of a longwave instability cutoff wavelength $\lambda_c$ from the classical value $2\pi r_0$ (a wire circumference) as a function of a surface composition deviation from its equilibrium value, a wire radius, and a bulk concentration of a minority component. Results of LSA are presented for AuNi, PtNi, and CoNi nanowires, where an important distinction is that a surface segregation curve for CoNi is qualitatively different from the one for AuNi and PtNi. For each nanowire there is a sizable region of a parameter space where $\lambda_c<2\pi r_0$ and correspondingly, a fastest growing perturbation wavelength $\lambda_{max}$ is also less than a wire circumference. This is in stark contrast to PR instability of a single-component nanowire transporting mass by surface diffusion - in this case $\lambda_c$ and $\lambda_{max}$ are larger than a wire circumference. Strong surface segregation is primarily responsible for unusually small $\lambda_c$ and $\lambda_{max}$. Results suggest that a large number of small and closely spaced nanoparticles may emerge upon disintegration via annealing of a binary alloy nanowire.