Axion topology in photonic crystal domain walls.

Axion insulators are 3D magnetic topological insulators supporting hinge states and quantized magnetoelectric effects, recently proposed for detecting dark-matter axionic particles via their axionic excitations. Beyond theoretical interest, obtaining a photonic counterpart of axion insulators offers potential for advancing magnetically-tunable photonic devices and axion haloscopes based on axion-photon conversion. This work proposes an axionic 3D phase within a photonic setup. By building inversion-symmetric domain-walls in gyrotropic photonic crystals, we bind chiral modes on inversion-related hinges, ultimately leading to the realization of an axionic channel of light. These states propagate embedded in a 3D structure, thus protected from radiation in the continuum. Employing a small external gyromagnetic bias, we transition across different axionic mode configurations, enabling effective topological switching of chiral photonic fibers. While demonstrating the possibility of realizing axion photonic crystals within state-of-the-art gyrotropic setups, we propose a general scheme for rendering axion topology at domain walls of Weyl semimetals.

Spin-resolved topology and partial axion angles in three-dimensional insulators.

Symmetry-protected topological crystalline insulators (TCIs) have primarily been characterized by their gapless boundary states. However, in time-reversal- ([Formula: see text]-) invariant (helical) 3D TCIs-termed higher-order TCIs (HOTIs)-the boundary signatures can manifest as a sample-dependent network of 1D hinge states. We here introduce nested spin-resolved Wilson loops and layer constructions as tools to characterize the intrinsic bulk topological properties of spinful 3D insulators. We discover that helical HOTIs realize one of three spin-resolved phases with distinct responses that are quantitatively robust to large deformations of the bulk spin-orbital texture: 3D quantum spin Hall insulators (QSHIs), "spin-Weyl" semimetals, and [Formula: see text]-doubled axion insulator (T-DAXI) states with nontrivial partial axion angles indicative of a 3D spin-magnetoelectric bulk response and half-quantized 2D TI surface states originating from a partial parity anomaly. Using ab-initio calculations, we demonstrate that ß-MoTe2 realizes a spin-Weyl state and that α-BiBr hosts both 3D QSHI and T-DAXI regimes.

Geometric characterization of anomalous Landau levels of isolated flat bands.

According to the Onsager's semiclassical quantization rule, the Landau levels of a band are bounded by its upper and lower band edges at zero magnetic field. However, there are two notable systems where the Landau level spectra violate this expectation, including topological bands and flat bands with singular band crossings, whose wave functions possess some singularities. Here, we introduce a distinct class of flat band systems where anomalous Landau level spreading (LLS) appears outside the zero-field energy bounds, although the relevant wave function is nonsingular. The anomalous LLS of isolated flat bands are governed by the cross-gap Berry connection that measures the wave-function geometry of multi bands. We also find that symmetry puts strong constraints on the LLS of flat bands. Our work demonstrates that an isolated flat band is an ideal system for studying the fundamental role of wave-function geometry in describing magnetic responses of solids.

Topological acoustic triple point.

Acoustic phonon is a classic example of triple degeneracy point in band structure. This triple point always appears in phonon spectrum because of the Nambu-Goldstone theorem. Here, we show that this triple point can carry a topological charge [Formula: see text] that is a property of three-band systems with space-time-inversion symmetry. The charge [Formula: see text] can equivalently be characterized by the skyrmion number of the longitudinal mode, or by the Euler number of the transverse modes. We call triple points with nontrivial [Formula: see text] the topological acoustic triple point (TATP). TATP can also appear at high-symmetry momenta in phonon and spinless electron spectrums when Oh or Th groups protect it. The charge [Formula: see text] constrains the nodal structure and wavefunction texture around TATP, and can induce anomalous thermal transport of phonons and orbital Hall effect of electrons. Gapless points protected by the Nambu-Goldstone theorem form a new platform to study the topology of band degeneracies.

Epileptic nystagmus and vertigo associated with bilateral temporal and frontal lobe epilepsy.

Epileptic nystagmus is defined as a quick, repetitive jerky movement of the eyeball associated with seizure activity. In cases of epileptic nystagmus associated with ictal discharge from multiple brain areas, localization of the exact epileptogenic zone could be extremely difficult. In a nine-year-old patient with epileptic nystagmus and vertigo associated with bilateral temporal and frontal lobe epilepsy, we could infer the epileptic focus by interpreting the patient's clinical picture, characteristics of nystagmus, and findings of electroencephalography.

Septoplasty improves life quality related to allergy in patients with septal deviation and allergic rhinitis.

OBJECTIVE: Evaluate the effect of septoplasty on the clinical course of allergic rhinitis by comparing (1) symptom change using the Visual Analogue Scale (VAS), (2) change of the medication score, and (3) improvement of the quality of life using a questionnaire. STUDY DESIGN: Prospective pilot. SETTING: Academic tertiary rhinological practice. SUBJECTS AND METHODS: Sixty-two patients who had undergone septoplasty and turbinoplasty for septal deviation and allergic rhinitis were enrolled in group A. Twenty-six patients who had undergone only turbinoplasty for allergic rhinitis were enrolled in group B. The VAS score, the Average Rescue Medication Score (ARMS), and the Rhinasthma Questionnaire for the quality of life were all obtained from each patient. These parameters were compared before and after the surgery and between the groups. RESULTS: Both groups showed significant improvement of the VAS score (P < .001). When the change of VAS was compared between groups, there was a significant difference in group A only for nasal obstruction (P = .047). Comparison of the ARMS between groups showed significant improvement in both groups after the surgery (P < .01). However, there were no differences between the groups. The Rhinasthma score of group A was significantly lowered after the surgery (56.4 ± 13.2 to 34.1 ± 12.3, P < .001). The Rhinasthma score of group A was significantly lower than that of group B after the surgery (P = .004). CONCLUSIONS: This is the first research about the potential effect of septoplasty on the clinical course of allergic rhinitis. Further studies are needed to elucidate the mechanisms underlying these effects.