Magnetic Gauge Research Articles

Coupling of branes and twisted self-duality in the Maxwell-Chern-Simons theory

We study three approaches to electric-magnetic duality in the 4-dimensional Maxwell theory coupled to a dyonic point charge and in the 5-dimensional Maxwell-Chern-Simons (MCS) theory coupled to an electric point charge and a magnetic string charge. The three approaches have been developed by Dirac, Bunster and Henneaux, and Pasti, Sorokin and Tonin (PST). In Dirac’s formulation, the electric magnetic duality is realized only on the level of the equations of motion. The other two formulations introduce a dual (magnetic) gauge potential to induce manifest twisted self-duality in the action. In particular, we study the relations connecting the three approaches. The main results of this paper are the Bunster-Henneaux and PST formulations of the MCS theory with sources. We compare our result to the PST formulation of 11-dimensional supergravity coupled to the M2- and M5-brane by Bandos, Berkovits, and Sorokin.

PENERAPAN SENSOR FLOAT MAGNETIC LEVEL GAUGE PADA SISTEM MONITORING LEVEL CAIRAN LIMBAH

In the industrial world, especially in the metal processing sector, in this case in the steel roll production process, the problem faced is that controlling the pump motor in the hydraulic room is still done manually so that the waste water reservoir in the hydraulic room overflows which causes the floor to be slippery and dangerous. . By using the float magnetic level gauge method which consists of a reed switch as the main component to take height level readings. The neodymium magnet used in the buoy functions as a trigger to activate the reed switch when the buoy height reaches a certain level. The use of the voltage divider principle is to obtain variations in the sensor output voltage which is then converted into water level readings. The process of monitoring waste liquid levels uses LabVIEW software. Research has been tested in one of the departments in the metal processing industrial area which obtained the results that the sensor readings correctly provide an output signal to the microcontroller which functions as a relay controller which activates the drain pump motor when it reaches full level. With a monitoring system, users can control the system via computer without having to go directly to the field to activate the pump motor manually

Natural orbitals and their occupation numbers for free anyons in the magnetic gauge

We investigate the properties of natural orbitals and their occupation numbers of the ground state of two noninteracting anyons characterized by the fractional statistics parameter α and confined in a harmonic trap. We work in the boson magnetic gauge where the anyons are modeled as composite bosons with magnetic flux quanta attached to their positions. We derive an asymptotic form of the weakly occupied natural orbitals, and show that their corresponding (ordered descendingly) occupation numbers decay according to the power law n−(4+2α), where n is the index of the natural orbital. We find remarkable numerical agreement of the theory with the natural orbitals and their occupation numbers computed from the spectral decomposition of the system's wave function. We explain that the same results apply to the fermion magnetic gauge. Published by the American Physical Society 2024

Visualization and monitoring dynamic water levels of steam generators based on deep learning

In a nuclear power system, the steam generator (SG) is the most important part of the second loop, and accurate monitoring of the internal water level of the SG has always been a challenge. In this study, a two-loop steam generator is mounted on a six-degrees-of-freedom (6-DoF) platform to fully imitate the marine condition of the SG, and the internal water level is visualized by opening a window on the SG. The heating power, period and angle of the 6-DoF platform are considered. By calibrating the relationship between vertical pixels and actual height of the water level, the recognition of water level position in the image is mapped to the actual water level height. 700 water level images were obtained for constructing the dataset. An enhanced deep learning recognition network (YOLO-v7-SE) is proposed to focus on the water level of SG, which is added a channel attention mechanism to the backbone network for enhancing the extraction of target features. Compared with the original YOLO-v7 network, the enhanced YOLO-v7-SE network enhanced the detection accuracy of water level recognition by 12.5% and the mean average accuracy (mAP) by 13.3%. In addition, as the heating power increases, the water level without feeding water drops faster, and that with feeding water keeps constant. The swing periods and angles have complex effects on the water level. In contrast, the traditional magnetic flap level gauge could not obtain the variation of the water level. This shows that the enhanced YOLO-v7-SE network can accuracy recognize the real-time water level change, and achieve fast dynamic response to the water level change, which is a reliable and powerful guarantee for the safety of the SG.

Chiral Gauge Field and Topological Magnetoelectric Response in Fully Spin-Polarized Magnetic Weyl Semimetal Co3Sn2S2

This study clarifies the relationship between magnetic ordering and chiral gauge fields in the ferromagnetic Weyl semimetal Co3Sn2S2, highlighting its spintronic potential using the topological magnetoelectric responses of Weyl fermions.

High-precision FBG-based sensor for soil settlement monitoring: A comparative study with magnetic settlement gauges and PIV technique

The primary objective of layered settlement monitoring is to detect subsidence issues in soil or foundational structures, in order to implement appropriate measures for ensuring the safety and stability of engineering projects. Conventional monitoring techniques have problems such as errors in manual readings, high costs, susceptibility to interference, and low levels of automation. A layered soil settlement sensor based on fiber Bragg grating (FBG) technology is proposed in this study. This sensor utilizes an equal-strength beam as an "intermediate bridge" to make the FBG sensor respond. The sensor is prepared by the laboratory's 3D fused deposition modelling (FDM) and calibrated by applying displacement loads through a fine-tuning platform. The sensitivity coefficient is 0.068 nm/mm, and the correlation coefficient exceeds 0.99. Finally, the sensor exhibited high precision when compared to measurements obtained from magnetic settlement gauges and particle image velocimetry (PIV). The discrepancies between the measurement outcomes of the sensor and the actual values of soil settlement does not exceed 3.33%.

Revisiting Gauge-Independent Kinetic Energy Densities in Meta-GGAs and Local Hybrid Calculations of Magnetizabilities.

In a recent study [J. Chem. Theory Comput. 2021, 17, 1457-1468], some of us examined the accuracy of magnetizabilities calculated with density functionals representing the local density approximation (LDA), generalized gradient approximation (GGA), meta-GGA (mGGA), as well as global hybrid (GH) and range-separated (RS) hybrid functionals by assessment against accurate reference values obtained with coupled-cluster theory with singles, doubles, and perturbative triples [CCSD(T)]. Our study was later extended to local hybrid (LH) functionals by Holzer et al. [J. Chem. Theory Comput. 2021, 17, 2928-2947]; in this work, we examine a larger selection of LH functionals, also including range-separated LH (RSLH) functionals and strong-correlation LH (scLH) functionals. Holzer et al. also studied the importance of the physically correct handling of the magnetic gauge dependence of the kinetic energy density (τ) in mGGA calculations by comparing the Maximoff-Scuseria formulation of τ used in our aforementioned study to the more physical current-density extension derived by Dobson. In this work, we also revisit this comparison with a larger selection of mGGA functionals. We find that the newly tested LH, RSLH, and scLH functionals outperform all of the functionals considered in the previous studies. The various LH functionals afford the seven lowest mean absolute errors while also showing remarkably small standard deviations and mean errors. Most strikingly, the best two functionals are scLHs that also perform remarkably well in cases with significant multiconfigurational character, such as the ozone molecule, which is traditionally excluded from statistical error evaluations due to its large errors with common density functionals.

RANCANG BANGUN SISTEM MONITORING LEVEL PERMUKAAN AIR BERBASIS INTERNET OF THINGS (IoT)

Indonesia is a country that has two seasons, namely the summer and the rainy season, when the rainy season arrives, the rainfall will be very high which can cause flooding. This can be overcome by technological innovation in the form of tools that can work in real-time to detect the condition of water flow in rivers so that losses due to flooding can be minimized. This tool uses a level sensor with the float magnetic level gauge method which is connected to the ESP32 microcontroller module as a sensor data controller and sends the sensor measurement data values ​​to the IoT platform. The sensor measurement results correspond to the water level in centimeters and are sent to the IoT platforms, namely Blynk and Telegram in real-time. The results of sending data to the Blynk and Telegram applications have an average error value of 1.5%.

Modulating saturation magnetization and topological Hall resistivity of flexible ferrimagnetic Mn4N films by bending strains

The ferrimagnetic rare-earth-free Mn4N films are considered as a good candidate in spintronics due to its low saturation magnetization (MS) and high Néel temperature. Here, Mn4N films are directly deposited on flexible mica to investigate strain-related magnetic and electronic transport properties. The MS variation of 11.0 nm Mn4N film reaches 453% at tensile strain of radius of curvature (ROC) = 2 mm. Bending strains cannot affect anomalous Hall resistivity and magnetoresistance. However, the topological Hall resistivity of 147.0 nm Mn4N film increases by 58% at tensile strain of ROC = 5 mm due to frustrated exchange interactions. The flexible Mn4N films have great potential applications in flexible magnetic sensor and strain gauge due to strain modulated MS, resistance, and stable magnetoresistance.

About Non-relativistic Quantum Mechanics and Electromagnetism

We describe here the coherent formulation of electromagnetism in the non-relativistic quantum-mechanical many-body theory of interacting charged particles. We use the mathematical frame of the field theory and its quantization in the spirit of the quantum electrodynamics (QED). This is necessary because a manifold of misinterpretations emerged especially regarding the magnetic field and gauge invariance. The situation was determined by the historical development of quantum mechanics, starting from the Schrödinger equation of a single particle in the presence of given electromagnetic fields, followed by the many-body theories of many charged identical particles having just Coulomb interactions. Our approach to the non-relativistic QED emphasizes the role of the gauge-invariance and of the external fields. We develop further the approximation of this theory allowing a closed description of the interacting charged particles without photons. The resulting Hamiltonian coincides with the quantized version of the Darwin Hamiltonian containing besides the Coulomb also a current-current diamagnetic interaction. We show on some examples the importance of this extension of the many-body theory.

Wire gauge analysis of planar spiral coil and its optimization technique in Wireless Power Transfer system

Planar spiral coil made of solid wire is widely used in wireless power transfer without magnetic core in high frequency operation system. Based on the magnetic field distribution of planar spiral coil and high frequency eddy current loss mechanism, the influence of magnetic field strength, frequency, and wire gauge on the AC resistance of winding are analysed. It reveals that the coil loss can be reduced by designing the wire gauge. Then the magnetic field strength and the winding loss calculation model are built, based on which the double wire gauge for segmental winding structure is proposed. This method can reduce the AC resistance and improve the quality factor on the premise of keeping inductance constant at high frequency. Through simulation and experiment, the AC resistance of coil based on the double wire gauge scheme can be greatly reduced comparing to the traditional method and the efficiency of the prototype is increased by 4%, which verifies the theory analysis to be correct and flexible.

Optical excitations of Skyrmions, knotted solitons, and defects in atoms

Analogies between non-trivial topologies of matter and light have inspired numerous studies, including defect formation in structured light and topological photonic band structures. Three-dimensional topological objects of localised particle-like nature attract broad interest across discipline boundaries from elementary particle physics and cosmology to condensed matter physics. Here we propose how simple structured light beams can be transformed into optical excitations of atoms with considerably more complex topologies representing three-dimensional particle-like Skyrmions. This construction can also be described in terms of linked Hopf maps, analogous to knotted solitons of the Skyrme-Faddeev model. We identify the transverse polarisation density current as the effective magnetic gauge potential for the Chern-Simons helicity term. While we prepare simpler two-dimensional baby-Skyrmions and singular defects using the traditional Stokes vectors on the Poincaré sphere for light, particle-like topologies can only be achieved in the full optical hypersphere description that no longer discards the variation of the total electromagnetic phase of vibration.

τRR minimization in presence of hypermultiplets

We compute τRR minimization in gauged supergravity for M-theory and String Theory truncations with both massless and massive vector multiplets. We explicitly compute, as anticipated in [1], that massive vector fields at the vacuum require the introduction of a constraint through a Lagrange multiplier. We illustrate this explicitly in two examples, namely the U(1)2-invariant truncation dual to the mABJM model and the ISO(7) truncation in massive IIA, the latter being a theory with both electric and magnetic gauging. We revisit the vacuum constraints at AdS4 and show how the supergravity analysis matches the results of the field theory dual computation.

Collective Excitations of Exciton-Polariton Condensates in a Synthetic Gauge Field.

Collective (elementary) excitations of quantum bosonic condensates, including condensates of exciton polaritons in semiconductor microcavities, are a sensitive probe of interparticle interactions. In anisotropic microcavities with momentum-dependent transverse-electric-transverse-magnetic splitting of the optical modes, the excitations' dispersions are predicted to be strongly anisotropic, which is a consequence of the synthetic magnetic gauge field of the cavity, as well as the interplay between different interaction strengths for polaritons in the singlet and triplet spin configurations. Here, by directly measuring the dispersion of the collective excitations in a high-density optically trapped exciton-polariton condensate, we observe excellent agreement with the theoretical predictions for spinor polariton excitations. We extract the interaction constants for polaritons of the same and opposite spin and map out the characteristic spin textures in an interacting spinor condensate of exciton polaritons.

Dressings and Asymptotic Symmetries in Quantum Field Theory

In quantum field theories with massless gauge bosons, the conventional formulation of scattering amplitudes in terms of momentum eigenstates lead to infrared divergences. To resolve this one should dress charged particles with an infinite number of low-energy (soft) gauge bosons. These dressings are closely related to the asymptotic symmetries of the the- ory. The aim of this dissertation is to investigate this relation in detail, and study the implications of dressings in a quantum field theoretical context in asymptotically flat and Schwarzschild spacetimes. In particular, the asymptotic symmetry of interest in gravity is the BMS supertranslation. First, we demonstrate in perturbative quantum gravity that the dressings facilitate charge conservation by carrying a definite supertranslation charge. We then use this property to derive dressed states from the charge conservation laws of asymp- totic symmetries. We develop a unified quantum mechanical framework for the construction of dressings at the null infinity and the horizon of a Schwarzschild black hole, and show that the black hole soft hairs are planted on the horizon by dressed particles falling into the black hole. This framework is then extended to the magnetic parity soft charges of electro- magnetism and gravity. It is shown that one can construct ’t Hooft line dressings at the asymptotic boundaries, which are charged under the magnetic large gauge transformations and the dual supertranslations. Finally, we study the standard and dual supertranslation charges at the black hole horizon. We find central terms in their algebra in the presence of singularities in the parameter functions, which hints at further interesting soft structures yet to be revealed.

Surface theory of a second-order topological insulator beyond the Dirac approximation

We study the surface states and chiral hinge states of a 3D second-order topological insulator in the presence of an external magnetic gauge field. Surfaces pierced by flux host Landau levels, while surfaces parallel to the applied field are not significantly affected. The chiral hinge modes mediate spectral flow between neighbouring surfaces. As the magnetic field strength is increased, the surface Landau quantization deviates from that of a massive Dirac cone. Quantitatively, the $n = 0$ Landau level falls inside the surface Dirac gap, and not at the gap edge. The $n \ne 0$ levels exhibit a further, qualitative discrepancy: while the massive Dirac cone is expected to produce pairs of levels ($\pm n$) which are symmetric around zero energy, the $n$ and $-n$ levels become asymmetric in our lattice model -- one of the pair may even be absent from the spectrum, or hybridized with the continuum. In order to resolve the issue, we extend the standard 2D massive Dirac surface theory, by including additional Hamiltonian terms at $\mathcal{O} (k^2)$. While these terms do not break particle-hole symmetry in the absence of magnetic field, they lead to the aforementioned Landau level asymmetry once the magnetic field is applied. We argue that similar $\mathcal{O}(k^2)$ correction terms are generically expected in lattice models containing gapped Dirac fermions, using the BHZ model of a 2D topological insulator as an example.

Computation of Solid-State Vibrational Circular Dichroism in the Periodic Gauge.

We introduce a new theoretical formalism to compute solid-state vibrational circular dichroism (VCD) spectra from molecular dynamics simulations. Having solved the origin-dependence problem of the periodic magnetic gauge, we present IR and VCD spectra of (1S,2S)-trans-1,2-cyclohexanediol obtained from first-principles molecular dynamics calculations and nuclear velocity perturbation theory, along with the experimental results. Because the structure model imposes periodic boundary conditions, the common origin of the rotational strength has hitherto been ill-defined and was approximated by means of averaging multiple origins. The new formalism reconnects the periodic model with the finite physical system and restores gauge freedom. It nevertheless fully accounts for nonlocal spatial couplings from the gauge transport term. We show that even for small simulation cells the rich nature of solid-state VCD spectra found in experiments can be reproduced to a very satisfactory level.

Wood Fuel Procurement to Bioenergy Facilities: Analysis of Moisture Content Variability and Optimal Sampling Strategy

Moisture content is the most relevant quality parameter for wood fuels. Effective and fast determination of moisture of incoming feedstock is essential in the management of bioenergy facilities. The availability of fast and reliable moisture meters based on innovative technologies simplifies this task. However, in Mediterranean conditions the inherent variability of wood fuels calls for a careful sampling strategy if representative results are required while facing acceptable analytic costs. The present study is aimed at measuring the fuel heterogeneity and defining accordingly the appropriate number of samples to be analyzed in order to get reliable moisture-content results. A total of 70 truckloads (about 2270 t of woodchips) were sampled during commercial operations in two different seasons. Five samples were collected from each load and measured with standard method and magnetic resonance gauge. Results show that the variability of moisture content is influenced by mixing of species and storage of biomass. Heterogeneity can vary greatly also within single truckloads, to the point that three samples are needed to achieve about 90% of estimates within the desired precision limits. In the case of larger lots, such as barge or ship loads, 20 samples can provide sufficient precision in most scenarios.

4d F(4) gauged supergravity and black holes of class \u2131

We perform a consistent reduction of 6d matter-coupled F(4) supergravity on a compact Riemann surface {Sigma}_{mathfrak{g}} of genus mathfrak{g} , at the level of the bosonic action. The result is an mathcal{N} = 2 gauged supergravity coupled to two vector multiplets and a single hypermultiplet. The four-dimensional model is holographically dual to the 3d superconformal field theories of class ℱ, describing different brane systems in massive type IIA and IIB wrapped on {Sigma}_{mathfrak{g}} . The naive reduction leads to a non-standard 4d mixed duality frame with both electric and magnetic gauge fields, as well as a massive tensor, that can be only described in the embedding tensor formalism. Upon a chain of electromagnetic dualities, we are able to determine the scalar manifolds and electric gaugings that uniquely specify the model in the standard supergravity frame. We then use the result to construct the first examples of static dyonic black holes in AdS6 and perform a microscopic counting of their entropy via the 5d topologically twisted index. Finally, we show the existence of further subtruncations to the massless sector of the 4d theory, such as the Fayet-Iliopoulos gauged T3 model and minimal gauged supergravity. We are in turn able to find new asymptotically AdS4 solutions, providing predictions for the squashed S3 partition functions and the superconformal and refined twisted indices of class ℱ theories.

Магнитные превращения и полиморфный переход ферромагнитных сталей при ударно-волновом нагружении

A.M. Molodets A.A. Golyshev, A.N. Emelyanov, A.A. Kozlov The method for recording magnetic transformation is presented for ferromagnetic steels under shock-wave loading. The operation of the magnetic transformation gauge is considered under shock-wave loading at the polymorphic transition pressure of ARMCO iron and 15Kh2NMFA (in Russian) nuclear reactors case steel. It is shown that the pressures of magnetic transformations of steels correlate with the pressures of polymorphic transitions of these shocked steels. Comparison of gauge readings and parameters of polymorphic transitions was performed for iron and steel during shock-wave compression and subsequent unloading