Transverse Geometry Research Articles

Vibration Characteristics of Magnetostrictive Composite Cantilever Resonator with Nonlocal Effect.

Taking the nonlocal effect into account, the vibration governing differential equation and boundary conditions of a magnetostrictive composite cantilever resonator were established based on the Euler magnetoelastic beam theory. The frequency equation and vibration mode function of the composite cantilever were obtained by means of the separation of variables method and the analytic solution of ordinary differential equations. The lateral deflection, vibration governing equations, and boundary conditions were nondimensionalized. Furthermore, the natural frequency and modal function of the composite beam were quantitatively analyzed with different nonlocal parameters and transverse geometry dimensions using numerical examples. Compared with the results without considering the nonlocal effect, the influence of the nonlocal effect on the vibration characteristics was analyzed. The numerical results show that the frequency shift and frequency band narrowing of the magnetostrictive cantilever resonator are induced by nonlocal effects. In particular, the high-frequency vibration characteristics, such as vibration amplitude and modal node of the composite beam, are significantly affected. These analysis results can provide a reference for the functional design and optimization of magnetostrictive resonators.

Higgs branch RG flows via decay and fission

Magnetic quivers have been an instrumental technique for advancing our understanding of Higgs branches of supersymmetric theories with eight supercharges. In this work, we present the “decay and fission” algorithm for unitary magnetic quivers. It enables the derivation of the complete phase (Hasse) diagram and is characterized by the following key attributes: First and foremost, the algorithm is inherently simple, just relying on convex linear algebra. Second, any magnetic quiver can only undergo decay or fission processes; these reflect the possible Higgs branch RG flows (Higgsings), and the quivers thereby generated are the magnetic quivers of the new RG fixed points. Third, the geometry of the decay or fission transition (i.e., the transverse slice) is simply read off. As a consequence, the algorithm does not rely on a complete list of minimal transitions, but rather outputs the transverse slice geometry automatically. As a proof of concept, its efficacy is showcased across various scenarios, encompassing superconformal field theories from dimensions 3 to 6, instanton moduli spaces, and little string theories. Published by the American Physical Society 2024

Decay and Fission of Magnetic Quivers.

In exploring supersymmetric theories with eight supercharges, the Higgs branches present an intriguing window into strong coupling dynamics. Magnetic quivers serve as crucial tools for understanding these branches. Here, we introduce the decay and fission algorithm for unitary magnetic quivers. It efficiently derives complete phase diagrams (Hasse diagrams) through convex linear algebra. It allows magnetic quivers to undergo decay or fission, reflecting Higgs branch RG flows in the theory. Importantly, the algorithm generates magnetic quivers for the RG fixed points and simplifies the understanding of transverse slice geometry with no need for a list of minimal transitions. In contrast, the algorithm hints to the existence of a new minimal transition, whose geometry and physics need to be explored.

Non-perturbative Symmetries of Little Strings and Affine Quiver Algebras

We consider Little String Theories (LSTs) that are engineered by N parallel M5-branes probing a transverse ℤM geometry. By exploiting a dual description in terms of F-theory compactified on a toric Calabi-Yau threefold XN,M, we establish numerous symmetries that leave the BPS partition function \U0001d4b5N,M invariant. They furthemore act in a non-perturbative fashion from the point of view of the low energy quiver gauge theory associated with the LST. We present different group theoretical organisations of these symmetries, thereby generalising the results of [1] to the case of generic M ≥ 1. We also provide a Mathematica package that allows to represent them in terms of matrices that act linearly on the Kähler parameters of XN,M. From the perspective of dual realisations of the LSTs the symmetries found here act in highly nontrivial ways: as an example, we consider a formulation of \U0001d4b5N,M in terms of correlation functions of a vertex operator algebra, whose commutation relations are governed by an affine quiver algebra. We show the impact of the symmetry transformations on the latter and discuss invariance of \U0001d4b5N,M from this perspective for concrete examples.

Groups of basic automorphisms of chaotic Cartan foliations with Eresmann connection

The purpose of the work is to study the groups of basic automorphisms of chaotic Cartan foliations with Ehresmann connection. Cartan foliations form a category where automorphisms preserve not only the foliation, but also its transverse Cartan geometry. The group of basic automorphisms of a foliation is the quotient group of the group of all automorphisms of this foliation by the normal subgroup of leaf automorphisms with respect to which each leaf is invariant. Cartan foliations include such wide classes of foliations as pseudo-Riemannian, Lorentzian, and foliations with transversal affine connection. No restrictions are imposed on the dimension of either the foliation or the foliated manifold. Compactness of the foliated manifold is not assumed. Methods. The proof of the structure theorem for chaotic Cartan foliations is based on the application of the foliated bundle construction, commonly used in the theory of foliations with transverse geometries. Results. The main result of this paper is the theorem stating that the group of basic automorphisms of any chaotic Cartan foliation with Ehresmann connection admits the structure of a Lie group and finding estimates for the dimension of this group. In particular, it is proved that if the set of closed leaves is countable, then the group of basic automorphisms of such a foliation is countable. Conclusion. In this paper, we prove a criterion according to which the chaoticity of a Cartan foliation of type (G, H) is equivalent to the chaoticity of a locally free action of the group H on the associated parallelizable manifold. Thus, the problem of the existence of chaos in Cartan foliations with Ehresmann connection reduces to the same problem for locally free actions of a Lie group on parallelizable manifolds.

Frequency‐Resolved Optical Gating in Transverse Geometry for On‐Chip Optical Pulse Diagnostics (Laser Photonics Rev. 17(12)/2023)

Frequency‐Resolved Optical Gating in Transverse Geometry for On‐Chip Optical Pulse Diagnostics (Laser Photonics Rev. 17(12)/2023)

Frequency‐Resolved Optical Gating in Transverse Geometry for On‐Chip Optical Pulse Diagnostics

AbstractA new on‐chip diagnostic tool is developed, allowing for real‐time full characterization of waveguided ultrashort optical pulses. This technique, called transverse frequency‐resolved optical gating (T‐FROG), relies on second harmonic generation (SHG) in a transverse (surface emitting) geometry. The T‐FROG is implemented on a thin‐film lithium niobate (LN) platform, demonstrating its versatility and consistency in accurately characterizing waveguided femtosecond pulses, including information about chirp and self‐phase modulation. In contrast to traditional FROG techniques, T‐FROG represents a significant improvement as it provides temporal amplitude and phase profiles of ultrafast optical pulses directly inside photonic integrated circuits. The real‐time in situ characteristics and dynamics of optical pulses offered by T‐FROG show promise for their potential applications in the design, testing, and optimization of ultrafast photonic integrated circuits.

Azimuthal Correlations within Exclusive Dijets with Large Momentum Transfer in Photon-Lead Collisions.

The structure of nucleons is multidimensional and depends on the transverse momenta, spatial geometry, and polarization of the constituent partons. Such a structure can be studied using high-energy photons produced in ultraperipheral heavy-ion collisions. The first measurement of the azimuthal angular correlations of exclusively produced events with two jets in photon-lead interactions at large momentum transfer is presented, a process that is considered to be sensitive to the underlying nuclear gluon polarization. This study uses a data sample of ultraperipheral lead-lead collisions at sqrt[s_{NN}]=5.02 TeV, corresponding to an integrated luminosity of 0.38 nb^{-1}, collected with the CMS experiment at the LHC. The measured second harmonic of the correlation between the sum and difference of the two jet transverse momentum vectors is found to be positive, and rising, as the dijet transverse momentum increases. A well-tuned model that has been successful at describing a wide range of proton scattering data from the HERA experiments fails to describe the observed correlations, suggesting the presence of gluon polarization effects.

Chirality-induced spin selectivity in functionalized carbon nanotube networks: The role of spin-orbit coupling.

Spin-orbit coupling in a chiral medium is generally assumed to be a necessary ingredient for the observation of the chirality-induced spin selectivity (CISS) effect. However, some recent studies have suggested that CISS may manifest even when the chiral medium has zero spin-orbit coupling. In such systems, CISS may arise due to an orbital polarization effect, which generates an electromagnetochiral anisotropy in two-terminal conductance. Here, we examine these concepts using a chirally functionalized carbon nanotube network as the chiral medium. A transverse measurement geometry is used, which nullifies any electromagnetochiral contribution but still exhibits the tell-tale signs of the CISS effect. This suggests that CISS may not be explained solely by electromagnetochiral effects. The role of nanotube spin-orbit coupling on the observed pure CISS signal is studied by systematically varying nanotube diameter. We find that the magnitude of the CISS signal scales proportionately with the spin-orbit coupling strength of the nanotubes. We also find that nanotube diameter dictates the supramolecular chirality of the medium, which in turn determines the sign of the CISS signal.

Numerical Study of the Impact of Transverse Ribs on the Energy Potential of Air-Based BIPV/T Envelope Systems

Overheating in BIPV/T applications is a concern due to its negative impacts on the electrical conversion efficiency of the solar cells. Forced air cooling can be an effective thermal management strategy. However, its effectiveness is limited by the thermal resistance associated with the boundary layer formation on the walls of the air channel. The heat transfer effectiveness can be improved by appending transverse ribs to the BIPV/T air channel. This study numerically investigates the energy improvements associated with appending transverse ribs to a BIPV/T air channel using CFD. The impact of the varying the transverse rib roughness shape, pitch and height on the thermo-hydraulic performance parameter, electrical efficiency of the BIPV and building heating/cooling load is quantified. With the optimized transverse rib geometry, the heat removal rate is 2.73 times greater than with the smooth channel. This translated to a 30.5% reduction in the PV surface temperature and an increase in the electrical efficiency by 11.3% compared with the smooth channel under peak summer conditions for a mild oceanic climate. The wall heat gain during summer is also reduced by 45.2%.

Large Anomalous Nernst Effects at Room Temperature in Fe3 Pt Thin Films.

Heat current in ferromagnets can generate a transverse electric voltage perpendicular to magnetization, known as anomalous Nernst effect (ANE). ANE originates intrinsically from the combination of large Berry curvature and density of states near the Fermi energy. It shows technical advantages over the conventional longitudinal Seebeck effect in converting waste heat to electricity due to its unique transverse geometry. However, materials showing giant ANE remain to be explored. Herein,a large ANE thermopower of Syx ≈ 2 µV K-1 at room temperature in ferromagnetic Fe3 Pt epitaxial films is reported, which also show a giant transverse thermoelectric conductivity of αyx ≈ 4 A K-1 m-1 and a remarkable coercive field of 1300Oe. The theoretical analysis reveals that the strong spin-orbit interaction in addition to the hybridization between Pt 5d and Fe 3d electrons leads to a series of distinct energy gaps and large Berry curvature in the Brillouin zone, which is the key for the large ANE. These results highlight the important roles of both Berry curvature and spin-orbit coupling in achieving large ANE at zero magnetic field, providing pathways to explore materials with giant transverse thermoelectric effect without an external magnetic field.

Enhanced spin Seebeck effect via oxygen manipulation

Spin Seebeck effect (SSE) refers to the generation of an electric voltage transverse to a temperature gradient via a magnon current. SSE offers the potential for efficient thermoelectric devices because the transverse geometry of SSE enables to utilize waste heat from a large-area source by greatly simplifying the device structure. However, SSE suffers from a low thermoelectric conversion efficiency that must be improved for widespread application. Here we show that the SSE substantially enhances by oxidizing a ferromagnet in normal metal/ferromagnet/oxide structures. In W/CoFeB/AlOx structures, voltage-induced interfacial oxidation of CoFeB modifies the SSE, resulting in the enhancement of thermoelectric signal by an order of magnitude. We describe a mechanism for the enhancement that results from a reduced exchange interaction of the oxidized region of ferromagnet, which in turn increases a temperature difference between magnons in the ferromagnet and electrons in the normal metal and/or a gradient of magnon chemical potential in the ferromagnet. Our result will invigorate research for thermoelectric conversion by suggesting a promising way of improving the SSE efficiency.

Negative mass black holes in de Sitter space

We show that asymptotically de Sitter black holes of negative mass can exist in Lovelock gravity. Such black holes have horizon geometries with non-constant curvature and are known as Exotic Black Holes. We explicitly examine the case of Gauss-Bonnet gravity. We briefly discuss the positive mass case where we show how the transverse space geometry affects whether a black hole will exist or not.For negative mass solutions we shown how three different black hole spacetimes are possible depending on the transverse space geometry. We also provide closed form expressions for the geometric parameters to ensure that a black hole spacetime is observed. We close with a discussion of the massless case, where there are many different spacetimes that are permitted.

FIVE-YEAR RSA RESULTS ASSESSING SUBSIDENCE AND ROTATION OF THE PARAGON HIP SYSTEM CONFIRMING IMPLANT STABILITY

Roentgen Stereophotogrammetric Analysis (RSA) is the gold standard for measuring implant micromotion thereby predicting implant loosening. Early migration has been associated with the risk of long-term clinical failure. We used RSA to assess the stability of the Australian designed cementless hip stem (Paragon TM) and now report our 5-year results.Fifty-three patients were prospectively and consecutively enrolled to receive a Paragon hip replacement. Tantalum beads were inserted into the bone as per RSA protocol and in the implant. RSA x-rays were taken at baseline 1–4 days post-surgery, at 6 weeks, 6 months, 12 months, 2 years, and 5 years. RSA was completed by an experienced, independent assessor.We reported the 2-year results on 46 hips (ANZJS 91 (3) March 2021 p398) and now present the 5-year results on 27 hips. From the 2-year cohort 5 patients had died, 8 patients were uncontactable, 1 patient was too unwell to attend, 5 patients had relocated too far away and declined. At 5 years the mean axial subsidence of the stem was 0.66mm (0.05 to 2.96); the mean rotation into retroversion was 0.49˚ (−0.78˚ to 2.09˚), rotation of the stem into valgus was −0.23˚ (−0.627˚ to 1.56˚). There was no detectable increase in subsidence or rotation between 6 weeks and 5 years. We compared our data to that published for the Corail cementless stem and a similar pattern of migration was noted, however greater rotational stability was achieved with the Paragon stem over a comparable follow-up period.The RSA results confirm that any minor motion of the Paragon cementless stem occurs in the first 6 weeks after which there is sustained stability for the next 5 years. The combination of a bi-planar wedge and transverse rectangular geometry provide excellent implant stability that is comparable to or better than other leading cementless stems.

The inverse problem for fractal curves solved with the dynamical approach method

The purpose of the present paper is to present the main applications of a new method for the determination of the fractal structure of plane curves. It is focused on the inverse problem, that is, given a curve in the plane, find its fractal dimension. It is shown that the dynamical approach extends the characterization of a curve as a fractal object introducing the effects of mass density, elastic properties, and transverse geometry. The dynamical dimension characterizes material objects and suggests that biological characterization can be much more complete with the methodology presented here.

Effect of design parameters on the ultimate strength and collapse behaviour of stiffened panels

Research about stiffened panel applications in ships has massively progressed with the amount of several methods to analyze it. Various studies had been conducted on stiffened panels using Finite Element Method (FEM). However, none have thoroughly explored the most optimal and efficient analysis methods and settings. Given the growing importance o f FEM in reliability analysis for ship structures, particularly stiffened panels, a comprehensive study comparing different approaches is o f paramount significance. Such research would not only streamline timeconsuming procedures but also offer invaluable recommendations to advance the field's understanding and practical applications. In this paper, a finite element analysis study was done to analyze the influence o f several parameter modeling o f stiffened panels not only to achieve the models' ultimate strength value and collapse behavior but also to offer practical recommendations on the most optimal and efficient methods for analyzing stiffened panels through FEM. Conducting modification o f three variations o f the model configuration, four variations o f boundary condition, and four variations o f transverse stiffener modeling to compare each other. Running time consumed when simulations are calculated in ANSYS APDL was also being considered. The results showed a significant difference in modifying the model configuration's case, while in contrast, the modification o f boundary conditions and transverse stiffener modeling only showed a slight difference in ultimate strength value. In addition, modification o f transverse stiffener geometry only gave the difference by around 0.5 MPa. The model configuration case (A1 v A2) showed the most remarkable running time difference, which reached six times difference.

Three-axis isotropic-sensitivity He4 magnetometer with alignment-based longitudinal parametric resonance

For measurements in near-zero magnetic fields, vector atomic magnetometers are promising alternatives to scalar versions, but generally suffer from inconsistent performance over three axes. We present a single-beam vector magnetometer with three-axis isotropic sensitivity based on $^{4}\mathrm{He}$ atomic alignment. Longitudinal parametric resonance with atoms pumped by linearly polarized light is proposed for the $z$-axis measurement, while the Hanle effect in transverse geometry is used for $x$- and $y$-axis measurements. The evolution of atomic alignment multipole components and expressions of the three-axis magnetic responses are analyzed in detail. We describe the experimental operation of the proposed magnetometer with a magnetic-field noise floor of $150\phantom{\rule{0.16em}{0ex}}\mathrm{fT}/{\mathrm{Hz}}^{1/2}$ for the three axes, which is attractive for biomagnetism requiring vector characterization and source reconstruction.

Fracture toughness of schist, amphibolite, and rhyolite from the Sanford Underground Research Facility (SURF), Lead, South Dakota

The Cracked Chevron Notched Brazilian Disc (CCNBD) method was selected for Mode I fracture toughness tests on Poorman schist, Yates amphibolite, and rhyolite dikes from the EGS Collab site at the SURF in Lead, South Dakota. The effects of lithology, anisotropy, and loading rate were investigated. Fracture toughness was greatest in amphibolite, with schist and rhyolite having similar toughness values ({K}_{amphibolite} > {K}_{rhyolite} ≈ {K}_{schist}). The effects of anisotropy on fracture toughness were investigated in the foliated schist samples. Schist samples were prepared in three geometries (divider, arrester, and short transverse) which controlled how the fracture would propagate relative to foliations. The divider geometry was strongest and short transverse geometry was the weakest ({K}_{divider} > {K}_{arrester} > {K}_{short transverse}). Fracture toughness was observed to decrease with decreasing loading rate. Optical and SEM microscopy revealed that for the short transverse geometry, fractures tended to propagate along grain boundaries, whereas in arrester and divider geometries fractures tended to propagate through grains. In foliated samples, the tortuosity of the fracture observed in thin section was greater in arrester and divider geometries than in short transverse geometries.

Large Room Temperature Anomalous Transverse Thermoelectric Effect in Kagome Antiferromagnet YMn6 Sn6.

Kagome magnets possess several novel nontrivial topological features owing to the strong correlation between topology and magnetism that extends to their applications in the field of thermoelectricity. Conventional thermoelectric (TE) devices use the Seebeck effect to convert heat into electrical energy. In contrast, transverse thermoelectric devices based on the Nernst effect are attracting recent attention due to their unique transverse geometry, which uses a single material to eliminate the need for a multitude of electrical connections compared to conventional TE devices. Here, a large anomalous transverse thermoelectric effect of ≈2 µV K-1 at room temperature in a kagome antiferromagnet YMn6 Sn6 single crystal is obtained. The obtained value is larger than that of state-of-the-art canted antiferromagnetic (AFM) materials and comparable with ferromagnetic systems. The large anomalous Nernst effect (ANE) can be attributed to the net Berry curvature near the Fermi level. Furthermore, the ANE of the AFM YMn6 Sn6 exceeds the magnetization scaling relationship of conventional ferromagnets. The results clearly illustrate that AFM material YMn6 Sn6 is an ideal topological material for room-temperature transverse thermoelectric applications.

On the deformation of spherical Au nanoparticles by slow highly charged Xe ions

We report a detailed study on the deformation of spherical Au nanoparticles (NPs) irradiated by slow highly charged ions (SHCIs) at fluence of 2 × 1012 ions/cm2. Highly charged Xeq+ (q = 10–16) ions are attracted and selected from Electron Cyclotron Resonance Ion Source (ECRIS) at energy 0.55 MeV, 1.10 MeV, 1.65 MeV, 2.20 MeV, 2.75 MeV, 3.30 MeV and 3.85 MeV, respectively. The anisotropic deformation of NPs is determined by Scanning electron microscopy (SEM). It demonstrates that Au NPs have expanded in transverse geometry which is perpendicular to incident direction. Negative correlation is determined experimentally between aspect ratio and electronic stopping power of the incoming ions. In addition, the charge state effect is also investigated for deformation of NPs. Particularly, it is verified that highly charged Xeq+ ions are capable of deforming Au NPs essentially even at low energy regime. Given this perspective, we provide an innovative approach that SHCIs have great potential to modulate Au NPs collectively and feasibly.