Spin Forces Research Articles

Muon spin force

Current discrepancy between the measurement and the prediction of the muon anomalous magnetic moment can be resolved in the presence of a long-range force created by ordinary atoms acting on the muon spin via axial-vector and/or pseudoscalar coupling, and requiring a tiny O(10−13 eV) spin energy splitting between muon state polarized in the vertical direction. We suggest that an extension of the muon spin resonance (μSR) experiments can provide a definitive test of this class of models. We also derive indirect constraints on the strength of the muon spin force by considering the muon-loop-induced interactions between nuclear spin and external directions. The limits on the muon spin force extracted from the comparison of Hg199/Hg201 and Xe129/Xe131 spin precession are strong for the pseudoscalar coupling but are significantly relaxed for the axial-vector one. These limits suffer from significant model uncertainties, poorly known proton/neutron spin content of these nuclei, and therefore do not exclude the possibility of a muon spin force relevant for the muon g−2. Published by the American Physical Society 2024

Muon g−2 , long-range muon spin force, and neutrino oscillations

Recent studies have proposed using a geocentric muon spin force to account for the (g−2)μ anomaly, with the long-range force mediator being a light axionlike particle. The mediator exhibits a CP-violating scalar coupling to nucleons and a normal derivative coupling to muons. Due to the weak symmetry, this axion inevitably couples to neutrinos, providing potential impact on neutrino oscillations. By utilizing neutrino data from BOREXINO, IceCube DeepCore, Super-Kamiokande, and SNO, we have identified that both atmospheric and solar neutrino data can impose stringent constraints on the long-range muon spin force model and the (g−2)μ parameter space. With optimized data analysis techniques and the potential from future experiments, such as JUNO, Hyper-Kamiokande, SNO+, and IceCube PINGU, there exists a promising opportunity to achieve even greater sensitivities. Indeed, neutrino oscillations offer a robust and distinctive cross-check for the model, offering stringent constraints on the (g−2)μ parameter space. Published by the American Physical Society 2024

Spin force analysis using the Brillouin function for spin half particles in magnetised non-relativistic quantum plasma

Spin force analysis using the Brillouin function for spin half particles in magnetised non-relativistic quantum plasma

Comparison of Spin Force and Bohm Potential Force in Laser Pulse–Magnetized Spin Plasma

Comparison of Spin Force and Bohm Potential Force in Laser Pulse–Magnetized Spin Plasma

Gravitational form factors of the nucleon and one pion graviproduction in chiral EFT

In the framework of chiral effective field theory of delta resonances, nucleons, and pions interacting with background gravitational field we calculate the gravitational form factors of the nucleon up to fourth order in the small scale expansion and obtain the long-range behavior of the corresponding contributions to the energy, spin, pressure, and shear force distributions. By comparing nucleon gravitational form factors with and without delta contributions we conclude that explicit inclusion of deltas plays an important role. Next we explore the Lorentz structure of the N↦Nπ transition matrix element of the conserved symmetric energy-momentum tensor and introduce its parametrization in terms of twelve transition form factors. We use the chiral effective field theory to calculate the tree-order contributions to the gravitational transition form factors of the pion graviproduction off the nucleon up to third order. Published by the American Physical Society 2024

Cooling the optical-spin driven limit cycle oscillations of a levitated gyroscope

Birefringent microspheres, trapped in vacuum and set into rotation by circularly polarised light, demonstrate remarkably stable translational motion. This is in marked contrast to isotropic particles in similar conditions. Here we demonstrate that this stability is obtained because the fast rotation of these birefringent spheres reduces the effect of azimuthal spin forces created by the inhomogeneous optical spin of circularly polarised light. At reduced pressures, the unique profile of these rotationally averaged, effective azimuthal forces results in the formation of nano-scale limit cycles. We demonstrate feedback cooling of these non-equilibrium oscillators, resulting in effective temperatures on the order of a milliKelvin. The principles we elaborate here can inform the design of high-stability rotors carrying enhanced centripetal loads or result in more efficient cooling schemes for autonomous limit cycle oscillations. Ultimately, this latter development could provide experimental access to non-equilibrium quantum effects within the mesoscopic regime.

A comparative analysis of the partitioning behaviour of SARS-CoV-2 RNA in liquid and solid fractions of wastewater

As fragments of SARS-CoV-2 RNA can be quantified and measured temporally in wastewater, surveillance of concentrations of SARS-CoV-2 in wastewater has become a vital resource for tracking the spread of COVID-19 in and among communities. However, the absence of standardized methods has affected the interpretation of data for public health efforts. In particular, analyzing either the liquid or solid fraction has implications for the interpretation of how viral RNA is quantified. Characterizing how SARS-CoV-2 or its RNA fragments partition in wastewater is a central part of understanding fate and behaviour in wastewater. In this study, partitioning of SARS-CoV-2 was investigated by use of centrifugation with varied durations of spin and centrifugal force, polyethylene glycol (PEG) precipitation followed by centrifugation, and ultrafiltration of wastewater. Partitioning of the endogenous pepper mild mottled virus (PMMoV), used to normalize the SARS-CoV-2 signal for fecal load in trend analysis, was also examined. Additionally, two surrogates for coronavirus, human coronavirus 229E and murine hepatitis virus, were analyzed as process controls. Even though SARS-CoV-2 has an affinity for solids, the total RNA copies of SARS-CoV-2 per wastewater sample, after centrifugation (12,000 g, 1.5 h, no brake), were partitioned evenly between the liquid and solid fractions. Centrifugation at greater speeds for longer durations resulted in a shift in partitioning for all viruses toward the solid fraction except for PMMoV, which remained mostly in the liquid fraction. The surrogates more closely reflected the partitioning of SARS-CoV-2 under high centrifugation speed and duration while PMMoV did not. Interestingly, ultrafiltration devices were inconsistent in estimating RNA copies in wastewater, which can influence the interpretation of partitioning. Developing a better understanding of the fate of SARS-CoV-2 in wastewater and creating a foundation of best practices is the key to supporting the current pandemic response and preparing for future potential infectious diseases.

Spin–phonon dispersion in magnetic materials

Microscopic coupling between the electron spin and the lattice vibration is responsible for an array of exotic properties from morphic effects in simple non magnets to magnetodielectric coupling in multiferroic spinels and hematites. Traditionally, a single spin–phonon coupling constant is used to characterize how effectively the lattice can affect the spin, but it is hardly enough to capture novel electromagnetic behaviors to the full extent. Here, we introduce a concept of spin–phonon dispersion to project the spin moment change along the phonon crystal momentum direction, so the entire spin change can be mapped out. Different from the phonon dispersion, the spin–phonon dispersion has both positive and negative frequency branches even in the equilibrium ground state, which correspond to the spin enhancement and spin reduction, respectively. Our study of bcc Fe and hcp Co reveals that the spin force matrix, that is, the second-order spatial derivative of spin moment, is similar to the vibrational force matrix, but its diagonal elements are smaller than the off-diagonal ones. This leads to the distinctive spin–phonon dispersion. The concept of spin–phonon dispersion expands the traditional Elliott-Yafet theory in nonmagnetic materials to the entire Brillouin zone in magnetic materials, thus opening the door to excited states in systems such as CoF2 and NiO, where a strong spin-lattice coupling is detected in the THz regime.

Nanofiber-Based Substrate for a Triboelectric Nanogenerator: High-Performance Flexible Energy Fiber Mats.

Flexible and stretchable triboelectric nanogenerators (TENGs) are the next-generation systems for wearable and portable electronics. In this study, we have demonstrated an all nanofiber-based TENG for energy harvesting and biomechanical sensing applications. The TENG was prepared using the Forcespinning (FS) method to produce poly(vinylidene fluoride) (PVDF) and thermoplastic polyurethane (TPU) nanofiber (NF) membranes. The TPU nanofiber membranes were interfaced with a homogeneously sputtered gold nanofilm. The experimental characterization of the PVDF-TPU/Au NF-TENG revealed that surface interfaced with dispersed gold in a TPU fiber membrane produced a maximum open-circuit voltage of 254 V and a short-circuit current of 86 μA output at a 240 bpm load frequency, which was, respectively, 112 and 87% greater than bare PVDF-TPU NF-based TENG. All systems were composed of an active contact surface area of 3.2 × 2.5 cm2. Furthermore, the TENG was able to light up 75 LEDs (1.5 V of each) by the hand-tapping motion. The resistive load and capacitor test results exemplified a TENG offering a simple and high-performance self-chargeable device. Furthermore, we have tested the TENG's response for biomechanical movements at different frequencies, suggesting the TENG's potential to be also used as a cost-effective self-powered flexible body motion sensor.

Perbandingan Gaya Tolak Terhadap Hasil Tolak Peluru

This study aims to compare the repulsion force between the obrein force and the spin force, this study uses a comparative causal research. The population in this study were all eighth grade students of SMP 1 Sijuk in the 2020/2021 academic year. Through purposive sampling technique, samples were obtained, namely the sample in this study was class VIII which collected 15 students. The design of this study uses a posttest only design, which is causal comparative. After completing the study, the group was given a posttest for data collection. The initial analysis used a hypothesis with the help of the SPSS24 (Statistical Product and Service Solution) computer program. The researcher's hypothesis test used the t-test (independent sample t-test). Based on the output of SPSS, the t-test (independent sample t-test) with a significant level of 0.04 with a lower limit determined at 0.05 was obtained count = 2.134 and ttable = 2.0484. The area of acceptance of H0 is if t count < 2.0484, it is clear that H0 is rejected. Thus it can be said that there is a comparison between the O'brien style and the Spin style, the Obrein style gives the best results on the learning outcomes of students of SMP 1 Sijuk, Belitung Regency.

Extraordinary and upper-hybrid waves in spin quantum magnetoplasmas with vacuum polarization effect

The propagation of extraordinary and upper-hybrid waves in spin quantum magnetoplasmas with vacuum polarization effect is investigated. Based on the quantum magnetohydrodynamics model including Bohm potential, arbitrary relativistic degeneracy pressure and spin force, and Maxwell's equations modified by the spin current and vacuum polarization current, the dispersion relations of extraordinary and upper-hybrid waves are derived. The analytical and numerical results show that quantum effects (Bohm potential, degeneracy pressure and spin magnetization energy) and the vacuum polarization effect modify the propagation of the extraordinary wave. Under the action of a strong magnetic field, the plasma frequency is obviously increased by the vacuum polarization effect.

On forcespinning of nonlinear rotating jets of viscoelastic Boger fluids

• Strong tensile force or stretching force makes jet of Boger fluid very thin. • Jet in three-dimension moves much faster than jet in two-dimension. • Strong centrifugal force can make jet thinner with increasing arc length. • Three-dimensionality of jet & presence of gravity are destabilizing. • High rotation & viscoelasticity can make jet of Boger fluid very thin. We consider forcespinning (FS) of nonlinear three-dimensional rotating viscoelastic jets of Boger fluids and in the presence of gravity effect. In FS process, a fluid jet is forced through an orifice of a rotating spinneret leading to the formation of a curved jet. Applying the upper-convected Maxwell constitutive model for the stress tensor part of the governing non-Newtonian jet system and using scaling and perturbation methods, we develop a model for the jet system. We determine the nonlinear solutions for the jet quantities such as the radius, speed, stretching force, compressive force, tensile force and the jet centerline, and we calculate these quantities for different values of the jet arc length and the parameters representing rotation, viscoelasticity, gravity, surface tension and polymer viscosity. We find that the effects of rotation, relaxation time, gravity and three-dimensionality of the modeling system on the jet of Boger fluid can be significant. Beyond a very short distance from the jet exit, the jet speed, tensile force, stretching force and the jet curvature are notably increased and the jet radius is much reduced with increasing the viscoelasticity, rotation rate and the jet arc length. Strong tensile force or stretching force corresponds to weak compressive force and very thin jet of Boger fluid.

Gravitational form factors of ρ meson with a light-cone constituent quark model

The $\rho$ meson gravitational form factors are studied based on a light-front constituent quark model which has been successfully employed to calculate its generalized parton distributions and some low-energy observables. The distributions of energy, spin, pressures, and shear forces inside the $\rho$ meson are explicitly given.

Optical binding and lateral forces on chiral particles in linearly polarized plane waves

We demonstrate numerically and analytically the optical binding between a pair of chiral nanoparticles immersed in a plane wave of linear polarization. The numerical results based on the full wave simulation show that, when the electric field of the incident wave is polarized along the pair axis (the line connecting the particle pair), the closest dimer can be formed at particle separation around $1.25\ensuremath{\lambda}$, with $\ensuremath{\lambda}$ denoting the incident wavelength, while when the electric field is polarized normal to the pair axis, the nearest dimer is formed with a separation of one wavelength. In both cases, there exist multiple stable dimer states due to the spatially oscillatory decaying behavior of the binding force with the increase of particle distance. Interestingly, there also appears a lateral optical force exerted on each particle in the direction normal to both the pair axis and light flow, when either or both particles have chirality. Analytical analysis within the dipole approximation indicates that the binding force comes dominantly from the gradient of the optical potential, irrespective of particle chirality. The lateral force, on the other hand, has multiple origins. In addition to the gradient force, the radiation force, the curl force, and the spin force may make significant contributions dependent on the particle chirality, as the particles approach each other.

Impact of a Spinning Supermassive Black Hole on the Orbit and Gravitational Waves of a Nearby Compact Binary

Abstract Recent theoretical studies suggest that stellar-mass binary black holes (BBHs) would merge more efficiently due to the Kozai–Lidov (K–L) mechanism if these binaries form in the vicinity of supermassive black holes (SMBHs). Since SMBHs are likely rotating rapidly, we continue our earlier study on the generalization of the K–L formalism to include the spin of the SMBH and study the evolution of a nearby BBH. We find that the eccentricity and orbital inclination of the BBH are significantly affected, because the spin (i) forces the orbital plane of the center-of-mass of the BBH around the SMBH to precess (the Lense–Thirring effect) and (ii) imposes an additional gravitomagnetic force on the BBH. As a result, the merger time of the BBH could be significantly different. We calculate the waveform from the BBH in one representative example and study its detectability with a milli-Hertz gravitational-wave detector, such as the Laser Interferometer Space Antenna (LISA). We find that the signal is distinguishable from that in the case without spin. Our results imply that the BBHs in the LISA band could potentially be used to probe the spin of the SMBHs in galaxy centers.

Nature of novel criticality in ternary transition-metal oxides

There are the chains of transition-metal cations alternating with the anions of oxygen in ternary transition-metal oxides. When a p-orbital of the oxygen connects the half-filled and empty d-orbitals of adjacent transition-metal cations, double-exchange ferromagnetism takes place. Although double exchange has been well explored, the nature of novel criticality, induced by it, is yet not uncovered. We explored the magnetic-field scaling in the heat capacity of a Sm0.55Sr0.45MnO3 manganite, one of the best ternary transition-metal oxides as it is completely ferromagnetic, and found novel criticality - unordinary critical exponents which are the consequence of coherence of Coulomb lattice distortion and ferromagnetism. The coherence is caused by the trinity of the mass, the charge and the spin of an electron. When the d and p orbitals overlaps, it quickly walks from one site to the another due its lightest mass. And due to its electric charge, it equalizes the valences of the transition-metal cations in the chains and so diminishes the Coulomb lattice distortion. At last, its spin forces magnetic moments of transition-metal cations to ferromagnetically arrange. The disappearance of Coulomb distortions widens the overlap and lowers the elastic lattice energy, so that not only the spin of an electron, but also its electric charge strengthens ferromagnetism. That nonlinear effect strengthens the critical behaviour and critical exponents come off any known universality classes. Thus, the symbiotic coherence of annihilating Coulomb distortions and arising ferromagnetism is a reason of the novel criticality.

Numerical modeling of electrostatic spray painting transfer processes in rotary bell cup for automotive painting

Here we implemented a 3D comprehensive Eulerian-Lagrangian model in order to investigate the electrostatic spray transfer processes in the high-speed rotary bell sprayer. This efficient algorithm contains spray dynamics, airflow, paint droplets tracking and an electrostatic effect to simulate atomization. The algorithm is implemented using the OpenFOAM package. A solver for the particle trajectory was used to illustrate the process of spray transport and also the interaction of the airflow and the particle that is solved by momentum coupling. Creating an initial condition of the particle approach has been proposed that is matched with practical applications. The fluid-dynamics is simulated by solving the unsteady 3D compressible Navier-Stokes equations. Unsteady flow is computed by using a Large eddy simulation (LES) turbulence approach, while the motion of the particles is simulated by tracking the droplet size distribution approach. The model correctly predicts that the bell cup spin forces the paint particles to fall off from the bell surface towards the high-velocity airflow. The present work illustrates a tentative benchmark and contains a systematic analysis of the recirculation zone length, the toroidal vortex, the overspray phenomena and the flowfield characteristics like mean velocity, pressure, turbulent kinetic energy and velocity fluctuation. The results indicate as dominant operating parameter the air-paint flow rate with voltage level deeply affecting the spray shape. A more uniform distribution of the coating is obtained by growing this high-velocity shaping airflow, although the values of the transfer efficiency (TE) are reduced. The distribution of the particle size is very sensitive to changes in the rotational speed. Experimental results obtained in this study put forward a clear link between the shaping air flow rate and the rotation frequency on the aerodynamics and also provide valuable insights to design modern ERBS. The paint spray distribution obtained in the present work is validated against coating experimental results with suitable accuracy.

Gravitational form factors of a spin one particle

We define the form factors of the quark and gluon symmetric energy-momentum tensor (EMT). The static EMT is related to the spatial distributions of energy, spin, pressure and shear forces. They are obtained in the form of a multipole expansion. The relations between gravitational form factors and the generalised parton distributions are given.

An inelastic bound on chaos

We study a generalization of the chaos bound that applies to out-of-time-ordered correlators between four different operators. We prove this bound under the same assumptions that apply for the usual chaos bound and extend it to non-hermitian operators. In a holographic theory, these correlators are controlled by inelastic scattering in the bulk and we comment on implications. In particular, for holographic theories the bound together with the equivalence principle suggests that gravity is the highest spin force, and the strongest one with that spin.

Nonlinear rotating viscoelastic jets during forcespinning process

In the usual forcespinning (FS) process, a fluid jet is forced through an orifice of a rotating spinneret leading to the formation of a jet with curved centreline. In this paper, we investigate the properties of nonlinear viscoelastic jets during the FS process. We apply scaling and perturbation techniques to determine the modelling system for the viscoelastic jets, subjected to the Giesekus constitutive equations for the stress tensor. We calculate numerically the expressions for the nonlinear steady solutions for the jet quantities such as radius, speed, stretching rate, strain rate, tensile force and trajectory. We determine these quantities for different values of the parameters such as those representing the effects due to rotation, surface tension, viscosity, jet drag and viscoelasticity. We find, in particular, that the fibre jet radius decreases and the tensile force increases with the jet arc length as well as with increasing the effects of rotation and viscoelasticity. Both viscosity and surface tension indicate stabilizing effect on the viscoelastic jet. In addition, strain rate, stretching rate and the jet speed increase with the arc length, viscoelasticity and rotation rate.